[llvm] [LV] Vectorize conditional scalar assignments (PR #158088)

Graham Hunter via llvm-commits llvm-commits at lists.llvm.org
Wed Nov 12 07:28:03 PST 2025


https://github.com/huntergr-arm updated https://github.com/llvm/llvm-project/pull/158088

>From 049428d087bb21bd9db251aea438936717a9b934 Mon Sep 17 00:00:00 2001
From: Graham Hunter <graham.hunter at arm.com>
Date: Wed, 26 Mar 2025 11:35:01 +0000
Subject: [PATCH 1/6] [LV] Vectorize conditional scalar assignments

Based on Michael Maitland's previous work:
https://github.com/llvm/llvm-project/pull/121222

This PR uses the existing recurrences code instead of introducing a
new pass just for CSA autovec. I've also made recipes that are more
generic.

I've enabled it by default to see the impact on tests; if there are
regressions we can put it behind a cli option.
---
 llvm/include/llvm/Analysis/IVDescriptors.h    |  23 +-
 llvm/lib/Analysis/IVDescriptors.cpp           |  45 +-
 .../AArch64/AArch64TargetTransformInfo.cpp    |   1 +
 .../Transforms/Vectorize/LoopVectorize.cpp    |  53 +-
 .../Transforms/Vectorize/SLPVectorizer.cpp    |   3 +
 llvm/lib/Transforms/Vectorize/VPlan.h         |  37 ++
 .../Transforms/Vectorize/VPlanAnalysis.cpp    |  19 +-
 .../lib/Transforms/Vectorize/VPlanRecipes.cpp |  48 ++
 .../Transforms/Vectorize/VPlanTransforms.cpp  |  78 +++
 .../Transforms/Vectorize/VPlanTransforms.h    |   8 +
 llvm/lib/Transforms/Vectorize/VPlanUtils.cpp  |   2 +-
 llvm/lib/Transforms/Vectorize/VPlanValue.h    |   1 +
 .../AArch64/conditional-scalar-assignment.ll  | 397 ++++++++++++
 .../conditional-scalar-assignment-vplan.ll    | 123 ++++
 .../LoopVectorize/iv-select-cmp-decreasing.ll | 339 +++++++++--
 .../LoopVectorize/iv-select-cmp-no-wrap.ll    |  88 ++-
 .../iv-select-cmp-non-const-iv-start.ll       | 373 ++++++++++--
 .../LoopVectorize/iv-select-cmp-trunc.ll      | 570 ++++++++++++++----
 .../Transforms/LoopVectorize/iv-select-cmp.ll | 190 +++++-
 .../Transforms/LoopVectorize/select-cmp.ll    | 141 ++++-
 20 files changed, 2239 insertions(+), 300 deletions(-)
 create mode 100644 llvm/test/Transforms/LoopVectorize/AArch64/conditional-scalar-assignment.ll
 create mode 100644 llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll

diff --git a/llvm/include/llvm/Analysis/IVDescriptors.h b/llvm/include/llvm/Analysis/IVDescriptors.h
index 654a5f10cea96..370c301731337 100644
--- a/llvm/include/llvm/Analysis/IVDescriptors.h
+++ b/llvm/include/llvm/Analysis/IVDescriptors.h
@@ -70,6 +70,9 @@ enum class RecurKind {
   FindLastIVUMax, ///< FindLast reduction with select(cmp(),x,y) where one of
                   ///< (x,y) is increasing loop induction, and both x and y
                   ///< are integer type, producing a UMax reduction.
+  FindLast,       ///< FindLast reduction with select(cmp(),x,y) where x and y
+                  ///< are an integer type, one is the current recurrence value,
+                  ///< and the other is an arbitrary value.
   // clang-format on
   // TODO: Any_of and FindLast reduction need not be restricted to integer type
   // only.
@@ -175,13 +178,12 @@ class RecurrenceDescriptor {
   /// Returns a struct describing whether the instruction is either a
   ///   Select(ICmp(A, B), X, Y), or
   ///   Select(FCmp(A, B), X, Y)
-  /// where one of (X, Y) is an increasing (FindLast) or decreasing (FindFirst)
-  /// loop induction variable, and the other is a PHI value.
-  // TODO: Support non-monotonic variable. FindLast does not need be restricted
-  // to increasing loop induction variables.
-  LLVM_ABI static InstDesc isFindIVPattern(RecurKind Kind, Loop *TheLoop,
-                                           PHINode *OrigPhi, Instruction *I,
-                                           ScalarEvolution &SE);
+  /// where one of (X, Y) is an increasing (FindLastIV) or decreasing
+  /// (FindFirstIV) loop induction variable, or an arbitrary integer value
+  /// (FindLast), and the other is a PHI value.
+  LLVM_ABI static InstDesc isFindPattern(RecurKind Kind, Loop *TheLoop,
+                                         PHINode *OrigPhi, Instruction *I,
+                                         ScalarEvolution &SE);
 
   /// Returns a struct describing if the instruction is a
   /// Select(FCmp(X, Y), (Z = X op PHINode), PHINode) instruction pattern.
@@ -305,6 +307,13 @@ class RecurrenceDescriptor {
            isFindLastIVRecurrenceKind(Kind);
   }
 
+  /// Returns true if the recurrence kind is of the form
+  ///   select(cmp(),x,y) where one of (x,y) is an arbitrary value and the
+  ///   other is a recurrence.
+  static bool isFindLastRecurrenceKind(RecurKind Kind) {
+    return Kind == RecurKind::FindLast;
+  }
+
   /// Returns the type of the recurrence. This type can be narrower than the
   /// actual type of the Phi if the recurrence has been type-promoted.
   Type *getRecurrenceType() const { return RecurrenceType; }
diff --git a/llvm/lib/Analysis/IVDescriptors.cpp b/llvm/lib/Analysis/IVDescriptors.cpp
index 9f8ac6e8e2e0b..7705c0459d829 100644
--- a/llvm/lib/Analysis/IVDescriptors.cpp
+++ b/llvm/lib/Analysis/IVDescriptors.cpp
@@ -56,6 +56,8 @@ bool RecurrenceDescriptor::isIntegerRecurrenceKind(RecurKind Kind) {
   case RecurKind::FindFirstIVUMin:
   case RecurKind::FindLastIVSMax:
   case RecurKind::FindLastIVUMax:
+  // TODO: Make type-agnostic.
+  case RecurKind::FindLast:
     return true;
   }
   return false;
@@ -691,9 +693,9 @@ RecurrenceDescriptor::isAnyOfPattern(Loop *Loop, PHINode *OrigPhi,
 // value of the data type or a non-constant value by using mask and multiple
 // reduction operations.
 RecurrenceDescriptor::InstDesc
-RecurrenceDescriptor::isFindIVPattern(RecurKind Kind, Loop *TheLoop,
-                                      PHINode *OrigPhi, Instruction *I,
-                                      ScalarEvolution &SE) {
+RecurrenceDescriptor::isFindPattern(RecurKind Kind, Loop *TheLoop,
+                                    PHINode *OrigPhi, Instruction *I,
+                                    ScalarEvolution &SE) {
   // TODO: Support the vectorization of FindLastIV when the reduction phi is
   // used by more than one select instruction. This vectorization is only
   // performed when the SCEV of each increasing induction variable used by the
@@ -702,8 +704,10 @@ RecurrenceDescriptor::isFindIVPattern(RecurKind Kind, Loop *TheLoop,
     return InstDesc(false, I);
 
   // We are looking for selects of the form:
-  //   select(cmp(), phi, loop_induction) or
-  //   select(cmp(), loop_induction, phi)
+  //   select(cmp(), phi, value) or
+  //   select(cmp(), value, phi)
+  // where 'value' is be a loop induction variable
+  // (for FindFirstIV/FindLastIV) or an arbitrary value (for FindLast).
   // TODO: Match selects with multi-use cmp conditions.
   Value *NonRdxPhi = nullptr;
   if (!match(I, m_CombineOr(m_Select(m_OneUse(m_Cmp()), m_Value(NonRdxPhi),
@@ -712,6 +716,25 @@ RecurrenceDescriptor::isFindIVPattern(RecurKind Kind, Loop *TheLoop,
                                      m_Value(NonRdxPhi)))))
     return InstDesc(false, I);
 
+  if (isFindLastRecurrenceKind(Kind)) {
+    // Must be an integer scalar.
+    Type *Type = OrigPhi->getType();
+    if (!Type->isIntegerTy())
+      return InstDesc(false, I);
+
+    // FIXME: Support more complex patterns, including multiple selects.
+    // The Select must be used only outside the loop and by the PHI.
+    for (User *U : I->users()) {
+      if (U == OrigPhi)
+        continue;
+      if (auto *UI = dyn_cast<Instruction>(U); UI && !TheLoop->contains(UI))
+        continue;
+      return InstDesc(false, I);
+    }
+
+    return InstDesc(I, RecurKind::FindLast);
+  }
+
   // Returns either FindFirstIV/FindLastIV, if such a pattern is found, or
   // std::nullopt.
   auto GetRecurKind = [&](Value *V) -> std::optional<RecurKind> {
@@ -920,8 +943,8 @@ RecurrenceDescriptor::InstDesc RecurrenceDescriptor::isRecurrenceInstr(
         Kind == RecurKind::Add || Kind == RecurKind::Mul ||
         Kind == RecurKind::Sub || Kind == RecurKind::AddChainWithSubs)
       return isConditionalRdxPattern(I);
-    if (isFindIVRecurrenceKind(Kind) && SE)
-      return isFindIVPattern(Kind, L, OrigPhi, I, *SE);
+    if ((isFindIVRecurrenceKind(Kind) || isFindLastRecurrenceKind(Kind)) && SE)
+      return isFindPattern(Kind, L, OrigPhi, I, *SE);
     [[fallthrough]];
   case Instruction::FCmp:
   case Instruction::ICmp:
@@ -1118,7 +1141,11 @@ bool RecurrenceDescriptor::isReductionPHI(PHINode *Phi, Loop *TheLoop,
                       << "\n");
     return true;
   }
-
+  if (AddReductionVar(Phi, RecurKind::FindLast, TheLoop, FMF, RedDes, DB, AC,
+                      DT, SE)) {
+    LLVM_DEBUG(dbgs() << "Found a FindLast reduction PHI." << *Phi << "\n");
+    return true;
+  }
   // Not a reduction of known type.
   return false;
 }
@@ -1248,6 +1275,8 @@ unsigned RecurrenceDescriptor::getOpcode(RecurKind Kind) {
   case RecurKind::FMaximumNum:
   case RecurKind::FMinimumNum:
     return Instruction::FCmp;
+  case RecurKind::FindLast:
+    return Instruction::Select;
   default:
     llvm_unreachable("Unknown recurrence operation");
   }
diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
index 197aae6e03cb1..b27dcbf7acd79 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -5451,6 +5451,7 @@ bool AArch64TTIImpl::isLegalToVectorizeReduction(
   case RecurKind::FMax:
   case RecurKind::FMulAdd:
   case RecurKind::AnyOf:
+  case RecurKind::FindLast:
     return true;
   default:
     return false;
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index b7224a33f47b1..0bbad6f657a24 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1275,6 +1275,7 @@ class LoopVectorizationCostModel {
                            "from latch block\n");
       return true;
     }
+
     if (IsVectorizing && InterleaveInfo.requiresScalarEpilogue()) {
       LLVM_DEBUG(dbgs() << "LV: Loop requires scalar epilogue: "
                            "interleaved group requires scalar epilogue\n");
@@ -4045,6 +4046,7 @@ static bool willGenerateVectors(VPlan &Plan, ElementCount VF,
         continue;
       case VPDef::VPReductionSC:
       case VPDef::VPActiveLaneMaskPHISC:
+      case VPDef::VPLastActiveMaskPHISC:
       case VPDef::VPWidenCallSC:
       case VPDef::VPWidenCanonicalIVSC:
       case VPDef::VPWidenCastSC:
@@ -4265,11 +4267,15 @@ bool LoopVectorizationPlanner::isCandidateForEpilogueVectorization(
     ElementCount VF) const {
   // Cross iteration phis such as fixed-order recurrences and FMaxNum/FMinNum
   // reductions need special handling and are currently unsupported.
+  // FindLast reductions also require special handling for the synthesized
+  // mask PHI.
   if (any_of(OrigLoop->getHeader()->phis(), [&](PHINode &Phi) {
         if (!Legal->isReductionVariable(&Phi))
           return Legal->isFixedOrderRecurrence(&Phi);
-        return RecurrenceDescriptor::isFPMinMaxNumRecurrenceKind(
-            Legal->getRecurrenceDescriptor(&Phi).getRecurrenceKind());
+        RecurKind Kind =
+            Legal->getRecurrenceDescriptor(&Phi).getRecurrenceKind();
+        return RecurrenceDescriptor::isFindLastRecurrenceKind(Kind) ||
+               RecurrenceDescriptor::isFPMinMaxNumRecurrenceKind(Kind);
       }))
     return false;
 
@@ -4559,6 +4565,12 @@ LoopVectorizationPlanner::selectInterleaveCount(VPlan &Plan, ElementCount VF,
       any_of(Plan.getVectorLoopRegion()->getEntryBasicBlock()->phis(),
              IsaPred<VPReductionPHIRecipe>);
 
+  // FIXME: implement interleaving for FindLast transform correctly.
+  for (auto &[_, RdxDesc] : Legal->getReductionVars())
+    if (RecurrenceDescriptor::isFindLastRecurrenceKind(
+            RdxDesc.getRecurrenceKind()))
+      return 1;
+
   // If we did not calculate the cost for VF (because the user selected the VF)
   // then we calculate the cost of VF here.
   if (LoopCost == 0) {
@@ -8488,6 +8500,10 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(
                                 *Plan, Builder))
     return nullptr;
 
+  // Create whole-vector selects for find-last recurrences.
+  VPlanTransforms::runPass(VPlanTransforms::convertFindLastRecurrences, *Plan,
+                           RecipeBuilder, Legal);
+
   if (useActiveLaneMask(Style)) {
     // TODO: Move checks to VPlanTransforms::addActiveLaneMask once
     // TailFoldingStyle is visible there.
@@ -8581,10 +8597,11 @@ void LoopVectorizationPlanner::adjustRecipesForReductions(
       continue;
 
     RecurKind Kind = PhiR->getRecurrenceKind();
-    assert(
-        !RecurrenceDescriptor::isAnyOfRecurrenceKind(Kind) &&
-        !RecurrenceDescriptor::isFindIVRecurrenceKind(Kind) &&
-        "AnyOf and FindIV reductions are not allowed for in-loop reductions");
+    assert(!RecurrenceDescriptor::isFindLastRecurrenceKind(Kind) &&
+           !RecurrenceDescriptor::isAnyOfRecurrenceKind(Kind) &&
+           !RecurrenceDescriptor::isFindIVRecurrenceKind(Kind) &&
+           "AnyOf, FindIV, and FindLast reductions are not allowed for in-loop "
+           "reductions");
 
     // Collect the chain of "link" recipes for the reduction starting at PhiR.
     SetVector<VPSingleDefRecipe *> Worklist;
@@ -8884,7 +8901,8 @@ void LoopVectorizationPlanner::adjustRecipesForReductions(
     RecurKind RK = RdxDesc.getRecurrenceKind();
     if ((!RecurrenceDescriptor::isAnyOfRecurrenceKind(RK) &&
          !RecurrenceDescriptor::isFindIVRecurrenceKind(RK) &&
-         !RecurrenceDescriptor::isMinMaxRecurrenceKind(RK))) {
+         !RecurrenceDescriptor::isMinMaxRecurrenceKind(RK) &&
+         !RecurrenceDescriptor::isFindLastRecurrenceKind(RK))) {
       VPBuilder PHBuilder(Plan->getVectorPreheader());
       VPValue *Iden = Plan->getOrAddLiveIn(
           getRecurrenceIdentity(RK, PhiTy, RdxDesc.getFastMathFlags()));
@@ -9294,7 +9312,7 @@ static void preparePlanForMainVectorLoop(VPlan &MainPlan, VPlan &EpiPlan) {
   SmallPtrSet<PHINode *, 2> EpiWidenedPhis;
   for (VPRecipeBase &R :
        EpiPlan.getVectorLoopRegion()->getEntryBasicBlock()->phis()) {
-    if (isa<VPCanonicalIVPHIRecipe>(&R))
+    if (isa<VPCanonicalIVPHIRecipe, VPLastActiveMaskPHIRecipe>(&R))
       continue;
     EpiWidenedPhis.insert(
         cast<PHINode>(R.getVPSingleValue()->getUnderlyingValue()));
@@ -9491,6 +9509,10 @@ static SmallVector<Instruction *> preparePlanForEpilogueVectorLoop(
           continue;
         }
       }
+    } else if (isa<VPLastActiveMaskPHIRecipe>(R)) {
+      // LastActiveMasks are only used as part of FindLast reductions,
+      // and aren't passed to the scalar loop.
+      continue;
     } else {
       // Retrieve the induction resume values for wide inductions from
       // their original phi nodes in the scalar loop.
@@ -10006,6 +10028,21 @@ bool LoopVectorizePass::processLoop(Loop *L) {
   // Override IC if user provided an interleave count.
   IC = UserIC > 0 ? UserIC : IC;
 
+  // FIXME: Enable interleaving for last_active reductions.
+  if (any_of(make_second_range(LVL.getReductionVars()), [&](auto &RdxDesc) {
+        return RecurrenceDescriptor::isFindLastRecurrenceKind(
+            RdxDesc.getRecurrenceKind());
+      })) {
+    LLVM_DEBUG(dbgs() << "LV: Not interleaving without vectorization due "
+                      << "to conditional scalar assignments.\n");
+    IntDiagMsg = {
+        "ConditionalAssignmentPreventsScalarInterleaving",
+        "Unable to interleave without vectorization due to conditional "
+        "assignments"};
+    InterleaveLoop = false;
+    IC = 1;
+  }
+
   // Emit diagnostic messages, if any.
   const char *VAPassName = Hints.vectorizeAnalysisPassName();
   if (!VectorizeLoop && !InterleaveLoop) {
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index df835a077f2a0..c6be736b41509 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -25174,6 +25174,7 @@ class HorizontalReduction {
         case RecurKind::FindFirstIVUMin:
         case RecurKind::FindLastIVSMax:
         case RecurKind::FindLastIVUMax:
+        case RecurKind::FindLast:
         case RecurKind::FMaxNum:
         case RecurKind::FMinNum:
         case RecurKind::FMaximumNum:
@@ -25315,6 +25316,7 @@ class HorizontalReduction {
     case RecurKind::FindFirstIVUMin:
     case RecurKind::FindLastIVSMax:
     case RecurKind::FindLastIVUMax:
+    case RecurKind::FindLast:
     case RecurKind::FMaxNum:
     case RecurKind::FMinNum:
     case RecurKind::FMaximumNum:
@@ -25421,6 +25423,7 @@ class HorizontalReduction {
     case RecurKind::FindFirstIVUMin:
     case RecurKind::FindLastIVSMax:
     case RecurKind::FindLastIVUMax:
+    case RecurKind::FindLast:
     case RecurKind::FMaxNum:
     case RecurKind::FMinNum:
     case RecurKind::FMaximumNum:
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 5851b3ab7978c..f0fe89ca9133d 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -548,6 +548,7 @@ class VPSingleDefRecipe : public VPRecipeBase, public VPValue {
     case VPRecipeBase::VPPredInstPHISC:
     case VPRecipeBase::VPCanonicalIVPHISC:
     case VPRecipeBase::VPActiveLaneMaskPHISC:
+    case VPRecipeBase::VPLastActiveMaskPHISC:
     case VPRecipeBase::VPFirstOrderRecurrencePHISC:
     case VPRecipeBase::VPWidenPHISC:
     case VPRecipeBase::VPWidenIntOrFpInductionSC:
@@ -1064,6 +1065,8 @@ class LLVM_ABI_FOR_TEST VPInstruction : public VPRecipeWithIRFlags,
     /// Returns the value for vscale.
     VScale,
     OpsEnd = VScale,
+    /// Extracts the last active lane based on a predicate vector operand.
+    ExtractLastActive,
   };
 
   /// Returns true if this VPInstruction generates scalar values for all lanes.
@@ -3556,6 +3559,40 @@ class VPActiveLaneMaskPHIRecipe : public VPHeaderPHIRecipe {
 #endif
 };
 
+// TODO: Can we unify the PHI recipe hierarchy a bit? VPPredInstPHISC is close
+//       to this (just a PHI of a predicate), but isn't a header phi so can't
+//       be used for the mask of FindLastActive reductions.
+//
+// This is basically a clone of VPActiveLaneMaskPHIRecipe, but won't run into
+// problems with transforms that expect there to only be a single ALM PHI, and
+// can be ignored by other code looking for a (non-existent) underlying value.
+class VPLastActiveMaskPHIRecipe : public VPHeaderPHIRecipe {
+public:
+  VPLastActiveMaskPHIRecipe(VPValue *StartMask, DebugLoc DL)
+      : VPHeaderPHIRecipe(VPDef::VPLastActiveMaskPHISC, nullptr, StartMask,
+                          DL) {}
+
+  ~VPLastActiveMaskPHIRecipe() override = default;
+
+  VPLastActiveMaskPHIRecipe *clone() override {
+    auto *R = new VPLastActiveMaskPHIRecipe(getOperand(0), getDebugLoc());
+    if (getNumOperands() == 2)
+      R->addOperand(getOperand(1));
+    return R;
+  }
+
+  VP_CLASSOF_IMPL(VPDef::VPLastActiveMaskPHISC);
+
+  /// Generate the mask phi
+  void execute(VPTransformState &State) override;
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  /// Print the recipe
+  void print(raw_ostream &O, const Twine &Indent,
+             VPSlotTracker &SlotTracker) const override;
+#endif
+};
+
 /// A recipe for generating the phi node for the current index of elements,
 /// adjusted in accordance with EVL value. It starts at the start value of the
 /// canonical induction and gets incremented by EVL in each iteration of the
diff --git a/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp b/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp
index 80a2e4bc3f754..3168d6652f03b 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp
@@ -118,7 +118,8 @@ Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPInstruction *R) {
     return Type::getIntNTy(Ctx, 64);
   case VPInstruction::ExtractLastElement:
   case VPInstruction::ExtractLastLanePerPart:
-  case VPInstruction::ExtractPenultimateElement: {
+  case VPInstruction::ExtractPenultimateElement:
+  case VPInstruction::ExtractLastActive: {
     Type *BaseTy = inferScalarType(R->getOperand(0));
     if (auto *VecTy = dyn_cast<VectorType>(BaseTy))
       return VecTy->getElementType();
@@ -276,14 +277,14 @@ Type *VPTypeAnalysis::inferScalarType(const VPValue *V) {
       TypeSwitch<const VPRecipeBase *, Type *>(V->getDefiningRecipe())
           .Case<VPActiveLaneMaskPHIRecipe, VPCanonicalIVPHIRecipe,
                 VPFirstOrderRecurrencePHIRecipe, VPReductionPHIRecipe,
-                VPWidenPointerInductionRecipe, VPEVLBasedIVPHIRecipe>(
-              [this](const auto *R) {
-                // Handle header phi recipes, except VPWidenIntOrFpInduction
-                // which needs special handling due it being possibly truncated.
-                // TODO: consider inferring/caching type of siblings, e.g.,
-                // backedge value, here and in cases below.
-                return inferScalarType(R->getStartValue());
-              })
+                VPWidenPointerInductionRecipe, VPEVLBasedIVPHIRecipe,
+                VPLastActiveMaskPHIRecipe>([this](const auto *R) {
+            // Handle header phi recipes, except VPWidenIntOrFpInduction
+            // which needs special handling due it being possibly truncated.
+            // TODO: consider inferring/caching type of siblings, e.g.,
+            // backedge value, here and in cases below.
+            return inferScalarType(R->getStartValue());
+          })
           .Case<VPWidenIntOrFpInductionRecipe, VPDerivedIVRecipe>(
               [](const auto *R) { return R->getScalarType(); })
           .Case<VPReductionRecipe, VPPredInstPHIRecipe, VPWidenPHIRecipe,
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 80cd112dbcd8a..7979cc12ea9f9 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -523,6 +523,7 @@ unsigned VPInstruction::getNumOperandsForOpcode(unsigned Opcode) {
   case Instruction::Load:
   case VPInstruction::AnyOf:
   case VPInstruction::BranchOnCond:
+  case VPInstruction::Broadcast:
   case VPInstruction::BuildStructVector:
   case VPInstruction::BuildVector:
   case VPInstruction::CalculateTripCountMinusVF:
@@ -550,6 +551,7 @@ unsigned VPInstruction::getNumOperandsForOpcode(unsigned Opcode) {
   case VPInstruction::ActiveLaneMask:
   case VPInstruction::ComputeAnyOfResult:
   case VPInstruction::ReductionStartVector:
+  case VPInstruction::ExtractLastActive:
     return 3;
   case VPInstruction::ComputeFindIVResult:
     return 4;
@@ -1005,6 +1007,17 @@ Value *VPInstruction::generate(VPTransformState &State) {
   }
   case VPInstruction::ResumeForEpilogue:
     return State.get(getOperand(0), true);
+  case VPInstruction::ExtractLastActive: {
+    Value *Data = State.get(getOperand(0));
+    Value *Mask = State.get(getOperand(1));
+    Value *Default = State.get(getOperand(2), /*IsScalar=*/true);
+    Type *VTy = Data->getType();
+
+    Module *M = State.Builder.GetInsertBlock()->getModule();
+    Function *ExtractLast = Intrinsic::getOrInsertDeclaration(
+        M, Intrinsic::experimental_vector_extract_last_active, {VTy});
+    return Builder.CreateCall(ExtractLast, {Data, Mask, Default});
+  }
   default:
     llvm_unreachable("Unsupported opcode for instruction");
   }
@@ -1141,6 +1154,15 @@ InstructionCost VPInstruction::computeCost(ElementCount VF,
                                   {PredTy, Type::getInt1Ty(Ctx.LLVMCtx)});
     return Ctx.TTI.getIntrinsicInstrCost(Attrs, Ctx.CostKind);
   }
+  case VPInstruction::ExtractLastActive: {
+    Type *ScalarTy = Ctx.Types.inferScalarType(this);
+    Type *VecTy = toVectorTy(ScalarTy, VF);
+    Type *MaskTy = toVectorTy(Type::getInt1Ty(Ctx.LLVMCtx), VF);
+    IntrinsicCostAttributes ICA(
+        Intrinsic::experimental_vector_extract_last_active, ScalarTy,
+        {VecTy, MaskTy, ScalarTy});
+    return Ctx.TTI.getIntrinsicInstrCost(ICA, Ctx.CostKind);
+  }
   case VPInstruction::FirstOrderRecurrenceSplice: {
     assert(VF.isVector() && "Scalar FirstOrderRecurrenceSplice?");
     SmallVector<int> Mask(VF.getKnownMinValue());
@@ -1197,6 +1219,7 @@ bool VPInstruction::isVectorToScalar() const {
          getOpcode() == VPInstruction::FirstActiveLane ||
          getOpcode() == VPInstruction::ComputeAnyOfResult ||
          getOpcode() == VPInstruction::ComputeFindIVResult ||
+         getOpcode() == VPInstruction::ExtractLastActive ||
          getOpcode() == VPInstruction::ComputeReductionResult ||
          getOpcode() == VPInstruction::AnyOf;
 }
@@ -1260,6 +1283,7 @@ bool VPInstruction::opcodeMayReadOrWriteFromMemory() const {
   case VPInstruction::ExtractPenultimateElement:
   case VPInstruction::ActiveLaneMask:
   case VPInstruction::FirstActiveLane:
+  case VPInstruction::ExtractLastActive:
   case VPInstruction::FirstOrderRecurrenceSplice:
   case VPInstruction::LogicalAnd:
   case VPInstruction::Not:
@@ -1445,6 +1469,9 @@ void VPInstruction::print(raw_ostream &O, const Twine &Indent,
   case VPInstruction::Unpack:
     O << "unpack";
     break;
+  case VPInstruction::ExtractLastActive:
+    O << "extract-last-active";
+    break;
   default:
     O << Instruction::getOpcodeName(getOpcode());
   }
@@ -4483,6 +4510,27 @@ void VPActiveLaneMaskPHIRecipe::print(raw_ostream &O, const Twine &Indent,
 }
 #endif
 
+void VPLastActiveMaskPHIRecipe::execute(VPTransformState &State) {
+  BasicBlock *VectorPH =
+      State.CFG.VPBB2IRBB.at(getParent()->getCFGPredecessor(0));
+  Value *StartMask = State.get(getOperand(0));
+  PHINode *Phi =
+      State.Builder.CreatePHI(StartMask->getType(), 2, "last.active.mask");
+  Phi->addIncoming(StartMask, VectorPH);
+  State.set(this, Phi);
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void VPLastActiveMaskPHIRecipe::print(raw_ostream &O, const Twine &Indent,
+                                      VPSlotTracker &SlotTracker) const {
+  O << Indent << "LAST-ACTIVE-MASK-PHI ";
+
+  printAsOperand(O, SlotTracker);
+  O << " = phi ";
+  printOperands(O, SlotTracker);
+}
+#endif
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 void VPEVLBasedIVPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                                   VPSlotTracker &SlotTracker) const {
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index 48bd697397f41..8fbd3686af117 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -36,6 +36,7 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/TypeSize.h"
 #include "llvm/Transforms/Utils/ScalarEvolutionExpander.h"
+#include "llvm/Transforms/Vectorize/LoopVectorizationLegality.h"
 
 using namespace llvm;
 using namespace VPlanPatternMatch;
@@ -4593,3 +4594,80 @@ void VPlanTransforms::addExitUsersForFirstOrderRecurrences(VPlan &Plan,
     }
   }
 }
+
+void VPlanTransforms::convertFindLastRecurrences(
+    VPlan &Plan, VPRecipeBuilder &RecipeBuilder,
+    LoopVectorizationLegality *Legal) {
+  assert(Legal && "Need valid LoopVecLegality");
+
+  // May need to do something better than this?
+  if (Plan.hasScalarVFOnly())
+    return;
+
+  // We want to create the following nodes:
+  // vec.body:
+  //   mask.phi = phi <VF x i1> [ all.false, vec.ph ], [ new.mask, vec.body ]
+  //   ...data.phi already exists, but needs updating...
+  //   data.phi = phi <VF x Ty> [ default.val, vec.ph ], [ new.data, vec.body ]
+  //
+  //   ...'data' and 'compare' created by existing nodes...
+  //
+  //   any_active = i1 any_of_reduction(compare)
+  //   new.mask = select any_active, compare, mask.phi
+  //   new.data = select any_active, data, data.phi
+  //
+  // middle.block:
+  //   result = extract-last-active new.data, new.mask, default.val
+
+  for (const auto &[Phi, RdxDesc] : Legal->getReductionVars()) {
+    if (RecurrenceDescriptor::isFindLastRecurrenceKind(
+            RdxDesc.getRecurrenceKind())) {
+      VPRecipeBase *PhiR = RecipeBuilder.getRecipe(Phi);
+      VPBuilder Builder = VPBuilder::getToInsertAfter(PhiR);
+
+      // Add mask phi
+      VPValue *False =
+          Plan.getOrAddLiveIn(ConstantInt::getFalse(Phi->getContext()));
+      auto *MaskPHI = new VPLastActiveMaskPHIRecipe(False, DebugLoc());
+      Builder.insert(MaskPHI);
+
+      // Find the condition for the select
+      SelectInst *Select = cast<SelectInst>(RdxDesc.getLoopExitInstr());
+      auto *SR = cast<VPWidenSelectRecipe>(RecipeBuilder.getRecipe(Select));
+      VPValue *Cond = SR->getCond();
+
+      // Add select for mask
+      Builder.setInsertPoint(SR);
+      VPValue *AnyOf = Builder.createNaryOp(VPInstruction::AnyOf, {Cond});
+      VPValue *MaskSelect = Builder.createSelect(AnyOf, Cond, MaskPHI);
+      MaskPHI->addOperand(MaskSelect);
+
+      // Replace select for data
+      VPValue *DataSelect = Builder.createSelect(
+          AnyOf, SR->getOperand(1), SR->getOperand(2), SR->getDebugLoc());
+      SR->replaceAllUsesWith(DataSelect);
+      SR->eraseFromParent();
+
+      // Find final reduction and replace it with an
+      // extract.last.active intrinsic.
+      VPInstruction *RdxResult = nullptr;
+      for (VPUser *U : DataSelect->users()) {
+        VPInstruction *I = dyn_cast<VPInstruction>(U);
+        if (I && I->getOpcode() == VPInstruction::ComputeReductionResult) {
+          RdxResult = I;
+          break;
+        }
+      }
+
+      assert(RdxResult);
+      Builder.setInsertPoint(RdxResult);
+      VPValue *Default = RecipeBuilder.getVPValueOrAddLiveIn(
+          RdxDesc.getRecurrenceStartValue());
+      auto *ExtractLastActive = Builder.createNaryOp(
+          VPInstruction::ExtractLastActive, {DataSelect, MaskSelect, Default},
+          RdxResult->getDebugLoc());
+      RdxResult->replaceAllUsesWith(ExtractLastActive);
+      RdxResult->eraseFromParent();
+    }
+  }
+}
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.h b/llvm/lib/Transforms/Vectorize/VPlanTransforms.h
index b28559b620e13..71aa6f9457c1c 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.h
@@ -23,6 +23,7 @@ namespace llvm {
 
 class InductionDescriptor;
 class Instruction;
+class LoopVectorizationLegality;
 class PHINode;
 class ScalarEvolution;
 class PredicatedScalarEvolution;
@@ -377,6 +378,13 @@ struct VPlanTransforms {
   /// users in the original exit block using the VPIRInstruction wrapping to the
   /// LCSSA phi.
   static void addExitUsersForFirstOrderRecurrences(VPlan &Plan, VFRange &Range);
+
+  /// Change FindLast reductions to save the appropriate state using selects
+  /// for entire vectors for both the latest mask containing at least one active
+  /// element and the corresponding data vector.
+  static void convertFindLastRecurrences(VPlan &Plan,
+                                         VPRecipeBuilder &RecipeBuilder,
+                                         LoopVectorizationLegality *Legal);
 };
 
 } // namespace llvm
diff --git a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
index e22c5dfdb9f38..67cf86b16c6fb 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
@@ -47,7 +47,7 @@ VPValue *vputils::getOrCreateVPValueForSCEVExpr(VPlan &Plan, const SCEV *Expr) {
 }
 
 bool vputils::isHeaderMask(const VPValue *V, const VPlan &Plan) {
-  if (isa<VPActiveLaneMaskPHIRecipe>(V))
+  if (isa<VPActiveLaneMaskPHIRecipe, VPLastActiveMaskPHIRecipe>(V))
     return true;
 
   auto IsWideCanonicalIV = [](VPValue *A) {
diff --git a/llvm/lib/Transforms/Vectorize/VPlanValue.h b/llvm/lib/Transforms/Vectorize/VPlanValue.h
index 5da74630ef626..7a3f4f63a09a1 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanValue.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanValue.h
@@ -366,6 +366,7 @@ class VPDef {
     // VPHeaderPHIRecipe need to be kept together.
     VPCanonicalIVPHISC,
     VPActiveLaneMaskPHISC,
+    VPLastActiveMaskPHISC,
     VPEVLBasedIVPHISC,
     VPFirstOrderRecurrencePHISC,
     VPWidenIntOrFpInductionSC,
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/conditional-scalar-assignment.ll b/llvm/test/Transforms/LoopVectorize/AArch64/conditional-scalar-assignment.ll
new file mode 100644
index 0000000000000..25c698f3df245
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/conditional-scalar-assignment.ll
@@ -0,0 +1,397 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 6
+; RUN: opt -passes=loop-vectorize,instcombine -S < %s 2>&1 | FileCheck %s --check-prefix=NEON
+; RUN: opt -passes=loop-vectorize,instcombine -mattr=+sve -S < %s 2>&1 | FileCheck %s --check-prefix=SVE
+
+;; The following run line caused an ICE before using a dedicated FindLast PHI recipe.
+;; We're not looking at the resulting IR, just confirming it doesn't crash.
+; RUN: opt -passes=loop-vectorize,instcombine -mattr=+sve -epilogue-vectorization-force-VF=4 -S < %s 2>&1 > /dev/null
+
+target triple = "aarch64-linux-gnu"
+
+define i32 @simple_csa_int_select(i64 %N, ptr %data, i32 %a) {
+; NEON-LABEL: define i32 @simple_csa_int_select(
+; NEON-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], i32 [[A:%.*]]) {
+; NEON-NEXT:  [[ENTRY:.*]]:
+; NEON-NEXT:    br label %[[LOOP:.*]]
+; NEON:       [[LOOP]]:
+; NEON-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[DATA_PHI:%.*]] = phi i32 [ -1, %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[DATA]], i64 [[IV]]
+; NEON-NEXT:    [[LD:%.*]] = load i32, ptr [[LD_ADDR]], align 4
+; NEON-NEXT:    [[SELECT_CMP:%.*]] = icmp slt i32 [[A]], [[LD]]
+; NEON-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], i32 [[LD]], i32 [[DATA_PHI]]
+; NEON-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; NEON-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; NEON-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; NEON:       [[EXIT]]:
+; NEON-NEXT:    ret i32 [[SELECT_DATA]]
+;
+; SVE-LABEL: define i32 @simple_csa_int_select(
+; SVE-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], i32 [[A:%.*]]) #[[ATTR0:[0-9]+]] {
+; SVE-NEXT:  [[ENTRY:.*]]:
+; SVE-NEXT:    [[A_FR:%.*]] = freeze i32 [[A]]
+; SVE-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; SVE-NEXT:    [[TMP1:%.*]] = shl nuw i64 [[TMP0]], 2
+; SVE-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], [[TMP1]]
+; SVE-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; SVE:       [[VECTOR_PH]]:
+; SVE-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; SVE-NEXT:    [[TMP3:%.*]] = shl nuw i64 [[TMP2]], 2
+; SVE-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], [[TMP3]]
+; SVE-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; SVE-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 4 x i32> zeroinitializer, i32 [[A_FR]], i64 0
+; SVE-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 4 x i32> [[BROADCAST_SPLATINSERT]], <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
+; SVE-NEXT:    br label %[[VECTOR_BODY:.*]]
+; SVE:       [[VECTOR_BODY]]:
+; SVE-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; SVE-NEXT:    [[VEC_PHI:%.*]] = phi <vscale x 4 x i32> [ splat (i32 -1), %[[VECTOR_PH]] ], [ [[TMP10:%.*]], %[[VECTOR_BODY]] ]
+; SVE-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <vscale x 4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP9:%.*]], %[[VECTOR_BODY]] ]
+; SVE-NEXT:    [[TMP6:%.*]] = getelementptr inbounds i32, ptr [[DATA]], i64 [[INDEX]]
+; SVE-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 4 x i32>, ptr [[TMP6]], align 4
+; SVE-NEXT:    [[WIDE_LOAD_FR:%.*]] = freeze <vscale x 4 x i32> [[WIDE_LOAD]]
+; SVE-NEXT:    [[TMP7:%.*]] = icmp slt <vscale x 4 x i32> [[BROADCAST_SPLAT]], [[WIDE_LOAD_FR]]
+; SVE-NEXT:    [[TMP8:%.*]] = call i1 @llvm.vector.reduce.or.nxv4i1(<vscale x 4 x i1> [[TMP7]])
+; SVE-NEXT:    [[TMP9]] = select i1 [[TMP8]], <vscale x 4 x i1> [[TMP7]], <vscale x 4 x i1> [[LAST_ACTIVE_MASK]]
+; SVE-NEXT:    [[TMP10]] = select i1 [[TMP8]], <vscale x 4 x i32> [[WIDE_LOAD_FR]], <vscale x 4 x i32> [[VEC_PHI]]
+; SVE-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
+; SVE-NEXT:    [[TMP11:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; SVE-NEXT:    br i1 [[TMP11]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; SVE:       [[MIDDLE_BLOCK]]:
+; SVE-NEXT:    [[TMP12:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.nxv4i32(<vscale x 4 x i32> [[TMP10]], <vscale x 4 x i1> [[TMP9]], i32 -1)
+; SVE-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N_MOD_VF]], 0
+; SVE-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; SVE:       [[SCALAR_PH]]:
+; SVE-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; SVE-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP12]], %[[MIDDLE_BLOCK]] ], [ -1, %[[ENTRY]] ]
+; SVE-NEXT:    br label %[[LOOP:.*]]
+; SVE:       [[LOOP]]:
+; SVE-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[DATA_PHI:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds i32, ptr [[DATA]], i64 [[IV]]
+; SVE-NEXT:    [[LD:%.*]] = load i32, ptr [[LD_ADDR]], align 4
+; SVE-NEXT:    [[SELECT_CMP:%.*]] = icmp slt i32 [[A_FR]], [[LD]]
+; SVE-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], i32 [[LD]], i32 [[DATA_PHI]]
+; SVE-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; SVE-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; SVE-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP3:![0-9]+]]
+; SVE:       [[EXIT]]:
+; SVE-NEXT:    [[SELECT_DATA_LCSSA:%.*]] = phi i32 [ [[SELECT_DATA]], %[[LOOP]] ], [ [[TMP12]], %[[MIDDLE_BLOCK]] ]
+; SVE-NEXT:    ret i32 [[SELECT_DATA_LCSSA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %data.phi = phi i32 [ -1, %entry ], [ %select.data, %loop ]
+  %ld.addr = getelementptr inbounds i32, ptr %data, i64 %iv
+  %ld = load i32, ptr %ld.addr, align 4
+  %select.cmp = icmp slt i32 %a, %ld
+  %select.data = select i1 %select.cmp, i32 %ld, i32 %data.phi
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exit.cmp = icmp eq i64 %iv.next, %N
+  br i1 %exit.cmp, label %exit, label %loop
+
+exit:
+  ret i32 %select.data
+}
+
+define ptr @simple_csa_ptr_select(i64 %N, ptr %data, i64 %a, ptr %init) {
+; NEON-LABEL: define ptr @simple_csa_ptr_select(
+; NEON-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], i64 [[A:%.*]], ptr [[INIT:%.*]]) {
+; NEON-NEXT:  [[ENTRY:.*]]:
+; NEON-NEXT:    br label %[[LOOP:.*]]
+; NEON:       [[LOOP]]:
+; NEON-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[DATA_PHI:%.*]] = phi ptr [ [[INIT]], %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds nuw ptr, ptr [[DATA]], i64 [[IV]]
+; NEON-NEXT:    [[LD:%.*]] = load ptr, ptr [[LD_ADDR]], align 4
+; NEON-NEXT:    [[LD_I64:%.*]] = ptrtoint ptr [[LD]] to i64
+; NEON-NEXT:    [[SELECT_CMP:%.*]] = icmp slt i64 [[A]], [[LD_I64]]
+; NEON-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], ptr [[LD]], ptr [[DATA_PHI]]
+; NEON-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; NEON-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; NEON-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; NEON:       [[EXIT]]:
+; NEON-NEXT:    ret ptr [[SELECT_DATA]]
+;
+; SVE-LABEL: define ptr @simple_csa_ptr_select(
+; SVE-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], i64 [[A:%.*]], ptr [[INIT:%.*]]) #[[ATTR0]] {
+; SVE-NEXT:  [[ENTRY:.*]]:
+; SVE-NEXT:    br label %[[LOOP:.*]]
+; SVE:       [[LOOP]]:
+; SVE-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[DATA_PHI:%.*]] = phi ptr [ [[INIT]], %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds nuw ptr, ptr [[DATA]], i64 [[IV]]
+; SVE-NEXT:    [[LD:%.*]] = load ptr, ptr [[LD_ADDR]], align 4
+; SVE-NEXT:    [[LD_I64:%.*]] = ptrtoint ptr [[LD]] to i64
+; SVE-NEXT:    [[SELECT_CMP:%.*]] = icmp slt i64 [[A]], [[LD_I64]]
+; SVE-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], ptr [[LD]], ptr [[DATA_PHI]]
+; SVE-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; SVE-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; SVE-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; SVE:       [[EXIT]]:
+; SVE-NEXT:    ret ptr [[SELECT_DATA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %data.phi = phi ptr [ %init, %entry ], [ %select.data, %loop ]
+  %ld.addr = getelementptr inbounds ptr, ptr %data, i64 %iv
+  %ld = load ptr, ptr %ld.addr, align 4
+  %ld.i64 = ptrtoint ptr %ld to i64
+  %select.cmp = icmp slt i64 %a, %ld.i64
+  %select.data = select i1 %select.cmp, ptr %ld, ptr %data.phi
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exit.cmp = icmp eq i64 %iv.next, %N
+  br i1 %exit.cmp, label %exit, label %loop
+
+exit:
+  ret ptr %select.data
+}
+
+define float @simple_csa_float_select(i64 %N, ptr %data, float %a) {
+; NEON-LABEL: define float @simple_csa_float_select(
+; NEON-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], float [[A:%.*]]) {
+; NEON-NEXT:  [[ENTRY:.*]]:
+; NEON-NEXT:    br label %[[LOOP:.*]]
+; NEON:       [[LOOP]]:
+; NEON-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[DATA_PHI:%.*]] = phi float [ -1.000000e+00, %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds nuw float, ptr [[DATA]], i64 [[IV]]
+; NEON-NEXT:    [[LD:%.*]] = load float, ptr [[LD_ADDR]], align 4
+; NEON-NEXT:    [[SELECT_CMP:%.*]] = fcmp olt float [[A]], [[LD]]
+; NEON-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], float [[LD]], float [[DATA_PHI]]
+; NEON-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; NEON-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; NEON-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; NEON:       [[EXIT]]:
+; NEON-NEXT:    ret float [[SELECT_DATA]]
+;
+; SVE-LABEL: define float @simple_csa_float_select(
+; SVE-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], float [[A:%.*]]) #[[ATTR0]] {
+; SVE-NEXT:  [[ENTRY:.*]]:
+; SVE-NEXT:    br label %[[LOOP:.*]]
+; SVE:       [[LOOP]]:
+; SVE-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[DATA_PHI:%.*]] = phi float [ -1.000000e+00, %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds nuw float, ptr [[DATA]], i64 [[IV]]
+; SVE-NEXT:    [[LD:%.*]] = load float, ptr [[LD_ADDR]], align 4
+; SVE-NEXT:    [[SELECT_CMP:%.*]] = fcmp olt float [[A]], [[LD]]
+; SVE-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], float [[LD]], float [[DATA_PHI]]
+; SVE-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; SVE-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; SVE-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; SVE:       [[EXIT]]:
+; SVE-NEXT:    ret float [[SELECT_DATA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %data.phi = phi float [ -1.0, %entry ], [ %select.data, %loop ]
+  %ld.addr = getelementptr inbounds float, ptr %data, i64 %iv
+  %ld = load float, ptr %ld.addr, align 4
+  %select.cmp = fcmp olt float %a, %ld
+  %select.data = select i1 %select.cmp, float %ld, float %data.phi
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exit.cmp = icmp eq i64 %iv.next, %N
+  br i1 %exit.cmp, label %exit, label %loop
+
+exit:
+  ret float %select.data
+}
+
+define i32 @multi_user_csa_int_select(i64 %N, ptr %data, ptr %results, i32 %a) {
+; NEON-LABEL: define i32 @multi_user_csa_int_select(
+; NEON-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], ptr [[RESULTS:%.*]], i32 [[A:%.*]]) {
+; NEON-NEXT:  [[ENTRY:.*]]:
+; NEON-NEXT:    br label %[[LOOP:.*]]
+; NEON:       [[LOOP]]:
+; NEON-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[DATA_PHI:%.*]] = phi i32 [ -1, %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[DATA]], i64 [[IV]]
+; NEON-NEXT:    [[LD:%.*]] = load i32, ptr [[LD_ADDR]], align 4
+; NEON-NEXT:    [[SELECT_CMP:%.*]] = icmp slt i32 [[A]], [[LD]]
+; NEON-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], i32 [[LD]], i32 [[DATA_PHI]]
+; NEON-NEXT:    [[RES_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[RESULTS]], i64 [[IV]]
+; NEON-NEXT:    store i32 [[SELECT_DATA]], ptr [[RES_ADDR]], align 4
+; NEON-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; NEON-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; NEON-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; NEON:       [[EXIT]]:
+; NEON-NEXT:    ret i32 [[SELECT_DATA]]
+;
+; SVE-LABEL: define i32 @multi_user_csa_int_select(
+; SVE-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], ptr [[RESULTS:%.*]], i32 [[A:%.*]]) #[[ATTR0]] {
+; SVE-NEXT:  [[ENTRY:.*]]:
+; SVE-NEXT:    br label %[[LOOP:.*]]
+; SVE:       [[LOOP]]:
+; SVE-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[DATA_PHI:%.*]] = phi i32 [ -1, %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[DATA]], i64 [[IV]]
+; SVE-NEXT:    [[LD:%.*]] = load i32, ptr [[LD_ADDR]], align 4
+; SVE-NEXT:    [[SELECT_CMP:%.*]] = icmp slt i32 [[A]], [[LD]]
+; SVE-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], i32 [[LD]], i32 [[DATA_PHI]]
+; SVE-NEXT:    [[RES_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[RESULTS]], i64 [[IV]]
+; SVE-NEXT:    store i32 [[SELECT_DATA]], ptr [[RES_ADDR]], align 4
+; SVE-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; SVE-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; SVE-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; SVE:       [[EXIT]]:
+; SVE-NEXT:    ret i32 [[SELECT_DATA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %data.phi = phi i32 [ -1, %entry ], [ %select.data, %loop ]
+  %ld.addr = getelementptr inbounds i32, ptr %data, i64 %iv
+  %ld = load i32, ptr %ld.addr, align 4
+  %select.cmp = icmp slt i32 %a, %ld
+  %select.data = select i1 %select.cmp, i32 %ld, i32 %data.phi
+  %res.addr = getelementptr inbounds i32, ptr %results, i64 %iv
+  store i32 %select.data, ptr %res.addr, align 4
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exit.cmp = icmp eq i64 %iv.next, %N
+  br i1 %exit.cmp, label %exit, label %loop
+
+exit:
+  ret i32 %select.data
+}
+
+
+define i32 @multi_use_cmp_for_csa_int_select(i64 %N, ptr %data, i32 %a) {
+; NEON-LABEL: define i32 @multi_use_cmp_for_csa_int_select(
+; NEON-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], i32 [[A:%.*]]) {
+; NEON-NEXT:  [[ENTRY:.*]]:
+; NEON-NEXT:    br label %[[LOOP:.*]]
+; NEON:       [[LOOP]]:
+; NEON-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[DATA_PHI:%.*]] = phi i32 [ -1, %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[IDX_PHI:%.*]] = phi i64 [ -1, %[[ENTRY]] ], [ [[SELECT_IDX:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[DATA]], i64 [[IV]]
+; NEON-NEXT:    [[LD:%.*]] = load i32, ptr [[LD_ADDR]], align 4
+; NEON-NEXT:    [[SELECT_CMP:%.*]] = icmp slt i32 [[A]], [[LD]]
+; NEON-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], i32 [[LD]], i32 [[DATA_PHI]]
+; NEON-NEXT:    [[SELECT_IDX]] = select i1 [[SELECT_CMP]], i64 [[IV]], i64 [[IDX_PHI]]
+; NEON-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; NEON-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; NEON-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; NEON:       [[EXIT]]:
+; NEON-NEXT:    [[IDX:%.*]] = trunc i64 [[SELECT_IDX]] to i32
+; NEON-NEXT:    [[RES:%.*]] = add i32 [[SELECT_DATA]], [[IDX]]
+; NEON-NEXT:    ret i32 [[RES]]
+;
+; SVE-LABEL: define i32 @multi_use_cmp_for_csa_int_select(
+; SVE-SAME: i64 [[N:%.*]], ptr [[DATA:%.*]], i32 [[A:%.*]]) #[[ATTR0]] {
+; SVE-NEXT:  [[ENTRY:.*]]:
+; SVE-NEXT:    br label %[[LOOP:.*]]
+; SVE:       [[LOOP]]:
+; SVE-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[DATA_PHI:%.*]] = phi i32 [ -1, %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[IDX_PHI:%.*]] = phi i64 [ -1, %[[ENTRY]] ], [ [[SELECT_IDX:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[LD_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[DATA]], i64 [[IV]]
+; SVE-NEXT:    [[LD:%.*]] = load i32, ptr [[LD_ADDR]], align 4
+; SVE-NEXT:    [[SELECT_CMP:%.*]] = icmp slt i32 [[A]], [[LD]]
+; SVE-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP]], i32 [[LD]], i32 [[DATA_PHI]]
+; SVE-NEXT:    [[SELECT_IDX]] = select i1 [[SELECT_CMP]], i64 [[IV]], i64 [[IDX_PHI]]
+; SVE-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; SVE-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; SVE-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; SVE:       [[EXIT]]:
+; SVE-NEXT:    [[IDX:%.*]] = trunc i64 [[SELECT_IDX]] to i32
+; SVE-NEXT:    [[RES:%.*]] = add i32 [[SELECT_DATA]], [[IDX]]
+; SVE-NEXT:    ret i32 [[RES]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %data.phi = phi i32 [ -1, %entry ], [ %select.data, %loop ]
+  %idx.phi = phi i64 [ -1, %entry ], [ %select.idx, %loop ]
+  %ld.addr = getelementptr inbounds i32, ptr %data, i64 %iv
+  %ld = load i32, ptr %ld.addr, align 4
+  %select.cmp = icmp slt i32 %a, %ld
+  %select.data = select i1 %select.cmp, i32 %ld, i32 %data.phi
+  %select.idx = select i1 %select.cmp, i64 %iv, i64 %idx.phi
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exit.cmp = icmp eq i64 %iv.next, %N
+  br i1 %exit.cmp, label %exit, label %loop
+
+exit:
+  %idx = trunc i64 %select.idx to i32
+  %res = add i32 %idx, %select.data
+  ret i32 %res
+}
+
+
+define i32 @chained_select_for_csa_int_select(i64 %N, ptr %data1, ptr %data2, i32 %a, i32 %b) {
+; NEON-LABEL: define i32 @chained_select_for_csa_int_select(
+; NEON-SAME: i64 [[N:%.*]], ptr [[DATA1:%.*]], ptr [[DATA2:%.*]], i32 [[A:%.*]], i32 [[B:%.*]]) {
+; NEON-NEXT:  [[ENTRY:.*]]:
+; NEON-NEXT:    br label %[[LOOP:.*]]
+; NEON:       [[LOOP]]:
+; NEON-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[DATA_PHI:%.*]] = phi i32 [ -1, %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; NEON-NEXT:    [[LD1_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[DATA1]], i64 [[IV]]
+; NEON-NEXT:    [[LD1:%.*]] = load i32, ptr [[LD1_ADDR]], align 4
+; NEON-NEXT:    [[SELECT_CMP1:%.*]] = icmp slt i32 [[A]], [[LD1]]
+; NEON-NEXT:    [[SELECT_LD1:%.*]] = select i1 [[SELECT_CMP1]], i32 [[LD1]], i32 [[DATA_PHI]]
+; NEON-NEXT:    [[LD2_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[DATA2]], i64 [[IV]]
+; NEON-NEXT:    [[LD2:%.*]] = load i32, ptr [[LD2_ADDR]], align 4
+; NEON-NEXT:    [[SELECT_CMP2:%.*]] = icmp sgt i32 [[B]], [[LD2]]
+; NEON-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP2]], i32 [[LD2]], i32 [[SELECT_LD1]]
+; NEON-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; NEON-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; NEON-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; NEON:       [[EXIT]]:
+; NEON-NEXT:    ret i32 [[SELECT_DATA]]
+;
+; SVE-LABEL: define i32 @chained_select_for_csa_int_select(
+; SVE-SAME: i64 [[N:%.*]], ptr [[DATA1:%.*]], ptr [[DATA2:%.*]], i32 [[A:%.*]], i32 [[B:%.*]]) #[[ATTR0]] {
+; SVE-NEXT:  [[ENTRY:.*]]:
+; SVE-NEXT:    br label %[[LOOP:.*]]
+; SVE:       [[LOOP]]:
+; SVE-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[DATA_PHI:%.*]] = phi i32 [ -1, %[[ENTRY]] ], [ [[SELECT_DATA:%.*]], %[[LOOP]] ]
+; SVE-NEXT:    [[LD1_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[DATA1]], i64 [[IV]]
+; SVE-NEXT:    [[LD1:%.*]] = load i32, ptr [[LD1_ADDR]], align 4
+; SVE-NEXT:    [[SELECT_CMP1:%.*]] = icmp slt i32 [[A]], [[LD1]]
+; SVE-NEXT:    [[SELECT_LD1:%.*]] = select i1 [[SELECT_CMP1]], i32 [[LD1]], i32 [[DATA_PHI]]
+; SVE-NEXT:    [[LD2_ADDR:%.*]] = getelementptr inbounds nuw i32, ptr [[DATA2]], i64 [[IV]]
+; SVE-NEXT:    [[LD2:%.*]] = load i32, ptr [[LD2_ADDR]], align 4
+; SVE-NEXT:    [[SELECT_CMP2:%.*]] = icmp sgt i32 [[B]], [[LD2]]
+; SVE-NEXT:    [[SELECT_DATA]] = select i1 [[SELECT_CMP2]], i32 [[LD2]], i32 [[SELECT_LD1]]
+; SVE-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; SVE-NEXT:    [[EXIT_CMP:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; SVE-NEXT:    br i1 [[EXIT_CMP]], label %[[EXIT:.*]], label %[[LOOP]]
+; SVE:       [[EXIT]]:
+; SVE-NEXT:    ret i32 [[SELECT_DATA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %data.phi = phi i32 [ -1, %entry ], [ %select.data, %loop ]
+  %ld1.addr = getelementptr inbounds i32, ptr %data1, i64 %iv
+  %ld1 = load i32, ptr %ld1.addr, align 4
+  %select.cmp1 = icmp slt i32 %a, %ld1
+  %select.ld1 = select i1 %select.cmp1, i32 %ld1, i32 %data.phi
+  %ld2.addr = getelementptr inbounds i32, ptr %data2, i64 %iv
+  %ld2 = load i32, ptr %ld2.addr, align 4
+  %select.cmp2 = icmp sgt i32 %b, %ld2
+  %select.data = select i1 %select.cmp2, i32 %ld2, i32 %select.ld1
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exit.cmp = icmp eq i64 %iv.next, %N
+  br i1 %exit.cmp, label %exit, label %loop
+
+exit:
+  ret i32 %select.data
+}
diff --git a/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll b/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll
new file mode 100644
index 0000000000000..e802093fc7886
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll
@@ -0,0 +1,123 @@
+; RUN: opt -passes=loop-vectorize -debug-only=loop-vectorize \
+; RUN:   -scalable-vectorization=on -force-target-supports-scalable-vectors \
+; RUN:   -disable-output 2>&1 < %s | FileCheck %s
+
+
+; This function is derived from the following C program:
+; int simple_csa_int_select(int N, int *data, int a) {
+;   int t = -1;
+;   for (int i = 0; i < N; i++) {
+;     if (a < data[i])
+;       t = data[i];
+;   }
+;   return t;
+; }
+define i32 @simple_csa_int_select(i64 %N, ptr %data, i32 %a) {
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %data.phi = phi i32 [ -1, %entry ], [ %select.data, %loop ]
+  %ld.addr = getelementptr inbounds i32, ptr %data, i64 %iv
+  %ld = load i32, ptr %ld.addr, align 4
+  %select.cmp = icmp slt i32 %a, %ld
+  %select.data = select i1 %select.cmp, i32 %ld, i32 %data.phi
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exit.cmp = icmp eq i64 %iv.next, %N
+  br i1 %exit.cmp, label %exit, label %loop
+
+exit:
+  ret i32 %select.data
+}
+
+
+; CHECK: VPlan 'Initial VPlan for VF={vscale x 1},UF>=1' {
+; CHECK-NEXT: Live-in vp<%0> = VF
+; CHECK-NEXT: Live-in vp<%1> = VF * UF
+; CHECK-NEXT: Live-in vp<%2> = vector-trip-count
+; CHECK-NEXT: Live-in ir<%N> = original trip-count
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<entry>:
+; CHECK-NEXT: Successor(s): scalar.ph, vector.ph
+; CHECK-EMPTY:
+; CHECK-NEXT: vector.ph:
+; CHECK-NEXT: Successor(s): vector loop
+; CHECK-EMPTY:
+; CHECK-NEXT: <x1> vector loop: {
+; CHECK-NEXT:   vector.body:
+; CHECK-NEXT:     EMIT vp<%3> = CANONICAL-INDUCTION ir<0>, vp<%index.next>
+; CHECK-NEXT:     WIDEN-REDUCTION-PHI ir<%data.phi> = phi ir<-1>, vp<%9>
+; CHECK-NEXT:     LAST-ACTIVE-MASK-PHI vp<%4> = phi ir<false>, vp<%8>
+; CHECK-NEXT:     vp<%5> = SCALAR-STEPS vp<%3>, ir<1>, vp<%0>
+; CHECK-NEXT:     CLONE ir<%ld.addr> = getelementptr inbounds ir<%data>, vp<%5>
+; CHECK-NEXT:     vp<%6> = vector-pointer ir<%ld.addr>
+; CHECK-NEXT:     WIDEN ir<%ld> = load vp<%6>
+; CHECK-NEXT:     WIDEN ir<%select.cmp> = icmp slt ir<%a>, ir<%ld>
+; CHECK-NEXT:     EMIT vp<%7> = any-of ir<%select.cmp>
+; CHECK-NEXT:     EMIT vp<%8> = select vp<%7>, ir<%select.cmp>, vp<%4>
+; CHECK-NEXT:     EMIT vp<%9> = select vp<%7>, ir<%ld>, ir<%data.phi>
+; CHECK-NEXT:     EMIT vp<%index.next> = add nuw vp<%3>, vp<%1>
+; CHECK-NEXT:     EMIT branch-on-count vp<%index.next>, vp<%2>
+; CHECK-NEXT:   No successors
+; CHECK-NEXT: }
+; CHECK-NEXT: Successor(s): middle.block
+; CHECK-EMPTY:
+; CHECK-NEXT: middle.block:
+; CHECK-NEXT:   EMIT vp<%11> = extract-last-active vp<%9>, vp<%8>, ir<-1>
+; CHECK-NEXT:   EMIT vp<%cmp.n> = icmp eq ir<%N>, vp<%2>
+; CHECK-NEXT:   EMIT branch-on-cond vp<%cmp.n>
+; CHECK-NEXT: Successor(s): ir-bb<exit>, scalar.ph
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<exit>:
+; CHECK-NEXT:   IR   %select.data.lcssa = phi i32 [ %select.data, %loop ] (extra operand: vp<%11> from middle.block)
+; CHECK-NEXT: No successors
+; CHECK-EMPTY:
+; CHECK-NEXT: scalar.ph:
+; CHECK-NEXT:   EMIT-SCALAR vp<%bc.resume.val> = phi [ vp<%2>, middle.block ], [ ir<0>, ir-bb<entry> ]
+; CHECK-NEXT:   EMIT-SCALAR vp<%bc.merge.rdx> = phi [ vp<%11>, middle.block ], [ ir<-1>, ir-bb<entry> ]
+; CHECK-NEXT: Successor(s): ir-bb<loop>
+; CHECK-EMPTY:
+; CHECK-NEXT: ir-bb<loop>:
+; CHECK-NEXT:   IR   %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ] (extra operand: vp<%bc.resume.val> from scalar.ph)
+; CHECK-NEXT:   IR   %data.phi = phi i32 [ -1, %entry ], [ %select.data, %loop ] (extra operand: vp<%bc.merge.rdx> from scalar.ph)
+; CHECK-NEXT:   IR   %ld.addr = getelementptr inbounds i32, ptr %data, i64 %iv
+; CHECK-NEXT:   IR   %ld = load i32, ptr %ld.addr, align 4
+; CHECK-NEXT:   IR   %select.cmp = icmp slt i32 %a, %ld
+; CHECK-NEXT:   IR   %select.data = select i1 %select.cmp, i32 %ld, i32 %data.phi
+; CHECK-NEXT:   IR   %iv.next = add nuw nsw i64 %iv, 1
+; CHECK-NEXT:   IR   %exit.cmp = icmp eq i64 %iv.next, %N
+; CHECK-NEXT: No successors
+; CHECK-NEXT: }
+
+; CHECK: Cost of 1 for VF vscale x 1: induction instruction   %iv.next = add nuw nsw i64 %iv, 1
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: induction instruction   %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: exit condition instruction   %exit.cmp = icmp eq i64 %iv.next, %N
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<%3> = CANONICAL-INDUCTION ir<0>, vp<%index.next>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN-REDUCTION-PHI ir<%data.phi> = phi ir<-1>, vp<%9>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: LAST-ACTIVE-MASK-PHI vp<%4> = phi ir<false>, vp<%8>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: vp<%5> = SCALAR-STEPS vp<%3>, ir<1>, vp<%0>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: CLONE ir<%ld.addr> = getelementptr inbounds ir<%data>, vp<%5>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: vp<%6> = vector-pointer ir<%ld.addr>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN ir<%ld> = load vp<%6>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN ir<%select.cmp> = icmp slt ir<%a>, ir<%ld>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<%7> = any-of ir<%select.cmp>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<%8> = select vp<%7>, ir<%select.cmp>, vp<%4>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<%9> = select vp<%7>, ir<%ld>, ir<%data.phi>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<%index.next> = add nuw vp<%3>, vp<%1>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT branch-on-count vp<%index.next>, vp<%2>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: vector loop backedge
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT-SCALAR vp<%bc.resume.val> = phi [ vp<%2>, middle.block ], [ ir<0>, ir-bb<entry> ]
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT-SCALAR vp<%bc.merge.rdx> = phi [ vp<%11>, middle.block ], [ ir<-1>, ir-bb<entry> ]
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ] (extra operand: vp<%bc.resume.val> from scalar.ph)
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %data.phi = phi i32 [ -1, %entry ], [ %select.data, %loop ] (extra operand: vp<%bc.merge.rdx> from scalar.ph)
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %ld.addr = getelementptr inbounds i32, ptr %data, i64 %iv
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %ld = load i32, ptr %ld.addr, align 4
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %select.cmp = icmp slt i32 %a, %ld
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %select.data = select i1 %select.cmp, i32 %ld, i32 %data.phi
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %iv.next = add nuw nsw i64 %iv, 1
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %exit.cmp = icmp eq i64 %iv.next, %N
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<%11> = extract-last-active vp<%9>, vp<%8>, ir<-1>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<%cmp.n> = icmp eq ir<%N>, vp<%2>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT branch-on-cond vp<%cmp.n>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %select.data.lcssa = phi i32 [ %select.data, %loop ] (extra operand: vp<%11> from middle.block)
diff --git a/llvm/test/Transforms/LoopVectorize/iv-select-cmp-decreasing.ll b/llvm/test/Transforms/LoopVectorize/iv-select-cmp-decreasing.ll
index 70b1ea13677b8..98fe48f4509f0 100644
--- a/llvm/test/Transforms/LoopVectorize/iv-select-cmp-decreasing.ll
+++ b/llvm/test/Transforms/LoopVectorize/iv-select-cmp-decreasing.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 5
-; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S < %s | FileCheck --check-prefixes=CHECK,IC1VF4 %s
-; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=4 -S < %s | FileCheck --check-prefixes=CHECK,IC4VF4 %s
-; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=1 -S < %s | FileCheck --check-prefixes=CHECK,IC4VF1 %s
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S < %s | FileCheck --check-prefix=IC1VF4 %s
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=4 -S < %s | FileCheck --check-prefix=IC4VF4 %s
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=1 -S < %s | FileCheck --check-prefix=IC4VF1 %s
 
 define i64 @select_decreasing_induction_icmp_const_start(ptr %a) {
 ; IC1VF4-LABEL: define i64 @select_decreasing_induction_icmp_const_start(
@@ -961,29 +961,142 @@ exit:                                             ; preds = %loop
 }
 
 ; The unsigned sentinel value for decreasing-IV vectorization is ULONG_MAX,
-; and since the IV hits this value, it is impossible to vectorize this case.
+; and since the IV hits this value, it cannot be vectorized as a FindLastIV
+; reduction. Instead, it is recognized and vectorized as a generic FindLast.
 ; In this test, %iv's range will include both signed and unsigned
 ; maximum (sentinel) values.
-define i64 @not_vectorized_select_decreasing_induction_icmp_iv_out_of_bound(ptr %a, ptr %b, i64 %rdx.start) {
-; CHECK-LABEL: define i64 @not_vectorized_select_decreasing_induction_icmp_iv_out_of_bound(
-; CHECK-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]]) {
-; CHECK-NEXT:  [[ENTRY:.*]]:
-; CHECK-NEXT:    br label %[[LOOP:.*]]
-; CHECK:       [[LOOP]]:
-; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ -1, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
-; CHECK-NEXT:    [[RDX:%.*]] = phi i64 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND:%.*]], %[[LOOP]] ]
-; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], -1
-; CHECK-NEXT:    [[GEP_A_IV:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[IV_NEXT]]
-; CHECK-NEXT:    [[LD_A:%.*]] = load i8, ptr [[GEP_A_IV]], align 1
-; CHECK-NEXT:    [[GEP_B_IV:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 [[IV_NEXT]]
-; CHECK-NEXT:    [[LD_B:%.*]] = load i8, ptr [[GEP_B_IV]], align 1
-; CHECK-NEXT:    [[CMP_A_B:%.*]] = icmp sgt i8 [[LD_A]], [[LD_B]]
-; CHECK-NEXT:    [[COND]] = select i1 [[CMP_A_B]], i64 [[IV_NEXT]], i64 [[RDX]]
-; CHECK-NEXT:    [[EXIT_COND:%.*]] = icmp eq i64 [[IV_NEXT]], 0
-; CHECK-NEXT:    br i1 [[EXIT_COND]], label %[[EXIT:.*]], label %[[LOOP]]
-; CHECK:       [[EXIT]]:
-; CHECK-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[LOOP]] ]
-; CHECK-NEXT:    ret i64 [[COND_LCSSA]]
+define i64 @select_decreasing_induction_icmp_iv_out_of_bound(ptr %a, ptr %b, i64 %rdx.start) {
+; IC1VF4-LABEL: define i64 @select_decreasing_induction_icmp_iv_out_of_bound(
+; IC1VF4-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]]) {
+; IC1VF4-NEXT:  [[ENTRY:.*:]]
+; IC1VF4-NEXT:    br label %[[VECTOR_PH:.*]]
+; IC1VF4:       [[VECTOR_PH]]:
+; IC1VF4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; IC1VF4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; IC1VF4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IC1VF4:       [[VECTOR_BODY]]:
+; IC1VF4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IC1VF4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 -1, i64 -2, i64 -3, i64 -4>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IC1VF4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP12:%.*]], %[[VECTOR_BODY]] ]
+; IC1VF4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP11:%.*]], %[[VECTOR_BODY]] ]
+; IC1VF4-NEXT:    [[TMP0:%.*]] = add <4 x i64> [[VEC_IND]], splat (i64 -1)
+; IC1VF4-NEXT:    [[TMP1:%.*]] = extractelement <4 x i64> [[TMP0]], i32 0
+; IC1VF4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[TMP1]]
+; IC1VF4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
+; IC1VF4-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i8, ptr [[TMP3]], i32 -3
+; IC1VF4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP4]], align 1
+; IC1VF4-NEXT:    [[REVERSE:%.*]] = shufflevector <4 x i8> [[WIDE_LOAD]], <4 x i8> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; IC1VF4-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 [[TMP1]]
+; IC1VF4-NEXT:    [[TMP6:%.*]] = getelementptr inbounds i8, ptr [[TMP5]], i32 0
+; IC1VF4-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i8, ptr [[TMP6]], i32 -3
+; IC1VF4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i8>, ptr [[TMP7]], align 1
+; IC1VF4-NEXT:    [[REVERSE2:%.*]] = shufflevector <4 x i8> [[WIDE_LOAD1]], <4 x i8> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; IC1VF4-NEXT:    [[TMP8:%.*]] = icmp sgt <4 x i8> [[REVERSE]], [[REVERSE2]]
+; IC1VF4-NEXT:    [[TMP9:%.*]] = freeze <4 x i1> [[TMP8]]
+; IC1VF4-NEXT:    [[TMP10:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP9]])
+; IC1VF4-NEXT:    [[TMP11]] = select i1 [[TMP10]], <4 x i1> [[TMP8]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; IC1VF4-NEXT:    [[TMP12]] = select i1 [[TMP10]], <4 x i64> [[TMP0]], <4 x i64> [[VEC_PHI]]
+; IC1VF4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; IC1VF4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 -4)
+; IC1VF4-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[INDEX_NEXT]], -4
+; IC1VF4-NEXT:    br i1 [[TMP13]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; IC1VF4:       [[MIDDLE_BLOCK]]:
+; IC1VF4-NEXT:    [[TMP14:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; IC1VF4-NEXT:    [[TMP15:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP12]], <4 x i1> [[TMP11]], i64 [[TMP14]])
+; IC1VF4-NEXT:    br label %[[SCALAR_PH:.*]]
+; IC1VF4:       [[SCALAR_PH]]:
+; IC1VF4-NEXT:    br label %[[LOOP:.*]]
+; IC1VF4:       [[LOOP]]:
+; IC1VF4-NEXT:    [[IV:%.*]] = phi i64 [ 3, %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; IC1VF4-NEXT:    [[RDX:%.*]] = phi i64 [ [[TMP15]], %[[SCALAR_PH]] ], [ [[COND:%.*]], %[[LOOP]] ]
+; IC1VF4-NEXT:    [[IV_NEXT]] = add i64 [[IV]], -1
+; IC1VF4-NEXT:    [[GEP_A_IV:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[IV_NEXT]]
+; IC1VF4-NEXT:    [[LD_A:%.*]] = load i8, ptr [[GEP_A_IV]], align 1
+; IC1VF4-NEXT:    [[GEP_B_IV:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 [[IV_NEXT]]
+; IC1VF4-NEXT:    [[LD_B:%.*]] = load i8, ptr [[GEP_B_IV]], align 1
+; IC1VF4-NEXT:    [[CMP_A_B:%.*]] = icmp sgt i8 [[LD_A]], [[LD_B]]
+; IC1VF4-NEXT:    [[COND]] = select i1 [[CMP_A_B]], i64 [[IV_NEXT]], i64 [[RDX]]
+; IC1VF4-NEXT:    [[EXIT_COND:%.*]] = icmp eq i64 [[IV_NEXT]], 0
+; IC1VF4-NEXT:    br i1 [[EXIT_COND]], label %[[EXIT:.*]], label %[[LOOP]], !llvm.loop [[LOOP7:![0-9]+]]
+; IC1VF4:       [[EXIT]]:
+; IC1VF4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[LOOP]] ]
+; IC1VF4-NEXT:    ret i64 [[COND_LCSSA]]
+;
+; IC4VF4-LABEL: define i64 @select_decreasing_induction_icmp_iv_out_of_bound(
+; IC4VF4-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]]) {
+; IC4VF4-NEXT:  [[ENTRY:.*:]]
+; IC4VF4-NEXT:    br label %[[VECTOR_PH:.*]]
+; IC4VF4:       [[VECTOR_PH]]:
+; IC4VF4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; IC4VF4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; IC4VF4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IC4VF4:       [[VECTOR_BODY]]:
+; IC4VF4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IC4VF4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 -1, i64 -2, i64 -3, i64 -4>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IC4VF4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP12:%.*]], %[[VECTOR_BODY]] ]
+; IC4VF4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP11:%.*]], %[[VECTOR_BODY]] ]
+; IC4VF4-NEXT:    [[TMP0:%.*]] = add <4 x i64> [[VEC_IND]], splat (i64 -1)
+; IC4VF4-NEXT:    [[TMP1:%.*]] = extractelement <4 x i64> [[TMP0]], i32 0
+; IC4VF4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[TMP1]]
+; IC4VF4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
+; IC4VF4-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i8, ptr [[TMP3]], i32 -3
+; IC4VF4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP4]], align 1
+; IC4VF4-NEXT:    [[REVERSE:%.*]] = shufflevector <4 x i8> [[WIDE_LOAD]], <4 x i8> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; IC4VF4-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 [[TMP1]]
+; IC4VF4-NEXT:    [[TMP6:%.*]] = getelementptr inbounds i8, ptr [[TMP5]], i32 0
+; IC4VF4-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i8, ptr [[TMP6]], i32 -3
+; IC4VF4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i8>, ptr [[TMP7]], align 1
+; IC4VF4-NEXT:    [[REVERSE2:%.*]] = shufflevector <4 x i8> [[WIDE_LOAD1]], <4 x i8> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; IC4VF4-NEXT:    [[TMP8:%.*]] = icmp sgt <4 x i8> [[REVERSE]], [[REVERSE2]]
+; IC4VF4-NEXT:    [[TMP9:%.*]] = freeze <4 x i1> [[TMP8]]
+; IC4VF4-NEXT:    [[TMP10:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP9]])
+; IC4VF4-NEXT:    [[TMP11]] = select i1 [[TMP10]], <4 x i1> [[TMP8]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; IC4VF4-NEXT:    [[TMP12]] = select i1 [[TMP10]], <4 x i64> [[TMP0]], <4 x i64> [[VEC_PHI]]
+; IC4VF4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; IC4VF4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 -4)
+; IC4VF4-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[INDEX_NEXT]], -4
+; IC4VF4-NEXT:    br i1 [[TMP13]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; IC4VF4:       [[MIDDLE_BLOCK]]:
+; IC4VF4-NEXT:    [[TMP14:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; IC4VF4-NEXT:    [[TMP15:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP12]], <4 x i1> [[TMP11]], i64 [[TMP14]])
+; IC4VF4-NEXT:    br label %[[SCALAR_PH:.*]]
+; IC4VF4:       [[SCALAR_PH]]:
+; IC4VF4-NEXT:    br label %[[LOOP:.*]]
+; IC4VF4:       [[LOOP]]:
+; IC4VF4-NEXT:    [[IV:%.*]] = phi i64 [ 3, %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; IC4VF4-NEXT:    [[RDX:%.*]] = phi i64 [ [[TMP15]], %[[SCALAR_PH]] ], [ [[COND:%.*]], %[[LOOP]] ]
+; IC4VF4-NEXT:    [[IV_NEXT]] = add i64 [[IV]], -1
+; IC4VF4-NEXT:    [[GEP_A_IV:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[IV_NEXT]]
+; IC4VF4-NEXT:    [[LD_A:%.*]] = load i8, ptr [[GEP_A_IV]], align 1
+; IC4VF4-NEXT:    [[GEP_B_IV:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 [[IV_NEXT]]
+; IC4VF4-NEXT:    [[LD_B:%.*]] = load i8, ptr [[GEP_B_IV]], align 1
+; IC4VF4-NEXT:    [[CMP_A_B:%.*]] = icmp sgt i8 [[LD_A]], [[LD_B]]
+; IC4VF4-NEXT:    [[COND]] = select i1 [[CMP_A_B]], i64 [[IV_NEXT]], i64 [[RDX]]
+; IC4VF4-NEXT:    [[EXIT_COND:%.*]] = icmp eq i64 [[IV_NEXT]], 0
+; IC4VF4-NEXT:    br i1 [[EXIT_COND]], label %[[EXIT:.*]], label %[[LOOP]], !llvm.loop [[LOOP7:![0-9]+]]
+; IC4VF4:       [[EXIT]]:
+; IC4VF4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[LOOP]] ]
+; IC4VF4-NEXT:    ret i64 [[COND_LCSSA]]
+;
+; IC4VF1-LABEL: define i64 @select_decreasing_induction_icmp_iv_out_of_bound(
+; IC4VF1-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]]) {
+; IC4VF1-NEXT:  [[ENTRY:.*]]:
+; IC4VF1-NEXT:    br label %[[LOOP:.*]]
+; IC4VF1:       [[LOOP]]:
+; IC4VF1-NEXT:    [[IV:%.*]] = phi i64 [ -1, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; IC4VF1-NEXT:    [[RDX:%.*]] = phi i64 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND:%.*]], %[[LOOP]] ]
+; IC4VF1-NEXT:    [[IV_NEXT]] = add i64 [[IV]], -1
+; IC4VF1-NEXT:    [[GEP_A_IV:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 [[IV_NEXT]]
+; IC4VF1-NEXT:    [[LD_A:%.*]] = load i8, ptr [[GEP_A_IV]], align 1
+; IC4VF1-NEXT:    [[GEP_B_IV:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 [[IV_NEXT]]
+; IC4VF1-NEXT:    [[LD_B:%.*]] = load i8, ptr [[GEP_B_IV]], align 1
+; IC4VF1-NEXT:    [[CMP_A_B:%.*]] = icmp sgt i8 [[LD_A]], [[LD_B]]
+; IC4VF1-NEXT:    [[COND]] = select i1 [[CMP_A_B]], i64 [[IV_NEXT]], i64 [[RDX]]
+; IC4VF1-NEXT:    [[EXIT_COND:%.*]] = icmp eq i64 [[IV_NEXT]], 0
+; IC4VF1-NEXT:    br i1 [[EXIT_COND]], label %[[EXIT:.*]], label %[[LOOP]]
+; IC4VF1:       [[EXIT]]:
+; IC4VF1-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[LOOP]] ]
+; IC4VF1-NEXT:    ret i64 [[COND_LCSSA]]
 ;
 entry:
   br label %loop
@@ -1005,26 +1118,164 @@ exit:
   ret i64 %cond
 }
 
-define i64 @not_vectorized_select_decreasing_induction_icmp_non_const_start(ptr %a, ptr %b, i64 %rdx.start, i64 %n) {
-; CHECK-LABEL: define i64 @not_vectorized_select_decreasing_induction_icmp_non_const_start(
-; CHECK-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]], i64 [[N:%.*]]) {
-; CHECK-NEXT:  [[ENTRY:.*]]:
-; CHECK-NEXT:    br label %[[LOOP:.*]]
-; CHECK:       [[LOOP]]:
-; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[LOOP]] ], [ [[N]], %[[ENTRY]] ]
-; CHECK-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[LOOP]] ], [ [[RDX_START]], %[[ENTRY]] ]
-; CHECK-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], -1
-; CHECK-NEXT:    [[GEP_A_IV:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV_NEXT]]
-; CHECK-NEXT:    [[LD_A:%.*]] = load i64, ptr [[GEP_A_IV]], align 8
-; CHECK-NEXT:    [[GEP_B_IV:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV_NEXT]]
-; CHECK-NEXT:    [[LD_B:%.*]] = load i64, ptr [[GEP_B_IV]], align 8
-; CHECK-NEXT:    [[CMP_A_B:%.*]] = icmp sgt i64 [[LD_A]], [[LD_B]]
-; CHECK-NEXT:    [[COND]] = select i1 [[CMP_A_B]], i64 [[IV_NEXT]], i64 [[RDX]]
-; CHECK-NEXT:    [[EXIT_COND:%.*]] = icmp ugt i64 [[IV]], 1
-; CHECK-NEXT:    br i1 [[EXIT_COND]], label %[[LOOP]], label %[[EXIT:.*]]
-; CHECK:       [[EXIT]]:
-; CHECK-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[LOOP]] ]
-; CHECK-NEXT:    ret i64 [[COND_LCSSA]]
+define i64 @select_decreasing_induction_icmp_non_const_start(ptr %a, ptr %b, i64 %rdx.start, i64 %n) {
+; IC1VF4-LABEL: define i64 @select_decreasing_induction_icmp_non_const_start(
+; IC1VF4-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]], i64 [[N:%.*]]) {
+; IC1VF4-NEXT:  [[ENTRY:.*]]:
+; IC1VF4-NEXT:    [[TMP0:%.*]] = add i64 [[N]], 1
+; IC1VF4-NEXT:    [[UMIN:%.*]] = call i64 @llvm.umin.i64(i64 [[N]], i64 1)
+; IC1VF4-NEXT:    [[TMP1:%.*]] = sub i64 [[TMP0]], [[UMIN]]
+; IC1VF4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP1]], 4
+; IC1VF4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; IC1VF4:       [[VECTOR_PH]]:
+; IC1VF4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP1]], 4
+; IC1VF4-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP1]], [[N_MOD_VF]]
+; IC1VF4-NEXT:    [[TMP2:%.*]] = sub i64 [[N]], [[N_VEC]]
+; IC1VF4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; IC1VF4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; IC1VF4-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i64> poison, i64 [[N]], i64 0
+; IC1VF4-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT1]], <4 x i64> poison, <4 x i32> zeroinitializer
+; IC1VF4-NEXT:    [[INDUCTION:%.*]] = add <4 x i64> [[BROADCAST_SPLAT2]], <i64 0, i64 -1, i64 -2, i64 -3>
+; IC1VF4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IC1VF4:       [[VECTOR_BODY]]:
+; IC1VF4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IC1VF4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IC1VF4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP15:%.*]], %[[VECTOR_BODY]] ]
+; IC1VF4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP14:%.*]], %[[VECTOR_BODY]] ]
+; IC1VF4-NEXT:    [[TMP3:%.*]] = add nsw <4 x i64> [[VEC_IND]], splat (i64 -1)
+; IC1VF4-NEXT:    [[TMP4:%.*]] = extractelement <4 x i64> [[TMP3]], i32 0
+; IC1VF4-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[TMP4]]
+; IC1VF4-NEXT:    [[TMP6:%.*]] = getelementptr inbounds i64, ptr [[TMP5]], i32 0
+; IC1VF4-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i64, ptr [[TMP6]], i32 -3
+; IC1VF4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP7]], align 8
+; IC1VF4-NEXT:    [[REVERSE:%.*]] = shufflevector <4 x i64> [[WIDE_LOAD]], <4 x i64> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; IC1VF4-NEXT:    [[TMP8:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[TMP4]]
+; IC1VF4-NEXT:    [[TMP9:%.*]] = getelementptr inbounds i64, ptr [[TMP8]], i32 0
+; IC1VF4-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i64, ptr [[TMP9]], i32 -3
+; IC1VF4-NEXT:    [[WIDE_LOAD3:%.*]] = load <4 x i64>, ptr [[TMP10]], align 8
+; IC1VF4-NEXT:    [[REVERSE4:%.*]] = shufflevector <4 x i64> [[WIDE_LOAD3]], <4 x i64> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; IC1VF4-NEXT:    [[TMP11:%.*]] = icmp sgt <4 x i64> [[REVERSE]], [[REVERSE4]]
+; IC1VF4-NEXT:    [[TMP12:%.*]] = freeze <4 x i1> [[TMP11]]
+; IC1VF4-NEXT:    [[TMP13:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP12]])
+; IC1VF4-NEXT:    [[TMP14]] = select i1 [[TMP13]], <4 x i1> [[TMP11]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; IC1VF4-NEXT:    [[TMP15]] = select i1 [[TMP13]], <4 x i64> [[TMP3]], <4 x i64> [[VEC_PHI]]
+; IC1VF4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; IC1VF4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 -4)
+; IC1VF4-NEXT:    [[TMP16:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; IC1VF4-NEXT:    br i1 [[TMP16]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; IC1VF4:       [[MIDDLE_BLOCK]]:
+; IC1VF4-NEXT:    [[TMP17:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; IC1VF4-NEXT:    [[TMP18:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP15]], <4 x i1> [[TMP14]], i64 [[TMP17]])
+; IC1VF4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP1]], [[N_VEC]]
+; IC1VF4-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; IC1VF4:       [[SCALAR_PH]]:
+; IC1VF4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP2]], %[[MIDDLE_BLOCK]] ], [ [[N]], %[[ENTRY]] ]
+; IC1VF4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP18]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[ENTRY]] ]
+; IC1VF4-NEXT:    br label %[[LOOP:.*]]
+; IC1VF4:       [[LOOP]]:
+; IC1VF4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[LOOP]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; IC1VF4-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[LOOP]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
+; IC1VF4-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], -1
+; IC1VF4-NEXT:    [[GEP_A_IV:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV_NEXT]]
+; IC1VF4-NEXT:    [[LD_A:%.*]] = load i64, ptr [[GEP_A_IV]], align 8
+; IC1VF4-NEXT:    [[GEP_B_IV:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV_NEXT]]
+; IC1VF4-NEXT:    [[LD_B:%.*]] = load i64, ptr [[GEP_B_IV]], align 8
+; IC1VF4-NEXT:    [[CMP_A_B:%.*]] = icmp sgt i64 [[LD_A]], [[LD_B]]
+; IC1VF4-NEXT:    [[COND]] = select i1 [[CMP_A_B]], i64 [[IV_NEXT]], i64 [[RDX]]
+; IC1VF4-NEXT:    [[EXIT_COND:%.*]] = icmp ugt i64 [[IV]], 1
+; IC1VF4-NEXT:    br i1 [[EXIT_COND]], label %[[LOOP]], label %[[EXIT]], !llvm.loop [[LOOP9:![0-9]+]]
+; IC1VF4:       [[EXIT]]:
+; IC1VF4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[LOOP]] ], [ [[TMP18]], %[[MIDDLE_BLOCK]] ]
+; IC1VF4-NEXT:    ret i64 [[COND_LCSSA]]
+;
+; IC4VF4-LABEL: define i64 @select_decreasing_induction_icmp_non_const_start(
+; IC4VF4-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]], i64 [[N:%.*]]) {
+; IC4VF4-NEXT:  [[ENTRY:.*]]:
+; IC4VF4-NEXT:    [[TMP0:%.*]] = add i64 [[N]], 1
+; IC4VF4-NEXT:    [[UMIN:%.*]] = call i64 @llvm.umin.i64(i64 [[N]], i64 1)
+; IC4VF4-NEXT:    [[TMP1:%.*]] = sub i64 [[TMP0]], [[UMIN]]
+; IC4VF4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP1]], 4
+; IC4VF4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; IC4VF4:       [[VECTOR_PH]]:
+; IC4VF4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP1]], 4
+; IC4VF4-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP1]], [[N_MOD_VF]]
+; IC4VF4-NEXT:    [[TMP2:%.*]] = sub i64 [[N]], [[N_VEC]]
+; IC4VF4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; IC4VF4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; IC4VF4-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i64> poison, i64 [[N]], i64 0
+; IC4VF4-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT1]], <4 x i64> poison, <4 x i32> zeroinitializer
+; IC4VF4-NEXT:    [[INDUCTION:%.*]] = add <4 x i64> [[BROADCAST_SPLAT2]], <i64 0, i64 -1, i64 -2, i64 -3>
+; IC4VF4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IC4VF4:       [[VECTOR_BODY]]:
+; IC4VF4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IC4VF4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IC4VF4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP15:%.*]], %[[VECTOR_BODY]] ]
+; IC4VF4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP14:%.*]], %[[VECTOR_BODY]] ]
+; IC4VF4-NEXT:    [[TMP3:%.*]] = add nsw <4 x i64> [[VEC_IND]], splat (i64 -1)
+; IC4VF4-NEXT:    [[TMP4:%.*]] = extractelement <4 x i64> [[TMP3]], i32 0
+; IC4VF4-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[TMP4]]
+; IC4VF4-NEXT:    [[TMP6:%.*]] = getelementptr inbounds i64, ptr [[TMP5]], i32 0
+; IC4VF4-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i64, ptr [[TMP6]], i32 -3
+; IC4VF4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP7]], align 8
+; IC4VF4-NEXT:    [[REVERSE:%.*]] = shufflevector <4 x i64> [[WIDE_LOAD]], <4 x i64> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; IC4VF4-NEXT:    [[TMP8:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[TMP4]]
+; IC4VF4-NEXT:    [[TMP9:%.*]] = getelementptr inbounds i64, ptr [[TMP8]], i32 0
+; IC4VF4-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i64, ptr [[TMP9]], i32 -3
+; IC4VF4-NEXT:    [[WIDE_LOAD3:%.*]] = load <4 x i64>, ptr [[TMP10]], align 8
+; IC4VF4-NEXT:    [[REVERSE4:%.*]] = shufflevector <4 x i64> [[WIDE_LOAD3]], <4 x i64> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; IC4VF4-NEXT:    [[TMP11:%.*]] = icmp sgt <4 x i64> [[REVERSE]], [[REVERSE4]]
+; IC4VF4-NEXT:    [[TMP12:%.*]] = freeze <4 x i1> [[TMP11]]
+; IC4VF4-NEXT:    [[TMP13:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP12]])
+; IC4VF4-NEXT:    [[TMP14]] = select i1 [[TMP13]], <4 x i1> [[TMP11]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; IC4VF4-NEXT:    [[TMP15]] = select i1 [[TMP13]], <4 x i64> [[TMP3]], <4 x i64> [[VEC_PHI]]
+; IC4VF4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; IC4VF4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 -4)
+; IC4VF4-NEXT:    [[TMP16:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; IC4VF4-NEXT:    br i1 [[TMP16]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; IC4VF4:       [[MIDDLE_BLOCK]]:
+; IC4VF4-NEXT:    [[TMP17:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; IC4VF4-NEXT:    [[TMP18:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP15]], <4 x i1> [[TMP14]], i64 [[TMP17]])
+; IC4VF4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP1]], [[N_VEC]]
+; IC4VF4-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; IC4VF4:       [[SCALAR_PH]]:
+; IC4VF4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP2]], %[[MIDDLE_BLOCK]] ], [ [[N]], %[[ENTRY]] ]
+; IC4VF4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP18]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[ENTRY]] ]
+; IC4VF4-NEXT:    br label %[[LOOP:.*]]
+; IC4VF4:       [[LOOP]]:
+; IC4VF4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[LOOP]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; IC4VF4-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[LOOP]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
+; IC4VF4-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], -1
+; IC4VF4-NEXT:    [[GEP_A_IV:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV_NEXT]]
+; IC4VF4-NEXT:    [[LD_A:%.*]] = load i64, ptr [[GEP_A_IV]], align 8
+; IC4VF4-NEXT:    [[GEP_B_IV:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV_NEXT]]
+; IC4VF4-NEXT:    [[LD_B:%.*]] = load i64, ptr [[GEP_B_IV]], align 8
+; IC4VF4-NEXT:    [[CMP_A_B:%.*]] = icmp sgt i64 [[LD_A]], [[LD_B]]
+; IC4VF4-NEXT:    [[COND]] = select i1 [[CMP_A_B]], i64 [[IV_NEXT]], i64 [[RDX]]
+; IC4VF4-NEXT:    [[EXIT_COND:%.*]] = icmp ugt i64 [[IV]], 1
+; IC4VF4-NEXT:    br i1 [[EXIT_COND]], label %[[LOOP]], label %[[EXIT]], !llvm.loop [[LOOP9:![0-9]+]]
+; IC4VF4:       [[EXIT]]:
+; IC4VF4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[LOOP]] ], [ [[TMP18]], %[[MIDDLE_BLOCK]] ]
+; IC4VF4-NEXT:    ret i64 [[COND_LCSSA]]
+;
+; IC4VF1-LABEL: define i64 @select_decreasing_induction_icmp_non_const_start(
+; IC4VF1-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]], i64 [[N:%.*]]) {
+; IC4VF1-NEXT:  [[ENTRY:.*]]:
+; IC4VF1-NEXT:    br label %[[LOOP:.*]]
+; IC4VF1:       [[LOOP]]:
+; IC4VF1-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[LOOP]] ], [ [[N]], %[[ENTRY]] ]
+; IC4VF1-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[LOOP]] ], [ [[RDX_START]], %[[ENTRY]] ]
+; IC4VF1-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], -1
+; IC4VF1-NEXT:    [[GEP_A_IV:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV_NEXT]]
+; IC4VF1-NEXT:    [[LD_A:%.*]] = load i64, ptr [[GEP_A_IV]], align 8
+; IC4VF1-NEXT:    [[GEP_B_IV:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV_NEXT]]
+; IC4VF1-NEXT:    [[LD_B:%.*]] = load i64, ptr [[GEP_B_IV]], align 8
+; IC4VF1-NEXT:    [[CMP_A_B:%.*]] = icmp sgt i64 [[LD_A]], [[LD_B]]
+; IC4VF1-NEXT:    [[COND]] = select i1 [[CMP_A_B]], i64 [[IV_NEXT]], i64 [[RDX]]
+; IC4VF1-NEXT:    [[EXIT_COND:%.*]] = icmp ugt i64 [[IV]], 1
+; IC4VF1-NEXT:    br i1 [[EXIT_COND]], label %[[LOOP]], label %[[EXIT:.*]]
+; IC4VF1:       [[EXIT]]:
+; IC4VF1-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[LOOP]] ]
+; IC4VF1-NEXT:    ret i64 [[COND_LCSSA]]
 ;
 entry:
   br label %loop
diff --git a/llvm/test/Transforms/LoopVectorize/iv-select-cmp-no-wrap.ll b/llvm/test/Transforms/LoopVectorize/iv-select-cmp-no-wrap.ll
index c958ea7b9b88e..6da4869e1fe78 100644
--- a/llvm/test/Transforms/LoopVectorize/iv-select-cmp-no-wrap.ll
+++ b/llvm/test/Transforms/LoopVectorize/iv-select-cmp-no-wrap.ll
@@ -145,10 +145,44 @@ define i64 @select_icmp_nuw(ptr %a, ptr %b, i64 %ii, i64 %n) {
 ; CHECK-LABEL: define i64 @select_icmp_nuw(
 ; CHECK-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[II:%.*]], i64 [[N:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], 4
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[II]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 0, i64 1, i64 2, i64 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX]]
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP10]], align 8
+; CHECK-NEXT:    [[TMP11:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[INDEX]]
+; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i64>, ptr [[TMP11]], align 8
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp sgt <4 x i64> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-NEXT:    [[TMP3:%.*]] = freeze <4 x i1> [[TMP2]]
+; CHECK-NEXT:    [[TMP4:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP3]])
+; CHECK-NEXT:    [[TMP5]] = select i1 [[TMP4]], <4 x i1> [[TMP2]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-NEXT:    [[TMP6]] = select i1 [[TMP4]], <4 x i64> [[VEC_IND]], <4 x i64> [[VEC_PHI]]
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
+; CHECK-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; CHECK-NEXT:    [[TMP9:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP6]], <4 x i1> [[TMP5]], i64 [[TMP8]])
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP9]], %[[MIDDLE_BLOCK]] ], [ [[II]], %[[ENTRY]] ]
 ; CHECK-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK:       [[FOR_BODY]]:
-; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ 0, %[[ENTRY]] ]
-; CHECK-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[II]], %[[ENTRY]] ]
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
 ; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV]]
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i64, ptr [[ARRAYIDX]], align 8
 ; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV]]
@@ -157,9 +191,9 @@ define i64 @select_icmp_nuw(ptr %a, ptr %b, i64 %ii, i64 %n) {
 ; CHECK-NEXT:    [[COND]] = select i1 [[CMP2]], i64 [[IV]], i64 [[RDX]]
 ; CHECK-NEXT:    [[INC]] = add nuw i64 [[IV]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[N]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
 ; CHECK:       [[EXIT]]:
-; CHECK-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP9]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-NEXT:    ret i64 [[COND_LCSSA]]
 ;
 entry:
@@ -186,10 +220,44 @@ define i64 @select_icmp_noflag(ptr %a, ptr %b, i64 %ii, i64 %n) {
 ; CHECK-LABEL: define i64 @select_icmp_noflag(
 ; CHECK-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[II:%.*]], i64 [[N:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], 4
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[II]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 0, i64 1, i64 2, i64 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX]]
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP10]], align 8
+; CHECK-NEXT:    [[TMP11:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[INDEX]]
+; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i64>, ptr [[TMP11]], align 8
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp sgt <4 x i64> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-NEXT:    [[TMP3:%.*]] = freeze <4 x i1> [[TMP2]]
+; CHECK-NEXT:    [[TMP4:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP3]])
+; CHECK-NEXT:    [[TMP5]] = select i1 [[TMP4]], <4 x i1> [[TMP2]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-NEXT:    [[TMP6]] = select i1 [[TMP4]], <4 x i64> [[VEC_IND]], <4 x i64> [[VEC_PHI]]
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
+; CHECK-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; CHECK-NEXT:    [[TMP9:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP6]], <4 x i1> [[TMP5]], i64 [[TMP8]])
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP9]], %[[MIDDLE_BLOCK]] ], [ [[II]], %[[ENTRY]] ]
 ; CHECK-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK:       [[FOR_BODY]]:
-; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ 0, %[[ENTRY]] ]
-; CHECK-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[II]], %[[ENTRY]] ]
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
 ; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV]]
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i64, ptr [[ARRAYIDX]], align 8
 ; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV]]
@@ -198,9 +266,9 @@ define i64 @select_icmp_noflag(ptr %a, ptr %b, i64 %ii, i64 %n) {
 ; CHECK-NEXT:    [[COND]] = select i1 [[CMP2]], i64 [[IV]], i64 [[RDX]]
 ; CHECK-NEXT:    [[INC]] = add i64 [[IV]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[N]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
 ; CHECK:       [[EXIT]]:
-; CHECK-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP9]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-NEXT:    ret i64 [[COND_LCSSA]]
 ;
 entry:
@@ -229,4 +297,8 @@ exit:                                             ; preds = %for.body
 ; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META2]], [[META1]]}
 ; CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]], [[META2]]}
 ; CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[META2]], [[META1]]}
+; CHECK: [[LOOP6]] = distinct !{[[LOOP6]], [[META1]], [[META2]]}
+; CHECK: [[LOOP7]] = distinct !{[[LOOP7]], [[META2]], [[META1]]}
+; CHECK: [[LOOP8]] = distinct !{[[LOOP8]], [[META1]], [[META2]]}
+; CHECK: [[LOOP9]] = distinct !{[[LOOP9]], [[META2]], [[META1]]}
 ;.
diff --git a/llvm/test/Transforms/LoopVectorize/iv-select-cmp-non-const-iv-start.ll b/llvm/test/Transforms/LoopVectorize/iv-select-cmp-non-const-iv-start.ll
index 72ed6537ef640..7a89c32b197d3 100644
--- a/llvm/test/Transforms/LoopVectorize/iv-select-cmp-non-const-iv-start.ll
+++ b/llvm/test/Transforms/LoopVectorize/iv-select-cmp-non-const-iv-start.ll
@@ -1,32 +1,156 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK
-; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK
-; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=1 -S < %s | FileCheck %s --check-prefix=CHECK
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK-VF4IC1
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=4 -S < %s | FileCheck %s --check-prefix=CHECK-VF4IC4
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=4 -force-vector-width=1 -S < %s | FileCheck %s --check-prefix=CHECK-VF1IC4
 
 define i64 @select_non_const_iv_start_signed_guard(ptr %a, i64 %rdx_start, i64 %iv_start ,i64 %n) {
-; CHECK-LABEL: define i64 @select_non_const_iv_start_signed_guard(
-; CHECK-SAME: ptr [[A:%.*]], i64 [[RDX_START:%.*]], i64 [[IV_START:%.*]], i64 [[N:%.*]]) {
-; CHECK-NEXT:  [[ENTRY:.*]]:
-; CHECK-NEXT:    [[GUARD:%.*]] = icmp slt i64 [[IV_START]], [[N]]
-; CHECK-NEXT:    br i1 [[GUARD]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
-; CHECK:       [[FOR_BODY_PREHEADER]]:
-; CHECK-NEXT:    br label %[[FOR_BODY:.*]]
-; CHECK:       [[FOR_BODY]]:
-; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[FOR_BODY]] ], [ [[IV_START]], %[[FOR_BODY_PREHEADER]] ]
-; CHECK-NEXT:    [[RDX_07:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[RDX_START]], %[[FOR_BODY_PREHEADER]] ]
-; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV]]
-; CHECK-NEXT:    [[TMP0:%.*]] = load i64, ptr [[ARRAYIDX]], align 4
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i64 [[TMP0]], 3
-; CHECK-NEXT:    [[COND]] = select i1 [[CMP1]], i64 [[IV]], i64 [[RDX_07]]
-; CHECK-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], 1
-; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
-; CHECK:       [[EXIT_LOOPEXIT]]:
-; CHECK-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ]
-; CHECK-NEXT:    br label %[[EXIT]]
-; CHECK:       [[EXIT]]:
-; CHECK-NEXT:    [[IDX_0_LCSSA:%.*]] = phi i64 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
-; CHECK-NEXT:    ret i64 [[IDX_0_LCSSA]]
+; CHECK-VF4IC1-LABEL: define i64 @select_non_const_iv_start_signed_guard(
+; CHECK-VF4IC1-SAME: ptr [[A:%.*]], i64 [[RDX_START:%.*]], i64 [[IV_START:%.*]], i64 [[N:%.*]]) {
+; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC1-NEXT:    [[GUARD:%.*]] = icmp slt i64 [[IV_START]], [[N]]
+; CHECK-VF4IC1-NEXT:    br i1 [[GUARD]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
+; CHECK-VF4IC1:       [[FOR_BODY_PREHEADER]]:
+; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = sub i64 [[N]], [[IV_START]]
+; CHECK-VF4IC1-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP0]], 4
+; CHECK-VF4IC1-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP0]], 4
+; CHECK-VF4IC1-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP0]], [[N_MOD_VF]]
+; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = add i64 [[IV_START]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i64> poison, i64 [[IV_START]], i64 0
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT1]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC1-NEXT:    [[INDUCTION:%.*]] = add <4 x i64> [[BROADCAST_SPLAT2]], <i64 0, i64 1, i64 2, i64 3>
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP7:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[OFFSET_IDX:%.*]] = add i64 [[IV_START]], [[INDEX]]
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[OFFSET_IDX]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP2]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = icmp sgt <4 x i64> [[WIDE_LOAD]], splat (i64 3)
+; CHECK-VF4IC1-NEXT:    [[TMP4:%.*]] = freeze <4 x i1> [[TMP3]]
+; CHECK-VF4IC1-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
+; CHECK-VF4IC1-NEXT:    [[TMP6]] = select i1 [[TMP5]], <4 x i1> [[TMP3]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP7]] = select i1 [[TMP5]], <4 x i64> [[VEC_IND]], <4 x i64> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
+; CHECK-VF4IC1-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP9:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC1-NEXT:    [[TMP10:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP7]], <4 x i1> [[TMP6]], i64 [[TMP9]])
+; CHECK-VF4IC1-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP0]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP1]], %[[MIDDLE_BLOCK]] ], [ [[IV_START]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP10]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
+; CHECK-VF4IC1:       [[FOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX_07:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[TMP11:%.*]] = load i64, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[CMP1:%.*]] = icmp sgt i64 [[TMP11]], 3
+; CHECK-VF4IC1-NEXT:    [[COND]] = select i1 [[CMP1]], i64 [[IV]], i64 [[RDX_07]]
+; CHECK-VF4IC1-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], 1
+; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK-VF4IC1:       [[EXIT_LOOPEXIT]]:
+; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP10]], %[[MIDDLE_BLOCK]] ]
+; CHECK-VF4IC1-NEXT:    br label %[[EXIT]]
+; CHECK-VF4IC1:       [[EXIT]]:
+; CHECK-VF4IC1-NEXT:    [[IDX_0_LCSSA:%.*]] = phi i64 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
+; CHECK-VF4IC1-NEXT:    ret i64 [[IDX_0_LCSSA]]
+;
+; CHECK-VF4IC4-LABEL: define i64 @select_non_const_iv_start_signed_guard(
+; CHECK-VF4IC4-SAME: ptr [[A:%.*]], i64 [[RDX_START:%.*]], i64 [[IV_START:%.*]], i64 [[N:%.*]]) {
+; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC4-NEXT:    [[GUARD:%.*]] = icmp slt i64 [[IV_START]], [[N]]
+; CHECK-VF4IC4-NEXT:    br i1 [[GUARD]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
+; CHECK-VF4IC4:       [[FOR_BODY_PREHEADER]]:
+; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = sub i64 [[N]], [[IV_START]]
+; CHECK-VF4IC4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP0]], 4
+; CHECK-VF4IC4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP0]], 4
+; CHECK-VF4IC4-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP0]], [[N_MOD_VF]]
+; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = add i64 [[IV_START]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i64> poison, i64 [[IV_START]], i64 0
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT1]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC4-NEXT:    [[INDUCTION:%.*]] = add <4 x i64> [[BROADCAST_SPLAT2]], <i64 0, i64 1, i64 2, i64 3>
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP7:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[OFFSET_IDX:%.*]] = add i64 [[IV_START]], [[INDEX]]
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[OFFSET_IDX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP2]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = icmp sgt <4 x i64> [[WIDE_LOAD]], splat (i64 3)
+; CHECK-VF4IC4-NEXT:    [[TMP4:%.*]] = freeze <4 x i1> [[TMP3]]
+; CHECK-VF4IC4-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
+; CHECK-VF4IC4-NEXT:    [[TMP6]] = select i1 [[TMP5]], <4 x i1> [[TMP3]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP7]] = select i1 [[TMP5]], <4 x i64> [[VEC_IND]], <4 x i64> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
+; CHECK-VF4IC4-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP9:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC4-NEXT:    [[TMP10:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP7]], <4 x i1> [[TMP6]], i64 [[TMP9]])
+; CHECK-VF4IC4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP0]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP1]], %[[MIDDLE_BLOCK]] ], [ [[IV_START]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP10]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
+; CHECK-VF4IC4:       [[FOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX_07:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[TMP11:%.*]] = load i64, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC4-NEXT:    [[CMP1:%.*]] = icmp sgt i64 [[TMP11]], 3
+; CHECK-VF4IC4-NEXT:    [[COND]] = select i1 [[CMP1]], i64 [[IV]], i64 [[RDX_07]]
+; CHECK-VF4IC4-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], 1
+; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK-VF4IC4:       [[EXIT_LOOPEXIT]]:
+; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP10]], %[[MIDDLE_BLOCK]] ]
+; CHECK-VF4IC4-NEXT:    br label %[[EXIT]]
+; CHECK-VF4IC4:       [[EXIT]]:
+; CHECK-VF4IC4-NEXT:    [[IDX_0_LCSSA:%.*]] = phi i64 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
+; CHECK-VF4IC4-NEXT:    ret i64 [[IDX_0_LCSSA]]
+;
+; CHECK-VF1IC4-LABEL: define i64 @select_non_const_iv_start_signed_guard(
+; CHECK-VF1IC4-SAME: ptr [[A:%.*]], i64 [[RDX_START:%.*]], i64 [[IV_START:%.*]], i64 [[N:%.*]]) {
+; CHECK-VF1IC4-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF1IC4-NEXT:    [[GUARD:%.*]] = icmp slt i64 [[IV_START]], [[N]]
+; CHECK-VF1IC4-NEXT:    br i1 [[GUARD]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
+; CHECK-VF1IC4:       [[FOR_BODY_PREHEADER]]:
+; CHECK-VF1IC4-NEXT:    br label %[[FOR_BODY:.*]]
+; CHECK-VF1IC4:       [[FOR_BODY]]:
+; CHECK-VF1IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[FOR_BODY]] ], [ [[IV_START]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF1IC4-NEXT:    [[RDX_07:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[RDX_START]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF1IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV]]
+; CHECK-VF1IC4-NEXT:    [[TMP0:%.*]] = load i64, ptr [[ARRAYIDX]], align 4
+; CHECK-VF1IC4-NEXT:    [[CMP1:%.*]] = icmp sgt i64 [[TMP0]], 3
+; CHECK-VF1IC4-NEXT:    [[COND]] = select i1 [[CMP1]], i64 [[IV]], i64 [[RDX_07]]
+; CHECK-VF1IC4-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], 1
+; CHECK-VF1IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-VF1IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF1IC4:       [[EXIT_LOOPEXIT]]:
+; CHECK-VF1IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF1IC4-NEXT:    br label %[[EXIT]]
+; CHECK-VF1IC4:       [[EXIT]]:
+; CHECK-VF1IC4-NEXT:    [[IDX_0_LCSSA:%.*]] = phi i64 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
+; CHECK-VF1IC4-NEXT:    ret i64 [[IDX_0_LCSSA]]
 ;
 entry:
   %guard = icmp slt i64 %iv_start, %n
@@ -49,32 +173,162 @@ exit:
 }
 
 define i32 @select_trunc_non_const_iv_start_signed_guard(ptr %a, i32 %rdx_start, i32 %iv_start ,i32 %n) {
-; CHECK-LABEL: define i32 @select_trunc_non_const_iv_start_signed_guard(
-; CHECK-SAME: ptr [[A:%.*]], i32 [[RDX_START:%.*]], i32 [[IV_START:%.*]], i32 [[N:%.*]]) {
-; CHECK-NEXT:  [[ENTRY:.*]]:
-; CHECK-NEXT:    [[GUARD:%.*]] = icmp slt i32 [[IV_START]], [[N]]
-; CHECK-NEXT:    br i1 [[GUARD]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
-; CHECK:       [[FOR_BODY_PREHEADER]]:
-; CHECK-NEXT:    [[TMP0:%.*]] = sext i32 [[IV_START]] to i64
-; CHECK-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = sext i32 [[N]] to i64
-; CHECK-NEXT:    br label %[[FOR_BODY:.*]]
-; CHECK:       [[FOR_BODY]]:
-; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[TMP0]], %[[FOR_BODY_PREHEADER]] ], [ [[IV_NEXT:%.*]], %[[FOR_BODY]] ]
-; CHECK-NEXT:    [[RDX_07:%.*]] = phi i32 [ [[RDX_START]], %[[FOR_BODY_PREHEADER]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
-; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-NEXT:    [[TMP1:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[TMP1]], 3
-; CHECK-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV]] to i32
-; CHECK-NEXT:    [[COND]] = select i1 [[CMP1]], i32 [[TMP2]], i32 [[RDX_07]]
-; CHECK-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], 1
-; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], [[WIDE_TRIP_COUNT]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
-; CHECK:       [[EXIT_LOOPEXIT]]:
-; CHECK-NEXT:    [[COND_LCSSA:%.*]] = phi i32 [ [[COND]], %[[FOR_BODY]] ]
-; CHECK-NEXT:    br label %[[EXIT]]
-; CHECK:       [[EXIT]]:
-; CHECK-NEXT:    [[IDX_0_LCSSA:%.*]] = phi i32 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
-; CHECK-NEXT:    ret i32 [[IDX_0_LCSSA]]
+; CHECK-VF4IC1-LABEL: define i32 @select_trunc_non_const_iv_start_signed_guard(
+; CHECK-VF4IC1-SAME: ptr [[A:%.*]], i32 [[RDX_START:%.*]], i32 [[IV_START:%.*]], i32 [[N:%.*]]) {
+; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC1-NEXT:    [[GUARD:%.*]] = icmp slt i32 [[IV_START]], [[N]]
+; CHECK-VF4IC1-NEXT:    br i1 [[GUARD]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
+; CHECK-VF4IC1:       [[FOR_BODY_PREHEADER]]:
+; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = sext i32 [[IV_START]] to i64
+; CHECK-VF4IC1-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = sext i32 [[N]] to i64
+; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = sub i64 [[WIDE_TRIP_COUNT]], [[TMP0]]
+; CHECK-VF4IC1-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP1]], 4
+; CHECK-VF4IC1-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP1]], 4
+; CHECK-VF4IC1-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP1]], [[N_MOD_VF]]
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = add i64 [[TMP0]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i32> poison, i32 [[RDX_START]], i64 0
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT]], <4 x i32> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i32> poison, i32 [[IV_START]], i64 0
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT1]], <4 x i32> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC1-NEXT:    [[INDUCTION:%.*]] = add <4 x i32> [[BROADCAST_SPLAT2]], <i32 0, i32 1, i32 2, i32 3>
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP8:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP7:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[OFFSET_IDX:%.*]] = add i64 [[TMP0]], [[INDEX]]
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[OFFSET_IDX]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP3]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP4:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], splat (i32 3)
+; CHECK-VF4IC1-NEXT:    [[TMP5:%.*]] = freeze <4 x i1> [[TMP4]]
+; CHECK-VF4IC1-NEXT:    [[TMP6:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP5]])
+; CHECK-VF4IC1-NEXT:    [[TMP7]] = select i1 [[TMP6]], <4 x i1> [[TMP4]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP8]] = select i1 [[TMP6]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC1-NEXT:    [[TMP9:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP9]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP10:%.*]] = extractelement <4 x i32> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC1-NEXT:    [[TMP11:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP8]], <4 x i1> [[TMP7]], i32 [[TMP10]])
+; CHECK-VF4IC1-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP1]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP2]], %[[MIDDLE_BLOCK]] ], [ [[TMP0]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP11]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
+; CHECK-VF4IC1:       [[FOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX_07:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[TMP12:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[TMP12]], 3
+; CHECK-VF4IC1-NEXT:    [[TMP13:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC1-NEXT:    [[COND]] = select i1 [[CMP1]], i32 [[TMP13]], i32 [[RDX_07]]
+; CHECK-VF4IC1-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], 1
+; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], [[WIDE_TRIP_COUNT]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK-VF4IC1:       [[EXIT_LOOPEXIT]]:
+; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i32 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP11]], %[[MIDDLE_BLOCK]] ]
+; CHECK-VF4IC1-NEXT:    br label %[[EXIT]]
+; CHECK-VF4IC1:       [[EXIT]]:
+; CHECK-VF4IC1-NEXT:    [[IDX_0_LCSSA:%.*]] = phi i32 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
+; CHECK-VF4IC1-NEXT:    ret i32 [[IDX_0_LCSSA]]
+;
+; CHECK-VF4IC4-LABEL: define i32 @select_trunc_non_const_iv_start_signed_guard(
+; CHECK-VF4IC4-SAME: ptr [[A:%.*]], i32 [[RDX_START:%.*]], i32 [[IV_START:%.*]], i32 [[N:%.*]]) {
+; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC4-NEXT:    [[GUARD:%.*]] = icmp slt i32 [[IV_START]], [[N]]
+; CHECK-VF4IC4-NEXT:    br i1 [[GUARD]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
+; CHECK-VF4IC4:       [[FOR_BODY_PREHEADER]]:
+; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = sext i32 [[IV_START]] to i64
+; CHECK-VF4IC4-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = sext i32 [[N]] to i64
+; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = sub i64 [[WIDE_TRIP_COUNT]], [[TMP0]]
+; CHECK-VF4IC4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP1]], 4
+; CHECK-VF4IC4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP1]], 4
+; CHECK-VF4IC4-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP1]], [[N_MOD_VF]]
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = add i64 [[TMP0]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i32> poison, i32 [[RDX_START]], i64 0
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT]], <4 x i32> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i32> poison, i32 [[IV_START]], i64 0
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT1]], <4 x i32> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC4-NEXT:    [[INDUCTION:%.*]] = add <4 x i32> [[BROADCAST_SPLAT2]], <i32 0, i32 1, i32 2, i32 3>
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP8:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP7:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[OFFSET_IDX:%.*]] = add i64 [[TMP0]], [[INDEX]]
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[OFFSET_IDX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP3]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP4:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], splat (i32 3)
+; CHECK-VF4IC4-NEXT:    [[TMP5:%.*]] = freeze <4 x i1> [[TMP4]]
+; CHECK-VF4IC4-NEXT:    [[TMP6:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP5]])
+; CHECK-VF4IC4-NEXT:    [[TMP7]] = select i1 [[TMP6]], <4 x i1> [[TMP4]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP8]] = select i1 [[TMP6]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC4-NEXT:    [[TMP9:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP9]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP10:%.*]] = extractelement <4 x i32> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC4-NEXT:    [[TMP11:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP8]], <4 x i1> [[TMP7]], i32 [[TMP10]])
+; CHECK-VF4IC4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP1]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP2]], %[[MIDDLE_BLOCK]] ], [ [[TMP0]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP11]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
+; CHECK-VF4IC4:       [[FOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX_07:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[TMP12:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC4-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[TMP12]], 3
+; CHECK-VF4IC4-NEXT:    [[TMP13:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC4-NEXT:    [[COND]] = select i1 [[CMP1]], i32 [[TMP13]], i32 [[RDX_07]]
+; CHECK-VF4IC4-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], 1
+; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], [[WIDE_TRIP_COUNT]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK-VF4IC4:       [[EXIT_LOOPEXIT]]:
+; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i32 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP11]], %[[MIDDLE_BLOCK]] ]
+; CHECK-VF4IC4-NEXT:    br label %[[EXIT]]
+; CHECK-VF4IC4:       [[EXIT]]:
+; CHECK-VF4IC4-NEXT:    [[IDX_0_LCSSA:%.*]] = phi i32 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
+; CHECK-VF4IC4-NEXT:    ret i32 [[IDX_0_LCSSA]]
+;
+; CHECK-VF1IC4-LABEL: define i32 @select_trunc_non_const_iv_start_signed_guard(
+; CHECK-VF1IC4-SAME: ptr [[A:%.*]], i32 [[RDX_START:%.*]], i32 [[IV_START:%.*]], i32 [[N:%.*]]) {
+; CHECK-VF1IC4-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF1IC4-NEXT:    [[GUARD:%.*]] = icmp slt i32 [[IV_START]], [[N]]
+; CHECK-VF1IC4-NEXT:    br i1 [[GUARD]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
+; CHECK-VF1IC4:       [[FOR_BODY_PREHEADER]]:
+; CHECK-VF1IC4-NEXT:    [[TMP0:%.*]] = sext i32 [[IV_START]] to i64
+; CHECK-VF1IC4-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = sext i32 [[N]] to i64
+; CHECK-VF1IC4-NEXT:    br label %[[FOR_BODY:.*]]
+; CHECK-VF1IC4:       [[FOR_BODY]]:
+; CHECK-VF1IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[TMP0]], %[[FOR_BODY_PREHEADER]] ], [ [[IV_NEXT:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF1IC4-NEXT:    [[RDX_07:%.*]] = phi i32 [ [[RDX_START]], %[[FOR_BODY_PREHEADER]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF1IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-VF1IC4-NEXT:    [[TMP1:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
+; CHECK-VF1IC4-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[TMP1]], 3
+; CHECK-VF1IC4-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF1IC4-NEXT:    [[COND]] = select i1 [[CMP1]], i32 [[TMP2]], i32 [[RDX_07]]
+; CHECK-VF1IC4-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], 1
+; CHECK-VF1IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], [[WIDE_TRIP_COUNT]]
+; CHECK-VF1IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF1IC4:       [[EXIT_LOOPEXIT]]:
+; CHECK-VF1IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i32 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF1IC4-NEXT:    br label %[[EXIT]]
+; CHECK-VF1IC4:       [[EXIT]]:
+; CHECK-VF1IC4-NEXT:    [[IDX_0_LCSSA:%.*]] = phi i32 [ [[RDX_START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
+; CHECK-VF1IC4-NEXT:    ret i32 [[IDX_0_LCSSA]]
 ;
 entry:
   %guard = icmp slt i32 %iv_start, %n
@@ -101,3 +355,18 @@ exit:
   %idx.0.lcssa = phi i32 [ %rdx_start, %entry ], [ %cond, %for.body ]
   ret i32 %idx.0.lcssa
 }
+;.
+; CHECK-VF4IC1: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
+; CHECK-VF4IC1: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
+; CHECK-VF4IC1: [[META2]] = !{!"llvm.loop.unroll.runtime.disable"}
+; CHECK-VF4IC1: [[LOOP3]] = distinct !{[[LOOP3]], [[META2]], [[META1]]}
+; CHECK-VF4IC1: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]], [[META2]]}
+; CHECK-VF4IC1: [[LOOP5]] = distinct !{[[LOOP5]], [[META2]], [[META1]]}
+;.
+; CHECK-VF4IC4: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
+; CHECK-VF4IC4: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
+; CHECK-VF4IC4: [[META2]] = !{!"llvm.loop.unroll.runtime.disable"}
+; CHECK-VF4IC4: [[LOOP3]] = distinct !{[[LOOP3]], [[META2]], [[META1]]}
+; CHECK-VF4IC4: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]], [[META2]]}
+; CHECK-VF4IC4: [[LOOP5]] = distinct !{[[LOOP5]], [[META2]], [[META1]]}
+;.
diff --git a/llvm/test/Transforms/LoopVectorize/iv-select-cmp-trunc.ll b/llvm/test/Transforms/LoopVectorize/iv-select-cmp-trunc.ll
index b991d58eb2b8d..3c6740a922b69 100644
--- a/llvm/test/Transforms/LoopVectorize/iv-select-cmp-trunc.ll
+++ b/llvm/test/Transforms/LoopVectorize/iv-select-cmp-trunc.ll
@@ -674,65 +674,125 @@ exit:                                             ; preds = %for.body
 
 ; Negative tests
 
-; This test can theoretically be vectorized, but only with a runtime-check.
-; The construct that are introduced by IndVarSimplify is:
+; This test can theoretically be vectorized as a FindLastIV reduction, but only
+; with a runtime-check. It will vectorize as a generic FindLast reduction.
+;
+; For FindLastIV, the construct that are introduced by IndVarSimplify is:
 ;   %1 = trunc i64 %iv to i32
 ; However, the loop guard is an i64:
 ;   %cmp.sgt = icmp sgt i64 %n, 0
 ; We cannot guarantee that %iv won't overflow an i32 value (and hence hit the
 ; sentinel value), and need a runtime-check to vectorize this case.
-define i32 @not_vectorized_select_icmp_const_truncated_iv_unwidened_exit(ptr %a, i64 %n) {
-; CHECK-VF4IC1-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_unwidened_exit(
+define i32 @select_icmp_const_truncated_iv_unwidened_exit(ptr %a, i64 %n) {
+; CHECK-VF4IC1-LABEL: define i32 @select_icmp_const_truncated_iv_unwidened_exit(
 ; CHECK-VF4IC1-SAME: ptr [[A:%.*]], i64 [[N:%.*]]) {
 ; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
 ; CHECK-VF4IC1-NEXT:    [[CMP_SGT:%.*]] = icmp sgt i64 [[N]], 0
 ; CHECK-VF4IC1-NEXT:    br i1 [[CMP_SGT]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY_PREHEADER]]:
+; CHECK-VF4IC1-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
+; CHECK-VF4IC1-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], 4
+; CHECK-VF4IC1-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 331), %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP4:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP8:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], splat (i32 3)
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = freeze <4 x i1> [[TMP8]]
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; CHECK-VF4IC1-NEXT:    [[TMP4]] = select i1 [[TMP3]], <4 x i1> [[TMP8]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP5]] = select i1 [[TMP3]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[IV]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC1-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP7:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP5]], <4 x i1> [[TMP4]], i32 331)
+; CHECK-VF4IC1-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP7]], %[[MIDDLE_BLOCK]] ], [ 331, %[[FOR_BODY_PREHEADER]] ]
 ; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY]]:
-; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ 0, %[[FOR_BODY_PREHEADER]] ]
-; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ], [ 331, %[[FOR_BODY_PREHEADER]] ]
-; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[IV1:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV1]]
+; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX1]], align 4
 ; CHECK-VF4IC1-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[TMP0]], 3
-; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV1]] to i32
 ; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP]], i32 [[TMP1]], i32 [[RDX]]
-; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV1]], 1
 ; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[N]]
-; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
 ; CHECK-VF4IC1:       [[EXIT_LOOPEXIT]]:
-; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ], [ [[TMP7]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC1-NEXT:    br label %[[EXIT]]
 ; CHECK-VF4IC1:       [[EXIT]]:
 ; CHECK-VF4IC1-NEXT:    [[RDX_LCSSA:%.*]] = phi i32 [ 331, %[[ENTRY]] ], [ [[SPEC_SELECT_LCSSA]], %[[EXIT_LOOPEXIT]] ]
 ; CHECK-VF4IC1-NEXT:    ret i32 [[RDX_LCSSA]]
 ;
-; CHECK-VF4IC4-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_unwidened_exit(
+; CHECK-VF4IC4-LABEL: define i32 @select_icmp_const_truncated_iv_unwidened_exit(
 ; CHECK-VF4IC4-SAME: ptr [[A:%.*]], i64 [[N:%.*]]) {
 ; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
 ; CHECK-VF4IC4-NEXT:    [[CMP_SGT:%.*]] = icmp sgt i64 [[N]], 0
 ; CHECK-VF4IC4-NEXT:    br i1 [[CMP_SGT]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY_PREHEADER]]:
+; CHECK-VF4IC4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
+; CHECK-VF4IC4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], 4
+; CHECK-VF4IC4-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 331), %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP4:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[INDEX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP0]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], splat (i32 3)
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = freeze <4 x i1> [[TMP1]]
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; CHECK-VF4IC4-NEXT:    [[TMP4]] = select i1 [[TMP3]], <4 x i1> [[TMP1]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP5]] = select i1 [[TMP3]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC4-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP7:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP5]], <4 x i1> [[TMP4]], i32 331)
+; CHECK-VF4IC4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP7]], %[[MIDDLE_BLOCK]] ], [ 331, %[[FOR_BODY_PREHEADER]] ]
 ; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY]]:
-; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ 0, %[[FOR_BODY_PREHEADER]] ]
-; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ], [ 331, %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
 ; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
-; CHECK-VF4IC4-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[TMP0]], 3
-; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV]] to i32
-; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP]], i32 [[TMP1]], i32 [[RDX]]
+; CHECK-VF4IC4-NEXT:    [[TMP8:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC4-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[TMP8]], 3
+; CHECK-VF4IC4-NEXT:    [[TMP9:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP]], i32 [[TMP9]], i32 [[RDX]]
 ; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
 ; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[N]]
-; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
 ; CHECK-VF4IC4:       [[EXIT_LOOPEXIT]]:
-; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ], [ [[TMP7]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC4-NEXT:    br label %[[EXIT]]
 ; CHECK-VF4IC4:       [[EXIT]]:
 ; CHECK-VF4IC4-NEXT:    [[RDX_LCSSA:%.*]] = phi i32 [ 331, %[[ENTRY]] ], [ [[SPEC_SELECT_LCSSA]], %[[EXIT_LOOPEXIT]] ]
 ; CHECK-VF4IC4-NEXT:    ret i32 [[RDX_LCSSA]]
 ;
-; CHECK-VF1IC4-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_unwidened_exit(
+; CHECK-VF1IC4-LABEL: define i32 @select_icmp_const_truncated_iv_unwidened_exit(
 ; CHECK-VF1IC4-SAME: ptr [[A:%.*]], i64 [[N:%.*]]) {
 ; CHECK-VF1IC4-NEXT:  [[ENTRY:.*]]:
 ; CHECK-VF1IC4-NEXT:    [[CMP_SGT:%.*]] = icmp sgt i64 [[N]], 0
@@ -778,67 +838,127 @@ exit:                                             ; preds = %for.body, %entry
   ret i32 %rdx.lcssa
 }
 
-; This test can theoretically be vectorized, but only with a runtime-check.
-; The construct that are introduced by IndVarSimplify is:
+; This test can theoretically be vectorized as a FindLastIV reduction, but only
+; with a runtime-check. It will vectorize as a generic FindLast reduction.
+;
+; For FindLastIV, the construct that are introduced by IndVarSimplify is:
 ;   %1 = trunc i64 %iv to i32
 ; However, the loop guard is unsigned:
 ;   %cmp.not = icmp eq i32 %n, 0
 ; We cannot guarantee that %iv won't overflow an i32 value (and hence hit the
 ; sentinel value), and need a runtime-check to vectorize this case.
-define i32 @not_vectorized_select_icmp_const_truncated_iv_unsigned_loop_guard(ptr %a, i32 %n) {
-; CHECK-VF4IC1-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_unsigned_loop_guard(
+define i32 @select_icmp_const_truncated_iv_unsigned_loop_guard(ptr %a, i32 %n) {
+; CHECK-VF4IC1-LABEL: define i32 @select_icmp_const_truncated_iv_unsigned_loop_guard(
 ; CHECK-VF4IC1-SAME: ptr [[A:%.*]], i32 [[N:%.*]]) {
 ; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
 ; CHECK-VF4IC1-NEXT:    [[CMP_NOT:%.*]] = icmp eq i32 [[N]], 0
 ; CHECK-VF4IC1-NEXT:    br i1 [[CMP_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY_PREHEADER:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY_PREHEADER]]:
 ; CHECK-VF4IC1-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[N]] to i64
+; CHECK-VF4IC1-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC1-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC1-NEXT:    [[N_VEC:%.*]] = sub i64 [[WIDE_TRIP_COUNT]], [[N_MOD_VF]]
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 331), %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP4:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP8:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], splat (i32 3)
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = freeze <4 x i1> [[TMP8]]
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; CHECK-VF4IC1-NEXT:    [[TMP4]] = select i1 [[TMP3]], <4 x i1> [[TMP8]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP5]] = select i1 [[TMP3]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[IV]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC1-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP7:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP5]], <4 x i1> [[TMP4]], i32 331)
+; CHECK-VF4IC1-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[WIDE_TRIP_COUNT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP7]], %[[MIDDLE_BLOCK]] ], [ 331, %[[FOR_BODY_PREHEADER]] ]
 ; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY]]:
-; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[FOR_BODY_PREHEADER]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ 331, %[[FOR_BODY_PREHEADER]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[IV1:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV1]]
+; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX1]], align 4
 ; CHECK-VF4IC1-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[TMP0]], 3
-; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV1]] to i32
 ; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP1]], i32 [[TMP1]], i32 [[RDX]]
-; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV1]], 1
 ; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[WIDE_TRIP_COUNT]]
-; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
 ; CHECK-VF4IC1:       [[EXIT_LOOPEXIT]]:
-; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ], [ [[TMP7]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC1-NEXT:    br label %[[EXIT]]
 ; CHECK-VF4IC1:       [[EXIT]]:
 ; CHECK-VF4IC1-NEXT:    [[RDX_LCSSA:%.*]] = phi i32 [ 331, %[[ENTRY]] ], [ [[SPEC_SELECT_LCSSA]], %[[EXIT_LOOPEXIT]] ]
 ; CHECK-VF4IC1-NEXT:    ret i32 [[RDX_LCSSA]]
 ;
-; CHECK-VF4IC4-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_unsigned_loop_guard(
+; CHECK-VF4IC4-LABEL: define i32 @select_icmp_const_truncated_iv_unsigned_loop_guard(
 ; CHECK-VF4IC4-SAME: ptr [[A:%.*]], i32 [[N:%.*]]) {
 ; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
 ; CHECK-VF4IC4-NEXT:    [[CMP_NOT:%.*]] = icmp eq i32 [[N]], 0
 ; CHECK-VF4IC4-NEXT:    br i1 [[CMP_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY_PREHEADER:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY_PREHEADER]]:
 ; CHECK-VF4IC4-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[N]] to i64
+; CHECK-VF4IC4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC4-NEXT:    [[N_VEC:%.*]] = sub i64 [[WIDE_TRIP_COUNT]], [[N_MOD_VF]]
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 331), %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP4:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[INDEX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP0]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], splat (i32 3)
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = freeze <4 x i1> [[TMP1]]
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; CHECK-VF4IC4-NEXT:    [[TMP4]] = select i1 [[TMP3]], <4 x i1> [[TMP1]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP5]] = select i1 [[TMP3]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC4-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP7:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP5]], <4 x i1> [[TMP4]], i32 331)
+; CHECK-VF4IC4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[WIDE_TRIP_COUNT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP7]], %[[MIDDLE_BLOCK]] ], [ 331, %[[FOR_BODY_PREHEADER]] ]
 ; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY]]:
-; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[FOR_BODY_PREHEADER]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ 331, %[[FOR_BODY_PREHEADER]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
 ; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
-; CHECK-VF4IC4-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[TMP0]], 3
-; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV]] to i32
-; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP1]], i32 [[TMP1]], i32 [[RDX]]
+; CHECK-VF4IC4-NEXT:    [[TMP8:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC4-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[TMP8]], 3
+; CHECK-VF4IC4-NEXT:    [[TMP9:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP1]], i32 [[TMP9]], i32 [[RDX]]
 ; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
 ; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[WIDE_TRIP_COUNT]]
-; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
 ; CHECK-VF4IC4:       [[EXIT_LOOPEXIT]]:
-; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ], [ [[TMP7]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC4-NEXT:    br label %[[EXIT]]
 ; CHECK-VF4IC4:       [[EXIT]]:
 ; CHECK-VF4IC4-NEXT:    [[RDX_LCSSA:%.*]] = phi i32 [ 331, %[[ENTRY]] ], [ [[SPEC_SELECT_LCSSA]], %[[EXIT_LOOPEXIT]] ]
 ; CHECK-VF4IC4-NEXT:    ret i32 [[RDX_LCSSA]]
 ;
-; CHECK-VF1IC4-LABEL: define i32 @not_vectorized_select_icmp_const_truncated_iv_unsigned_loop_guard(
+; CHECK-VF1IC4-LABEL: define i32 @select_icmp_const_truncated_iv_unsigned_loop_guard(
 ; CHECK-VF1IC4-SAME: ptr [[A:%.*]], i32 [[N:%.*]]) {
 ; CHECK-VF1IC4-NEXT:  [[ENTRY:.*]]:
 ; CHECK-VF1IC4-NEXT:    [[CMP_NOT:%.*]] = icmp eq i32 [[N]], 0
@@ -899,41 +1019,61 @@ exit:                                             ; preds = %for.body, %entry
 define i32 @not_vectorized_select_icmp_truncated_iv_out_of_bound(ptr %a) {
 ; CHECK-VF4IC1-LABEL: define i32 @not_vectorized_select_icmp_truncated_iv_out_of_bound(
 ; CHECK-VF4IC1-SAME: ptr [[A:%.*]]) {
-; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
-; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
-; CHECK-VF4IC1:       [[FOR_BODY]]:
-; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 4294967294, %[[ENTRY]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ 331, %[[ENTRY]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:  [[ENTRY:.*:]]
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 331), %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP4:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 -2, i32 -1, i32 0, i32 1>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = add i64 4294967294, [[INDEX]]
 ; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
-; CHECK-VF4IC1-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[TMP0]], 3
-; CHECK-VF4IC1-NEXT:    [[CONV:%.*]] = trunc i64 [[IV]] to i32
-; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP]], i32 [[CONV]], i32 [[RDX]]
-; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
-; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], 9223372036854775806
-; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], splat (i32 3)
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = freeze <4 x i1> [[TMP1]]
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; CHECK-VF4IC1-NEXT:    [[TMP4]] = select i1 [[TMP3]], <4 x i1> [[TMP1]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP5]] = select i1 [[TMP3]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC1-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 9223372032559808512
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP11:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP7:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP5]], <4 x i1> [[TMP4]], i32 331)
+; CHECK-VF4IC1-NEXT:    br label %[[EXIT:.*]]
 ; CHECK-VF4IC1:       [[EXIT]]:
-; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    ret i32 [[SPEC_SELECT_LCSSA]]
+; CHECK-VF4IC1-NEXT:    ret i32 [[TMP7]]
 ;
 ; CHECK-VF4IC4-LABEL: define i32 @not_vectorized_select_icmp_truncated_iv_out_of_bound(
 ; CHECK-VF4IC4-SAME: ptr [[A:%.*]]) {
-; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
-; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
-; CHECK-VF4IC4:       [[FOR_BODY]]:
-; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ 4294967294, %[[ENTRY]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ 331, %[[ENTRY]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:  [[ENTRY:.*:]]
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 331), %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP4:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 -2, i32 -1, i32 0, i32 1>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = add i64 4294967294, [[INDEX]]
 ; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
-; CHECK-VF4IC4-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[TMP0]], 3
-; CHECK-VF4IC4-NEXT:    [[CONV:%.*]] = trunc i64 [[IV]] to i32
-; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP]], i32 [[CONV]], i32 [[RDX]]
-; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
-; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], 9223372036854775806
-; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], splat (i32 3)
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = freeze <4 x i1> [[TMP1]]
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; CHECK-VF4IC4-NEXT:    [[TMP4]] = select i1 [[TMP3]], <4 x i1> [[TMP1]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP5]] = select i1 [[TMP3]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC4-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 9223372032559808512
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP11:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP7:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP5]], <4 x i1> [[TMP4]], i32 331)
+; CHECK-VF4IC4-NEXT:    br label %[[EXIT:.*]]
 ; CHECK-VF4IC4:       [[EXIT]]:
-; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ]
-; CHECK-VF4IC4-NEXT:    ret i32 [[SPEC_SELECT_LCSSA]]
+; CHECK-VF4IC4-NEXT:    ret i32 [[TMP7]]
 ;
 ; CHECK-VF1IC4-LABEL: define i32 @not_vectorized_select_icmp_truncated_iv_out_of_bound(
 ; CHECK-VF1IC4-SAME: ptr [[A:%.*]]) {
@@ -980,44 +1120,112 @@ define i32 @not_vectorized_select_iv_icmp_no_guard(ptr %a, ptr %b, i32 %start, i
 ; CHECK-VF4IC1-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i32 [[START:%.*]], i32 [[N:%.*]]) {
 ; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
 ; CHECK-VF4IC1-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[N]] to i64
+; CHECK-VF4IC1-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC1-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC1-NEXT:    [[N_VEC:%.*]] = sub i64 [[WIDE_TRIP_COUNT]], [[N_MOD_VF]]
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i32> poison, i32 [[START]], i64 0
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT]], <4 x i32> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP10]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP11:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = freeze <4 x i1> [[TMP11]]
+; CHECK-VF4IC1-NEXT:    [[TMP4:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP3]])
+; CHECK-VF4IC1-NEXT:    [[TMP5]] = select i1 [[TMP4]], <4 x i1> [[TMP11]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP6]] = select i1 [[TMP4]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[IV]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC1-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP12:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP8:%.*]] = extractelement <4 x i32> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC1-NEXT:    [[TMP9:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP6]], <4 x i1> [[TMP5]], i32 [[TMP8]])
+; CHECK-VF4IC1-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[WIDE_TRIP_COUNT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP9]], %[[MIDDLE_BLOCK]] ], [ [[START]], %[[ENTRY]] ]
 ; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY]]:
-; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ [[START]], %[[ENTRY]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
-; CHECK-VF4IC1-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[IV1:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV1]]
+; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX1]], align 4
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV1]]
 ; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = load i32, ptr [[ARRAYIDX2]], align 4
 ; CHECK-VF4IC1-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[TMP0]], [[TMP1]]
-; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV1]] to i32
 ; CHECK-VF4IC1-NEXT:    [[COND]] = select i1 [[CMP]], i32 [[TMP2]], i32 [[RDX]]
-; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV1]], 1
 ; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[WIDE_TRIP_COUNT]]
-; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP13:![0-9]+]]
 ; CHECK-VF4IC1:       [[EXIT]]:
-; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i32 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i32 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP9]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC1-NEXT:    ret i32 [[COND_LCSSA]]
 ;
 ; CHECK-VF4IC4-LABEL: define i32 @not_vectorized_select_iv_icmp_no_guard(
 ; CHECK-VF4IC4-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i32 [[START:%.*]], i32 [[N:%.*]]) {
 ; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
 ; CHECK-VF4IC4-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[N]] to i64
+; CHECK-VF4IC4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC4-NEXT:    [[N_VEC:%.*]] = sub i64 [[WIDE_TRIP_COUNT]], [[N_MOD_VF]]
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i32> poison, i32 [[START]], i64 0
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT]], <4 x i32> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP10]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP11:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = freeze <4 x i1> [[TMP11]]
+; CHECK-VF4IC4-NEXT:    [[TMP4:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP3]])
+; CHECK-VF4IC4-NEXT:    [[TMP5]] = select i1 [[TMP4]], <4 x i1> [[TMP11]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP6]] = select i1 [[TMP4]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[IV]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC4-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP12:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP8:%.*]] = extractelement <4 x i32> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC4-NEXT:    [[TMP9:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP6]], <4 x i1> [[TMP5]], i32 [[TMP8]])
+; CHECK-VF4IC4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[WIDE_TRIP_COUNT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP9]], %[[MIDDLE_BLOCK]] ], [ [[START]], %[[ENTRY]] ]
 ; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY]]:
-; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ [[START]], %[[ENTRY]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
-; CHECK-VF4IC4-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[IV1:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV1]]
+; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX1]], align 4
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV1]]
 ; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = load i32, ptr [[ARRAYIDX2]], align 4
 ; CHECK-VF4IC4-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[TMP0]], [[TMP1]]
-; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV1]] to i32
 ; CHECK-VF4IC4-NEXT:    [[COND]] = select i1 [[CMP]], i32 [[TMP2]], i32 [[RDX]]
-; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV1]], 1
 ; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[WIDE_TRIP_COUNT]]
-; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP13:![0-9]+]]
 ; CHECK-VF4IC4:       [[EXIT]]:
-; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i32 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i32 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP9]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC4-NEXT:    ret i32 [[COND_LCSSA]]
 ;
 ; CHECK-VF1IC4-LABEL: define i32 @not_vectorized_select_iv_icmp_no_guard(
@@ -1071,38 +1279,84 @@ exit:                                             ; preds = %for.body
 define i32 @not_vectorized_select_fcmp_invalid_const_ub(ptr %a) {
 ; CHECK-VF4IC1-LABEL: define i32 @not_vectorized_select_fcmp_invalid_const_ub(
 ; CHECK-VF4IC1-SAME: ptr [[A:%.*]]) {
-; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC1-NEXT:  [[ENTRY:.*:]]
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 -1), %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP4:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds float, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x float>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP8:%.*]] = fcmp fast olt <4 x float> [[WIDE_LOAD]], zeroinitializer
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = freeze <4 x i1> [[TMP8]]
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; CHECK-VF4IC1-NEXT:    [[TMP4]] = select i1 [[TMP3]], <4 x i1> [[TMP8]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP5]] = select i1 [[TMP3]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[IV]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC1-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 2147483648
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP14:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP7:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP5]], <4 x i1> [[TMP4]], i32 -1)
+; CHECK-VF4IC1-NEXT:    br label %[[SCALAR_PH:.*]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
 ; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY]]:
-; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ -1, %[[ENTRY]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds float, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load float, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[IV1:%.*]] = phi i64 [ 2147483648, %[[SCALAR_PH]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ [[TMP7]], %[[SCALAR_PH]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds float, ptr [[A]], i64 [[IV1]]
+; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load float, ptr [[ARRAYIDX1]], align 4
 ; CHECK-VF4IC1-NEXT:    [[CMP:%.*]] = fcmp fast olt float [[TMP0]], 0.000000e+00
-; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV1]] to i32
 ; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP]], i32 [[TMP1]], i32 [[RDX]]
-; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV1]], 1
 ; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], 2147483649
-; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]], !llvm.loop [[LOOP15:![0-9]+]]
 ; CHECK-VF4IC1:       [[EXIT]]:
 ; CHECK-VF4IC1-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ]
 ; CHECK-VF4IC1-NEXT:    ret i32 [[SPEC_SELECT_LCSSA]]
 ;
 ; CHECK-VF4IC4-LABEL: define i32 @not_vectorized_select_fcmp_invalid_const_ub(
 ; CHECK-VF4IC4-SAME: ptr [[A:%.*]]) {
-; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC4-NEXT:  [[ENTRY:.*:]]
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 -1), %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP4:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds float, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x float>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP8:%.*]] = fcmp fast olt <4 x float> [[WIDE_LOAD]], zeroinitializer
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = freeze <4 x i1> [[TMP8]]
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; CHECK-VF4IC4-NEXT:    [[TMP4]] = select i1 [[TMP3]], <4 x i1> [[TMP8]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP5]] = select i1 [[TMP3]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[IV]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
+; CHECK-VF4IC4-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 2147483648
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP14:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP7:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP5]], <4 x i1> [[TMP4]], i32 -1)
+; CHECK-VF4IC4-NEXT:    br label %[[SCALAR_PH:.*]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
 ; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY]]:
-; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ -1, %[[ENTRY]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds float, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load float, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC4-NEXT:    [[IV1:%.*]] = phi i64 [ 2147483648, %[[SCALAR_PH]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ [[TMP7]], %[[SCALAR_PH]] ], [ [[SPEC_SELECT:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds float, ptr [[A]], i64 [[IV1]]
+; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load float, ptr [[ARRAYIDX1]], align 4
 ; CHECK-VF4IC4-NEXT:    [[CMP:%.*]] = fcmp fast olt float [[TMP0]], 0.000000e+00
-; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV]] to i32
+; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = trunc i64 [[IV1]] to i32
 ; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT]] = select i1 [[CMP]], i32 [[TMP1]], i32 [[RDX]]
-; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV1]], 1
 ; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], 2147483649
-; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]], !llvm.loop [[LOOP15:![0-9]+]]
 ; CHECK-VF4IC4:       [[EXIT]]:
 ; CHECK-VF4IC4-NEXT:    [[SPEC_SELECT_LCSSA:%.*]] = phi i32 [ [[SPEC_SELECT]], %[[FOR_BODY]] ]
 ; CHECK-VF4IC4-NEXT:    ret i32 [[SPEC_SELECT_LCSSA]]
@@ -1156,22 +1410,56 @@ define i16 @not_vectorized_select_iv_icmp_overflow_unwidened_tripcount(ptr %a, p
 ; CHECK-VF4IC1-NEXT:    br i1 [[CMP9]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY_PREHEADER]]:
 ; CHECK-VF4IC1-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[N]] to i64
+; CHECK-VF4IC1-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC1-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC1-NEXT:    [[N_VEC:%.*]] = sub i64 [[WIDE_TRIP_COUNT]], [[N_MOD_VF]]
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i16> poison, i16 [[START]], i64 0
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i16> [[BROADCAST_SPLATINSERT]], <4 x i16> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i16> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i16> [ <i16 0, i16 1, i16 2, i16 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP10]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP11:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = freeze <4 x i1> [[TMP11]]
+; CHECK-VF4IC1-NEXT:    [[TMP4:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP3]])
+; CHECK-VF4IC1-NEXT:    [[TMP5]] = select i1 [[TMP4]], <4 x i1> [[TMP11]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP6]] = select i1 [[TMP4]], <4 x i16> [[VEC_IND]], <4 x i16> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[IV]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i16> [[VEC_IND]], splat (i16 4)
+; CHECK-VF4IC1-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP16:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP8:%.*]] = extractelement <4 x i16> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC1-NEXT:    [[TMP9:%.*]] = call i16 @llvm.experimental.vector.extract.last.active.v4i16(<4 x i16> [[TMP6]], <4 x i1> [[TMP5]], i16 [[TMP8]])
+; CHECK-VF4IC1-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[WIDE_TRIP_COUNT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i16 [ [[TMP9]], %[[MIDDLE_BLOCK]] ], [ [[START]], %[[FOR_BODY_PREHEADER]] ]
 ; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY]]:
-; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[FOR_BODY_PREHEADER]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i16 [ [[START]], %[[FOR_BODY_PREHEADER]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
-; CHECK-VF4IC1-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[IV1:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i16 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV1]]
+; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX1]], align 4
+; CHECK-VF4IC1-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV1]]
 ; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = load i32, ptr [[ARRAYIDX2]], align 4
 ; CHECK-VF4IC1-NEXT:    [[CMP3:%.*]] = icmp sgt i32 [[TMP0]], [[TMP1]]
-; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV]] to i16
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV1]] to i16
 ; CHECK-VF4IC1-NEXT:    [[COND]] = select i1 [[CMP3]], i16 [[TMP2]], i16 [[RDX]]
-; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV1]], 1
 ; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[WIDE_TRIP_COUNT]]
-; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP17:![0-9]+]]
 ; CHECK-VF4IC1:       [[EXIT_LOOPEXIT]]:
-; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i16 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i16 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP9]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC1-NEXT:    br label %[[EXIT]]
 ; CHECK-VF4IC1:       [[EXIT]]:
 ; CHECK-VF4IC1-NEXT:    [[RDX_0_LCSSA:%.*]] = phi i16 [ [[START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
@@ -1184,22 +1472,56 @@ define i16 @not_vectorized_select_iv_icmp_overflow_unwidened_tripcount(ptr %a, p
 ; CHECK-VF4IC4-NEXT:    br i1 [[CMP9]], label %[[FOR_BODY_PREHEADER:.*]], label %[[EXIT:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY_PREHEADER]]:
 ; CHECK-VF4IC4-NEXT:    [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[N]] to i64
+; CHECK-VF4IC4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[WIDE_TRIP_COUNT]], 4
+; CHECK-VF4IC4-NEXT:    [[N_VEC:%.*]] = sub i64 [[WIDE_TRIP_COUNT]], [[N_MOD_VF]]
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i16> poison, i16 [[START]], i64 0
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i16> [[BROADCAST_SPLATINSERT]], <4 x i16> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i16> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i16> [ <i16 0, i16 1, i16 2, i16 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[ARRAYIDX]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP10]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP11:%.*]] = icmp sgt <4 x i32> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = freeze <4 x i1> [[TMP11]]
+; CHECK-VF4IC4-NEXT:    [[TMP4:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP3]])
+; CHECK-VF4IC4-NEXT:    [[TMP5]] = select i1 [[TMP4]], <4 x i1> [[TMP11]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP6]] = select i1 [[TMP4]], <4 x i16> [[VEC_IND]], <4 x i16> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[IV]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i16> [[VEC_IND]], splat (i16 4)
+; CHECK-VF4IC4-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP16:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP8:%.*]] = extractelement <4 x i16> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC4-NEXT:    [[TMP9:%.*]] = call i16 @llvm.experimental.vector.extract.last.active.v4i16(<4 x i16> [[TMP6]], <4 x i1> [[TMP5]], i16 [[TMP8]])
+; CHECK-VF4IC4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[WIDE_TRIP_COUNT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[CMP_N]], label %[[EXIT_LOOPEXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[FOR_BODY_PREHEADER]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i16 [ [[TMP9]], %[[MIDDLE_BLOCK]] ], [ [[START]], %[[FOR_BODY_PREHEADER]] ]
 ; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY]]:
-; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[FOR_BODY_PREHEADER]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i16 [ [[START]], %[[FOR_BODY_PREHEADER]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
-; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV]]
-; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX]], align 4
-; CHECK-VF4IC4-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[IV1:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INC:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i16 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[COND:%.*]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[IV1]]
+; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load i32, ptr [[ARRAYIDX1]], align 4
+; CHECK-VF4IC4-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[IV1]]
 ; CHECK-VF4IC4-NEXT:    [[TMP1:%.*]] = load i32, ptr [[ARRAYIDX2]], align 4
 ; CHECK-VF4IC4-NEXT:    [[CMP3:%.*]] = icmp sgt i32 [[TMP0]], [[TMP1]]
-; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV]] to i16
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = trunc i64 [[IV1]] to i16
 ; CHECK-VF4IC4-NEXT:    [[COND]] = select i1 [[CMP3]], i16 [[TMP2]], i16 [[RDX]]
-; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV1]], 1
 ; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[WIDE_TRIP_COUNT]]
-; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT_LOOPEXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP17:![0-9]+]]
 ; CHECK-VF4IC4:       [[EXIT_LOOPEXIT]]:
-; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i16 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i16 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP9]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC4-NEXT:    br label %[[EXIT]]
 ; CHECK-VF4IC4:       [[EXIT]]:
 ; CHECK-VF4IC4-NEXT:    [[RDX_0_LCSSA:%.*]] = phi i16 [ [[START]], %[[ENTRY]] ], [ [[COND_LCSSA]], %[[EXIT_LOOPEXIT]] ]
diff --git a/llvm/test/Transforms/LoopVectorize/iv-select-cmp.ll b/llvm/test/Transforms/LoopVectorize/iv-select-cmp.ll
index 91c83103bf8f2..c6b0572973302 100644
--- a/llvm/test/Transforms/LoopVectorize/iv-select-cmp.ll
+++ b/llvm/test/Transforms/LoopVectorize/iv-select-cmp.ll
@@ -1948,16 +1948,52 @@ exit:                                             ; preds = %for.body
 }
 
 ; The sentinel value for increasing-IV vectorization is -LONG_MAX, and since
-; the IV hits this value, it is impossible to vectorize this case.
+; the IV hits this value, it is vectorized as a generic last-active reduction.
 define i64 @not_vectorized_select_icmp_iv_out_of_bound(ptr %a, ptr %b, i64 %rdx.start, i64 %n) {
 ; CHECK-VF4IC1-LABEL: define i64 @not_vectorized_select_icmp_iv_out_of_bound(
 ; CHECK-VF4IC1-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]], i64 [[N:%.*]]) {
 ; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC1-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
+; CHECK-VF4IC1-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], 4
+; CHECK-VF4IC1-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-VF4IC1-NEXT:    [[TMP11:%.*]] = add i64 -9223372036854775808, [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 -9223372036854775808, i64 -9223372036854775807, i64 -9223372036854775806, i64 -9223372036854775805>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP7:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[TMP12:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP12]], align 8
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[INDEX]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i64>, ptr [[TMP2]], align 8
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = icmp sgt <4 x i64> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-VF4IC1-NEXT:    [[TMP4:%.*]] = freeze <4 x i1> [[TMP3]]
+; CHECK-VF4IC1-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
+; CHECK-VF4IC1-NEXT:    [[TMP6]] = select i1 [[TMP5]], <4 x i1> [[TMP3]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP7]] = select i1 [[TMP5]], <4 x i64> [[VEC_IND]], <4 x i64> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
+; CHECK-VF4IC1-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP20:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP9:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC1-NEXT:    [[TMP10:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP7]], <4 x i1> [[TMP6]], i64 [[TMP9]])
+; CHECK-VF4IC1-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP11]], %[[MIDDLE_BLOCK]] ], [ -9223372036854775808, %[[ENTRY]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL2:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP10]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[ENTRY]] ]
 ; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY]]:
-; CHECK-VF4IC1-NEXT:    [[IV_J:%.*]] = phi i64 [ [[INC3:%.*]], %[[FOR_BODY]] ], [ -9223372036854775808, %[[ENTRY]] ]
-; CHECK-VF4IC1-NEXT:    [[IV_I:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ 0, %[[ENTRY]] ]
-; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[RDX_START]], %[[ENTRY]] ]
+; CHECK-VF4IC1-NEXT:    [[IV_J:%.*]] = phi i64 [ [[INC3:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC1-NEXT:    [[IV_I:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL2]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
 ; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV_I]]
 ; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i64, ptr [[ARRAYIDX]], align 8
 ; CHECK-VF4IC1-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV_I]]
@@ -1967,19 +2003,55 @@ define i64 @not_vectorized_select_icmp_iv_out_of_bound(ptr %a, ptr %b, i64 %rdx.
 ; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV_I]], 1
 ; CHECK-VF4IC1-NEXT:    [[INC3]] = add nsw i64 [[IV_J]], 1
 ; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[N]]
-; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP21:![0-9]+]]
 ; CHECK-VF4IC1:       [[EXIT]]:
-; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP10]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC1-NEXT:    ret i64 [[COND_LCSSA]]
 ;
 ; CHECK-VF4IC4-LABEL: define i64 @not_vectorized_select_icmp_iv_out_of_bound(
 ; CHECK-VF4IC4-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[RDX_START:%.*]], i64 [[N:%.*]]) {
 ; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
+; CHECK-VF4IC4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], 4
+; CHECK-VF4IC4-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-VF4IC4-NEXT:    [[TMP11:%.*]] = add i64 -9223372036854775808, [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 -9223372036854775808, i64 -9223372036854775807, i64 -9223372036854775806, i64 -9223372036854775805>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP7:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[TMP12:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP12]], align 8
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[INDEX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i64>, ptr [[TMP2]], align 8
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = icmp sgt <4 x i64> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-VF4IC4-NEXT:    [[TMP4:%.*]] = freeze <4 x i1> [[TMP3]]
+; CHECK-VF4IC4-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
+; CHECK-VF4IC4-NEXT:    [[TMP6]] = select i1 [[TMP5]], <4 x i1> [[TMP3]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP7]] = select i1 [[TMP5]], <4 x i64> [[VEC_IND]], <4 x i64> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
+; CHECK-VF4IC4-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP20:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP9:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC4-NEXT:    [[TMP10:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP7]], <4 x i1> [[TMP6]], i64 [[TMP9]])
+; CHECK-VF4IC4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP11]], %[[MIDDLE_BLOCK]] ], [ -9223372036854775808, %[[ENTRY]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL2:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP10]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[ENTRY]] ]
 ; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY]]:
-; CHECK-VF4IC4-NEXT:    [[IV_J:%.*]] = phi i64 [ [[INC3:%.*]], %[[FOR_BODY]] ], [ -9223372036854775808, %[[ENTRY]] ]
-; CHECK-VF4IC4-NEXT:    [[IV_I:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ 0, %[[ENTRY]] ]
-; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[RDX_START]], %[[ENTRY]] ]
+; CHECK-VF4IC4-NEXT:    [[IV_J:%.*]] = phi i64 [ [[INC3:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC4-NEXT:    [[IV_I:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL2]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
 ; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV_I]]
 ; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load i64, ptr [[ARRAYIDX]], align 8
 ; CHECK-VF4IC4-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV_I]]
@@ -1989,9 +2061,9 @@ define i64 @not_vectorized_select_icmp_iv_out_of_bound(ptr %a, ptr %b, i64 %rdx.
 ; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV_I]], 1
 ; CHECK-VF4IC4-NEXT:    [[INC3]] = add nsw i64 [[IV_J]], 1
 ; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[N]]
-; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP21:![0-9]+]]
 ; CHECK-VF4IC4:       [[EXIT]]:
-; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP10]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC4-NEXT:    ret i64 [[COND_LCSSA]]
 ;
 ; CHECK-VF1IC4-LABEL: define i64 @not_vectorized_select_icmp_iv_out_of_bound(
@@ -2042,10 +2114,50 @@ define i64 @not_vectorized_select_icmp_non_const_iv_start_value(ptr %a, ptr %b,
 ; CHECK-VF4IC1-LABEL: define i64 @not_vectorized_select_icmp_non_const_iv_start_value(
 ; CHECK-VF4IC1-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[IVSTART:%.*]], i64 [[RDX_START:%.*]], i64 [[N:%.*]]) {
 ; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC1-NEXT:    [[TMP12:%.*]] = sub i64 [[N]], [[IVSTART]]
+; CHECK-VF4IC1-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP12]], 4
+; CHECK-VF4IC1-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP12]], 4
+; CHECK-VF4IC1-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP12]], [[N_MOD_VF]]
+; CHECK-VF4IC1-NEXT:    [[TMP13:%.*]] = add i64 [[IVSTART]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i64> poison, i64 [[IVSTART]], i64 0
+; CHECK-VF4IC1-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT1]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC1-NEXT:    [[INDUCTION:%.*]] = add <4 x i64> [[BROADCAST_SPLAT2]], <i64 0, i64 1, i64 2, i64 3>
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP8:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP7:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[OFFSET_IDX:%.*]] = add i64 [[IVSTART]], [[INDEX]]
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[OFFSET_IDX]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP2]], align 8
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[OFFSET_IDX]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD3:%.*]] = load <4 x i64>, ptr [[TMP3]], align 8
+; CHECK-VF4IC1-NEXT:    [[TMP4:%.*]] = icmp sgt <4 x i64> [[WIDE_LOAD]], [[WIDE_LOAD3]]
+; CHECK-VF4IC1-NEXT:    [[TMP5:%.*]] = freeze <4 x i1> [[TMP4]]
+; CHECK-VF4IC1-NEXT:    [[TMP6:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP5]])
+; CHECK-VF4IC1-NEXT:    [[TMP7]] = select i1 [[TMP6]], <4 x i1> [[TMP4]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP8]] = select i1 [[TMP6]], <4 x i64> [[VEC_IND]], <4 x i64> [[VEC_PHI]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC1-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
+; CHECK-VF4IC1-NEXT:    [[TMP9:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP9]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP22:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP10:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC1-NEXT:    [[TMP11:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP8]], <4 x i1> [[TMP7]], i64 [[TMP10]])
+; CHECK-VF4IC1-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP12]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP13]], %[[MIDDLE_BLOCK]] ], [ [[IVSTART]], %[[ENTRY]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP11]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[ENTRY]] ]
 ; CHECK-VF4IC1-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC1:       [[FOR_BODY]]:
-; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[IVSTART]], %[[ENTRY]] ]
-; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[RDX_START]], %[[ENTRY]] ]
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
 ; CHECK-VF4IC1-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV]]
 ; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = load i64, ptr [[ARRAYIDX]], align 8
 ; CHECK-VF4IC1-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV]]
@@ -2054,18 +2166,58 @@ define i64 @not_vectorized_select_icmp_non_const_iv_start_value(ptr %a, ptr %b,
 ; CHECK-VF4IC1-NEXT:    [[COND]] = select i1 [[CMP2]], i64 [[IV]], i64 [[RDX]]
 ; CHECK-VF4IC1-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
 ; CHECK-VF4IC1-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[N]]
-; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP23:![0-9]+]]
 ; CHECK-VF4IC1:       [[EXIT]]:
-; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP11]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC1-NEXT:    ret i64 [[COND_LCSSA]]
 ;
 ; CHECK-VF4IC4-LABEL: define i64 @not_vectorized_select_icmp_non_const_iv_start_value(
 ; CHECK-VF4IC4-SAME: ptr [[A:%.*]], ptr [[B:%.*]], i64 [[IVSTART:%.*]], i64 [[RDX_START:%.*]], i64 [[N:%.*]]) {
 ; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC4-NEXT:    [[TMP12:%.*]] = sub i64 [[N]], [[IVSTART]]
+; CHECK-VF4IC4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP12]], 4
+; CHECK-VF4IC4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP12]], 4
+; CHECK-VF4IC4-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP12]], [[N_MOD_VF]]
+; CHECK-VF4IC4-NEXT:    [[TMP13:%.*]] = add i64 [[IVSTART]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[RDX_START]], i64 0
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i64> poison, i64 [[IVSTART]], i64 0
+; CHECK-VF4IC4-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT1]], <4 x i64> poison, <4 x i32> zeroinitializer
+; CHECK-VF4IC4-NEXT:    [[INDUCTION:%.*]] = add <4 x i64> [[BROADCAST_SPLAT2]], <i64 0, i64 1, i64 2, i64 3>
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ [[BROADCAST_SPLAT]], %[[VECTOR_PH]] ], [ [[TMP8:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP7:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[OFFSET_IDX:%.*]] = add i64 [[IVSTART]], [[INDEX]]
+; CHECK-VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[OFFSET_IDX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP2]], align 8
+; CHECK-VF4IC4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[OFFSET_IDX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD3:%.*]] = load <4 x i64>, ptr [[TMP3]], align 8
+; CHECK-VF4IC4-NEXT:    [[TMP4:%.*]] = icmp sgt <4 x i64> [[WIDE_LOAD]], [[WIDE_LOAD3]]
+; CHECK-VF4IC4-NEXT:    [[TMP5:%.*]] = freeze <4 x i1> [[TMP4]]
+; CHECK-VF4IC4-NEXT:    [[TMP6:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP5]])
+; CHECK-VF4IC4-NEXT:    [[TMP7]] = select i1 [[TMP6]], <4 x i1> [[TMP4]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP8]] = select i1 [[TMP6]], <4 x i64> [[VEC_IND]], <4 x i64> [[VEC_PHI]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC4-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
+; CHECK-VF4IC4-NEXT:    [[TMP9:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP9]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP22:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP10:%.*]] = extractelement <4 x i64> [[BROADCAST_SPLAT]], i32 0
+; CHECK-VF4IC4-NEXT:    [[TMP11:%.*]] = call i64 @llvm.experimental.vector.extract.last.active.v4i64(<4 x i64> [[TMP8]], <4 x i1> [[TMP7]], i64 [[TMP10]])
+; CHECK-VF4IC4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP12]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[TMP13]], %[[MIDDLE_BLOCK]] ], [ [[IVSTART]], %[[ENTRY]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i64 [ [[TMP11]], %[[MIDDLE_BLOCK]] ], [ [[RDX_START]], %[[ENTRY]] ]
 ; CHECK-VF4IC4-NEXT:    br label %[[FOR_BODY:.*]]
 ; CHECK-VF4IC4:       [[FOR_BODY]]:
-; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[IVSTART]], %[[ENTRY]] ]
-; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[RDX_START]], %[[ENTRY]] ]
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], %[[FOR_BODY]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i64 [ [[COND:%.*]], %[[FOR_BODY]] ], [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ]
 ; CHECK-VF4IC4-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[IV]]
 ; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = load i64, ptr [[ARRAYIDX]], align 8
 ; CHECK-VF4IC4-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i64, ptr [[B]], i64 [[IV]]
@@ -2074,9 +2226,9 @@ define i64 @not_vectorized_select_icmp_non_const_iv_start_value(ptr %a, ptr %b,
 ; CHECK-VF4IC4-NEXT:    [[COND]] = select i1 [[CMP2]], i64 [[IV]], i64 [[RDX]]
 ; CHECK-VF4IC4-NEXT:    [[INC]] = add nuw nsw i64 [[IV]], 1
 ; CHECK-VF4IC4-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], [[N]]
-; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[FOR_BODY]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[FOR_BODY]], !llvm.loop [[LOOP23:![0-9]+]]
 ; CHECK-VF4IC4:       [[EXIT]]:
-; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[COND_LCSSA:%.*]] = phi i64 [ [[COND]], %[[FOR_BODY]] ], [ [[TMP11]], %[[MIDDLE_BLOCK]] ]
 ; CHECK-VF4IC4-NEXT:    ret i64 [[COND_LCSSA]]
 ;
 ; CHECK-VF1IC4-LABEL: define i64 @not_vectorized_select_icmp_non_const_iv_start_value(
diff --git a/llvm/test/Transforms/LoopVectorize/select-cmp.ll b/llvm/test/Transforms/LoopVectorize/select-cmp.ll
index e4922d3e4f627..8b62693de87fc 100644
--- a/llvm/test/Transforms/LoopVectorize/select-cmp.ll
+++ b/llvm/test/Transforms/LoopVectorize/select-cmp.ll
@@ -1128,27 +1128,124 @@ exit:                                     ; preds = %loop
   ret float %sel
 }
 
-; We don't support selecting loop-variant values.
 define i32 @select_variant_i32_from_icmp(ptr %v1, ptr %v2, i64 %n) {
-; CHECK-LABEL: define i32 @select_variant_i32_from_icmp(
-; CHECK-SAME: ptr [[V1:%.*]], ptr [[V2:%.*]], i64 [[N:%.*]]) {
-; CHECK-NEXT:  [[ENTRY:.*]]:
-; CHECK-NEXT:    br label %[[LOOP:.*]]
-; CHECK:       [[LOOP]]:
-; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
-; CHECK-NEXT:    [[RDX:%.*]] = phi i32 [ 3, %[[ENTRY]] ], [ [[SEL:%.*]], %[[LOOP]] ]
-; CHECK-NEXT:    [[GEP_V1_IV:%.*]] = getelementptr inbounds i32, ptr [[V1]], i64 [[IV]]
-; CHECK-NEXT:    [[LOAD_V1_IV:%.*]] = load i32, ptr [[GEP_V1_IV]], align 4
-; CHECK-NEXT:    [[GEP_V2_IV:%.*]] = getelementptr inbounds i32, ptr [[V2]], i64 [[IV]]
-; CHECK-NEXT:    [[LOAD_V2_IV:%.*]] = load i32, ptr [[GEP_V2_IV]], align 4
-; CHECK-NEXT:    [[CMP_V1_IV_3:%.*]] = icmp eq i32 [[LOAD_V1_IV]], 3
-; CHECK-NEXT:    [[SEL]] = select i1 [[CMP_V1_IV_3]], i32 [[RDX]], i32 [[LOAD_V2_IV]]
-; CHECK-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
-; CHECK-NEXT:    [[EXIT_COND:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
-; CHECK-NEXT:    br i1 [[EXIT_COND]], label %[[EXIT:.*]], label %[[LOOP]]
-; CHECK:       [[EXIT]]:
-; CHECK-NEXT:    [[SEL_LCSSA:%.*]] = phi i32 [ [[SEL]], %[[LOOP]] ]
-; CHECK-NEXT:    ret i32 [[SEL_LCSSA]]
+; CHECK-VF4IC1-LABEL: define i32 @select_variant_i32_from_icmp(
+; CHECK-VF4IC1-SAME: ptr [[V1:%.*]], ptr [[V2:%.*]], i64 [[N:%.*]]) {
+; CHECK-VF4IC1-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC1-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
+; CHECK-VF4IC1-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC1:       [[VECTOR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], 4
+; CHECK-VF4IC1-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-VF4IC1-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC1:       [[VECTOR_BODY]]:
+; CHECK-VF4IC1-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 3), %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP5:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC1-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i32, ptr [[V1]], i64 [[INDEX]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP0]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[V2]], i64 [[INDEX]]
+; CHECK-VF4IC1-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP1]], align 4
+; CHECK-VF4IC1-NEXT:    [[TMP2:%.*]] = icmp eq <4 x i32> [[WIDE_LOAD]], splat (i32 3)
+; CHECK-VF4IC1-NEXT:    [[TMP3:%.*]] = freeze <4 x i1> [[TMP2]]
+; CHECK-VF4IC1-NEXT:    [[TMP4:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP3]])
+; CHECK-VF4IC1-NEXT:    [[TMP5]] = select i1 [[TMP4]], <4 x i1> [[TMP2]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC1-NEXT:    [[TMP6]] = select i1 [[TMP4]], <4 x i32> [[VEC_PHI]], <4 x i32> [[WIDE_LOAD1]]
+; CHECK-VF4IC1-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC1-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP14:![0-9]+]]
+; CHECK-VF4IC1:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC1-NEXT:    [[TMP8:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP6]], <4 x i1> [[TMP5]], i32 3)
+; CHECK-VF4IC1-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-VF4IC1-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC1:       [[SCALAR_PH]]:
+; CHECK-VF4IC1-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-VF4IC1-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP8]], %[[MIDDLE_BLOCK]] ], [ 3, %[[ENTRY]] ]
+; CHECK-VF4IC1-NEXT:    br label %[[LOOP:.*]]
+; CHECK-VF4IC1:       [[LOOP]]:
+; CHECK-VF4IC1-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; CHECK-VF4IC1-NEXT:    [[RDX:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[SEL:%.*]], %[[LOOP]] ]
+; CHECK-VF4IC1-NEXT:    [[GEP_V1_IV:%.*]] = getelementptr inbounds i32, ptr [[V1]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[LOAD_V1_IV:%.*]] = load i32, ptr [[GEP_V1_IV]], align 4
+; CHECK-VF4IC1-NEXT:    [[GEP_V2_IV:%.*]] = getelementptr inbounds i32, ptr [[V2]], i64 [[IV]]
+; CHECK-VF4IC1-NEXT:    [[LOAD_V2_IV:%.*]] = load i32, ptr [[GEP_V2_IV]], align 4
+; CHECK-VF4IC1-NEXT:    [[CMP_V1_IV_3:%.*]] = icmp eq i32 [[LOAD_V1_IV]], 3
+; CHECK-VF4IC1-NEXT:    [[SEL]] = select i1 [[CMP_V1_IV_3]], i32 [[RDX]], i32 [[LOAD_V2_IV]]
+; CHECK-VF4IC1-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC1-NEXT:    [[EXIT_COND:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-VF4IC1-NEXT:    br i1 [[EXIT_COND]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP15:![0-9]+]]
+; CHECK-VF4IC1:       [[EXIT]]:
+; CHECK-VF4IC1-NEXT:    [[SEL_LCSSA:%.*]] = phi i32 [ [[SEL]], %[[LOOP]] ], [ [[TMP8]], %[[MIDDLE_BLOCK]] ]
+; CHECK-VF4IC1-NEXT:    ret i32 [[SEL_LCSSA]]
+;
+; CHECK-VF4IC4-LABEL: define i32 @select_variant_i32_from_icmp(
+; CHECK-VF4IC4-SAME: ptr [[V1:%.*]], ptr [[V2:%.*]], i64 [[N:%.*]]) {
+; CHECK-VF4IC4-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF4IC4-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
+; CHECK-VF4IC4-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-VF4IC4:       [[VECTOR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], 4
+; CHECK-VF4IC4-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-VF4IC4-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK-VF4IC4:       [[VECTOR_BODY]]:
+; CHECK-VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ splat (i32 3), %[[VECTOR_PH]] ], [ [[TMP27:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[LAST_ACTIVE_MASK:%.*]] = phi <4 x i1> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP23:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i32, ptr [[V1]], i64 [[INDEX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD9:%.*]] = load <4 x i32>, ptr [[TMP0]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i32, ptr [[V2]], i64 [[INDEX]]
+; CHECK-VF4IC4-NEXT:    [[WIDE_LOAD13:%.*]] = load <4 x i32>, ptr [[TMP4]], align 4
+; CHECK-VF4IC4-NEXT:    [[TMP11:%.*]] = icmp eq <4 x i32> [[WIDE_LOAD9]], splat (i32 3)
+; CHECK-VF4IC4-NEXT:    [[TMP17:%.*]] = freeze <4 x i1> [[TMP11]]
+; CHECK-VF4IC4-NEXT:    [[TMP19:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP17]])
+; CHECK-VF4IC4-NEXT:    [[TMP23]] = select i1 [[TMP19]], <4 x i1> [[TMP11]], <4 x i1> [[LAST_ACTIVE_MASK]]
+; CHECK-VF4IC4-NEXT:    [[TMP27]] = select i1 [[TMP19]], <4 x i32> [[VEC_PHI]], <4 x i32> [[WIDE_LOAD13]]
+; CHECK-VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-VF4IC4-NEXT:    [[TMP28:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[TMP28]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP14:![0-9]+]]
+; CHECK-VF4IC4:       [[MIDDLE_BLOCK]]:
+; CHECK-VF4IC4-NEXT:    [[TMP8:%.*]] = call i32 @llvm.experimental.vector.extract.last.active.v4i32(<4 x i32> [[TMP27]], <4 x i1> [[TMP23]], i32 3)
+; CHECK-VF4IC4-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-VF4IC4-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK-VF4IC4:       [[SCALAR_PH]]:
+; CHECK-VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; CHECK-VF4IC4-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP8]], %[[MIDDLE_BLOCK]] ], [ 3, %[[ENTRY]] ]
+; CHECK-VF4IC4-NEXT:    br label %[[LOOP:.*]]
+; CHECK-VF4IC4:       [[LOOP]]:
+; CHECK-VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; CHECK-VF4IC4-NEXT:    [[RDX:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[SEL:%.*]], %[[LOOP]] ]
+; CHECK-VF4IC4-NEXT:    [[GEP_V1_IV:%.*]] = getelementptr inbounds i32, ptr [[V1]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[LOAD_V1_IV:%.*]] = load i32, ptr [[GEP_V1_IV]], align 4
+; CHECK-VF4IC4-NEXT:    [[GEP_V2_IV:%.*]] = getelementptr inbounds i32, ptr [[V2]], i64 [[IV]]
+; CHECK-VF4IC4-NEXT:    [[LOAD_V2_IV:%.*]] = load i32, ptr [[GEP_V2_IV]], align 4
+; CHECK-VF4IC4-NEXT:    [[CMP_V1_IV_3:%.*]] = icmp eq i32 [[LOAD_V1_IV]], 3
+; CHECK-VF4IC4-NEXT:    [[SEL]] = select i1 [[CMP_V1_IV_3]], i32 [[RDX]], i32 [[LOAD_V2_IV]]
+; CHECK-VF4IC4-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF4IC4-NEXT:    [[EXIT_COND:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-VF4IC4-NEXT:    br i1 [[EXIT_COND]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP15:![0-9]+]]
+; CHECK-VF4IC4:       [[EXIT]]:
+; CHECK-VF4IC4-NEXT:    [[SEL_LCSSA:%.*]] = phi i32 [ [[SEL]], %[[LOOP]] ], [ [[TMP8]], %[[MIDDLE_BLOCK]] ]
+; CHECK-VF4IC4-NEXT:    ret i32 [[SEL_LCSSA]]
+;
+; CHECK-VF1IC4-LABEL: define i32 @select_variant_i32_from_icmp(
+; CHECK-VF1IC4-SAME: ptr [[V1:%.*]], ptr [[V2:%.*]], i64 [[N:%.*]]) {
+; CHECK-VF1IC4-NEXT:  [[ENTRY:.*]]:
+; CHECK-VF1IC4-NEXT:    br label %[[LOOP:.*]]
+; CHECK-VF1IC4:       [[LOOP]]:
+; CHECK-VF1IC4-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; CHECK-VF1IC4-NEXT:    [[RDX:%.*]] = phi i32 [ 3, %[[ENTRY]] ], [ [[SEL:%.*]], %[[LOOP]] ]
+; CHECK-VF1IC4-NEXT:    [[GEP_V1_IV:%.*]] = getelementptr inbounds i32, ptr [[V1]], i64 [[IV]]
+; CHECK-VF1IC4-NEXT:    [[LOAD_V1_IV:%.*]] = load i32, ptr [[GEP_V1_IV]], align 4
+; CHECK-VF1IC4-NEXT:    [[GEP_V2_IV:%.*]] = getelementptr inbounds i32, ptr [[V2]], i64 [[IV]]
+; CHECK-VF1IC4-NEXT:    [[LOAD_V2_IV:%.*]] = load i32, ptr [[GEP_V2_IV]], align 4
+; CHECK-VF1IC4-NEXT:    [[CMP_V1_IV_3:%.*]] = icmp eq i32 [[LOAD_V1_IV]], 3
+; CHECK-VF1IC4-NEXT:    [[SEL]] = select i1 [[CMP_V1_IV_3]], i32 [[RDX]], i32 [[LOAD_V2_IV]]
+; CHECK-VF1IC4-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-VF1IC4-NEXT:    [[EXIT_COND:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-VF1IC4-NEXT:    br i1 [[EXIT_COND]], label %[[EXIT:.*]], label %[[LOOP]]
+; CHECK-VF1IC4:       [[EXIT]]:
+; CHECK-VF1IC4-NEXT:    [[SEL_LCSSA:%.*]] = phi i32 [ [[SEL]], %[[LOOP]] ]
+; CHECK-VF1IC4-NEXT:    ret i32 [[SEL_LCSSA]]
 ;
 entry:
   br label %loop
@@ -1220,6 +1317,8 @@ exit:                                     ; preds = %loop
 ; CHECK-VF4IC1: [[LOOP11]] = distinct !{[[LOOP11]], [[META2]], [[META1]]}
 ; CHECK-VF4IC1: [[LOOP12]] = distinct !{[[LOOP12]], [[META1]], [[META2]]}
 ; CHECK-VF4IC1: [[LOOP13]] = distinct !{[[LOOP13]], [[META2]], [[META1]]}
+; CHECK-VF4IC1: [[LOOP14]] = distinct !{[[LOOP14]], [[META1]], [[META2]]}
+; CHECK-VF4IC1: [[LOOP15]] = distinct !{[[LOOP15]], [[META2]], [[META1]]}
 ;.
 ; CHECK-VF4IC4: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
 ; CHECK-VF4IC4: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
@@ -1235,6 +1334,8 @@ exit:                                     ; preds = %loop
 ; CHECK-VF4IC4: [[LOOP11]] = distinct !{[[LOOP11]], [[META2]], [[META1]]}
 ; CHECK-VF4IC4: [[LOOP12]] = distinct !{[[LOOP12]], [[META1]], [[META2]]}
 ; CHECK-VF4IC4: [[LOOP13]] = distinct !{[[LOOP13]], [[META2]], [[META1]]}
+; CHECK-VF4IC4: [[LOOP14]] = distinct !{[[LOOP14]], [[META1]], [[META2]]}
+; CHECK-VF4IC4: [[LOOP15]] = distinct !{[[LOOP15]], [[META2]], [[META1]]}
 ;.
 ; CHECK-VF1IC4: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
 ; CHECK-VF1IC4: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}

>From 0c902a66416871cbc7ffe9ff11094d899f2af04b Mon Sep 17 00:00:00 2001
From: Graham Hunter <graham.hunter at arm.com>
Date: Tue, 11 Nov 2025 10:26:04 +0000
Subject: [PATCH 2/6] Apply suggestion from @MacDue

Co-authored-by: Benjamin Maxwell <macdue at dueutil.tech>
---
 llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 0bbad6f657a24..288eebe66d1c0 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1275,7 +1275,6 @@ class LoopVectorizationCostModel {
                            "from latch block\n");
       return true;
     }
-
     if (IsVectorizing && InterleaveInfo.requiresScalarEpilogue()) {
       LLVM_DEBUG(dbgs() << "LV: Loop requires scalar epilogue: "
                            "interleaved group requires scalar epilogue\n");

>From 41bbf8d5acc336537dc85628c880b6af127f2d08 Mon Sep 17 00:00:00 2001
From: Graham Hunter <graham.hunter at arm.com>
Date: Tue, 11 Nov 2025 16:02:27 +0000
Subject: [PATCH 3/6] Remove LVL param

---
 .../Transforms/Vectorize/LoopVectorize.cpp    |   6 +-
 .../Transforms/Vectorize/VPlanTransforms.cpp  | 101 +++++++++---------
 .../Transforms/Vectorize/VPlanTransforms.h    |   4 +-
 3 files changed, 51 insertions(+), 60 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 288eebe66d1c0..b7b04d91e1d95 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -8501,7 +8501,7 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(
 
   // Create whole-vector selects for find-last recurrences.
   VPlanTransforms::runPass(VPlanTransforms::convertFindLastRecurrences, *Plan,
-                           RecipeBuilder, Legal);
+                           RecipeBuilder);
 
   if (useActiveLaneMask(Style)) {
     // TODO: Move checks to VPlanTransforms::addActiveLaneMask once
@@ -9508,10 +9508,6 @@ static SmallVector<Instruction *> preparePlanForEpilogueVectorLoop(
           continue;
         }
       }
-    } else if (isa<VPLastActiveMaskPHIRecipe>(R)) {
-      // LastActiveMasks are only used as part of FindLast reductions,
-      // and aren't passed to the scalar loop.
-      continue;
     } else {
       // Retrieve the induction resume values for wide inductions from
       // their original phi nodes in the scalar loop.
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index 8fbd3686af117..c62e53952b9df 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -36,7 +36,6 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/TypeSize.h"
 #include "llvm/Transforms/Utils/ScalarEvolutionExpander.h"
-#include "llvm/Transforms/Vectorize/LoopVectorizationLegality.h"
 
 using namespace llvm;
 using namespace VPlanPatternMatch;
@@ -4596,9 +4595,7 @@ void VPlanTransforms::addExitUsersForFirstOrderRecurrences(VPlan &Plan,
 }
 
 void VPlanTransforms::convertFindLastRecurrences(
-    VPlan &Plan, VPRecipeBuilder &RecipeBuilder,
-    LoopVectorizationLegality *Legal) {
-  assert(Legal && "Need valid LoopVecLegality");
+    VPlan &Plan, VPRecipeBuilder &RecipeBuilder) {
 
   // May need to do something better than this?
   if (Plan.hasScalarVFOnly())
@@ -4619,55 +4616,55 @@ void VPlanTransforms::convertFindLastRecurrences(
   // middle.block:
   //   result = extract-last-active new.data, new.mask, default.val
 
-  for (const auto &[Phi, RdxDesc] : Legal->getReductionVars()) {
-    if (RecurrenceDescriptor::isFindLastRecurrenceKind(
-            RdxDesc.getRecurrenceKind())) {
-      VPRecipeBase *PhiR = RecipeBuilder.getRecipe(Phi);
-      VPBuilder Builder = VPBuilder::getToInsertAfter(PhiR);
-
-      // Add mask phi
-      VPValue *False =
-          Plan.getOrAddLiveIn(ConstantInt::getFalse(Phi->getContext()));
-      auto *MaskPHI = new VPLastActiveMaskPHIRecipe(False, DebugLoc());
-      Builder.insert(MaskPHI);
-
-      // Find the condition for the select
-      SelectInst *Select = cast<SelectInst>(RdxDesc.getLoopExitInstr());
-      auto *SR = cast<VPWidenSelectRecipe>(RecipeBuilder.getRecipe(Select));
-      VPValue *Cond = SR->getCond();
-
-      // Add select for mask
-      Builder.setInsertPoint(SR);
-      VPValue *AnyOf = Builder.createNaryOp(VPInstruction::AnyOf, {Cond});
-      VPValue *MaskSelect = Builder.createSelect(AnyOf, Cond, MaskPHI);
-      MaskPHI->addOperand(MaskSelect);
-
-      // Replace select for data
-      VPValue *DataSelect = Builder.createSelect(
-          AnyOf, SR->getOperand(1), SR->getOperand(2), SR->getDebugLoc());
-      SR->replaceAllUsesWith(DataSelect);
-      SR->eraseFromParent();
-
-      // Find final reduction and replace it with an
-      // extract.last.active intrinsic.
-      VPInstruction *RdxResult = nullptr;
-      for (VPUser *U : DataSelect->users()) {
-        VPInstruction *I = dyn_cast<VPInstruction>(U);
-        if (I && I->getOpcode() == VPInstruction::ComputeReductionResult) {
-          RdxResult = I;
-          break;
-        }
-      }
+  for (auto &Phi : Plan.getVectorLoopRegion()->getEntryBasicBlock()->phis()) {
+    auto *PhiR = dyn_cast<VPReductionPHIRecipe>(&Phi);
+    if (!PhiR || !RecurrenceDescriptor::isFindLastRecurrenceKind(
+                     PhiR->getRecurrenceKind()))
+      continue;
 
-      assert(RdxResult);
-      Builder.setInsertPoint(RdxResult);
-      VPValue *Default = RecipeBuilder.getVPValueOrAddLiveIn(
-          RdxDesc.getRecurrenceStartValue());
-      auto *ExtractLastActive = Builder.createNaryOp(
-          VPInstruction::ExtractLastActive, {DataSelect, MaskSelect, Default},
-          RdxResult->getDebugLoc());
-      RdxResult->replaceAllUsesWith(ExtractLastActive);
-      RdxResult->eraseFromParent();
+    // Find the condition for the select
+    auto *SR = dyn_cast<VPWidenSelectRecipe>(&PhiR->getBackedgeRecipe());
+    if (!SR)
+      continue;
+    VPValue *Cond = SR->getCond();
+
+    // Add mask phi
+    VPBuilder Builder = VPBuilder::getToInsertAfter(PhiR);
+    VPValue *False = Plan.getOrAddLiveIn(
+        ConstantInt::getFalse(PhiR->getUnderlyingValue()->getContext()));
+    auto *MaskPHI = new VPLastActiveMaskPHIRecipe(False, DebugLoc());
+    Builder.insert(MaskPHI);
+
+    // Add select for mask
+    Builder.setInsertPoint(SR);
+    VPValue *AnyOf = Builder.createNaryOp(VPInstruction::AnyOf, {Cond});
+    VPValue *MaskSelect = Builder.createSelect(AnyOf, Cond, MaskPHI);
+    MaskPHI->addOperand(MaskSelect);
+
+    // Replace select for data
+    VPValue *DataSelect = Builder.createSelect(
+        AnyOf, SR->getOperand(1), SR->getOperand(2), SR->getDebugLoc());
+    SR->replaceAllUsesWith(DataSelect);
+    SR->eraseFromParent();
+
+    // Find final reduction and replace it with an
+    // extract.last.active intrinsic.
+    VPInstruction *RdxResult = nullptr;
+    for (VPUser *U : DataSelect->users()) {
+      VPInstruction *I = dyn_cast<VPInstruction>(U);
+      if (I && I->getOpcode() == VPInstruction::ComputeReductionResult) {
+        RdxResult = I;
+        break;
+      }
     }
+
+    assert(RdxResult);
+    Builder.setInsertPoint(RdxResult);
+    auto *ExtractLastActive =
+        Builder.createNaryOp(VPInstruction::ExtractLastActive,
+                             {DataSelect, MaskSelect, PhiR->getStartValue()},
+                             RdxResult->getDebugLoc());
+    RdxResult->replaceAllUsesWith(ExtractLastActive);
+    RdxResult->eraseFromParent();
   }
 }
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.h b/llvm/lib/Transforms/Vectorize/VPlanTransforms.h
index 71aa6f9457c1c..d8bd8e2d6a966 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.h
@@ -23,7 +23,6 @@ namespace llvm {
 
 class InductionDescriptor;
 class Instruction;
-class LoopVectorizationLegality;
 class PHINode;
 class ScalarEvolution;
 class PredicatedScalarEvolution;
@@ -383,8 +382,7 @@ struct VPlanTransforms {
   /// for entire vectors for both the latest mask containing at least one active
   /// element and the corresponding data vector.
   static void convertFindLastRecurrences(VPlan &Plan,
-                                         VPRecipeBuilder &RecipeBuilder,
-                                         LoopVectorizationLegality *Legal);
+                                         VPRecipeBuilder &RecipeBuilder);
 };
 
 } // namespace llvm

>From e78b2087c794f665420ebbf8ff26c64cf36725bd Mon Sep 17 00:00:00 2001
From: Graham Hunter <graham.hunter at arm.com>
Date: Wed, 12 Nov 2025 11:40:02 +0000
Subject: [PATCH 4/6] Remove VPLastActiveMaskPHIRecipe

---
 llvm/lib/Analysis/IVDescriptors.cpp           |  8 ----
 .../Transforms/Vectorize/LoopVectorize.cpp    |  2 +-
 llvm/lib/Transforms/Vectorize/VPlan.h         | 43 +++----------------
 .../Transforms/Vectorize/VPlanAnalysis.cpp    | 16 +++----
 .../lib/Transforms/Vectorize/VPlanRecipes.cpp | 26 +++--------
 .../Transforms/Vectorize/VPlanTransforms.cpp  |  2 +-
 llvm/lib/Transforms/Vectorize/VPlanUtils.cpp  |  2 +-
 .../conditional-scalar-assignment-vplan.ll    |  4 +-
 8 files changed, 25 insertions(+), 78 deletions(-)

diff --git a/llvm/lib/Analysis/IVDescriptors.cpp b/llvm/lib/Analysis/IVDescriptors.cpp
index 7705c0459d829..a17342f8282f5 100644
--- a/llvm/lib/Analysis/IVDescriptors.cpp
+++ b/llvm/lib/Analysis/IVDescriptors.cpp
@@ -724,14 +724,6 @@ RecurrenceDescriptor::isFindPattern(RecurKind Kind, Loop *TheLoop,
 
     // FIXME: Support more complex patterns, including multiple selects.
     // The Select must be used only outside the loop and by the PHI.
-    for (User *U : I->users()) {
-      if (U == OrigPhi)
-        continue;
-      if (auto *UI = dyn_cast<Instruction>(U); UI && !TheLoop->contains(UI))
-        continue;
-      return InstDesc(false, I);
-    }
-
     return InstDesc(I, RecurKind::FindLast);
   }
 
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index b7b04d91e1d95..283e8324ecb6a 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -9311,7 +9311,7 @@ static void preparePlanForMainVectorLoop(VPlan &MainPlan, VPlan &EpiPlan) {
   SmallPtrSet<PHINode *, 2> EpiWidenedPhis;
   for (VPRecipeBase &R :
        EpiPlan.getVectorLoopRegion()->getEntryBasicBlock()->phis()) {
-    if (isa<VPCanonicalIVPHIRecipe, VPLastActiveMaskPHIRecipe>(&R))
+    if (isa<VPCanonicalIVPHIRecipe>(&R))
       continue;
     EpiWidenedPhis.insert(
         cast<PHINode>(R.getVPSingleValue()->getUnderlyingValue()));
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index f0fe89ca9133d..96ccddc63b156 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -2276,8 +2276,9 @@ class LLVM_ABI_FOR_TEST VPWidenPHIRecipe : public VPSingleDefRecipe,
   }
 
   VPWidenPHIRecipe *clone() override {
-    auto *C = new VPWidenPHIRecipe(cast<PHINode>(getUnderlyingValue()),
-                                   getOperand(0), getDebugLoc(), Name);
+    auto *C =
+        new VPWidenPHIRecipe(cast_if_present<PHINode>(getUnderlyingValue()),
+                             getOperand(0), getDebugLoc(), Name);
     for (VPValue *Op : llvm::drop_begin(operands()))
       C->addOperand(Op);
     return C;
@@ -2290,6 +2291,10 @@ class LLVM_ABI_FOR_TEST VPWidenPHIRecipe : public VPSingleDefRecipe,
   /// Generate the phi/select nodes.
   void execute(VPTransformState &State) override;
 
+  /// Return the cost of this VPWidenPHIRecipe.
+  InstructionCost computeCost(ElementCount VF,
+                              VPCostContext &Ctx) const override;
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
   /// Print the recipe.
   void print(raw_ostream &O, const Twine &Indent,
@@ -3559,40 +3564,6 @@ class VPActiveLaneMaskPHIRecipe : public VPHeaderPHIRecipe {
 #endif
 };
 
-// TODO: Can we unify the PHI recipe hierarchy a bit? VPPredInstPHISC is close
-//       to this (just a PHI of a predicate), but isn't a header phi so can't
-//       be used for the mask of FindLastActive reductions.
-//
-// This is basically a clone of VPActiveLaneMaskPHIRecipe, but won't run into
-// problems with transforms that expect there to only be a single ALM PHI, and
-// can be ignored by other code looking for a (non-existent) underlying value.
-class VPLastActiveMaskPHIRecipe : public VPHeaderPHIRecipe {
-public:
-  VPLastActiveMaskPHIRecipe(VPValue *StartMask, DebugLoc DL)
-      : VPHeaderPHIRecipe(VPDef::VPLastActiveMaskPHISC, nullptr, StartMask,
-                          DL) {}
-
-  ~VPLastActiveMaskPHIRecipe() override = default;
-
-  VPLastActiveMaskPHIRecipe *clone() override {
-    auto *R = new VPLastActiveMaskPHIRecipe(getOperand(0), getDebugLoc());
-    if (getNumOperands() == 2)
-      R->addOperand(getOperand(1));
-    return R;
-  }
-
-  VP_CLASSOF_IMPL(VPDef::VPLastActiveMaskPHISC);
-
-  /// Generate the mask phi
-  void execute(VPTransformState &State) override;
-
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-  /// Print the recipe
-  void print(raw_ostream &O, const Twine &Indent,
-             VPSlotTracker &SlotTracker) const override;
-#endif
-};
-
 /// A recipe for generating the phi node for the current index of elements,
 /// adjusted in accordance with EVL value. It starts at the start value of the
 /// canonical induction and gets incremented by EVL in each iteration of the
diff --git a/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp b/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp
index 3168d6652f03b..eada2c65bc820 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp
@@ -277,14 +277,14 @@ Type *VPTypeAnalysis::inferScalarType(const VPValue *V) {
       TypeSwitch<const VPRecipeBase *, Type *>(V->getDefiningRecipe())
           .Case<VPActiveLaneMaskPHIRecipe, VPCanonicalIVPHIRecipe,
                 VPFirstOrderRecurrencePHIRecipe, VPReductionPHIRecipe,
-                VPWidenPointerInductionRecipe, VPEVLBasedIVPHIRecipe,
-                VPLastActiveMaskPHIRecipe>([this](const auto *R) {
-            // Handle header phi recipes, except VPWidenIntOrFpInduction
-            // which needs special handling due it being possibly truncated.
-            // TODO: consider inferring/caching type of siblings, e.g.,
-            // backedge value, here and in cases below.
-            return inferScalarType(R->getStartValue());
-          })
+                VPWidenPointerInductionRecipe, VPEVLBasedIVPHIRecipe>(
+              [this](const auto *R) {
+                // Handle header phi recipes, except VPWidenIntOrFpInduction
+                // which needs special handling due it being possibly truncated.
+                // TODO: consider inferring/caching type of siblings, e.g.,
+                // backedge value, here and in cases below.
+                return inferScalarType(R->getStartValue());
+              })
           .Case<VPWidenIntOrFpInductionRecipe, VPDerivedIVRecipe>(
               [](const auto *R) { return R->getScalarType(); })
           .Case<VPReductionRecipe, VPPredInstPHIRecipe, VPWidenPHIRecipe,
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 7979cc12ea9f9..c2c105dc21345 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -4476,6 +4476,11 @@ void VPWidenPHIRecipe::execute(VPTransformState &State) {
   State.set(this, VecPhi);
 }
 
+InstructionCost VPWidenPHIRecipe::computeCost(ElementCount VF,
+                                              VPCostContext &Ctx) const {
+  return Ctx.TTI.getCFInstrCost(Instruction::PHI, Ctx.CostKind);
+}
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 void VPWidenPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                              VPSlotTracker &SlotTracker) const {
@@ -4510,27 +4515,6 @@ void VPActiveLaneMaskPHIRecipe::print(raw_ostream &O, const Twine &Indent,
 }
 #endif
 
-void VPLastActiveMaskPHIRecipe::execute(VPTransformState &State) {
-  BasicBlock *VectorPH =
-      State.CFG.VPBB2IRBB.at(getParent()->getCFGPredecessor(0));
-  Value *StartMask = State.get(getOperand(0));
-  PHINode *Phi =
-      State.Builder.CreatePHI(StartMask->getType(), 2, "last.active.mask");
-  Phi->addIncoming(StartMask, VectorPH);
-  State.set(this, Phi);
-}
-
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-void VPLastActiveMaskPHIRecipe::print(raw_ostream &O, const Twine &Indent,
-                                      VPSlotTracker &SlotTracker) const {
-  O << Indent << "LAST-ACTIVE-MASK-PHI ";
-
-  printAsOperand(O, SlotTracker);
-  O << " = phi ";
-  printOperands(O, SlotTracker);
-}
-#endif
-
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 void VPEVLBasedIVPHIRecipe::print(raw_ostream &O, const Twine &Indent,
                                   VPSlotTracker &SlotTracker) const {
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index c62e53952b9df..8fa8b95210ed1 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -4632,7 +4632,7 @@ void VPlanTransforms::convertFindLastRecurrences(
     VPBuilder Builder = VPBuilder::getToInsertAfter(PhiR);
     VPValue *False = Plan.getOrAddLiveIn(
         ConstantInt::getFalse(PhiR->getUnderlyingValue()->getContext()));
-    auto *MaskPHI = new VPLastActiveMaskPHIRecipe(False, DebugLoc());
+    auto *MaskPHI = new VPWidenPHIRecipe(nullptr, False, DebugLoc());
     Builder.insert(MaskPHI);
 
     // Add select for mask
diff --git a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
index 67cf86b16c6fb..e22c5dfdb9f38 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
@@ -47,7 +47,7 @@ VPValue *vputils::getOrCreateVPValueForSCEVExpr(VPlan &Plan, const SCEV *Expr) {
 }
 
 bool vputils::isHeaderMask(const VPValue *V, const VPlan &Plan) {
-  if (isa<VPActiveLaneMaskPHIRecipe, VPLastActiveMaskPHIRecipe>(V))
+  if (isa<VPActiveLaneMaskPHIRecipe>(V))
     return true;
 
   auto IsWideCanonicalIV = [](VPValue *A) {
diff --git a/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll b/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll
index e802093fc7886..6d63e2f927df1 100644
--- a/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll
+++ b/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll
@@ -48,7 +48,7 @@ exit:
 ; CHECK-NEXT:   vector.body:
 ; CHECK-NEXT:     EMIT vp<%3> = CANONICAL-INDUCTION ir<0>, vp<%index.next>
 ; CHECK-NEXT:     WIDEN-REDUCTION-PHI ir<%data.phi> = phi ir<-1>, vp<%9>
-; CHECK-NEXT:     LAST-ACTIVE-MASK-PHI vp<%4> = phi ir<false>, vp<%8>
+; CHECK-NEXT:     WIDEN-PHI vp<%4> = phi [ ir<false>, vector.ph ], [ vp<%8>, vector.body ]
 ; CHECK-NEXT:     vp<%5> = SCALAR-STEPS vp<%3>, ir<1>, vp<%0>
 ; CHECK-NEXT:     CLONE ir<%ld.addr> = getelementptr inbounds ir<%data>, vp<%5>
 ; CHECK-NEXT:     vp<%6> = vector-pointer ir<%ld.addr>
@@ -95,7 +95,7 @@ exit:
 ; CHECK-NEXT: Cost of 1 for VF vscale x 1: exit condition instruction   %exit.cmp = icmp eq i64 %iv.next, %N
 ; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<%3> = CANONICAL-INDUCTION ir<0>, vp<%index.next>
 ; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN-REDUCTION-PHI ir<%data.phi> = phi ir<-1>, vp<%9>
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: LAST-ACTIVE-MASK-PHI vp<%4> = phi ir<false>, vp<%8>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN-PHI vp<%4> = phi [ ir<false>, vector.ph ], [ vp<%8>, vector.body ]
 ; CHECK-NEXT: Cost of 0 for VF vscale x 1: vp<%5> = SCALAR-STEPS vp<%3>, ir<1>, vp<%0>
 ; CHECK-NEXT: Cost of 0 for VF vscale x 1: CLONE ir<%ld.addr> = getelementptr inbounds ir<%data>, vp<%5>
 ; CHECK-NEXT: Cost of 0 for VF vscale x 1: vp<%6> = vector-pointer ir<%ld.addr>

>From b937d1bd20a7d150b147b54de93316c76dfa3ac8 Mon Sep 17 00:00:00 2001
From: Graham Hunter <graham.hunter at arm.com>
Date: Wed, 12 Nov 2025 14:25:37 +0000
Subject: [PATCH 5/6] Add regex matches to vplan test

---
 .../conditional-scalar-assignment-vplan.ll    | 122 +++++++++---------
 1 file changed, 61 insertions(+), 61 deletions(-)

diff --git a/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll b/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll
index 6d63e2f927df1..23964f65b7aae 100644
--- a/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll
+++ b/llvm/test/Transforms/LoopVectorize/conditional-scalar-assignment-vplan.ll
@@ -33,10 +33,10 @@ exit:
 
 
 ; CHECK: VPlan 'Initial VPlan for VF={vscale x 1},UF>=1' {
-; CHECK-NEXT: Live-in vp<%0> = VF
-; CHECK-NEXT: Live-in vp<%1> = VF * UF
-; CHECK-NEXT: Live-in vp<%2> = vector-trip-count
-; CHECK-NEXT: Live-in ir<%N> = original trip-count
+; CHECK-NEXT: Live-in vp<[[VF:%.*]]> = VF
+; CHECK-NEXT: Live-in vp<[[VFxUF:%.*]]> = VF * UF
+; CHECK-NEXT: Live-in vp<[[VECTC:%.*]]> = vector-trip-count
+; CHECK-NEXT: Live-in ir<[[ORIGTC:%.*]]> = original trip-count
 ; CHECK-EMPTY:
 ; CHECK-NEXT: ir-bb<entry>:
 ; CHECK-NEXT: Successor(s): scalar.ph, vector.ph
@@ -46,78 +46,78 @@ exit:
 ; CHECK-EMPTY:
 ; CHECK-NEXT: <x1> vector loop: {
 ; CHECK-NEXT:   vector.body:
-; CHECK-NEXT:     EMIT vp<%3> = CANONICAL-INDUCTION ir<0>, vp<%index.next>
-; CHECK-NEXT:     WIDEN-REDUCTION-PHI ir<%data.phi> = phi ir<-1>, vp<%9>
-; CHECK-NEXT:     WIDEN-PHI vp<%4> = phi [ ir<false>, vector.ph ], [ vp<%8>, vector.body ]
-; CHECK-NEXT:     vp<%5> = SCALAR-STEPS vp<%3>, ir<1>, vp<%0>
-; CHECK-NEXT:     CLONE ir<%ld.addr> = getelementptr inbounds ir<%data>, vp<%5>
-; CHECK-NEXT:     vp<%6> = vector-pointer ir<%ld.addr>
-; CHECK-NEXT:     WIDEN ir<%ld> = load vp<%6>
-; CHECK-NEXT:     WIDEN ir<%select.cmp> = icmp slt ir<%a>, ir<%ld>
-; CHECK-NEXT:     EMIT vp<%7> = any-of ir<%select.cmp>
-; CHECK-NEXT:     EMIT vp<%8> = select vp<%7>, ir<%select.cmp>, vp<%4>
-; CHECK-NEXT:     EMIT vp<%9> = select vp<%7>, ir<%ld>, ir<%data.phi>
-; CHECK-NEXT:     EMIT vp<%index.next> = add nuw vp<%3>, vp<%1>
-; CHECK-NEXT:     EMIT branch-on-count vp<%index.next>, vp<%2>
+; CHECK-NEXT:     EMIT vp<[[CIV:%.*]]> = CANONICAL-INDUCTION ir<0>, vp<[[INDEXNEXT:%.*]]>
+; CHECK-NEXT:     WIDEN-REDUCTION-PHI ir<[[DATAPHI:%.*]]> = phi ir<-1>, vp<[[DATASELECT:%.*]]>
+; CHECK-NEXT:     WIDEN-PHI vp<[[MASKPHI:%.*]]> = phi [ ir<false>, vector.ph ], [ vp<[[MASKSELECT:%.*]]>, vector.body ]
+; CHECK-NEXT:     vp<[[STEPS:%.*]]> = SCALAR-STEPS vp<[[CIV]]>, ir<1>, vp<[[VF]]>
+; CHECK-NEXT:     CLONE ir<[[LDADDR:%.*]]> = getelementptr inbounds ir<%data>, vp<[[STEPS:%.*]]>
+; CHECK-NEXT:     vp<[[VPTR:%.*]]> = vector-pointer ir<[[LDADDR]]>
+; CHECK-NEXT:     WIDEN ir<[[LD:%.*]]> = load vp<[[VPTR]]>
+; CHECK-NEXT:     WIDEN ir<[[SELECTCMP:%.*]]> = icmp slt ir<%a>, ir<[[LD]]>
+; CHECK-NEXT:     EMIT vp<[[ANYOF:%.*]]> = any-of ir<[[SELECTCMP]]>
+; CHECK-NEXT:     EMIT vp<[[MASKSELECT]]> = select vp<[[ANYOF]]>, ir<[[SELECTCMP]]>, vp<[[MASKPHI]]>
+; CHECK-NEXT:     EMIT vp<[[DATASELECT]]> = select vp<[[ANYOF]]>, ir<[[LD]]>, ir<[[DATAPHI]]>
+; CHECK-NEXT:     EMIT vp<[[INDEXNEXT]]> = add nuw vp<[[CIV]]>, vp<[[VFxUF]]>
+; CHECK-NEXT:     EMIT branch-on-count vp<[[INDEXNEXT]]>, vp<[[VECTC]]>
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
 ; CHECK-NEXT: Successor(s): middle.block
 ; CHECK-EMPTY:
 ; CHECK-NEXT: middle.block:
-; CHECK-NEXT:   EMIT vp<%11> = extract-last-active vp<%9>, vp<%8>, ir<-1>
-; CHECK-NEXT:   EMIT vp<%cmp.n> = icmp eq ir<%N>, vp<%2>
-; CHECK-NEXT:   EMIT branch-on-cond vp<%cmp.n>
+; CHECK-NEXT:   EMIT vp<[[EXTRACTLAST:%.*]]> = extract-last-active vp<[[DATASELECT]]>, vp<[[MASKSELECT]]>, ir<-1>
+; CHECK-NEXT:   EMIT vp<[[TCCMP:%.*]]> = icmp eq ir<[[ORIGTC]]>, vp<[[VECTC]]>
+; CHECK-NEXT:   EMIT branch-on-cond vp<[[TCCMP]]>
 ; CHECK-NEXT: Successor(s): ir-bb<exit>, scalar.ph
 ; CHECK-EMPTY:
 ; CHECK-NEXT: ir-bb<exit>:
-; CHECK-NEXT:   IR   %select.data.lcssa = phi i32 [ %select.data, %loop ] (extra operand: vp<%11> from middle.block)
+; CHECK-NEXT:   IR   [[SELECTLCSSA:%.*]] = phi i32 [ [[SELECTDATA:%.*]], %loop ] (extra operand: vp<[[EXTRACTLAST]]> from middle.block)
 ; CHECK-NEXT: No successors
 ; CHECK-EMPTY:
 ; CHECK-NEXT: scalar.ph:
-; CHECK-NEXT:   EMIT-SCALAR vp<%bc.resume.val> = phi [ vp<%2>, middle.block ], [ ir<0>, ir-bb<entry> ]
-; CHECK-NEXT:   EMIT-SCALAR vp<%bc.merge.rdx> = phi [ vp<%11>, middle.block ], [ ir<-1>, ir-bb<entry> ]
+; CHECK-NEXT:   EMIT-SCALAR vp<[[RESUMEVAL:%.*]]> = phi [ vp<[[VECTC]]>, middle.block ], [ ir<0>, ir-bb<entry> ]
+; CHECK-NEXT:   EMIT-SCALAR vp<[[MERGERDX:%.*]]> = phi [ vp<[[EXTRACTLAST]]>, middle.block ], [ ir<-1>, ir-bb<entry> ]
 ; CHECK-NEXT: Successor(s): ir-bb<loop>
 ; CHECK-EMPTY:
 ; CHECK-NEXT: ir-bb<loop>:
-; CHECK-NEXT:   IR   %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ] (extra operand: vp<%bc.resume.val> from scalar.ph)
-; CHECK-NEXT:   IR   %data.phi = phi i32 [ -1, %entry ], [ %select.data, %loop ] (extra operand: vp<%bc.merge.rdx> from scalar.ph)
-; CHECK-NEXT:   IR   %ld.addr = getelementptr inbounds i32, ptr %data, i64 %iv
-; CHECK-NEXT:   IR   %ld = load i32, ptr %ld.addr, align 4
-; CHECK-NEXT:   IR   %select.cmp = icmp slt i32 %a, %ld
-; CHECK-NEXT:   IR   %select.data = select i1 %select.cmp, i32 %ld, i32 %data.phi
-; CHECK-NEXT:   IR   %iv.next = add nuw nsw i64 %iv, 1
-; CHECK-NEXT:   IR   %exit.cmp = icmp eq i64 %iv.next, %N
+; CHECK-NEXT:   IR   [[IV:%.*]] = phi i64 [ 0, %entry ], [ [[IVNEXT:%.*]], %loop ] (extra operand: vp<[[RESUMEVAL]]> from scalar.ph)
+; CHECK-NEXT:   IR   [[DATAPHI]] = phi i32 [ -1, %entry ], [ [[SELECTDATA]], %loop ] (extra operand: vp<[[MERGERDX]]> from scalar.ph)
+; CHECK-NEXT:   IR   [[LDADDR]] = getelementptr inbounds i32, ptr %data, i64 [[IV]]
+; CHECK-NEXT:   IR   [[LD]] = load i32, ptr [[LDADDR]], align 4
+; CHECK-NEXT:   IR   [[SELECTCMP]] = icmp slt i32 %a, [[LD]]
+; CHECK-NEXT:   IR   [[SELECTDATA]] = select i1 [[SELECTCMP]], i32 [[LD]], i32 [[DATAPHI]]
+; CHECK-NEXT:   IR   [[IVNEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT:   IR   [[EXITCMP:%.*]] = icmp eq i64 [[IVNEXT]], [[ORIGTC]]
 ; CHECK-NEXT: No successors
 ; CHECK-NEXT: }
 
-; CHECK: Cost of 1 for VF vscale x 1: induction instruction   %iv.next = add nuw nsw i64 %iv, 1
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: induction instruction   %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: exit condition instruction   %exit.cmp = icmp eq i64 %iv.next, %N
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<%3> = CANONICAL-INDUCTION ir<0>, vp<%index.next>
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN-REDUCTION-PHI ir<%data.phi> = phi ir<-1>, vp<%9>
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN-PHI vp<%4> = phi [ ir<false>, vector.ph ], [ vp<%8>, vector.body ]
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: vp<%5> = SCALAR-STEPS vp<%3>, ir<1>, vp<%0>
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: CLONE ir<%ld.addr> = getelementptr inbounds ir<%data>, vp<%5>
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: vp<%6> = vector-pointer ir<%ld.addr>
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN ir<%ld> = load vp<%6>
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN ir<%select.cmp> = icmp slt ir<%a>, ir<%ld>
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<%7> = any-of ir<%select.cmp>
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<%8> = select vp<%7>, ir<%select.cmp>, vp<%4>
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<%9> = select vp<%7>, ir<%ld>, ir<%data.phi>
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<%index.next> = add nuw vp<%3>, vp<%1>
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT branch-on-count vp<%index.next>, vp<%2>
+; CHECK: Cost of 1 for VF vscale x 1: induction instruction   [[IVNEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: induction instruction   [[IV]] = phi i64 [ 0, %entry ], [ [[IVNEXT]], %loop ]
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: exit condition instruction   [[EXITCMP:%.*]] = icmp eq i64 [[IVNEXT]], [[ORIGTC]]
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<[[CIV]]> = CANONICAL-INDUCTION ir<0>, vp<[[INDEXNEXT]]>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN-REDUCTION-PHI ir<[[DATAPHI]]> = phi ir<-1>, vp<[[DATASELECT]]>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN-PHI vp<[[MASKPHI]]> = phi [ ir<false>, vector.ph ], [ vp<[[MASKSELECT]]>, vector.body ]
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: vp<[[STEPS:%.*]]> = SCALAR-STEPS vp<[[CIV]]>, ir<1>, vp<[[VF]]>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: CLONE ir<[[LDADDR]]> = getelementptr inbounds ir<%data>, vp<[[STEPS:%.*]]>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: vp<[[VPTR]]> = vector-pointer ir<[[LDADDR]]>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN ir<[[LD]]> = load vp<[[VPTR]]>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: WIDEN ir<[[SELECTCMP]]> = icmp slt ir<%a>, ir<[[LD]]>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<[[ANYOF]]> = any-of ir<[[SELECTCMP]]>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<[[MASKSELECT]]> = select vp<[[ANYOF]]>, ir<[[SELECTCMP]]>, vp<[[MASKPHI]]>
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<[[DATASELECT]]> = select vp<[[ANYOF]]>, ir<[[LD]]>, ir<[[DATAPHI]]>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<[[INDEXNEXT]]> = add nuw vp<[[CIV]]>, vp<[[VFxUF]]>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT branch-on-count vp<[[INDEXNEXT]]>, vp<[[VECTC]]>
 ; CHECK-NEXT: Cost of 1 for VF vscale x 1: vector loop backedge
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT-SCALAR vp<%bc.resume.val> = phi [ vp<%2>, middle.block ], [ ir<0>, ir-bb<entry> ]
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT-SCALAR vp<%bc.merge.rdx> = phi [ vp<%11>, middle.block ], [ ir<-1>, ir-bb<entry> ]
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ] (extra operand: vp<%bc.resume.val> from scalar.ph)
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %data.phi = phi i32 [ -1, %entry ], [ %select.data, %loop ] (extra operand: vp<%bc.merge.rdx> from scalar.ph)
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %ld.addr = getelementptr inbounds i32, ptr %data, i64 %iv
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %ld = load i32, ptr %ld.addr, align 4
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %select.cmp = icmp slt i32 %a, %ld
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %select.data = select i1 %select.cmp, i32 %ld, i32 %data.phi
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %iv.next = add nuw nsw i64 %iv, 1
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %exit.cmp = icmp eq i64 %iv.next, %N
-; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<%11> = extract-last-active vp<%9>, vp<%8>, ir<-1>
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<%cmp.n> = icmp eq ir<%N>, vp<%2>
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT branch-on-cond vp<%cmp.n>
-; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   %select.data.lcssa = phi i32 [ %select.data, %loop ] (extra operand: vp<%11> from middle.block)
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT-SCALAR vp<[[RESUMEVAL]]> = phi [ vp<[[VECTC]]>, middle.block ], [ ir<0>, ir-bb<entry> ]
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT-SCALAR vp<[[MERGERDX]]> = phi [ vp<[[EXTRACTLAST]]>, middle.block ], [ ir<-1>, ir-bb<entry> ]
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   [[IV]] = phi i64 [ 0, %entry ], [ [[IVNEXT]], %loop ] (extra operand: vp<[[RESUMEVAL]]> from scalar.ph)
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   [[DATAPHI]] = phi i32 [ -1, %entry ], [ [[SELECTDATA]], %loop ] (extra operand: vp<[[MERGERDX]]> from scalar.ph)
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   [[LDADDR]] = getelementptr inbounds i32, ptr %data, i64 [[IV]]
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   [[LD]] = load i32, ptr [[LDADDR]], align 4
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   [[SELECTCMP]] = icmp slt i32 %a, [[LD]]
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   [[SELECTDATA]] = select i1 [[SELECTCMP]], i32 [[LD]], i32 [[DATAPHI]]
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   [[IVNEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   [[EXITCMP:%.*]] = icmp eq i64 [[IVNEXT]], [[ORIGTC]]
+; CHECK-NEXT: Cost of 1 for VF vscale x 1: EMIT vp<[[EXTRACTLAST]]> = extract-last-active vp<[[DATASELECT]]>, vp<[[MASKSELECT]]>, ir<-1>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT vp<[[TCCMP]]> = icmp eq ir<[[ORIGTC]]>, vp<[[VECTC]]>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: EMIT branch-on-cond vp<[[TCCMP]]>
+; CHECK-NEXT: Cost of 0 for VF vscale x 1: IR   [[SELECTLCSSA]] = phi i32 [ [[SELECTDATA]], %loop ] (extra operand: vp<[[EXTRACTLAST]]> from middle.block)

>From 883a7708d5d448344c889e740f85a1017bf46b32 Mon Sep 17 00:00:00 2001
From: Graham Hunter <graham.hunter at arm.com>
Date: Wed, 12 Nov 2025 15:22:22 +0000
Subject: [PATCH 6/6] Use find_if

---
 .../Transforms/Vectorize/VPlanTransforms.cpp    | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index 8fa8b95210ed1..51886ce96236f 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -4647,18 +4647,15 @@ void VPlanTransforms::convertFindLastRecurrences(
     SR->replaceAllUsesWith(DataSelect);
     SR->eraseFromParent();
 
-    // Find final reduction and replace it with an
+    // Find final reduction computation and replace it with an
     // extract.last.active intrinsic.
-    VPInstruction *RdxResult = nullptr;
-    for (VPUser *U : DataSelect->users()) {
+    VPUser **ComputeRdx = find_if(DataSelect->users(), [](VPUser *U) {
       VPInstruction *I = dyn_cast<VPInstruction>(U);
-      if (I && I->getOpcode() == VPInstruction::ComputeReductionResult) {
-        RdxResult = I;
-        break;
-      }
-    }
-
-    assert(RdxResult);
+      return I && I->getOpcode() == VPInstruction::ComputeReductionResult;
+    });
+    assert(ComputeRdx != DataSelect->user_end() &&
+           "Unable to find Reduction Result Recipe");
+    VPInstruction *RdxResult = cast<VPInstruction>(*ComputeRdx);
     Builder.setInsertPoint(RdxResult);
     auto *ExtractLastActive =
         Builder.createNaryOp(VPInstruction::ExtractLastActive,



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