[llvm] [VPlan] Introduce VPInstruction::InsertLastLane for start value of VPFirstOrderRecurrencePHIRecipe. (PR #171590)

via llvm-commits llvm-commits at lists.llvm.org
Wed Dec 10 02:16:48 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-vectorizers

Author: Mel Chen (Mel-Chen)

<details>
<summary>Changes</summary>

Currently, VPFirstOrderRecurrencePHIRecipe sets the start value from the preheader to [poison, ..., poison, start] only during ::execute when generating the PHI node. This patch uses VPInstruction::InsertLastLane directly in the VPlan to represent this behavior, instead of hiding it in ::execute. This allows redundant VPInstruction::InsertLastLane to be eliminated via VPlanTransform::cse.

---

Patch is 61.61 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/171590.diff


18 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/VPlan.h (+2) 
- (modified) llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp (+1) 
- (modified) llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp (+17-19) 
- (modified) llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp (+20-1) 
- (modified) llvm/test/Transforms/LoopVectorize/AArch64/first-order-recurrence.ll (+1-1) 
- (modified) llvm/test/Transforms/LoopVectorize/AArch64/reduction-recurrence-costs-sve.ll (+14-22) 
- (modified) llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll (+4-4) 
- (modified) llvm/test/Transforms/LoopVectorize/RISCV/first-order-recurrence-scalable-vf1.ll (+2-2) 
- (modified) llvm/test/Transforms/LoopVectorize/RISCV/tail-folding-fixed-order-recurrence.ll (+24-24) 
- (modified) llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics-fixed-order-recurrence.ll (+3-2) 
- (modified) llvm/test/Transforms/LoopVectorize/first-order-recurrence-chains-vplan.ll (+18-9) 
- (modified) llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll (+3-3) 
- (modified) llvm/test/Transforms/LoopVectorize/first-order-recurrence-dead-instructions.ll (+2-1) 
- (modified) llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll (+14-8) 
- (modified) llvm/test/Transforms/LoopVectorize/first-order-recurrence.ll (+2-2) 
- (modified) llvm/test/Transforms/LoopVectorize/scalable-first-order-recurrence.ll (+4-4) 
- (modified) llvm/test/Transforms/LoopVectorize/vplan-printing.ll (+2-1) 
- (modified) llvm/test/Transforms/LoopVectorize/vplan-sink-scalars-and-merge.ll (+2-1) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index afb654ed882f4..20ca30b029bb9 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1082,6 +1082,8 @@ class LLVM_ABI_FOR_TEST VPInstruction : public VPRecipeWithIRFlags,
     // part if it is scalar. In the latter case, the recipe will be removed
     // during unrolling.
     ExtractPenultimateElement,
+    // Inserts the second operand into the last lane of first operand.
+    InsertLastLane,
     LogicalAnd, // Non-poison propagating logical And.
     // Add an offset in bytes (second operand) to a base pointer (first
     // operand). Only generates scalar values (either for the first lane only or
diff --git a/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp b/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp
index c64b97579881a..f83af484dee9b 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanAnalysis.cpp
@@ -77,6 +77,7 @@ Type *VPTypeAnalysis::inferScalarTypeForRecipe(const VPInstruction *R) {
   case Instruction::Freeze:
   case VPInstruction::ReductionStartVector:
   case VPInstruction::ResumeForEpilogue:
+  case VPInstruction::InsertLastLane:
     return inferScalarType(R->getOperand(0));
   case Instruction::Select: {
     Type *ResTy = inferScalarType(R->getOperand(1));
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index b0c8564ad231a..08d078c56a4aa 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -456,6 +456,7 @@ unsigned VPInstruction::getNumOperandsForOpcode(unsigned Opcode) {
   case VPInstruction::FirstOrderRecurrenceSplice:
   case VPInstruction::LogicalAnd:
   case VPInstruction::PtrAdd:
+  case VPInstruction::InsertLastLane:
   case VPInstruction::WidePtrAdd:
   case VPInstruction::WideIVStep:
     return 2;
@@ -702,6 +703,15 @@ Value *VPInstruction::generate(VPTransformState &State) {
                                         Builder.getInt32(Idx));
     return Res;
   }
+  case VPInstruction::InsertLastLane: {
+    if (State.VF.isScalar())
+      return State.get(getOperand(1), true);
+    Value *Vec = State.get(getOperand(0));
+    Value *Elt = State.get(getOperand(1), /*IsScalar=*/true);
+    Value *RuntimeVF = getRuntimeVF(Builder, Builder.getInt32Ty(), State.VF);
+    Value *LastIdx = Builder.CreateSub(RuntimeVF, Builder.getInt32(1));
+    return Builder.CreateInsertElement(Vec, Elt, LastIdx);
+  }
   case VPInstruction::ReductionStartVector: {
     if (State.VF.isScalar())
       return State.get(getOperand(0), true);
@@ -1193,6 +1203,7 @@ bool VPInstruction::opcodeMayReadOrWriteFromMemory() const {
   case VPInstruction::ExtractLastLane:
   case VPInstruction::ExtractLastPart:
   case VPInstruction::ExtractPenultimateElement:
+  case VPInstruction::InsertLastLane:
   case VPInstruction::ActiveLaneMask:
   case VPInstruction::ExplicitVectorLength:
   case VPInstruction::FirstActiveLane:
@@ -1222,6 +1233,7 @@ bool VPInstruction::usesFirstLaneOnly(const VPValue *Op) const {
   default:
     return false;
   case Instruction::ExtractElement:
+  case VPInstruction::InsertLastLane:
     return Op == getOperand(1);
   case Instruction::PHI:
     return true;
@@ -1337,6 +1349,9 @@ void VPInstruction::printRecipe(raw_ostream &O, const Twine &Indent,
   case VPInstruction::BuildVector:
     O << "buildvector";
     break;
+  case VPInstruction::InsertLastLane:
+    O << "insert-last-lane";
+    break;
   case VPInstruction::ExtractLane:
     O << "extract-lane";
     break;
@@ -4304,27 +4319,10 @@ void VPWidenCanonicalIVRecipe::printRecipe(raw_ostream &O, const Twine &Indent,
 #endif
 
 void VPFirstOrderRecurrencePHIRecipe::execute(VPTransformState &State) {
-  auto &Builder = State.Builder;
-  // Create a vector from the initial value.
-  auto *VectorInit = getStartValue()->getLiveInIRValue();
-
-  Type *VecTy = State.VF.isScalar()
-                    ? VectorInit->getType()
-                    : VectorType::get(VectorInit->getType(), State.VF);
-
+  Value *VectorInit = State.get(getStartValue(), State.VF.isScalar());
+  Type *VecTy = VectorInit->getType();
   BasicBlock *VectorPH =
       State.CFG.VPBB2IRBB.at(getParent()->getCFGPredecessor(0));
-  if (State.VF.isVector()) {
-    auto *IdxTy = Builder.getInt32Ty();
-    auto *One = ConstantInt::get(IdxTy, 1);
-    IRBuilder<>::InsertPointGuard Guard(Builder);
-    Builder.SetInsertPoint(VectorPH->getTerminator());
-    auto *RuntimeVF = getRuntimeVF(Builder, IdxTy, State.VF);
-    auto *LastIdx = Builder.CreateSub(RuntimeVF, One);
-    VectorInit = Builder.CreateInsertElement(
-        PoisonValue::get(VecTy), VectorInit, LastIdx, "vector.recur.init");
-  }
-
   // Create a phi node for the new recurrence.
   PHINode *Phi = PHINode::Create(VecTy, 2, "vector.recur");
   Phi->insertBefore(State.CFG.PrevBB->getFirstInsertionPt());
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index 852196e589c59..c1fdda94aae4a 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -1443,8 +1443,16 @@ static void simplifyRecipe(VPSingleDefRecipe *Def, VPTypeAnalysis &TypeInfo) {
     return;
   }
 
+  if (match(Def, m_VPInstruction<VPInstruction::InsertLastLane>(
+                     m_VPValue(), m_VPValue(A))))
+    if (Plan->hasScalarVFOnly())
+      return Def->replaceAllUsesWith(A);
+
   if (auto *Phi = dyn_cast<VPFirstOrderRecurrencePHIRecipe>(Def)) {
-    if (Phi->getOperand(0) == Phi->getOperand(1))
+    if (Phi->getOperand(0) == Phi->getOperand(1) ||
+        match(Phi->getOperand(0),
+              m_VPInstruction<VPInstruction::InsertLastLane>(
+                  m_VPValue(), m_Specific(Phi->getOperand(1)))))
       Phi->replaceAllUsesWith(Phi->getOperand(0));
     return;
   }
@@ -2238,6 +2246,8 @@ static bool hoistPreviousBeforeFORUsers(VPFirstOrderRecurrencePHIRecipe *FOR,
 bool VPlanTransforms::adjustFixedOrderRecurrences(VPlan &Plan,
                                                   VPBuilder &LoopBuilder) {
   VPDominatorTree VPDT(Plan);
+  VPTypeAnalysis TypeInfo(Plan);
+  VPBuilder PHBuilder(Plan.getVectorPreheader());
 
   SmallVector<VPFirstOrderRecurrencePHIRecipe *> RecurrencePhis;
   for (VPRecipeBase &R :
@@ -2246,6 +2256,15 @@ bool VPlanTransforms::adjustFixedOrderRecurrences(VPlan &Plan,
       RecurrencePhis.push_back(FOR);
 
   for (VPFirstOrderRecurrencePHIRecipe *FOR : RecurrencePhis) {
+    /// Adjust start value of fixed-order recurrence phi to [poison, ... ,
+    /// poison, start value].
+    VPValue *StartV = FOR->getStartValue();
+    VPValue *NewStart = PHBuilder.createNaryOp(
+        VPInstruction::InsertLastLane, {Plan.getOrAddLiveIn(PoisonValue::get(
+                                            TypeInfo.inferScalarType(StartV))),
+                                        StartV});
+    FOR->setOperand(0, NewStart);
+
     SmallPtrSet<VPFirstOrderRecurrencePHIRecipe *, 4> SeenPhis;
     VPRecipeBase *Previous = FOR->getBackedgeValue()->getDefiningRecipe();
     // Fixed-order recurrences do not contain cycles, so this loop is guaranteed
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/first-order-recurrence.ll b/llvm/test/Transforms/LoopVectorize/AArch64/first-order-recurrence.ll
index 16e9d410e4aa7..6ddb23079a287 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/first-order-recurrence.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/first-order-recurrence.ll
@@ -69,7 +69,7 @@ for.body:
 define void @PR34711(ptr %a, ptr %b, ptr %c, i64 %n) #0 {
 ; CHECK-VF4UF1-LABEL: @PR34711
 ; CHECK-VF4UF1: vector.body
-; CHECK-VF4UF1: %[[VEC_RECUR:.*]] = phi <vscale x 4 x i16> [ %vector.recur.init, %vector.ph ], [ %[[MGATHER:.*]], %vector.body ]
+; CHECK-VF4UF1: %[[VEC_RECUR:.*]] = phi <vscale x 4 x i16> [ %[[VEC_RECUR_INIT:.*]], %vector.ph ], [ %[[MGATHER:.*]], %vector.body ]
 ; CHECK-VF4UF1: %[[MGATHER]] = call <vscale x 4 x i16> @llvm.masked.gather.nxv4i16.nxv4p0(<vscale x 4 x ptr> {{.*}}, <vscale x 4 x i1> splat (i1 true), <vscale x 4 x i16> poison)
 ; CHECK-VF4UF1-NEXT: %[[SPLICE:.*]] = call <vscale x 4 x i16> @llvm.vector.splice.nxv4i16(<vscale x 4 x i16> %[[VEC_RECUR]], <vscale x 4 x i16> %[[MGATHER]], i32 -1)
 ; CHECK-VF4UF1-NEXT: %[[SXT1:.*]] = sext <vscale x 4 x i16> %[[SPLICE]] to <vscale x 4 x i32>
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/reduction-recurrence-costs-sve.ll b/llvm/test/Transforms/LoopVectorize/AArch64/reduction-recurrence-costs-sve.ll
index f2c0ca30a6c18..c5d389fa19e2e 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/reduction-recurrence-costs-sve.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/reduction-recurrence-costs-sve.ll
@@ -61,6 +61,10 @@ define i32 @chained_recurrences(i32 %x, i64 %y, ptr %src.1, i32 %z, ptr %src.2)
 ; VSCALEFORTUNING2-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP0]], [[N_MOD_VF]]
 ; VSCALEFORTUNING2-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 4 x i32> poison, i32 [[X]], i64 0
 ; VSCALEFORTUNING2-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 4 x i32> [[BROADCAST_SPLATINSERT]], <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
+; VSCALEFORTUNING2-NEXT:    [[TMP5:%.*]] = call i32 @llvm.vscale.i32()
+; VSCALEFORTUNING2-NEXT:    [[TMP6:%.*]] = mul nuw i32 [[TMP5]], 4
+; VSCALEFORTUNING2-NEXT:    [[TMP17:%.*]] = sub i32 [[TMP6]], 1
+; VSCALEFORTUNING2-NEXT:    [[TMP18:%.*]] = insertelement <vscale x 4 x i32> poison, i32 0, i32 [[TMP17]]
 ; VSCALEFORTUNING2-NEXT:    [[TMP7:%.*]] = add i64 [[Y]], 1
 ; VSCALEFORTUNING2-NEXT:    [[TMP8:%.*]] = getelementptr i32, ptr [[SRC_1]], i64 [[TMP7]]
 ; VSCALEFORTUNING2-NEXT:    [[TMP9:%.*]] = lshr <vscale x 4 x i32> [[BROADCAST_SPLAT]], splat (i32 1)
@@ -73,19 +77,11 @@ define i32 @chained_recurrences(i32 %x, i64 %y, ptr %src.1, i32 %z, ptr %src.2)
 ; VSCALEFORTUNING2-NEXT:    [[TMP14:%.*]] = xor <vscale x 4 x i32> [[TMP13]], splat (i32 1)
 ; VSCALEFORTUNING2-NEXT:    [[TMP15:%.*]] = zext <vscale x 4 x i32> [[TMP14]] to <vscale x 4 x i64>
 ; VSCALEFORTUNING2-NEXT:    [[DOTSPLAT:%.*]] = getelementptr i32, ptr [[SRC_2]], <vscale x 4 x i64> [[TMP15]]
-; VSCALEFORTUNING2-NEXT:    [[TMP18:%.*]] = call i32 @llvm.vscale.i32()
-; VSCALEFORTUNING2-NEXT:    [[TMP19:%.*]] = mul nuw i32 [[TMP18]], 4
-; VSCALEFORTUNING2-NEXT:    [[TMP20:%.*]] = sub i32 [[TMP19]], 1
-; VSCALEFORTUNING2-NEXT:    [[VECTOR_RECUR_INIT:%.*]] = insertelement <vscale x 4 x i32> poison, i32 0, i32 [[TMP20]]
-; VSCALEFORTUNING2-NEXT:    [[TMP21:%.*]] = call i32 @llvm.vscale.i32()
-; VSCALEFORTUNING2-NEXT:    [[TMP22:%.*]] = mul nuw i32 [[TMP21]], 4
-; VSCALEFORTUNING2-NEXT:    [[TMP23:%.*]] = sub i32 [[TMP22]], 1
-; VSCALEFORTUNING2-NEXT:    [[VECTOR_RECUR_INIT3:%.*]] = insertelement <vscale x 4 x i32> poison, i32 0, i32 [[TMP23]]
 ; VSCALEFORTUNING2-NEXT:    br label %[[VECTOR_BODY:.*]]
 ; VSCALEFORTUNING2:       [[VECTOR_BODY]]:
 ; VSCALEFORTUNING2-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; VSCALEFORTUNING2-NEXT:    [[VECTOR_RECUR:%.*]] = phi <vscale x 4 x i32> [ [[VECTOR_RECUR_INIT]], %[[VECTOR_PH]] ], [ [[BROADCAST_SPLAT7:%.*]], %[[VECTOR_BODY]] ]
-; VSCALEFORTUNING2-NEXT:    [[VECTOR_RECUR4:%.*]] = phi <vscale x 4 x i32> [ [[VECTOR_RECUR_INIT3]], %[[VECTOR_PH]] ], [ [[TMP26:%.*]], %[[VECTOR_BODY]] ]
+; VSCALEFORTUNING2-NEXT:    [[VECTOR_RECUR:%.*]] = phi <vscale x 4 x i32> [ [[TMP18]], %[[VECTOR_PH]] ], [ [[BROADCAST_SPLAT7:%.*]], %[[VECTOR_BODY]] ]
+; VSCALEFORTUNING2-NEXT:    [[VECTOR_RECUR4:%.*]] = phi <vscale x 4 x i32> [ [[TMP18]], %[[VECTOR_PH]] ], [ [[TMP26:%.*]], %[[VECTOR_BODY]] ]
 ; VSCALEFORTUNING2-NEXT:    [[VEC_PHI:%.*]] = phi <vscale x 4 x i32> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP47:%.*]], %[[VECTOR_BODY]] ]
 ; VSCALEFORTUNING2-NEXT:    [[VEC_PHI5:%.*]] = phi <vscale x 4 x i32> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP48:%.*]], %[[VECTOR_BODY]] ]
 ; VSCALEFORTUNING2-NEXT:    [[TMP24:%.*]] = load i32, ptr [[TMP8]], align 4
@@ -133,13 +129,13 @@ define i32 @chained_recurrences(i32 %x, i64 %y, ptr %src.1, i32 %z, ptr %src.2)
 ; VSCALEFORTUNING2-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
 ; VSCALEFORTUNING2:       [[SCALAR_PH]]:
 ; VSCALEFORTUNING2-NEXT:    [[SCALAR_RECUR_INIT:%.*]] = phi i32 [ [[TMP24]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
-; VSCALEFORTUNING2-NEXT:    [[SCALAR_RECUR_INIT11:%.*]] = phi i32 [ [[VECTOR_RECUR_EXTRACT]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; VSCALEFORTUNING2-NEXT:    [[SCALAR_RECUR_INIT10:%.*]] = phi i32 [ [[VECTOR_RECUR_EXTRACT]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
 ; VSCALEFORTUNING2-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
 ; VSCALEFORTUNING2-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP50]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
 ; VSCALEFORTUNING2-NEXT:    br label %[[LOOP:.*]]
 ; VSCALEFORTUNING2:       [[LOOP]]:
 ; VSCALEFORTUNING2-NEXT:    [[TMP54:%.*]] = phi i32 [ [[SCALAR_RECUR_INIT]], %[[SCALAR_PH]] ], [ [[TMP57:%.*]], %[[LOOP]] ]
-; VSCALEFORTUNING2-NEXT:    [[TMP55:%.*]] = phi i32 [ [[SCALAR_RECUR_INIT11]], %[[SCALAR_PH]] ], [ [[TMP54]], %[[LOOP]] ]
+; VSCALEFORTUNING2-NEXT:    [[TMP55:%.*]] = phi i32 [ [[SCALAR_RECUR_INIT10]], %[[SCALAR_PH]] ], [ [[TMP54]], %[[LOOP]] ]
 ; VSCALEFORTUNING2-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
 ; VSCALEFORTUNING2-NEXT:    [[SUM_RED:%.*]] = phi i32 [ [[BC_MERGE_RDX]], %[[SCALAR_PH]] ], [ [[RED_2:%.*]], %[[LOOP]] ]
 ; VSCALEFORTUNING2-NEXT:    [[TMP56:%.*]] = add i64 [[Y]], 1
@@ -182,6 +178,10 @@ define i32 @chained_recurrences(i32 %x, i64 %y, ptr %src.1, i32 %z, ptr %src.2)
 ; PRED-NEXT:    [[TMP2:%.*]] = mul nuw i64 [[TMP1]], 4
 ; PRED-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <vscale x 4 x i32> poison, i32 [[X]], i64 0
 ; PRED-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 4 x i32> [[BROADCAST_SPLATINSERT1]], <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
+; PRED-NEXT:    [[TMP3:%.*]] = call i32 @llvm.vscale.i32()
+; PRED-NEXT:    [[TMP4:%.*]] = mul nuw i32 [[TMP3]], 4
+; PRED-NEXT:    [[TMP5:%.*]] = sub i32 [[TMP4]], 1
+; PRED-NEXT:    [[TMP21:%.*]] = insertelement <vscale x 4 x i32> poison, i32 0, i32 [[TMP5]]
 ; PRED-NEXT:    [[TMP6:%.*]] = call i64 @llvm.vscale.i64()
 ; PRED-NEXT:    [[TMP7:%.*]] = shl nuw i64 [[TMP6]], 2
 ; PRED-NEXT:    [[TMP8:%.*]] = sub i64 [[TMP0]], [[TMP7]]
@@ -200,20 +200,12 @@ define i32 @chained_recurrences(i32 %x, i64 %y, ptr %src.1, i32 %z, ptr %src.2)
 ; PRED-NEXT:    [[TMP18:%.*]] = xor <vscale x 4 x i32> [[TMP17]], splat (i32 1)
 ; PRED-NEXT:    [[TMP19:%.*]] = zext <vscale x 4 x i32> [[TMP18]] to <vscale x 4 x i64>
 ; PRED-NEXT:    [[DOTSPLAT:%.*]] = getelementptr i32, ptr [[SRC_2]], <vscale x 4 x i64> [[TMP19]]
-; PRED-NEXT:    [[TMP22:%.*]] = call i32 @llvm.vscale.i32()
-; PRED-NEXT:    [[TMP23:%.*]] = mul nuw i32 [[TMP22]], 4
-; PRED-NEXT:    [[TMP24:%.*]] = sub i32 [[TMP23]], 1
-; PRED-NEXT:    [[VECTOR_RECUR_INIT:%.*]] = insertelement <vscale x 4 x i32> poison, i32 0, i32 [[TMP24]]
-; PRED-NEXT:    [[TMP25:%.*]] = call i32 @llvm.vscale.i32()
-; PRED-NEXT:    [[TMP26:%.*]] = mul nuw i32 [[TMP25]], 4
-; PRED-NEXT:    [[TMP27:%.*]] = sub i32 [[TMP26]], 1
-; PRED-NEXT:    [[VECTOR_RECUR_INIT3:%.*]] = insertelement <vscale x 4 x i32> poison, i32 0, i32 [[TMP27]]
 ; PRED-NEXT:    br label %[[VECTOR_BODY:.*]]
 ; PRED:       [[VECTOR_BODY]]:
 ; PRED-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
 ; PRED-NEXT:    [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 4 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[VECTOR_PH]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; PRED-NEXT:    [[VECTOR_RECUR:%.*]] = phi <vscale x 4 x i32> [ [[VECTOR_RECUR_INIT]], %[[VECTOR_PH]] ], [ [[BROADCAST_SPLAT6:%.*]], %[[VECTOR_BODY]] ]
-; PRED-NEXT:    [[VECTOR_RECUR4:%.*]] = phi <vscale x 4 x i32> [ [[VECTOR_RECUR_INIT3]], %[[VECTOR_PH]] ], [ [[TMP29:%.*]], %[[VECTOR_BODY]] ]
+; PRED-NEXT:    [[VECTOR_RECUR:%.*]] = phi <vscale x 4 x i32> [ [[TMP21]], %[[VECTOR_PH]] ], [ [[BROADCAST_SPLAT6:%.*]], %[[VECTOR_BODY]] ]
+; PRED-NEXT:    [[VECTOR_RECUR4:%.*]] = phi <vscale x 4 x i32> [ [[TMP21]], %[[VECTOR_PH]] ], [ [[TMP29:%.*]], %[[VECTOR_BODY]] ]
 ; PRED-NEXT:    [[VEC_PHI:%.*]] = phi <vscale x 4 x i32> [ zeroinitializer, %[[VECTOR_PH]] ], [ [[TMP41:%.*]], %[[VECTOR_BODY]] ]
 ; PRED-NEXT:    [[TMP28:%.*]] = load i32, ptr [[TMP12]], align 4
 ; PRED-NEXT:    [[BROADCAST_SPLATINSERT5:%.*]] = insertelement <vscale x 4 x i32> poison, i32 [[TMP28]], i64 0
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll b/llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll
index 8935010e71676..d59baf2169794 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll
@@ -1272,15 +1272,15 @@ define void @PR34743(ptr %a, ptr %b, i64 %n) #1 {
 ; CHECK-NEXT:    [[DOTNOT:%.*]] = sub nsw i64 0, [[TMP10]]
 ; CHECK-NEXT:    [[N_VEC:%.*]] = and i64 [[TMP1]], [[DOTNOT]]
 ; CHECK-NEXT:    [[IND_END:%.*]] = shl i64 [[N_VEC]], 1
+; CHECK-NEXT:    [[TMP11:%.*]] = call i32 @llvm.vscale.i32()
+; CHECK-NEXT:    [[TMP12:%.*]] = shl nuw nsw i32 [[TMP11]], 2
+; CHECK-NEXT:    [[TMP13:%.*]] = add nsw i32 [[TMP12]], -1
+; CHECK-NEXT:    [[VECTOR_RECUR_INIT:%.*]] = insertelement <vscale x 4 x i16> poison, i16 [[DOTPRE]], i32 [[TMP13]]
 ; CHECK-NEXT:    [[TMP14:%.*]] = call <vscale x 4 x i64> @llvm.stepvector.nxv4i64()
 ; CHECK-NEXT:    [[TMP15:%.*]] = shl nuw nsw <vscale x 4 x i64> [[TMP14]], splat (i64 1)
 ; CHECK-NEXT:    [[TMP17:%.*]] = shl nuw nsw i64 [[TMP9]], 3
 ; CHECK-NEXT:    [[DOTSPLATINSERT:%.*]] = insertelement <vscale x 4 x i64> poison, i64 [[TMP17]], i64 0
 ; CHECK-NEXT:    [[DOTSPLAT:%.*]] = shufflevector <vscale x 4 x i64> [[DOTSPLATINSERT]], <vscale x 4 x i64> poison, <vscale x 4 x i32> zeroinitializer
-; CHECK-NEXT:    [[TMP33:%.*]] = call i32 @llvm.vscale.i32()
-; CHECK-NEXT:    [[TMP16:%.*]] = shl nuw nsw i32 [[TMP33]], 2
-; CHECK-NEXT:    [[TMP34:%.*]] = add nsw i32 [[TMP16]], -1
-; CHECK-NEXT:    [[VECTOR_RECUR_INIT:%.*]] = insertelement <vscale x 4 x i16> poison, i16 [[DOTPRE]], i32 [[TMP34]]
 ; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
 ; CHECK:       vector.body:
 ; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/first-order-recurrence-scalable-vf1.ll b/llvm/test/Transforms/LoopVectorize/RISCV/first-order-recurrence-scalable-vf1.ll
index e35db479dc963..d61b1d5a9843d 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/first-order-recurrence-scalable-vf1.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/first-order-recurrence-scalable-vf1.ll
@@ -12,17 +12,17 @@ define i64 @pr97452_scalable_vf1_for(ptr %src, ptr noalias %dst) #0 {
 ; CHECK:       [[VECTOR_PH]]:
 ; CHECK-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[TMP1:%.*]] = mul nuw i64 [[TMP0]], 2
-; CHECK-NEXT:    [[TMP2:%.*]] = trunc i64 [[TMP1]] to i32
 ; CHECK-NEXT:    [[TMP3:%.*]] = call i32 @llvm.vscale.i32()
 ; CHECK-NEXT:    [[TMP4:%.*]] = mul nuw i32 [[TMP3]], 2
 ; CHECK-NEXT:    [[TMP5:%.*]] = sub i32 [[TMP4]], 1
 ; CHECK-NEXT:    [[VECTOR_RECUR_INIT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 0, i32 [[TMP5]]
+; CHECK-NEXT:    [[TMP7:%.*]] = trunc i64 [[TMP1]] to i32
 ; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
 ; CHECK:       [[VECTOR_BODY]]:
 ; CHECK-NEXT:    [[EVL_BASED_IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_EVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
 ; CHECK-NEXT:    [[VECTOR_RECUR:%.*]] = phi <vscale x 2 x i64> [ [[VECTOR_RECUR_INIT]], %[[VECTOR_PH]] ], [ [[VP_OP_LOAD:%.*]], %[[VECTOR_BODY]] ]
 ; CHECK-NEXT:    [[AVL:%.*]] = phi i64 [ 23, %[[VECTOR_PH]] ], [ [[AVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; CHECK-NEXT:    [[PREV_EVL:%.*]] = phi i32 [ [[TMP2]], %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[PREV_EVL:%.*]] = phi i32 [ [[TMP7]], %[[VECTOR_PH]] ], [ [[TMP6:%.*]], %[[VECTOR_BODY]] ]
 ; CHECK-NEXT:    [[TMP6]] = call i32 @llvm.experimental.get.vector.length.i64(i64 [[AV...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/171590


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