[llvm] [LV] Don't predicate divs with invariant divisor when folding tail (PR #98904)

Florian Hahn via llvm-commits llvm-commits at lists.llvm.org
Wed Jul 24 14:23:18 PDT 2024


https://github.com/fhahn updated https://github.com/llvm/llvm-project/pull/98904

>From b6ab904f399e9b12a5a1423817f876d96362fd06 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Mon, 15 Jul 2024 12:48:55 +0100
Subject: [PATCH 1/7] [LV] Check isPredInst instead of isScalarWithPred in
 uniform analysis.

Any instruction marked as uniform will result in a uniform
VPReplicateRecipe. If it requires predication, it will be placed in a
replicate region, even if isScalarWithPredication returns false.

Check isPredicatedInst instead of isScalarWithPredication to avoid
generating uniform VPReplicateRecipes placed inside a replicate region.
This fixes an assertion when using scalable VFs.

Fixes https://github.com/llvm/llvm-project/issues/80416.
Fixes https://github.com/llvm/llvm-project/issues/94328.
---
 .../Transforms/Vectorize/LoopVectorize.cpp    |  11 +-
 .../AArch64/divs-with-scalable-vfs.ll         | 391 ++++++++++++++++++
 .../X86/consecutive-ptr-uniforms.ll           |   2 +-
 3 files changed, 399 insertions(+), 5 deletions(-)
 create mode 100644 llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 5520baef7152d..3d7df2efd6b85 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3907,7 +3907,7 @@ void LoopVectorizationCostModel::collectLoopUniforms(ElementCount VF) {
   SetVector<Instruction *> Worklist;
 
   // Add uniform instructions demanding lane 0 to the worklist. Instructions
-  // that are scalar with predication must not be considered uniform after
+  // that are require predication must not be considered uniform after
   // vectorization, because that would create an erroneous replicating region
   // where only a single instance out of VF should be formed.
   // TODO: optimize such seldom cases if found important, see PR40816.
@@ -3917,9 +3917,10 @@ void LoopVectorizationCostModel::collectLoopUniforms(ElementCount VF) {
                         << *I << "\n");
       return;
     }
-    if (isScalarWithPredication(I, VF)) {
-      LLVM_DEBUG(dbgs() << "LV: Found not uniform being ScalarWithPredication: "
-                        << *I << "\n");
+    if (isPredicatedInst(I)) {
+      LLVM_DEBUG(
+          dbgs() << "LV: Found not uniform due to requiring predication: " << *I
+                 << "\n");
       return;
     }
     LLVM_DEBUG(dbgs() << "LV: Found uniform instruction: " << *I << "\n");
@@ -9482,6 +9483,8 @@ void VPInterleaveRecipe::execute(VPTransformState &State) {
 void VPReplicateRecipe::execute(VPTransformState &State) {
   Instruction *UI = getUnderlyingInstr();
   if (State.Instance) { // Generate a single instance.
+    assert((State.VF.isScalar() || !isUniform()) &&
+           "uniform recipe shouldn't be predicated");
     assert(!State.VF.isScalable() && "Can't scalarize a scalable vector");
     State.ILV->scalarizeInstruction(UI, this, *State.Instance, State);
     // Insert scalar instance packing it into a vector.
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
new file mode 100644
index 0000000000000..6182e005c4938
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
@@ -0,0 +1,391 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -p loop-vectorize -mtriple aarch64 -mcpu=neoverse-v1 -S %s | FileCheck %s
+
+; Test case for https://github.com/llvm/llvm-project/issues/94328.
+define void @sdiv_feeding_gep(ptr %dst, i32 %x, i64 %M, i64 %conv6, i64 %N) {
+; CHECK-LABEL: define void @sdiv_feeding_gep(
+; CHECK-SAME: ptr [[DST:%.*]], i32 [[X:%.*]], i64 [[M:%.*]], i64 [[CONV6:%.*]], i64 [[N:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    [[CONV61:%.*]] = zext i32 [[X]] to i64
+; CHECK-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP1:%.*]] = mul i64 [[TMP0]], 4
+; CHECK-NEXT:    [[TMP2:%.*]] = call i64 @llvm.umax.i64(i64 8, i64 [[TMP1]])
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], [[TMP2]]
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_SCEVCHECK:.*]]
+; CHECK:       [[VECTOR_SCEVCHECK]]:
+; CHECK-NEXT:    [[TMP3:%.*]] = add i64 [[N]], -1
+; CHECK-NEXT:    [[TMP4:%.*]] = trunc i64 [[TMP3]] to i32
+; CHECK-NEXT:    [[TMP5:%.*]] = icmp slt i32 [[TMP4]], 0
+; CHECK-NEXT:    [[TMP6:%.*]] = icmp ugt i64 [[TMP3]], 4294967295
+; CHECK-NEXT:    [[TMP7:%.*]] = or i1 [[TMP5]], [[TMP6]]
+; CHECK-NEXT:    br i1 [[TMP7]], label %[[SCALAR_PH]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP9:%.*]] = mul i64 [[TMP8]], 4
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], [[TMP9]]
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT:    [[TMP10:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP11:%.*]] = mul i64 [[TMP10]], 4
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP12:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP13:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP14:%.*]] = mul i64 [[TMP13]], 2
+; CHECK-NEXT:    [[TMP15:%.*]] = add i64 [[TMP14]], 0
+; CHECK-NEXT:    [[TMP16:%.*]] = mul i64 [[TMP15]], 1
+; CHECK-NEXT:    [[TMP17:%.*]] = add i64 [[INDEX]], [[TMP16]]
+; CHECK-NEXT:    [[TMP18:%.*]] = sdiv i64 [[M]], [[CONV6]]
+; CHECK-NEXT:    [[TMP19:%.*]] = sdiv i64 [[M]], [[CONV6]]
+; CHECK-NEXT:    [[TMP20:%.*]] = trunc i64 [[TMP18]] to i32
+; CHECK-NEXT:    [[TMP21:%.*]] = trunc i64 [[TMP19]] to i32
+; CHECK-NEXT:    [[TMP22:%.*]] = mul i64 [[TMP18]], [[CONV61]]
+; CHECK-NEXT:    [[TMP23:%.*]] = mul i64 [[TMP19]], [[CONV61]]
+; CHECK-NEXT:    [[TMP24:%.*]] = sub i64 [[TMP12]], [[TMP22]]
+; CHECK-NEXT:    [[TMP25:%.*]] = sub i64 [[TMP17]], [[TMP23]]
+; CHECK-NEXT:    [[TMP26:%.*]] = trunc i64 [[TMP24]] to i32
+; CHECK-NEXT:    [[TMP27:%.*]] = trunc i64 [[TMP25]] to i32
+; CHECK-NEXT:    [[TMP28:%.*]] = mul i32 [[X]], [[TMP20]]
+; CHECK-NEXT:    [[TMP29:%.*]] = mul i32 [[X]], [[TMP21]]
+; CHECK-NEXT:    [[TMP30:%.*]] = add i32 [[TMP28]], [[TMP26]]
+; CHECK-NEXT:    [[TMP31:%.*]] = add i32 [[TMP29]], [[TMP27]]
+; CHECK-NEXT:    [[TMP32:%.*]] = sext i32 [[TMP30]] to i64
+; CHECK-NEXT:    [[TMP33:%.*]] = sext i32 [[TMP31]] to i64
+; CHECK-NEXT:    [[TMP34:%.*]] = getelementptr double, ptr [[DST]], i64 [[TMP32]]
+; CHECK-NEXT:    [[TMP35:%.*]] = getelementptr double, ptr [[DST]], i64 [[TMP33]]
+; CHECK-NEXT:    [[TMP36:%.*]] = getelementptr double, ptr [[TMP34]], i32 0
+; CHECK-NEXT:    [[TMP37:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP38:%.*]] = mul i64 [[TMP37]], 2
+; CHECK-NEXT:    [[TMP39:%.*]] = getelementptr double, ptr [[TMP34]], i64 [[TMP38]]
+; CHECK-NEXT:    store <vscale x 2 x double> zeroinitializer, ptr [[TMP36]], align 8
+; CHECK-NEXT:    store <vscale x 2 x double> zeroinitializer, ptr [[TMP39]], align 8
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP11]]
+; CHECK-NEXT:    [[TMP40:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP40]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; 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]] ], [ 0, %[[VECTOR_SCEVCHECK]] ]
+; CHECK-NEXT:    br label %[[LOOP:.*]]
+; CHECK:       [[LOOP]]:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; CHECK-NEXT:    [[DIV18:%.*]] = sdiv i64 [[M]], [[CONV6]]
+; CHECK-NEXT:    [[CONV20:%.*]] = trunc i64 [[DIV18]] to i32
+; CHECK-NEXT:    [[MUL30:%.*]] = mul i64 [[DIV18]], [[CONV61]]
+; CHECK-NEXT:    [[SUB31:%.*]] = sub i64 [[IV]], [[MUL30]]
+; CHECK-NEXT:    [[CONV34:%.*]] = trunc i64 [[SUB31]] to i32
+; CHECK-NEXT:    [[MUL35:%.*]] = mul i32 [[X]], [[CONV20]]
+; CHECK-NEXT:    [[ADD36:%.*]] = add i32 [[MUL35]], [[CONV34]]
+; CHECK-NEXT:    [[IDXPROM:%.*]] = sext i32 [[ADD36]] to i64
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr double, ptr [[DST]], i64 [[IDXPROM]]
+; CHECK-NEXT:    store double 0.000000e+00, ptr [[GEP]], align 8
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[EC:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-NEXT:    br i1 [[EC]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %conv61 = zext i32 %x to i64
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %div18 = sdiv i64 %M, %conv6
+  %conv20 = trunc i64 %div18 to i32
+  %mul30 = mul i64 %div18, %conv61
+  %sub31 = sub i64 %iv, %mul30
+  %conv34 = trunc i64 %sub31 to i32
+  %mul35 = mul i32 %x, %conv20
+  %add36 = add i32 %mul35, %conv34
+  %idxprom = sext i32 %add36 to i64
+  %gep = getelementptr double, ptr %dst, i64 %idxprom
+  store double 0.000000e+00, ptr %gep, align 8
+  %iv.next = add i64 %iv, 1
+  %ec = icmp eq i64 %iv.next, %N
+  br i1 %ec, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+define void @sdiv_feeding_gep_predicated(ptr %dst, i32 %x, i64 %M, i64 %conv6, i64 %N) {
+; CHECK-LABEL: define void @sdiv_feeding_gep_predicated(
+; CHECK-SAME: ptr [[DST:%.*]], i32 [[X:%.*]], i64 [[M:%.*]], i64 [[CONV6:%.*]], i64 [[N:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    [[CONV61:%.*]] = zext i32 [[X]] to i64
+; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_SCEVCHECK:.*]]
+; CHECK:       [[VECTOR_SCEVCHECK]]:
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[N]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = trunc i64 [[TMP0]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp slt i32 [[TMP1]], 0
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp ugt i64 [[TMP0]], 4294967295
+; CHECK-NEXT:    [[TMP4:%.*]] = or i1 [[TMP2]], [[TMP3]]
+; CHECK-NEXT:    br i1 [[TMP4]], label %[[SCALAR_PH]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP6:%.*]] = mul i64 [[TMP5]], 2
+; CHECK-NEXT:    [[TMP7:%.*]] = sub i64 [[TMP6]], 1
+; CHECK-NEXT:    [[N_RND_UP:%.*]] = add i64 [[N]], [[TMP7]]
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N_RND_UP]], [[TMP6]]
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[N_RND_UP]], [[N_MOD_VF]]
+; CHECK-NEXT:    [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP9:%.*]] = mul i64 [[TMP8]], 2
+; CHECK-NEXT:    [[TMP10:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP11:%.*]] = mul i64 [[TMP10]], 2
+; CHECK-NEXT:    [[TMP12:%.*]] = sub i64 [[N]], [[TMP11]]
+; CHECK-NEXT:    [[TMP13:%.*]] = icmp ugt i64 [[N]], [[TMP11]]
+; CHECK-NEXT:    [[TMP14:%.*]] = select i1 [[TMP13]], i64 [[TMP12]], i64 0
+; CHECK-NEXT:    [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 [[N]])
+; CHECK-NEXT:    [[TMP15:%.*]] = call <vscale x 2 x i64> @llvm.experimental.stepvector.nxv2i64()
+; CHECK-NEXT:    [[TMP16:%.*]] = add <vscale x 2 x i64> [[TMP15]], zeroinitializer
+; CHECK-NEXT:    [[TMP17:%.*]] = mul <vscale x 2 x i64> [[TMP16]], shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[INDUCTION:%.*]] = add <vscale x 2 x i64> zeroinitializer, [[TMP17]]
+; CHECK-NEXT:    [[TMP18:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP19:%.*]] = mul i64 [[TMP18]], 2
+; CHECK-NEXT:    [[TMP20:%.*]] = mul i64 1, [[TMP19]]
+; CHECK-NEXT:    [[DOTSPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[TMP20]], i64 0
+; CHECK-NEXT:    [[DOTSPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[DOTSPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[M]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[CONV6]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT1]], <vscale x 2 x i64> poison, <vscale x 2 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:    [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[VECTOR_PH]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <vscale x 2 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP21:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP22:%.*]] = icmp ule <vscale x 2 x i64> [[VEC_IND]], [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[TMP23:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i1> [[TMP22]], <vscale x 2 x i1> zeroinitializer
+; CHECK-NEXT:    [[TMP24:%.*]] = select <vscale x 2 x i1> [[TMP23]], <vscale x 2 x i64> [[BROADCAST_SPLAT2]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP25:%.*]] = sdiv <vscale x 2 x i64> [[BROADCAST_SPLAT]], [[TMP24]]
+; CHECK-NEXT:    [[TMP26:%.*]] = extractelement <vscale x 2 x i64> [[TMP25]], i32 0
+; CHECK-NEXT:    [[TMP27:%.*]] = trunc i64 [[TMP26]] to i32
+; CHECK-NEXT:    [[TMP28:%.*]] = mul i64 [[TMP26]], [[CONV61]]
+; CHECK-NEXT:    [[TMP29:%.*]] = sub i64 [[TMP21]], [[TMP28]]
+; CHECK-NEXT:    [[TMP30:%.*]] = trunc i64 [[TMP29]] to i32
+; CHECK-NEXT:    [[TMP31:%.*]] = mul i32 [[X]], [[TMP27]]
+; CHECK-NEXT:    [[TMP32:%.*]] = add i32 [[TMP31]], [[TMP30]]
+; CHECK-NEXT:    [[TMP33:%.*]] = sext i32 [[TMP32]] to i64
+; CHECK-NEXT:    [[TMP34:%.*]] = getelementptr double, ptr [[DST]], i64 [[TMP33]]
+; CHECK-NEXT:    [[TMP35:%.*]] = getelementptr double, ptr [[TMP34]], i32 0
+; CHECK-NEXT:    call void @llvm.masked.store.nxv2f64.p0(<vscale x 2 x double> zeroinitializer, ptr [[TMP35]], i32 8, <vscale x 2 x i1> [[TMP23]])
+; CHECK-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], [[TMP9]]
+; CHECK-NEXT:    [[ACTIVE_LANE_MASK_NEXT]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 [[INDEX]], i64 [[TMP14]])
+; CHECK-NEXT:    [[TMP36:%.*]] = xor <vscale x 2 x i1> [[ACTIVE_LANE_MASK_NEXT]], shufflevector (<vscale x 2 x i1> insertelement (<vscale x 2 x i1> poison, i1 true, i64 0), <vscale x 2 x i1> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 2 x i64> [[VEC_IND]], [[DOTSPLAT]]
+; CHECK-NEXT:    [[TMP37:%.*]] = extractelement <vscale x 2 x i1> [[TMP36]], i32 0
+; CHECK-NEXT:    br i1 [[TMP37]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br i1 true, label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ], [ 0, %[[VECTOR_SCEVCHECK]] ]
+; CHECK-NEXT:    br label %[[LOOP:.*]]
+; CHECK:       [[LOOP]]:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp ule i64 [[IV]], [[M]]
+; CHECK-NEXT:    br i1 [[C]], label %[[THEN:.*]], label %[[LOOP_LATCH]]
+; CHECK:       [[THEN]]:
+; CHECK-NEXT:    [[DIV18:%.*]] = sdiv i64 [[M]], [[CONV6]]
+; CHECK-NEXT:    [[CONV20:%.*]] = trunc i64 [[DIV18]] to i32
+; CHECK-NEXT:    [[MUL30:%.*]] = mul i64 [[DIV18]], [[CONV61]]
+; CHECK-NEXT:    [[SUB31:%.*]] = sub i64 [[IV]], [[MUL30]]
+; CHECK-NEXT:    [[CONV34:%.*]] = trunc i64 [[SUB31]] to i32
+; CHECK-NEXT:    [[MUL35:%.*]] = mul i32 [[X]], [[CONV20]]
+; CHECK-NEXT:    [[ADD36:%.*]] = add i32 [[MUL35]], [[CONV34]]
+; CHECK-NEXT:    [[IDXPROM:%.*]] = sext i32 [[ADD36]] to i64
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr double, ptr [[DST]], i64 [[IDXPROM]]
+; CHECK-NEXT:    store double 0.000000e+00, ptr [[GEP]], align 8
+; CHECK-NEXT:    br label %[[LOOP_LATCH]]
+; CHECK:       [[LOOP_LATCH]]:
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[EC:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
+; CHECK-NEXT:    br i1 [[EC]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %conv61 = zext i32 %x to i64
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %c = icmp ule i64 %iv, %M
+  br i1 %c, label %then, label %loop.latch
+
+then:
+  %div18 = sdiv i64 %M, %conv6
+  %conv20 = trunc i64 %div18 to i32
+  %mul30 = mul i64 %div18, %conv61
+  %sub31 = sub i64 %iv, %mul30
+  %conv34 = trunc i64 %sub31 to i32
+  %mul35 = mul i32 %x, %conv20
+  %add36 = add i32 %mul35, %conv34
+  %idxprom = sext i32 %add36 to i64
+  %gep = getelementptr double, ptr %dst, i64 %idxprom
+  store double 0.000000e+00, ptr %gep, align 8
+  br label %loop.latch
+
+loop.latch:
+  %iv.next = add i64 %iv, 1
+  %ec = icmp eq i64 %iv.next, %N
+  br i1 %ec, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; Test case for https://github.com/llvm/llvm-project/issues/80416.
+define void @udiv_urem_feeding_gep(i64 %x, ptr %dst, i64 %N) {
+; CHECK-LABEL: define void @udiv_urem_feeding_gep(
+; CHECK-SAME: i64 [[X:%.*]], ptr [[DST:%.*]], i64 [[N:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    [[MUL_1_I:%.*]] = mul i64 [[X]], [[X]]
+; CHECK-NEXT:    [[MUL_2_I:%.*]] = mul i64 [[MUL_1_I]], [[X]]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[N]], 1
+; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_SCEVCHECK:.*]]
+; CHECK:       [[VECTOR_SCEVCHECK]]:
+; CHECK-NEXT:    [[TMP1:%.*]] = trunc i64 [[N]] to i32
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp slt i32 [[TMP1]], 0
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp ugt i64 [[N]], 4294967295
+; CHECK-NEXT:    [[TMP4:%.*]] = or i1 [[TMP2]], [[TMP3]]
+; CHECK-NEXT:    br i1 [[TMP4]], label %[[SCALAR_PH]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP6:%.*]] = mul i64 [[TMP5]], 2
+; CHECK-NEXT:    [[TMP7:%.*]] = sub i64 [[TMP6]], 1
+; CHECK-NEXT:    [[N_RND_UP:%.*]] = add i64 [[TMP0]], [[TMP7]]
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N_RND_UP]], [[TMP6]]
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[N_RND_UP]], [[N_MOD_VF]]
+; CHECK-NEXT:    [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP9:%.*]] = mul i64 [[TMP8]], 2
+; CHECK-NEXT:    [[TMP10:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP11:%.*]] = mul i64 [[TMP10]], 2
+; CHECK-NEXT:    [[TMP12:%.*]] = sub i64 [[TMP0]], [[TMP11]]
+; CHECK-NEXT:    [[TMP13:%.*]] = icmp ugt i64 [[TMP0]], [[TMP11]]
+; CHECK-NEXT:    [[TMP14:%.*]] = select i1 [[TMP13]], i64 [[TMP12]], i64 0
+; CHECK-NEXT:    [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 [[TMP0]])
+; CHECK-NEXT:    [[TMP15:%.*]] = call <vscale x 2 x i64> @llvm.experimental.stepvector.nxv2i64()
+; CHECK-NEXT:    [[TMP16:%.*]] = add <vscale x 2 x i64> [[TMP15]], zeroinitializer
+; CHECK-NEXT:    [[TMP17:%.*]] = mul <vscale x 2 x i64> [[TMP16]], shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[INDUCTION:%.*]] = add <vscale x 2 x i64> zeroinitializer, [[TMP17]]
+; CHECK-NEXT:    [[TMP18:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP19:%.*]] = mul i64 [[TMP18]], 2
+; CHECK-NEXT:    [[TMP20:%.*]] = mul i64 1, [[TMP19]]
+; CHECK-NEXT:    [[DOTSPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[TMP20]], i64 0
+; CHECK-NEXT:    [[DOTSPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[DOTSPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[MUL_2_I]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[MUL_1_I]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT1]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT3:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[X]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT4:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT3]], <vscale x 2 x i64> poison, <vscale x 2 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:    [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[VECTOR_PH]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <vscale x 2 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP21:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP22:%.*]] = udiv <vscale x 2 x i64> [[VEC_IND]], [[TMP21]]
+; CHECK-NEXT:    [[TMP23:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP24:%.*]] = urem <vscale x 2 x i64> [[VEC_IND]], [[TMP23]]
+; CHECK-NEXT:    [[TMP25:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT2]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP26:%.*]] = udiv <vscale x 2 x i64> [[TMP24]], [[TMP25]]
+; CHECK-NEXT:    [[TMP27:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT2]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP28:%.*]] = urem <vscale x 2 x i64> [[TMP24]], [[TMP27]]
+; CHECK-NEXT:    [[TMP29:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT4]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP30:%.*]] = udiv <vscale x 2 x i64> [[TMP28]], [[TMP29]]
+; CHECK-NEXT:    [[TMP31:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT4]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP32:%.*]] = urem <vscale x 2 x i64> [[TMP28]], [[TMP31]]
+; CHECK-NEXT:    [[TMP33:%.*]] = extractelement <vscale x 2 x i64> [[TMP22]], i32 0
+; CHECK-NEXT:    [[TMP34:%.*]] = mul i64 [[X]], [[TMP33]]
+; CHECK-NEXT:    [[TMP35:%.*]] = extractelement <vscale x 2 x i64> [[TMP26]], i32 0
+; CHECK-NEXT:    [[TMP36:%.*]] = add i64 [[TMP34]], [[TMP35]]
+; CHECK-NEXT:    [[TMP37:%.*]] = mul i64 [[TMP36]], [[X]]
+; CHECK-NEXT:    [[TMP38:%.*]] = extractelement <vscale x 2 x i64> [[TMP30]], i32 0
+; CHECK-NEXT:    [[TMP39:%.*]] = add i64 [[TMP37]], [[TMP38]]
+; CHECK-NEXT:    [[TMP40:%.*]] = mul i64 [[TMP39]], [[X]]
+; CHECK-NEXT:    [[TMP41:%.*]] = extractelement <vscale x 2 x i64> [[TMP32]], i32 0
+; CHECK-NEXT:    [[TMP42:%.*]] = add i64 [[TMP40]], [[TMP41]]
+; CHECK-NEXT:    [[TMP43:%.*]] = shl i64 [[TMP42]], 32
+; CHECK-NEXT:    [[TMP44:%.*]] = ashr i64 [[TMP43]], 32
+; CHECK-NEXT:    [[TMP45:%.*]] = getelementptr i64, ptr [[DST]], i64 [[TMP44]]
+; CHECK-NEXT:    [[TMP46:%.*]] = getelementptr i64, ptr [[TMP45]], i32 0
+; CHECK-NEXT:    call void @llvm.masked.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP22]], ptr [[TMP46]], i32 4, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]])
+; CHECK-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], [[TMP9]]
+; CHECK-NEXT:    [[ACTIVE_LANE_MASK_NEXT]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 [[INDEX]], i64 [[TMP14]])
+; CHECK-NEXT:    [[TMP47:%.*]] = xor <vscale x 2 x i1> [[ACTIVE_LANE_MASK_NEXT]], shufflevector (<vscale x 2 x i1> insertelement (<vscale x 2 x i1> poison, i1 true, i64 0), <vscale x 2 x i1> poison, <vscale x 2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 2 x i64> [[VEC_IND]], [[DOTSPLAT]]
+; CHECK-NEXT:    [[TMP48:%.*]] = extractelement <vscale x 2 x i1> [[TMP47]], i32 0
+; CHECK-NEXT:    br i1 [[TMP48]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br i1 true, label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ], [ 0, %[[VECTOR_SCEVCHECK]] ]
+; CHECK-NEXT:    br label %[[LOOP:.*]]
+; CHECK:       [[LOOP]]:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; CHECK-NEXT:    [[DIV_I:%.*]] = udiv i64 [[IV]], [[MUL_2_I]]
+; CHECK-NEXT:    [[REM_I:%.*]] = urem i64 [[IV]], [[MUL_2_I]]
+; CHECK-NEXT:    [[DIV_1_I:%.*]] = udiv i64 [[REM_I]], [[MUL_1_I]]
+; CHECK-NEXT:    [[REM_1_I:%.*]] = urem i64 [[REM_I]], [[MUL_1_I]]
+; CHECK-NEXT:    [[DIV_2_I:%.*]] = udiv i64 [[REM_1_I]], [[X]]
+; CHECK-NEXT:    [[REM_2_I:%.*]] = urem i64 [[REM_1_I]], [[X]]
+; CHECK-NEXT:    [[MUL_I:%.*]] = mul i64 [[X]], [[DIV_I]]
+; CHECK-NEXT:    [[ADD_I:%.*]] = add i64 [[MUL_I]], [[DIV_1_I]]
+; CHECK-NEXT:    [[MUL_1_I9:%.*]] = mul i64 [[ADD_I]], [[X]]
+; CHECK-NEXT:    [[ADD_1_I:%.*]] = add i64 [[MUL_1_I9]], [[DIV_2_I]]
+; CHECK-NEXT:    [[MUL_2_I11:%.*]] = mul i64 [[ADD_1_I]], [[X]]
+; CHECK-NEXT:    [[ADD_2_I:%.*]] = add i64 [[MUL_2_I11]], [[REM_2_I]]
+; CHECK-NEXT:    [[SEXT_I:%.*]] = shl i64 [[ADD_2_I]], 32
+; CHECK-NEXT:    [[CONV6_I:%.*]] = ashr i64 [[SEXT_I]], 32
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr i64, ptr [[DST]], i64 [[CONV6_I]]
+; CHECK-NEXT:    store i64 [[DIV_I]], ptr [[GEP]], align 4
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV]], [[N]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %mul.1.i = mul i64 %x, %x
+  %mul.2.i = mul i64 %mul.1.i, %x
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %div.i = udiv i64 %iv, %mul.2.i
+  %rem.i = urem i64 %iv, %mul.2.i
+  %div.1.i = udiv i64 %rem.i, %mul.1.i
+  %rem.1.i = urem i64 %rem.i, %mul.1.i
+  %div.2.i = udiv i64 %rem.1.i, %x
+  %rem.2.i = urem i64 %rem.1.i, %x
+  %mul.i = mul i64 %x, %div.i
+  %add.i = add i64 %mul.i, %div.1.i
+  %mul.1.i9 = mul i64 %add.i, %x
+  %add.1.i = add i64 %mul.1.i9, %div.2.i
+  %mul.2.i11 = mul i64 %add.1.i, %x
+  %add.2.i = add i64 %mul.2.i11, %rem.2.i
+  %sext.i = shl i64 %add.2.i, 32
+  %conv6.i = ashr i64 %sext.i, 32
+  %gep = getelementptr i64, ptr %dst, i64 %conv6.i
+  store i64 %div.i, ptr %gep, align 4
+  %iv.next = add i64 %iv, 1
+  %exitcond.not = icmp eq i64 %iv, %N
+  br i1 %exitcond.not, label %exit, label %loop
+
+exit:
+  ret void
+}
+;.
+; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
+; CHECK: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
+; CHECK: [[META2]] = !{!"llvm.loop.unroll.runtime.disable"}
+; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META1]]}
+; CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]], [[META2]]}
+; CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]]}
+; CHECK: [[LOOP6]] = distinct !{[[LOOP6]], [[META1]], [[META2]]}
+; CHECK: [[LOOP7]] = distinct !{[[LOOP7]], [[META1]]}
+;.
diff --git a/llvm/test/Transforms/LoopVectorize/X86/consecutive-ptr-uniforms.ll b/llvm/test/Transforms/LoopVectorize/X86/consecutive-ptr-uniforms.ll
index bee5b397ecb47..bb35806cea20a 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/consecutive-ptr-uniforms.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/consecutive-ptr-uniforms.ll
@@ -76,7 +76,7 @@ attributes #0 = { "target-cpu"="knl" }
 ; CHECK:     LV: Found trip count: 3
 ; CHECK:     LV: Found uniform instruction:   {{%.*}} = icmp eq i32 {{%.*}}, 0
 ; CHECK-NOT: LV: Found uniform instruction:   {{%.*}} = load i32, ptr {{%.*}}, align 1
-; CHECK:     LV: Found not uniform being ScalarWithPredication:  {{%.*}} = load i32, ptr {{%.*}}, align 1
+; CHECK:     LV: Found not uniform due to requiring predication:  {{%.*}} = load i32, ptr {{%.*}}, align 1
 ; CHECK:     LV: Found scalar instruction:   {{%.*}} = getelementptr inbounds [3 x i32], ptr @a, i32 0, i32 {{%.*}}
 ;
 ; FORCE-LABEL: @PR40816(

>From 1782e6c3528aa44dba269faa09ace8c76cfe2c7d Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Mon, 15 Jul 2024 14:43:15 +0100
Subject: [PATCH 2/7] [LV] Don't predicate uniform divides with loop-invariant
 divisor.

When folding the tail, at least one of the lanes must execute
unconditionally. If the divisor is loop-invariant no predication is
needed, as predication would not prevent the divide-by-0 on the executed
lane.

Depends on https://github.com/llvm/llvm-project/pull/98892.
---
 .../Transforms/Vectorize/LoopVectorize.cpp    |  39 ++++--
 .../Transforms/Vectorize/VPRecipeBuilder.h    |   2 +-
 .../AArch64/divs-with-scalable-vfs.ll         |  35 ++---
 .../X86/divs-with-tail-folding.ll             | 122 +++++-------------
 4 files changed, 70 insertions(+), 128 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 3d7df2efd6b85..f5a860e980c74 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1402,7 +1402,8 @@ class LoopVectorizationCostModel {
   /// Returns true if \p I is an instruction that needs to be predicated
   /// at runtime.  The result is independent of the predication mechanism.
   /// Superset of instructions that return true for isScalarWithPredication.
-  bool isPredicatedInst(Instruction *I) const;
+  bool isPredicatedInst(Instruction *I, ElementCount VF,
+                        bool IsKnownUniform = false) const;
 
   /// Return the costs for our two available strategies for lowering a
   /// div/rem operation which requires speculating at least one lane.
@@ -3637,7 +3638,7 @@ void LoopVectorizationCostModel::collectLoopScalars(ElementCount VF) {
 
 bool LoopVectorizationCostModel::isScalarWithPredication(
     Instruction *I, ElementCount VF) const {
-  if (!isPredicatedInst(I))
+  if (!isPredicatedInst(I, VF))
     return false;
 
   // Do we have a non-scalar lowering for this predicated
@@ -3676,7 +3677,9 @@ bool LoopVectorizationCostModel::isScalarWithPredication(
   }
 }
 
-bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
+bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I,
+                                                  ElementCount VF,
+                                                  bool IsKnownUniform) const {
   if (!blockNeedsPredicationForAnyReason(I->getParent()))
     return false;
 
@@ -3710,6 +3713,15 @@ bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
   case Instruction::SDiv:
   case Instruction::SRem:
   case Instruction::URem:
+    // When folding the tail, at least one of the lanes must execute
+    // unconditionally. If the divisor is loop-invariant no predication is
+    // needed, as predication would not prevent the divide-by-0 on the executed
+    // lane.
+    if (foldTailByMasking() && !Legal->blockNeedsPredication(I->getParent()) &&
+        TheLoop->isLoopInvariant(I->getOperand(1)) &&
+        (IsKnownUniform || isUniformAfterVectorization(I, VF)))
+      return false;
+
     // TODO: We can use the loop-preheader as context point here and get
     // context sensitive reasoning
     return !isSafeToSpeculativelyExecute(I);
@@ -3917,7 +3929,7 @@ void LoopVectorizationCostModel::collectLoopUniforms(ElementCount VF) {
                         << *I << "\n");
       return;
     }
-    if (isPredicatedInst(I)) {
+    if (isPredicatedInst(I, VF, true)) {
       LLVM_DEBUG(
           dbgs() << "LV: Found not uniform due to requiring predication: " << *I
                  << "\n");
@@ -5634,7 +5646,7 @@ bool LoopVectorizationCostModel::useEmulatedMaskMemRefHack(Instruction *I,
   // from moving "masked load/store" check from legality to cost model.
   // Masked Load/Gather emulation was previously never allowed.
   // Limited number of Masked Store/Scatter emulation was allowed.
-  assert((isPredicatedInst(I)) &&
+  assert((isPredicatedInst(I, VF)) &&
          "Expecting a scalar emulated instruction");
   return isa<LoadInst>(I) ||
          (isa<StoreInst>(I) &&
@@ -5913,7 +5925,7 @@ LoopVectorizationCostModel::getMemInstScalarizationCost(Instruction *I,
   // If we have a predicated load/store, it will need extra i1 extracts and
   // conditional branches, but may not be executed for each vector lane. Scale
   // the cost by the probability of executing the predicated block.
-  if (isPredicatedInst(I)) {
+  if (isPredicatedInst(I, VF)) {
     Cost /= getReciprocalPredBlockProb();
 
     // Add the cost of an i1 extract and a branch
@@ -6773,7 +6785,7 @@ LoopVectorizationCostModel::getInstructionCost(Instruction *I,
   case Instruction::SDiv:
   case Instruction::URem:
   case Instruction::SRem:
-    if (VF.isVector() && isPredicatedInst(I)) {
+    if (VF.isVector() && isPredicatedInst(I, VF)) {
       const auto [ScalarCost, SafeDivisorCost] = getDivRemSpeculationCost(I, VF);
       return isDivRemScalarWithPredication(ScalarCost, SafeDivisorCost) ?
         ScalarCost : SafeDivisorCost;
@@ -8445,7 +8457,7 @@ bool VPRecipeBuilder::shouldWiden(Instruction *I, VFRange &Range) const {
 
 VPWidenRecipe *VPRecipeBuilder::tryToWiden(Instruction *I,
                                            ArrayRef<VPValue *> Operands,
-                                           VPBasicBlock *VPBB) {
+                                           VPBasicBlock *VPBB, VFRange &Range) {
   switch (I->getOpcode()) {
   default:
     return nullptr;
@@ -8455,7 +8467,10 @@ VPWidenRecipe *VPRecipeBuilder::tryToWiden(Instruction *I,
   case Instruction::URem: {
     // If not provably safe, use a select to form a safe divisor before widening the
     // div/rem operation itself.  Otherwise fall through to general handling below.
-    if (CM.isPredicatedInst(I)) {
+    bool IsPredicated = LoopVectorizationPlanner::getDecisionAndClampRange(
+        [&](ElementCount VF) -> bool { return CM.isPredicatedInst(I, VF); },
+        Range);
+    if (IsPredicated) {
       SmallVector<VPValue *> Ops(Operands.begin(), Operands.end());
       VPValue *Mask = getBlockInMask(I->getParent());
       VPValue *One =
@@ -8505,8 +8520,8 @@ VPReplicateRecipe *VPRecipeBuilder::handleReplication(Instruction *I,
       [&](ElementCount VF) { return CM.isUniformAfterVectorization(I, VF); },
       Range);
 
-  bool IsPredicated = CM.isPredicatedInst(I);
-
+  bool IsPredicated = LoopVectorizationPlanner::getDecisionAndClampRange(
+      [&](ElementCount VF) { return CM.isPredicatedInst(I, VF); }, Range);
   // Even if the instruction is not marked as uniform, there are certain
   // intrinsic calls that can be effectively treated as such, so we check for
   // them here. Conservatively, we only do this for scalable vectors, since
@@ -8626,7 +8641,7 @@ VPRecipeBuilder::tryToCreateWidenRecipe(Instruction *Instr,
                                  *CI);
   }
 
-  return tryToWiden(Instr, Operands, VPBB);
+  return tryToWiden(Instr, Operands, VPBB, Range);
 }
 
 void LoopVectorizationPlanner::buildVPlansWithVPRecipes(ElementCount MinVF,
diff --git a/llvm/lib/Transforms/Vectorize/VPRecipeBuilder.h b/llvm/lib/Transforms/Vectorize/VPRecipeBuilder.h
index b4c7ab02f928f..0c7c47258bf9e 100644
--- a/llvm/lib/Transforms/Vectorize/VPRecipeBuilder.h
+++ b/llvm/lib/Transforms/Vectorize/VPRecipeBuilder.h
@@ -100,7 +100,7 @@ class VPRecipeBuilder {
   /// if it can. The function should only be called if the cost-model indicates
   /// that widening should be performed.
   VPWidenRecipe *tryToWiden(Instruction *I, ArrayRef<VPValue *> Operands,
-                            VPBasicBlock *VPBB);
+                            VPBasicBlock *VPBB, VFRange &Range);
 
 public:
   VPRecipeBuilder(VPlan &Plan, Loop *OrigLoop, const TargetLibraryInfo *TLI,
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
index 6182e005c4938..e1ce8d430e741 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
@@ -274,50 +274,39 @@ define void @udiv_urem_feeding_gep(i64 %x, ptr %dst, i64 %N) {
 ; CHECK-NEXT:    [[TMP18:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[TMP19:%.*]] = mul i64 [[TMP18]], 2
 ; CHECK-NEXT:    [[TMP20:%.*]] = mul i64 1, [[TMP19]]
-; CHECK-NEXT:    [[DOTSPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[TMP20]], i64 0
-; CHECK-NEXT:    [[DOTSPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[DOTSPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
-; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[MUL_2_I]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[TMP20]], i64 0
 ; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
-; CHECK-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[MUL_1_I]], i64 0
-; CHECK-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT1]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
-; CHECK-NEXT:    [[BROADCAST_SPLATINSERT3:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[X]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT3:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[MUL_2_I]], i64 0
 ; CHECK-NEXT:    [[BROADCAST_SPLAT4:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT3]], <vscale x 2 x i64> poison, <vscale x 2 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:    [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[VECTOR_PH]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <vscale x 2 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; CHECK-NEXT:    [[TMP21:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
-; CHECK-NEXT:    [[TMP22:%.*]] = udiv <vscale x 2 x i64> [[VEC_IND]], [[TMP21]]
-; CHECK-NEXT:    [[TMP23:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
-; CHECK-NEXT:    [[TMP24:%.*]] = urem <vscale x 2 x i64> [[VEC_IND]], [[TMP23]]
-; CHECK-NEXT:    [[TMP25:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT2]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
-; CHECK-NEXT:    [[TMP26:%.*]] = udiv <vscale x 2 x i64> [[TMP24]], [[TMP25]]
-; CHECK-NEXT:    [[TMP27:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT2]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
-; CHECK-NEXT:    [[TMP28:%.*]] = urem <vscale x 2 x i64> [[TMP24]], [[TMP27]]
+; CHECK-NEXT:    [[TMP28:%.*]] = phi <vscale x 2 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP21:%.*]] = add i64 [[INDEX]], 0
 ; CHECK-NEXT:    [[TMP29:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT4]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
 ; CHECK-NEXT:    [[TMP30:%.*]] = udiv <vscale x 2 x i64> [[TMP28]], [[TMP29]]
-; CHECK-NEXT:    [[TMP31:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT4]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
-; CHECK-NEXT:    [[TMP32:%.*]] = urem <vscale x 2 x i64> [[TMP28]], [[TMP31]]
-; CHECK-NEXT:    [[TMP33:%.*]] = extractelement <vscale x 2 x i64> [[TMP22]], i32 0
+; CHECK-NEXT:    [[TMP24:%.*]] = urem i64 [[TMP21]], [[MUL_2_I]]
+; CHECK-NEXT:    [[TMP35:%.*]] = udiv i64 [[TMP24]], [[MUL_1_I]]
+; CHECK-NEXT:    [[TMP26:%.*]] = urem i64 [[TMP24]], [[MUL_1_I]]
+; CHECK-NEXT:    [[TMP38:%.*]] = udiv i64 [[TMP26]], [[X]]
+; CHECK-NEXT:    [[TMP41:%.*]] = urem i64 [[TMP26]], [[X]]
+; CHECK-NEXT:    [[TMP33:%.*]] = extractelement <vscale x 2 x i64> [[TMP30]], i32 0
 ; CHECK-NEXT:    [[TMP34:%.*]] = mul i64 [[X]], [[TMP33]]
-; CHECK-NEXT:    [[TMP35:%.*]] = extractelement <vscale x 2 x i64> [[TMP26]], i32 0
 ; CHECK-NEXT:    [[TMP36:%.*]] = add i64 [[TMP34]], [[TMP35]]
 ; CHECK-NEXT:    [[TMP37:%.*]] = mul i64 [[TMP36]], [[X]]
-; CHECK-NEXT:    [[TMP38:%.*]] = extractelement <vscale x 2 x i64> [[TMP30]], i32 0
 ; CHECK-NEXT:    [[TMP39:%.*]] = add i64 [[TMP37]], [[TMP38]]
 ; CHECK-NEXT:    [[TMP40:%.*]] = mul i64 [[TMP39]], [[X]]
-; CHECK-NEXT:    [[TMP41:%.*]] = extractelement <vscale x 2 x i64> [[TMP32]], i32 0
 ; CHECK-NEXT:    [[TMP42:%.*]] = add i64 [[TMP40]], [[TMP41]]
 ; CHECK-NEXT:    [[TMP43:%.*]] = shl i64 [[TMP42]], 32
 ; CHECK-NEXT:    [[TMP44:%.*]] = ashr i64 [[TMP43]], 32
 ; CHECK-NEXT:    [[TMP45:%.*]] = getelementptr i64, ptr [[DST]], i64 [[TMP44]]
 ; CHECK-NEXT:    [[TMP46:%.*]] = getelementptr i64, ptr [[TMP45]], i32 0
-; CHECK-NEXT:    call void @llvm.masked.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP22]], ptr [[TMP46]], i32 4, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]])
+; CHECK-NEXT:    call void @llvm.masked.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP30]], ptr [[TMP46]], i32 4, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]])
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], [[TMP9]]
 ; CHECK-NEXT:    [[ACTIVE_LANE_MASK_NEXT]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 [[INDEX]], i64 [[TMP14]])
 ; CHECK-NEXT:    [[TMP47:%.*]] = xor <vscale x 2 x i1> [[ACTIVE_LANE_MASK_NEXT]], shufflevector (<vscale x 2 x i1> insertelement (<vscale x 2 x i1> poison, i1 true, i64 0), <vscale x 2 x i1> poison, <vscale x 2 x i32> zeroinitializer)
-; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 2 x i64> [[VEC_IND]], [[DOTSPLAT]]
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 2 x i64> [[TMP28]], [[BROADCAST_SPLAT]]
 ; CHECK-NEXT:    [[TMP48:%.*]] = extractelement <vscale x 2 x i1> [[TMP47]], i32 0
 ; CHECK-NEXT:    br i1 [[TMP48]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
 ; CHECK:       [[MIDDLE_BLOCK]]:
diff --git a/llvm/test/Transforms/LoopVectorize/X86/divs-with-tail-folding.ll b/llvm/test/Transforms/LoopVectorize/X86/divs-with-tail-folding.ll
index 42a9ab0ca270f..d0dc456c91d6d 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/divs-with-tail-folding.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/divs-with-tail-folding.ll
@@ -23,42 +23,15 @@ define void @sdiv_feeding_gep(ptr %dst, i32 %x, i64 %M, i64 %conv6, i64 %N) {
 ; CHECK-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT1]], <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:%.*]], %[[PRED_SDIV_CONTINUE8:.*]] ]
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
 ; CHECK-NEXT:    [[TMP5:%.*]] = add i64 [[INDEX]], 0
 ; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[INDEX]], i64 0
 ; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT]], <4 x i64> poison, <4 x i32> zeroinitializer
 ; CHECK-NEXT:    [[VEC_IV:%.*]] = add <4 x i64> [[BROADCAST_SPLAT]], <i64 0, i64 1, i64 2, i64 3>
 ; CHECK-NEXT:    [[TMP6:%.*]] = icmp ule <4 x i64> [[VEC_IV]], [[BROADCAST_SPLAT2]]
-; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <4 x i1> [[TMP6]], i32 0
-; CHECK-NEXT:    br i1 [[TMP7]], label %[[PRED_SDIV_IF:.*]], label %[[PRED_SDIV_CONTINUE:.*]]
-; CHECK:       [[PRED_SDIV_IF]]:
-; CHECK-NEXT:    [[TMP8:%.*]] = sdiv i64 [[M]], [[CONV6]]
-; CHECK-NEXT:    br label %[[PRED_SDIV_CONTINUE]]
-; CHECK:       [[PRED_SDIV_CONTINUE]]:
-; CHECK-NEXT:    [[TMP9:%.*]] = phi i64 [ poison, %[[VECTOR_BODY]] ], [ [[TMP8]], %[[PRED_SDIV_IF]] ]
-; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <4 x i1> [[TMP6]], i32 1
-; CHECK-NEXT:    br i1 [[TMP10]], label %[[PRED_SDIV_IF3:.*]], label %[[PRED_SDIV_CONTINUE4:.*]]
-; CHECK:       [[PRED_SDIV_IF3]]:
-; CHECK-NEXT:    [[TMP11:%.*]] = sdiv i64 [[M]], [[CONV6]]
-; CHECK-NEXT:    br label %[[PRED_SDIV_CONTINUE4]]
-; CHECK:       [[PRED_SDIV_CONTINUE4]]:
-; CHECK-NEXT:    [[TMP12:%.*]] = phi i64 [ poison, %[[PRED_SDIV_CONTINUE]] ], [ [[TMP11]], %[[PRED_SDIV_IF3]] ]
-; CHECK-NEXT:    [[TMP13:%.*]] = extractelement <4 x i1> [[TMP6]], i32 2
-; CHECK-NEXT:    br i1 [[TMP13]], label %[[PRED_SDIV_IF5:.*]], label %[[PRED_SDIV_CONTINUE6:.*]]
-; CHECK:       [[PRED_SDIV_IF5]]:
-; CHECK-NEXT:    [[TMP14:%.*]] = sdiv i64 [[M]], [[CONV6]]
-; CHECK-NEXT:    br label %[[PRED_SDIV_CONTINUE6]]
-; CHECK:       [[PRED_SDIV_CONTINUE6]]:
-; CHECK-NEXT:    [[TMP15:%.*]] = phi i64 [ poison, %[[PRED_SDIV_CONTINUE4]] ], [ [[TMP14]], %[[PRED_SDIV_IF5]] ]
-; CHECK-NEXT:    [[TMP16:%.*]] = extractelement <4 x i1> [[TMP6]], i32 3
-; CHECK-NEXT:    br i1 [[TMP16]], label %[[PRED_SDIV_IF7:.*]], label %[[PRED_SDIV_CONTINUE8]]
-; CHECK:       [[PRED_SDIV_IF7]]:
 ; CHECK-NEXT:    [[TMP17:%.*]] = sdiv i64 [[M]], [[CONV6]]
-; CHECK-NEXT:    br label %[[PRED_SDIV_CONTINUE8]]
-; CHECK:       [[PRED_SDIV_CONTINUE8]]:
-; CHECK-NEXT:    [[TMP18:%.*]] = phi i64 [ poison, %[[PRED_SDIV_CONTINUE6]] ], [ [[TMP17]], %[[PRED_SDIV_IF7]] ]
-; CHECK-NEXT:    [[TMP19:%.*]] = trunc i64 [[TMP9]] to i32
-; CHECK-NEXT:    [[TMP20:%.*]] = mul i64 [[TMP9]], [[CONV61]]
+; CHECK-NEXT:    [[TMP19:%.*]] = trunc i64 [[TMP17]] to i32
+; CHECK-NEXT:    [[TMP20:%.*]] = mul i64 [[TMP17]], [[CONV61]]
 ; CHECK-NEXT:    [[TMP21:%.*]] = sub i64 [[TMP5]], [[TMP20]]
 ; CHECK-NEXT:    [[TMP22:%.*]] = trunc i64 [[TMP21]] to i32
 ; CHECK-NEXT:    [[TMP23:%.*]] = mul i32 [[X]], [[TMP19]]
@@ -271,92 +244,57 @@ define void @udiv_urem_feeding_gep(i64 %x, ptr %dst, i64 %N) {
 ; 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:%.*]], %[[PRED_UREM_CONTINUE6:.*]] ]
-; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 0, i64 1, i64 2, i64 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_UREM_CONTINUE6]] ]
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_UDIV_CONTINUE6:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 0, i64 1, i64 2, i64 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_UDIV_CONTINUE6]] ]
+; CHECK-NEXT:    [[TMP7:%.*]] = add i64 [[INDEX]], 0
 ; CHECK-NEXT:    [[TMP5:%.*]] = icmp ule <4 x i64> [[VEC_IND]], [[BROADCAST_SPLAT]]
 ; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <4 x i1> [[TMP5]], i32 0
-; CHECK-NEXT:    br i1 [[TMP6]], label %[[PRED_UREM_IF:.*]], label %[[PRED_UREM_CONTINUE:.*]]
-; CHECK:       [[PRED_UREM_IF]]:
-; CHECK-NEXT:    [[TMP7:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    br i1 [[TMP6]], label %[[PRED_UDIV_IF:.*]], label %[[PRED_UDIV_CONTINUE:.*]]
+; CHECK:       [[PRED_UDIV_IF]]:
 ; CHECK-NEXT:    [[TMP8:%.*]] = udiv i64 [[TMP7]], [[MUL_2_I]]
 ; CHECK-NEXT:    [[TMP9:%.*]] = insertelement <4 x i64> poison, i64 [[TMP8]], i32 0
-; CHECK-NEXT:    [[TMP10:%.*]] = urem i64 [[TMP7]], [[MUL_2_I]]
-; CHECK-NEXT:    [[TMP11:%.*]] = udiv i64 [[TMP10]], [[MUL_1_I]]
-; CHECK-NEXT:    [[TMP12:%.*]] = urem i64 [[TMP10]], [[MUL_1_I]]
-; CHECK-NEXT:    [[TMP13:%.*]] = udiv i64 [[TMP12]], [[X]]
-; CHECK-NEXT:    [[TMP14:%.*]] = urem i64 [[TMP12]], [[X]]
-; CHECK-NEXT:    br label %[[PRED_UREM_CONTINUE]]
-; CHECK:       [[PRED_UREM_CONTINUE]]:
-; CHECK-NEXT:    [[TMP15:%.*]] = phi <4 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP9]], %[[PRED_UREM_IF]] ]
-; CHECK-NEXT:    [[TMP16:%.*]] = phi i64 [ poison, %[[VECTOR_BODY]] ], [ [[TMP10]], %[[PRED_UREM_IF]] ]
-; CHECK-NEXT:    [[TMP17:%.*]] = phi i64 [ poison, %[[VECTOR_BODY]] ], [ [[TMP11]], %[[PRED_UREM_IF]] ]
-; CHECK-NEXT:    [[TMP18:%.*]] = phi i64 [ poison, %[[VECTOR_BODY]] ], [ [[TMP12]], %[[PRED_UREM_IF]] ]
-; CHECK-NEXT:    [[TMP19:%.*]] = phi i64 [ poison, %[[VECTOR_BODY]] ], [ [[TMP13]], %[[PRED_UREM_IF]] ]
-; CHECK-NEXT:    [[TMP20:%.*]] = phi i64 [ poison, %[[VECTOR_BODY]] ], [ [[TMP14]], %[[PRED_UREM_IF]] ]
+; CHECK-NEXT:    br label %[[PRED_UDIV_CONTINUE]]
+; CHECK:       [[PRED_UDIV_CONTINUE]]:
+; CHECK-NEXT:    [[TMP15:%.*]] = phi <4 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP9]], %[[PRED_UDIV_IF]] ]
 ; CHECK-NEXT:    [[TMP21:%.*]] = extractelement <4 x i1> [[TMP5]], i32 1
-; CHECK-NEXT:    br i1 [[TMP21]], label %[[PRED_UREM_IF1:.*]], label %[[PRED_UREM_CONTINUE2:.*]]
-; CHECK:       [[PRED_UREM_IF1]]:
+; CHECK-NEXT:    br i1 [[TMP21]], label %[[PRED_UDIV_IF1:.*]], label %[[PRED_UDIV_CONTINUE2:.*]]
+; CHECK:       [[PRED_UDIV_IF1]]:
 ; CHECK-NEXT:    [[TMP22:%.*]] = add i64 [[INDEX]], 1
 ; CHECK-NEXT:    [[TMP23:%.*]] = udiv i64 [[TMP22]], [[MUL_2_I]]
 ; CHECK-NEXT:    [[TMP24:%.*]] = insertelement <4 x i64> [[TMP15]], i64 [[TMP23]], i32 1
-; CHECK-NEXT:    [[TMP25:%.*]] = urem i64 [[TMP22]], [[MUL_2_I]]
-; CHECK-NEXT:    [[TMP26:%.*]] = udiv i64 [[TMP25]], [[MUL_1_I]]
-; CHECK-NEXT:    [[TMP27:%.*]] = urem i64 [[TMP25]], [[MUL_1_I]]
-; CHECK-NEXT:    [[TMP28:%.*]] = udiv i64 [[TMP27]], [[X]]
-; CHECK-NEXT:    [[TMP29:%.*]] = urem i64 [[TMP27]], [[X]]
-; CHECK-NEXT:    br label %[[PRED_UREM_CONTINUE2]]
-; CHECK:       [[PRED_UREM_CONTINUE2]]:
-; CHECK-NEXT:    [[TMP30:%.*]] = phi <4 x i64> [ [[TMP15]], %[[PRED_UREM_CONTINUE]] ], [ [[TMP24]], %[[PRED_UREM_IF1]] ]
-; CHECK-NEXT:    [[TMP31:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE]] ], [ [[TMP25]], %[[PRED_UREM_IF1]] ]
-; CHECK-NEXT:    [[TMP32:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE]] ], [ [[TMP26]], %[[PRED_UREM_IF1]] ]
-; CHECK-NEXT:    [[TMP33:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE]] ], [ [[TMP27]], %[[PRED_UREM_IF1]] ]
-; CHECK-NEXT:    [[TMP34:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE]] ], [ [[TMP28]], %[[PRED_UREM_IF1]] ]
-; CHECK-NEXT:    [[TMP35:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE]] ], [ [[TMP29]], %[[PRED_UREM_IF1]] ]
+; CHECK-NEXT:    br label %[[PRED_UDIV_CONTINUE2]]
+; CHECK:       [[PRED_UDIV_CONTINUE2]]:
+; CHECK-NEXT:    [[TMP30:%.*]] = phi <4 x i64> [ [[TMP15]], %[[PRED_UDIV_CONTINUE]] ], [ [[TMP24]], %[[PRED_UDIV_IF1]] ]
 ; CHECK-NEXT:    [[TMP36:%.*]] = extractelement <4 x i1> [[TMP5]], i32 2
-; CHECK-NEXT:    br i1 [[TMP36]], label %[[PRED_UREM_IF3:.*]], label %[[PRED_UREM_CONTINUE4:.*]]
-; CHECK:       [[PRED_UREM_IF3]]:
+; CHECK-NEXT:    br i1 [[TMP36]], label %[[PRED_UDIV_IF3:.*]], label %[[PRED_UDIV_CONTINUE4:.*]]
+; CHECK:       [[PRED_UDIV_IF3]]:
 ; CHECK-NEXT:    [[TMP37:%.*]] = add i64 [[INDEX]], 2
 ; CHECK-NEXT:    [[TMP38:%.*]] = udiv i64 [[TMP37]], [[MUL_2_I]]
 ; CHECK-NEXT:    [[TMP39:%.*]] = insertelement <4 x i64> [[TMP30]], i64 [[TMP38]], i32 2
-; CHECK-NEXT:    [[TMP40:%.*]] = urem i64 [[TMP37]], [[MUL_2_I]]
-; CHECK-NEXT:    [[TMP41:%.*]] = udiv i64 [[TMP40]], [[MUL_1_I]]
-; CHECK-NEXT:    [[TMP42:%.*]] = urem i64 [[TMP40]], [[MUL_1_I]]
-; CHECK-NEXT:    [[TMP43:%.*]] = udiv i64 [[TMP42]], [[X]]
-; CHECK-NEXT:    [[TMP44:%.*]] = urem i64 [[TMP42]], [[X]]
-; CHECK-NEXT:    br label %[[PRED_UREM_CONTINUE4]]
-; CHECK:       [[PRED_UREM_CONTINUE4]]:
-; CHECK-NEXT:    [[TMP45:%.*]] = phi <4 x i64> [ [[TMP30]], %[[PRED_UREM_CONTINUE2]] ], [ [[TMP39]], %[[PRED_UREM_IF3]] ]
-; CHECK-NEXT:    [[TMP46:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE2]] ], [ [[TMP40]], %[[PRED_UREM_IF3]] ]
-; CHECK-NEXT:    [[TMP47:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE2]] ], [ [[TMP41]], %[[PRED_UREM_IF3]] ]
-; CHECK-NEXT:    [[TMP48:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE2]] ], [ [[TMP42]], %[[PRED_UREM_IF3]] ]
-; CHECK-NEXT:    [[TMP49:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE2]] ], [ [[TMP43]], %[[PRED_UREM_IF3]] ]
-; CHECK-NEXT:    [[TMP50:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE2]] ], [ [[TMP44]], %[[PRED_UREM_IF3]] ]
+; CHECK-NEXT:    br label %[[PRED_UDIV_CONTINUE4]]
+; CHECK:       [[PRED_UDIV_CONTINUE4]]:
+; CHECK-NEXT:    [[TMP45:%.*]] = phi <4 x i64> [ [[TMP30]], %[[PRED_UDIV_CONTINUE2]] ], [ [[TMP39]], %[[PRED_UDIV_IF3]] ]
 ; CHECK-NEXT:    [[TMP51:%.*]] = extractelement <4 x i1> [[TMP5]], i32 3
-; CHECK-NEXT:    br i1 [[TMP51]], label %[[PRED_UREM_IF5:.*]], label %[[PRED_UREM_CONTINUE6]]
-; CHECK:       [[PRED_UREM_IF5]]:
+; CHECK-NEXT:    br i1 [[TMP51]], label %[[PRED_UDIV_IF5:.*]], label %[[PRED_UDIV_CONTINUE6]]
+; CHECK:       [[PRED_UDIV_IF5]]:
 ; CHECK-NEXT:    [[TMP52:%.*]] = add i64 [[INDEX]], 3
 ; CHECK-NEXT:    [[TMP53:%.*]] = udiv i64 [[TMP52]], [[MUL_2_I]]
 ; CHECK-NEXT:    [[TMP54:%.*]] = insertelement <4 x i64> [[TMP45]], i64 [[TMP53]], i32 3
-; CHECK-NEXT:    [[TMP55:%.*]] = urem i64 [[TMP52]], [[MUL_2_I]]
+; CHECK-NEXT:    br label %[[PRED_UDIV_CONTINUE6]]
+; CHECK:       [[PRED_UDIV_CONTINUE6]]:
+; CHECK-NEXT:    [[TMP60:%.*]] = phi <4 x i64> [ [[TMP45]], %[[PRED_UDIV_CONTINUE4]] ], [ [[TMP54]], %[[PRED_UDIV_IF5]] ]
+; CHECK-NEXT:    [[TMP55:%.*]] = urem i64 [[TMP7]], [[MUL_2_I]]
 ; CHECK-NEXT:    [[TMP56:%.*]] = udiv i64 [[TMP55]], [[MUL_1_I]]
 ; CHECK-NEXT:    [[TMP57:%.*]] = urem i64 [[TMP55]], [[MUL_1_I]]
 ; CHECK-NEXT:    [[TMP58:%.*]] = udiv i64 [[TMP57]], [[X]]
 ; CHECK-NEXT:    [[TMP59:%.*]] = urem i64 [[TMP57]], [[X]]
-; CHECK-NEXT:    br label %[[PRED_UREM_CONTINUE6]]
-; CHECK:       [[PRED_UREM_CONTINUE6]]:
-; CHECK-NEXT:    [[TMP60:%.*]] = phi <4 x i64> [ [[TMP45]], %[[PRED_UREM_CONTINUE4]] ], [ [[TMP54]], %[[PRED_UREM_IF5]] ]
-; CHECK-NEXT:    [[TMP61:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE4]] ], [ [[TMP55]], %[[PRED_UREM_IF5]] ]
-; CHECK-NEXT:    [[TMP62:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE4]] ], [ [[TMP56]], %[[PRED_UREM_IF5]] ]
-; CHECK-NEXT:    [[TMP63:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE4]] ], [ [[TMP57]], %[[PRED_UREM_IF5]] ]
-; CHECK-NEXT:    [[TMP64:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE4]] ], [ [[TMP58]], %[[PRED_UREM_IF5]] ]
-; CHECK-NEXT:    [[TMP65:%.*]] = phi i64 [ poison, %[[PRED_UREM_CONTINUE4]] ], [ [[TMP59]], %[[PRED_UREM_IF5]] ]
 ; CHECK-NEXT:    [[TMP66:%.*]] = extractelement <4 x i64> [[TMP60]], i32 0
 ; CHECK-NEXT:    [[TMP67:%.*]] = mul i64 [[X]], [[TMP66]]
-; CHECK-NEXT:    [[TMP68:%.*]] = add i64 [[TMP67]], [[TMP17]]
+; CHECK-NEXT:    [[TMP68:%.*]] = add i64 [[TMP67]], [[TMP56]]
 ; CHECK-NEXT:    [[TMP69:%.*]] = mul i64 [[TMP68]], [[X]]
-; CHECK-NEXT:    [[TMP70:%.*]] = add i64 [[TMP69]], [[TMP19]]
+; CHECK-NEXT:    [[TMP70:%.*]] = add i64 [[TMP69]], [[TMP58]]
 ; CHECK-NEXT:    [[TMP71:%.*]] = mul i64 [[TMP70]], [[X]]
-; CHECK-NEXT:    [[TMP72:%.*]] = add i64 [[TMP71]], [[TMP20]]
+; CHECK-NEXT:    [[TMP72:%.*]] = add i64 [[TMP71]], [[TMP59]]
 ; CHECK-NEXT:    [[TMP73:%.*]] = shl i64 [[TMP72]], 32
 ; CHECK-NEXT:    [[TMP74:%.*]] = ashr i64 [[TMP73]], 32
 ; CHECK-NEXT:    [[TMP75:%.*]] = getelementptr i64, ptr [[DST]], i64 [[TMP74]]

>From f0b1ea43920a8cf6279bb62fc1d085cb6d7c5b4b Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Fri, 19 Jul 2024 21:53:51 +0100
Subject: [PATCH 3/7] !fixup

---
 .../Transforms/Vectorize/LoopVectorize.cpp    |  4 +--
 .../AArch64/divs-with-scalable-vfs.ll         |  3 +-
 .../AArch64/reduction-recurrence-costs-sve.ll | 35 +++++++++----------
 3 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 37ebb558e0b4c..f44d80c416cab 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3729,9 +3729,7 @@ bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I,
     // unconditionally. If the divisor is loop-invariant no predication is
     // needed, as predication would not prevent the divide-by-0 on the executed
     // lane.
-    if (foldTailByMasking() && !Legal->blockNeedsPredication(I->getParent()) &&
-        TheLoop->isLoopInvariant(I->getOperand(1)) &&
-        (IsKnownUniform || isUniformAfterVectorization(I, VF)))
+    if (!Legal->blockNeedsPredication(I->getParent()) && TheLoop->isLoopInvariant(I->getOperand(1)))
       return false;
 
     // TODO: We can use the loop-preheader as context point here and get
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
index adbc9ca74a80a..e8e34762ba238 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
@@ -285,8 +285,7 @@ define void @udiv_urem_feeding_gep(i64 %x, ptr %dst, i64 %N) {
 ; CHECK-NEXT:    [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[VECTOR_PH]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
 ; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <vscale x 2 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
 ; CHECK-NEXT:    [[TMP21:%.*]] = add i64 [[INDEX]], 0
-; CHECK-NEXT:    [[TMP22:%.*]] = select <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> [[BROADCAST_SPLAT4]], <vscale x 2 x i64> shufflevector (<vscale x 2 x i64> insertelement (<vscale x 2 x i64> poison, i64 1, i64 0), <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer)
-; CHECK-NEXT:    [[TMP23:%.*]] = udiv <vscale x 2 x i64> [[VEC_IND]], [[TMP22]]
+; CHECK-NEXT:    [[TMP23:%.*]] = udiv <vscale x 2 x i64> [[VEC_IND]], [[BROADCAST_SPLAT4]]
 ; CHECK-NEXT:    [[TMP24:%.*]] = urem i64 [[TMP21]], [[MUL_2_I]]
 ; CHECK-NEXT:    [[TMP25:%.*]] = udiv i64 [[TMP24]], [[MUL_1_I]]
 ; CHECK-NEXT:    [[TMP26:%.*]] = urem i64 [[TMP24]], [[MUL_1_I]]
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 2b2c224dbefe0..95588d1176dcd 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/reduction-recurrence-costs-sve.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/reduction-recurrence-costs-sve.ll
@@ -380,41 +380,40 @@ define i16 @reduce_udiv(ptr %src, i16 %x, i64 %N) #0 {
 ; PRED-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
 ; PRED:       vector.ph:
 ; PRED-NEXT:    [[TMP1:%.*]] = call i64 @llvm.vscale.i64()
-; PRED-NEXT:    [[TMP2:%.*]] = mul i64 [[TMP1]], 8
+; PRED-NEXT:    [[TMP2:%.*]] = mul i64 [[TMP1]], 4
 ; PRED-NEXT:    [[TMP5:%.*]] = sub i64 [[TMP2]], 1
 ; PRED-NEXT:    [[N_RND_UP:%.*]] = add i64 [[TMP0]], [[TMP5]]
 ; PRED-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N_RND_UP]], [[TMP2]]
 ; PRED-NEXT:    [[N_VEC:%.*]] = sub i64 [[N_RND_UP]], [[N_MOD_VF]]
 ; PRED-NEXT:    [[TMP6:%.*]] = call i64 @llvm.vscale.i64()
-; PRED-NEXT:    [[TMP7:%.*]] = mul i64 [[TMP6]], 8
+; PRED-NEXT:    [[TMP7:%.*]] = mul i64 [[TMP6]], 4
 ; PRED-NEXT:    [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
-; PRED-NEXT:    [[TMP9:%.*]] = mul i64 [[TMP8]], 8
+; PRED-NEXT:    [[TMP9:%.*]] = mul i64 [[TMP8]], 4
 ; PRED-NEXT:    [[TMP10:%.*]] = sub i64 [[TMP0]], [[TMP9]]
 ; PRED-NEXT:    [[TMP11:%.*]] = icmp ugt i64 [[TMP0]], [[TMP9]]
 ; PRED-NEXT:    [[TMP12:%.*]] = select i1 [[TMP11]], i64 [[TMP10]], i64 0
-; PRED-NEXT:    [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 8 x i1> @llvm.get.active.lane.mask.nxv8i1.i64(i64 0, i64 [[TMP0]])
-; PRED-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 8 x i16> poison, i16 [[X]], i64 0
-; PRED-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 8 x i16> [[BROADCAST_SPLATINSERT]], <vscale x 8 x i16> poison, <vscale x 8 x i32> zeroinitializer
+; PRED-NEXT:    [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 4 x i1> @llvm.get.active.lane.mask.nxv4i1.i64(i64 0, i64 [[TMP0]])
+; PRED-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 4 x i16> poison, i16 [[X]], i64 0
+; PRED-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 4 x i16> [[BROADCAST_SPLATINSERT]], <vscale x 4 x i16> poison, <vscale x 4 x i32> zeroinitializer
 ; PRED-NEXT:    br label [[VECTOR_BODY:%.*]]
 ; PRED:       vector.body:
 ; PRED-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
-; PRED-NEXT:    [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 8 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], [[VECTOR_PH]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], [[VECTOR_BODY]] ]
-; PRED-NEXT:    [[VEC_PHI:%.*]] = phi <vscale x 8 x i16> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP19:%.*]], [[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:    [[VEC_PHI:%.*]] = phi <vscale x 4 x i16> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP16:%.*]], [[VECTOR_BODY]] ]
 ; PRED-NEXT:    [[TMP13:%.*]] = add i64 [[INDEX]], 0
 ; PRED-NEXT:    [[TMP14:%.*]] = getelementptr i16, ptr [[SRC]], i64 [[TMP13]]
 ; PRED-NEXT:    [[TMP15:%.*]] = getelementptr i16, ptr [[TMP14]], i32 0
-; PRED-NEXT:    [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 8 x i16> @llvm.masked.load.nxv8i16.p0(ptr [[TMP15]], i32 2, <vscale x 8 x i1> [[ACTIVE_LANE_MASK]], <vscale x 8 x i16> poison)
-; PRED-NEXT:    [[TMP16:%.*]] = select <vscale x 8 x i1> [[ACTIVE_LANE_MASK]], <vscale x 8 x i16> [[BROADCAST_SPLAT]], <vscale x 8 x i16> shufflevector (<vscale x 8 x i16> insertelement (<vscale x 8 x i16> poison, i16 1, i64 0), <vscale x 8 x i16> poison, <vscale x 8 x i32> zeroinitializer)
-; PRED-NEXT:    [[TMP17:%.*]] = udiv <vscale x 8 x i16> [[WIDE_MASKED_LOAD]], [[TMP16]]
-; PRED-NEXT:    [[TMP18:%.*]] = or <vscale x 8 x i16> [[TMP17]], [[VEC_PHI]]
-; PRED-NEXT:    [[TMP19]] = select <vscale x 8 x i1> [[ACTIVE_LANE_MASK]], <vscale x 8 x i16> [[TMP18]], <vscale x 8 x i16> [[VEC_PHI]]
+; PRED-NEXT:    [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 4 x i16> @llvm.masked.load.nxv4i16.p0(ptr [[TMP15]], i32 2, <vscale x 4 x i1> [[ACTIVE_LANE_MASK]], <vscale x 4 x i16> poison)
+; PRED-NEXT:    [[TMP19:%.*]] = udiv <vscale x 4 x i16> [[WIDE_MASKED_LOAD]], [[BROADCAST_SPLAT]]
+; PRED-NEXT:    [[TMP20:%.*]] = or <vscale x 4 x i16> [[TMP19]], [[VEC_PHI]]
+; PRED-NEXT:    [[TMP16]] = select <vscale x 4 x i1> [[ACTIVE_LANE_MASK]], <vscale x 4 x i16> [[TMP20]], <vscale x 4 x i16> [[VEC_PHI]]
 ; PRED-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], [[TMP7]]
-; PRED-NEXT:    [[ACTIVE_LANE_MASK_NEXT]] = call <vscale x 8 x i1> @llvm.get.active.lane.mask.nxv8i1.i64(i64 [[INDEX]], i64 [[TMP12]])
-; PRED-NEXT:    [[TMP20:%.*]] = xor <vscale x 8 x i1> [[ACTIVE_LANE_MASK_NEXT]], shufflevector (<vscale x 8 x i1> insertelement (<vscale x 8 x i1> poison, i1 true, i64 0), <vscale x 8 x i1> poison, <vscale x 8 x i32> zeroinitializer)
-; PRED-NEXT:    [[TMP21:%.*]] = extractelement <vscale x 8 x i1> [[TMP20]], i32 0
-; PRED-NEXT:    br i1 [[TMP21]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; PRED-NEXT:    [[ACTIVE_LANE_MASK_NEXT]] = call <vscale x 4 x i1> @llvm.get.active.lane.mask.nxv4i1.i64(i64 [[INDEX]], i64 [[TMP12]])
+; PRED-NEXT:    [[TMP17:%.*]] = xor <vscale x 4 x i1> [[ACTIVE_LANE_MASK_NEXT]], shufflevector (<vscale x 4 x i1> insertelement (<vscale x 4 x i1> poison, i1 true, i64 0), <vscale x 4 x i1> poison, <vscale x 4 x i32> zeroinitializer)
+; PRED-NEXT:    [[TMP18:%.*]] = extractelement <vscale x 4 x i1> [[TMP17]], i32 0
+; PRED-NEXT:    br i1 [[TMP18]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
 ; PRED:       middle.block:
-; PRED-NEXT:    [[TMP22:%.*]] = call i16 @llvm.vector.reduce.or.nxv8i16(<vscale x 8 x i16> [[TMP19]])
+; PRED-NEXT:    [[TMP22:%.*]] = call i16 @llvm.vector.reduce.or.nxv4i16(<vscale x 4 x i16> [[TMP16]])
 ; PRED-NEXT:    br i1 true, label [[EXIT:%.*]], label [[SCALAR_PH]]
 ; PRED:       scalar.ph:
 ; PRED-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]

>From e7e75641eefcf05571db39d790186babd1283f56 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Sat, 20 Jul 2024 12:56:22 +0100
Subject: [PATCH 4/7] !fixup adjust tests.

---
 .../X86/divs-with-tail-folding.ll             | 87 +------------------
 1 file changed, 2 insertions(+), 85 deletions(-)

diff --git a/llvm/test/Transforms/LoopVectorize/X86/divs-with-tail-folding.ll b/llvm/test/Transforms/LoopVectorize/X86/divs-with-tail-folding.ll
index d0dc456c91d6d..32964d650ea0f 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/divs-with-tail-folding.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/divs-with-tail-folding.ll
@@ -227,90 +227,9 @@ define void @udiv_urem_feeding_gep(i64 %x, ptr %dst, i64 %N) {
 ; CHECK-NEXT:  [[ENTRY:.*]]:
 ; CHECK-NEXT:    [[MUL_1_I:%.*]] = mul i64 [[X]], [[X]]
 ; CHECK-NEXT:    [[MUL_2_I:%.*]] = mul i64 [[MUL_1_I]], [[X]]
-; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[N]], 1
-; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_SCEVCHECK:.*]]
-; CHECK:       [[VECTOR_SCEVCHECK]]:
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc i64 [[N]] to i32
-; CHECK-NEXT:    [[TMP2:%.*]] = icmp slt i32 [[TMP1]], 0
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp ugt i64 [[N]], 4294967295
-; CHECK-NEXT:    [[TMP4:%.*]] = or i1 [[TMP2]], [[TMP3]]
-; CHECK-NEXT:    br i1 [[TMP4]], label %[[SCALAR_PH]], label %[[VECTOR_PH:.*]]
-; CHECK:       [[VECTOR_PH]]:
-; CHECK-NEXT:    [[N_RND_UP:%.*]] = add i64 [[TMP0]], 3
-; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N_RND_UP]], 4
-; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[N_RND_UP]], [[N_MOD_VF]]
-; CHECK-NEXT:    [[TRIP_COUNT_MINUS_1:%.*]] = sub i64 [[TMP0]], 1
-; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i64> poison, i64 [[TRIP_COUNT_MINUS_1]], 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:%.*]], %[[PRED_UDIV_CONTINUE6:.*]] ]
-; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 0, i64 1, i64 2, i64 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_UDIV_CONTINUE6]] ]
-; CHECK-NEXT:    [[TMP7:%.*]] = add i64 [[INDEX]], 0
-; CHECK-NEXT:    [[TMP5:%.*]] = icmp ule <4 x i64> [[VEC_IND]], [[BROADCAST_SPLAT]]
-; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <4 x i1> [[TMP5]], i32 0
-; CHECK-NEXT:    br i1 [[TMP6]], label %[[PRED_UDIV_IF:.*]], label %[[PRED_UDIV_CONTINUE:.*]]
-; CHECK:       [[PRED_UDIV_IF]]:
-; CHECK-NEXT:    [[TMP8:%.*]] = udiv i64 [[TMP7]], [[MUL_2_I]]
-; CHECK-NEXT:    [[TMP9:%.*]] = insertelement <4 x i64> poison, i64 [[TMP8]], i32 0
-; CHECK-NEXT:    br label %[[PRED_UDIV_CONTINUE]]
-; CHECK:       [[PRED_UDIV_CONTINUE]]:
-; CHECK-NEXT:    [[TMP15:%.*]] = phi <4 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP9]], %[[PRED_UDIV_IF]] ]
-; CHECK-NEXT:    [[TMP21:%.*]] = extractelement <4 x i1> [[TMP5]], i32 1
-; CHECK-NEXT:    br i1 [[TMP21]], label %[[PRED_UDIV_IF1:.*]], label %[[PRED_UDIV_CONTINUE2:.*]]
-; CHECK:       [[PRED_UDIV_IF1]]:
-; CHECK-NEXT:    [[TMP22:%.*]] = add i64 [[INDEX]], 1
-; CHECK-NEXT:    [[TMP23:%.*]] = udiv i64 [[TMP22]], [[MUL_2_I]]
-; CHECK-NEXT:    [[TMP24:%.*]] = insertelement <4 x i64> [[TMP15]], i64 [[TMP23]], i32 1
-; CHECK-NEXT:    br label %[[PRED_UDIV_CONTINUE2]]
-; CHECK:       [[PRED_UDIV_CONTINUE2]]:
-; CHECK-NEXT:    [[TMP30:%.*]] = phi <4 x i64> [ [[TMP15]], %[[PRED_UDIV_CONTINUE]] ], [ [[TMP24]], %[[PRED_UDIV_IF1]] ]
-; CHECK-NEXT:    [[TMP36:%.*]] = extractelement <4 x i1> [[TMP5]], i32 2
-; CHECK-NEXT:    br i1 [[TMP36]], label %[[PRED_UDIV_IF3:.*]], label %[[PRED_UDIV_CONTINUE4:.*]]
-; CHECK:       [[PRED_UDIV_IF3]]:
-; CHECK-NEXT:    [[TMP37:%.*]] = add i64 [[INDEX]], 2
-; CHECK-NEXT:    [[TMP38:%.*]] = udiv i64 [[TMP37]], [[MUL_2_I]]
-; CHECK-NEXT:    [[TMP39:%.*]] = insertelement <4 x i64> [[TMP30]], i64 [[TMP38]], i32 2
-; CHECK-NEXT:    br label %[[PRED_UDIV_CONTINUE4]]
-; CHECK:       [[PRED_UDIV_CONTINUE4]]:
-; CHECK-NEXT:    [[TMP45:%.*]] = phi <4 x i64> [ [[TMP30]], %[[PRED_UDIV_CONTINUE2]] ], [ [[TMP39]], %[[PRED_UDIV_IF3]] ]
-; CHECK-NEXT:    [[TMP51:%.*]] = extractelement <4 x i1> [[TMP5]], i32 3
-; CHECK-NEXT:    br i1 [[TMP51]], label %[[PRED_UDIV_IF5:.*]], label %[[PRED_UDIV_CONTINUE6]]
-; CHECK:       [[PRED_UDIV_IF5]]:
-; CHECK-NEXT:    [[TMP52:%.*]] = add i64 [[INDEX]], 3
-; CHECK-NEXT:    [[TMP53:%.*]] = udiv i64 [[TMP52]], [[MUL_2_I]]
-; CHECK-NEXT:    [[TMP54:%.*]] = insertelement <4 x i64> [[TMP45]], i64 [[TMP53]], i32 3
-; CHECK-NEXT:    br label %[[PRED_UDIV_CONTINUE6]]
-; CHECK:       [[PRED_UDIV_CONTINUE6]]:
-; CHECK-NEXT:    [[TMP60:%.*]] = phi <4 x i64> [ [[TMP45]], %[[PRED_UDIV_CONTINUE4]] ], [ [[TMP54]], %[[PRED_UDIV_IF5]] ]
-; CHECK-NEXT:    [[TMP55:%.*]] = urem i64 [[TMP7]], [[MUL_2_I]]
-; CHECK-NEXT:    [[TMP56:%.*]] = udiv i64 [[TMP55]], [[MUL_1_I]]
-; CHECK-NEXT:    [[TMP57:%.*]] = urem i64 [[TMP55]], [[MUL_1_I]]
-; CHECK-NEXT:    [[TMP58:%.*]] = udiv i64 [[TMP57]], [[X]]
-; CHECK-NEXT:    [[TMP59:%.*]] = urem i64 [[TMP57]], [[X]]
-; CHECK-NEXT:    [[TMP66:%.*]] = extractelement <4 x i64> [[TMP60]], i32 0
-; CHECK-NEXT:    [[TMP67:%.*]] = mul i64 [[X]], [[TMP66]]
-; CHECK-NEXT:    [[TMP68:%.*]] = add i64 [[TMP67]], [[TMP56]]
-; CHECK-NEXT:    [[TMP69:%.*]] = mul i64 [[TMP68]], [[X]]
-; CHECK-NEXT:    [[TMP70:%.*]] = add i64 [[TMP69]], [[TMP58]]
-; CHECK-NEXT:    [[TMP71:%.*]] = mul i64 [[TMP70]], [[X]]
-; CHECK-NEXT:    [[TMP72:%.*]] = add i64 [[TMP71]], [[TMP59]]
-; CHECK-NEXT:    [[TMP73:%.*]] = shl i64 [[TMP72]], 32
-; CHECK-NEXT:    [[TMP74:%.*]] = ashr i64 [[TMP73]], 32
-; CHECK-NEXT:    [[TMP75:%.*]] = getelementptr i64, ptr [[DST]], i64 [[TMP74]]
-; CHECK-NEXT:    [[TMP76:%.*]] = getelementptr i64, ptr [[TMP75]], i32 0
-; CHECK-NEXT:    call void @llvm.masked.store.v4i64.p0(<4 x i64> [[TMP60]], ptr [[TMP76]], i32 4, <4 x i1> [[TMP5]])
-; CHECK-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], 4
-; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], <i64 4, i64 4, i64 4, i64 4>
-; CHECK-NEXT:    [[TMP77:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[TMP77]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
-; CHECK:       [[MIDDLE_BLOCK]]:
-; CHECK-NEXT:    br i1 true, label %[[EXIT:.*]], label %[[SCALAR_PH]]
-; CHECK:       [[SCALAR_PH]]:
-; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ], [ 0, %[[VECTOR_SCEVCHECK]] ]
 ; CHECK-NEXT:    br label %[[LOOP:.*]]
 ; CHECK:       [[LOOP]]:
-; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
 ; CHECK-NEXT:    [[DIV_I:%.*]] = udiv i64 [[IV]], [[MUL_2_I]]
 ; CHECK-NEXT:    [[REM_I:%.*]] = urem i64 [[IV]], [[MUL_2_I]]
 ; CHECK-NEXT:    [[DIV_1_I:%.*]] = udiv i64 [[REM_I]], [[MUL_1_I]]
@@ -329,7 +248,7 @@ define void @udiv_urem_feeding_gep(i64 %x, ptr %dst, i64 %N) {
 ; CHECK-NEXT:    store i64 [[DIV_I]], ptr [[GEP]], align 4
 ; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV]], [[N]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[EXIT:.*]], label %[[LOOP]]
 ; CHECK:       [[EXIT]]:
 ; CHECK-NEXT:    ret void
 ;
@@ -370,6 +289,4 @@ exit:
 ; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META1]]}
 ; CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]], [[META2]]}
 ; CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]]}
-; CHECK: [[LOOP6]] = distinct !{[[LOOP6]], [[META1]], [[META2]]}
-; CHECK: [[LOOP7]] = distinct !{[[LOOP7]], [[META1]]}
 ;.

>From 2c8de7cd4dab602cc2388857e1449de3f7b1065f Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Sat, 20 Jul 2024 14:13:51 +0100
Subject: [PATCH 5/7] !fixup generalize logic

---
 .../Transforms/Vectorize/LoopVectorize.cpp    | 59 ++++++++++---------
 ...-order-recurrence-sink-replicate-region.ll | 47 +++++----------
 2 files changed, 45 insertions(+), 61 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index cd8ddc6cb388a..b73979724c9c0 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3696,47 +3696,48 @@ bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I,
     return false;
 
   // Can we prove this instruction is safe to unconditionally execute?
-  // If not, we must use some form of predication.
+  if (I->getOpcode() == Instruction::Call)
+    return Legal->isMaskRequired(I);
+
+  if (isa<LoadInst, StoreInst>(I) && !Legal->isMaskRequired(I))
+    return false;
+
+  // TODO: We can use the loop-preheader as context point here and get
+  // context sensitive reasoning
+  if (isa<BranchInst, PHINode>(I) || isSafeToSpeculativelyExecute(I))
+    return false;
+
+  // If the instruction was executed conditionally in the original scalar loop,
+  // predication is needed.
+  if (Legal->blockNeedsPredication(I->getParent()))
+    return true;
+
+  // Tail folding may introduce additional predication, but we're guaranteed to
+  // always have at least one active lane. If the instruction in the original
+  // scalar loop was executed unconditionally, it may not need predication,
+  // depending on its operands.
   switch(I->getOpcode()) {
   default:
-    return false;
+    llvm_unreachable(
+        "instruction should have been considered to not require predication "
+        "by earlier checks");
   case Instruction::Load:
+    // If the address is loop invariant no predication is needed.
+    return !Legal->isInvariant(getLoadStorePointerOperand(I));
   case Instruction::Store: {
-    if (!Legal->isMaskRequired(I))
-      return false;
-    // When we know the load's address is loop invariant and the instruction
-    // in the original scalar loop was unconditionally executed then we
-    // don't need to mark it as a predicated instruction. Tail folding may
-    // introduce additional predication, but we're guaranteed to always have
-    // at least one active lane.  We call Legal->blockNeedsPredication here
-    // because it doesn't query tail-folding.  For stores, we need to prove
+    // For stores, we need to prove
     // both speculation safety (which follows from the same argument as loads),
     // but also must prove the value being stored is correct.  The easiest
     // form of the later is to require that all values stored are the same.
-    if (Legal->isInvariant(getLoadStorePointerOperand(I)) &&
-        (isa<LoadInst>(I) ||
-         (isa<StoreInst>(I) &&
-          TheLoop->isLoopInvariant(cast<StoreInst>(I)->getValueOperand()))) &&
-        !Legal->blockNeedsPredication(I->getParent()))
-      return false;
-    return true;
+    return !(Legal->isInvariant(getLoadStorePointerOperand(I)) &&
+             TheLoop->isLoopInvariant(cast<StoreInst>(I)->getValueOperand()));
   }
   case Instruction::UDiv:
   case Instruction::SDiv:
   case Instruction::SRem:
   case Instruction::URem:
-    // When folding the tail, at least one of the lanes must execute
-    // unconditionally. If the divisor is loop-invariant no predication is
-    // needed, as predication would not prevent the divide-by-0 on the executed
-    // lane.
-    if (!Legal->blockNeedsPredication(I->getParent()) && TheLoop->isLoopInvariant(I->getOperand(1)))
-      return false;
-
-    // TODO: We can use the loop-preheader as context point here and get
-    // context sensitive reasoning
-    return !isSafeToSpeculativelyExecute(I);
-  case Instruction::Call:
-    return Legal->isMaskRequired(I);
+    // If the divisor is loop-invariant no predication is needed.
+    return !TheLoop->isLoopInvariant(I->getOperand(1));
   }
 }
 
diff --git a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
index 048b670f0fec8..06fbeafba31c0 100644
--- a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
+++ b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
@@ -62,9 +62,9 @@ define void @sink_replicate_region_1(i32 %x, ptr %ptr, ptr noalias %dst) optsize
 ; CHECK-NEXT:   pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.2
+; CHECK-NEXT: Successor(s): loop.1
 ; CHECK-EMPTY:
-; CHECK-NEXT: loop.2:
+; CHECK-NEXT: loop.1:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -134,8 +134,8 @@ define void @sink_replicate_region_2(i32 %x, i8 %y, ptr %ptr) optsize {
 ; CHECK-NEXT:  Successor(s): pred.store.if, pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:  pred.store.if:
-; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     vp<[[STEPS:%.+]]> = SCALAR-STEPS vp<[[CAN_IV]]>, ir<1>
+; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%gep> = getelementptr ir<%ptr>, vp<[[STEPS]]>
 ; CHECK-NEXT:     REPLICATE ir<%add> = add ir<%rem>, ir<%recur.next>
 ; CHECK-NEXT:     REPLICATE store ir<%add>, ir<%gep>
@@ -144,9 +144,9 @@ define void @sink_replicate_region_2(i32 %x, i8 %y, ptr %ptr) optsize {
 ; CHECK-NEXT:   pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.1
+; CHECK-NEXT: Successor(s): loop.0
 ; CHECK-EMPTY:
-; CHECK-NEXT: loop.1:
+; CHECK-NEXT: loop.0:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -207,25 +207,8 @@ define i32 @sink_replicate_region_3_reduction(i32 %x, i8 %y, ptr %ptr) optsize {
 ; CHECK-NEXT:   EMIT vp<[[MASK:%.+]]> = icmp ule vp<[[WIDEN_CAN]]>, vp<[[BTC]]>
 ; CHECK-NEXT:   WIDEN-CAST ir<%recur.next> = sext ir<%y> to i32
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%recur>, ir<%recur.next>
-; CHECK-NEXT: Successor(s): pred.srem
-; CHECK-EMPTY:
-; CHECK-NEXT: <xVFxUF> pred.srem: {
-; CHECK-NEXT:   pred.srem.entry:
-; CHECK-NEXT:     BRANCH-ON-MASK vp<[[MASK]]>
-; CHECK-NEXT:   Successor(s): pred.srem.if, pred.srem.continue
-; CHECK-EMPTY:
-; CHECK-NEXT:   pred.srem.if:
-; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x> (S->V)
-; CHECK-NEXT:   Successor(s): pred.srem.continue
-; CHECK-EMPTY:
-; CHECK-NEXT:   pred.srem.continue:
-; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<[[PRED:%.+]]> = ir<%rem>
-; CHECK-NEXT:   No successors
-; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.0
-; CHECK-EMPTY:
-; CHECK-NEXT: loop.0:
-; CHECK-NEXT:   WIDEN ir<%add> = add vp<[[PRED]]>, ir<%recur.next>
+; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
+; CHECK-NEXT:   WIDEN ir<%add> = add ir<%rem>, ir<%recur.next>
 ; CHECK-NEXT:   WIDEN ir<%and.red.next> = and ir<%and.red>, ir<%add>
 ; CHECK-NEXT:   EMIT vp<[[SEL:%.+]]> = select vp<[[MASK]]>, ir<%and.red.next>, ir<%and.red>
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add vp<[[CAN_IV]]>, vp<[[VFxUF]]>
@@ -320,8 +303,8 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT:   Successor(s): pred.store.if, pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK:        pred.store.if:
-; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%lv.2> = load ir<%gep>
+; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%conv.lv.2> = sext ir<%lv.2>
 ; CHECK-NEXT:     REPLICATE ir<%add.1> = add ir<%conv>, ir<%rem>
 ; CHECK-NEXT:     REPLICATE ir<%gep.dst> = getelementptr ir<%dst>, vp<[[STEPS]]>
@@ -332,9 +315,9 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK:        pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT:   Successor(s): loop.3
+; CHECK-NEXT:   Successor(s): loop.2
 ; CHECK-EMPTY:
-; CHECK:      loop.3:
+; CHECK:      loop.2:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -424,9 +407,9 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-NEXT:   pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.3
+; CHECK-NEXT: Successor(s): loop.2
 ; CHECK-EMPTY:
-; CHECK-NEXT: loop.3:
+; CHECK-NEXT: loop.2:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -497,18 +480,18 @@ define void @need_new_block_after_sinking_pr56146(i32 %x, ptr %src, ptr noalias
 ; CHECK-NEXT:     Successor(s): pred.store.if, pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:     pred.store.if:
-; CHECK-NEXT:       REPLICATE ir<%val> = sdiv vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:       vp<[[SCALAR_STEPS:%.+]]> = SCALAR-STEPS vp<[[DERIVED_IV]]>, ir<1>
 ; CHECK-NEXT:       REPLICATE ir<%gep.dst> = getelementptr ir<%dst>, vp<[[SCALAR_STEPS]]>
+; CHECK-NEXT:       REPLICATE ir<%val> = sdiv vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:       REPLICATE store ir<%val>, ir<%gep.dst>
 ; CHECK-NEXT:     Successor(s): pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:     pred.store.continue:
 ; CHECK-NEXT:     No successors
 ; CHECK-NEXT:   }
-; CHECK-NEXT:   Successor(s): loop.1
+; CHECK-NEXT:   Successor(s): loop.0
 ; CHECK-EMPTY:
-; CHECK-NEXT:   loop.1:
+; CHECK-NEXT:   loop.0:
 ; CHECK-NEXT:     EMIT vp<[[CAN_IV_NEXT:%.+]]> = add vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:     EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT:   No successors

>From 8a71ea7e80040f31100837e471b99a37aadfff65 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Sat, 20 Jul 2024 14:20:56 +0100
Subject: [PATCH 6/7] !fixup remove extra args from isPredicatedInst

---
 .../Transforms/Vectorize/LoopVectorize.cpp    | 30 ++++++++-----------
 .../Transforms/Vectorize/VPRecipeBuilder.h    |  2 +-
 2 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index b73979724c9c0..3f36160d1ec91 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1410,8 +1410,7 @@ class LoopVectorizationCostModel {
   /// Returns true if \p I is an instruction that needs to be predicated
   /// at runtime.  The result is independent of the predication mechanism.
   /// Superset of instructions that return true for isScalarWithPredication.
-  bool isPredicatedInst(Instruction *I, ElementCount VF,
-                        bool IsKnownUniform = false) const;
+  bool isPredicatedInst(Instruction *I) const;
 
   /// Return the costs for our two available strategies for lowering a
   /// div/rem operation which requires speculating at least one lane.
@@ -3650,7 +3649,7 @@ void LoopVectorizationCostModel::collectLoopScalars(ElementCount VF) {
 
 bool LoopVectorizationCostModel::isScalarWithPredication(
     Instruction *I, ElementCount VF) const {
-  if (!isPredicatedInst(I, VF))
+  if (!isPredicatedInst(I))
     return false;
 
   // Do we have a non-scalar lowering for this predicated
@@ -3689,9 +3688,7 @@ bool LoopVectorizationCostModel::isScalarWithPredication(
   }
 }
 
-bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I,
-                                                  ElementCount VF,
-                                                  bool IsKnownUniform) const {
+bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
   if (!blockNeedsPredicationForAnyReason(I->getParent()))
     return false;
 
@@ -3939,7 +3936,7 @@ void LoopVectorizationCostModel::collectLoopUniforms(ElementCount VF) {
                         << *I << "\n");
       return;
     }
-    if (isPredicatedInst(I, VF, true)) {
+    if (isPredicatedInst(I)) {
       LLVM_DEBUG(
           dbgs() << "LV: Found not uniform due to requiring predication: " << *I
                  << "\n");
@@ -5674,7 +5671,7 @@ bool LoopVectorizationCostModel::useEmulatedMaskMemRefHack(Instruction *I,
   // from moving "masked load/store" check from legality to cost model.
   // Masked Load/Gather emulation was previously never allowed.
   // Limited number of Masked Store/Scatter emulation was allowed.
-  assert((isPredicatedInst(I, VF)) &&
+  assert((isPredicatedInst(I)) &&
          "Expecting a scalar emulated instruction");
   return isa<LoadInst>(I) ||
          (isa<StoreInst>(I) &&
@@ -5953,7 +5950,7 @@ LoopVectorizationCostModel::getMemInstScalarizationCost(Instruction *I,
   // If we have a predicated load/store, it will need extra i1 extracts and
   // conditional branches, but may not be executed for each vector lane. Scale
   // the cost by the probability of executing the predicated block.
-  if (isPredicatedInst(I, VF)) {
+  if (isPredicatedInst(I)) {
     Cost /= getReciprocalPredBlockProb();
 
     // Add the cost of an i1 extract and a branch
@@ -6813,7 +6810,7 @@ LoopVectorizationCostModel::getInstructionCost(Instruction *I,
   case Instruction::SDiv:
   case Instruction::URem:
   case Instruction::SRem:
-    if (VF.isVector() && isPredicatedInst(I, VF)) {
+    if (VF.isVector() && isPredicatedInst(I)) {
       const auto [ScalarCost, SafeDivisorCost] = getDivRemSpeculationCost(I, VF);
       return isDivRemScalarWithPredication(ScalarCost, SafeDivisorCost) ?
         ScalarCost : SafeDivisorCost;
@@ -8485,7 +8482,7 @@ bool VPRecipeBuilder::shouldWiden(Instruction *I, VFRange &Range) const {
 
 VPWidenRecipe *VPRecipeBuilder::tryToWiden(Instruction *I,
                                            ArrayRef<VPValue *> Operands,
-                                           VPBasicBlock *VPBB, VFRange &Range) {
+                                           VPBasicBlock *VPBB) {
   switch (I->getOpcode()) {
   default:
     return nullptr;
@@ -8495,10 +8492,7 @@ VPWidenRecipe *VPRecipeBuilder::tryToWiden(Instruction *I,
   case Instruction::URem: {
     // If not provably safe, use a select to form a safe divisor before widening the
     // div/rem operation itself.  Otherwise fall through to general handling below.
-    bool IsPredicated = LoopVectorizationPlanner::getDecisionAndClampRange(
-        [&](ElementCount VF) -> bool { return CM.isPredicatedInst(I, VF); },
-        Range);
-    if (IsPredicated) {
+    if (CM.isPredicatedInst(I)) {
       SmallVector<VPValue *> Ops(Operands.begin(), Operands.end());
       VPValue *Mask = getBlockInMask(I->getParent());
       VPValue *One =
@@ -8548,8 +8542,8 @@ VPReplicateRecipe *VPRecipeBuilder::handleReplication(Instruction *I,
       [&](ElementCount VF) { return CM.isUniformAfterVectorization(I, VF); },
       Range);
 
-  bool IsPredicated = LoopVectorizationPlanner::getDecisionAndClampRange(
-      [&](ElementCount VF) { return CM.isPredicatedInst(I, VF); }, Range);
+  bool IsPredicated = CM.isPredicatedInst(I);
+
   // Even if the instruction is not marked as uniform, there are certain
   // intrinsic calls that can be effectively treated as such, so we check for
   // them here. Conservatively, we only do this for scalable vectors, since
@@ -8675,7 +8669,7 @@ VPRecipeBuilder::tryToCreateWidenRecipe(Instruction *Instr,
                                  *CI);
   }
 
-  return tryToWiden(Instr, Operands, VPBB, Range);
+  return tryToWiden(Instr, Operands, VPBB);
 }
 
 void LoopVectorizationPlanner::buildVPlansWithVPRecipes(ElementCount MinVF,
diff --git a/llvm/lib/Transforms/Vectorize/VPRecipeBuilder.h b/llvm/lib/Transforms/Vectorize/VPRecipeBuilder.h
index 0c7c47258bf9e..b4c7ab02f928f 100644
--- a/llvm/lib/Transforms/Vectorize/VPRecipeBuilder.h
+++ b/llvm/lib/Transforms/Vectorize/VPRecipeBuilder.h
@@ -100,7 +100,7 @@ class VPRecipeBuilder {
   /// if it can. The function should only be called if the cost-model indicates
   /// that widening should be performed.
   VPWidenRecipe *tryToWiden(Instruction *I, ArrayRef<VPValue *> Operands,
-                            VPBasicBlock *VPBB, VFRange &Range);
+                            VPBasicBlock *VPBB);
 
 public:
   VPRecipeBuilder(VPlan &Plan, Loop *OrigLoop, const TargetLibraryInfo *TLI,

>From f9581e063ef611b6bc61785fb942b0cf9622d940 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Wed, 24 Jul 2024 22:20:14 +0100
Subject: [PATCH 7/7] !fixup address latest comments, thanks!

---
 .../Transforms/Vectorize/LoopVectorize.cpp    | 46 +++++++++----------
 .../AArch64/divs-with-scalable-vfs.ll         |  1 -
 2 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index f3e30581e476f..741897940386e 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3340,43 +3340,43 @@ bool LoopVectorizationCostModel::isScalarWithPredication(
 }
 
 bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
-  if (!blockNeedsPredicationForAnyReason(I->getParent()))
-    return false;
-
-  // Can we prove this instruction is safe to unconditionally execute?
-  if (I->getOpcode() == Instruction::Call)
-    return Legal->isMaskRequired(I);
-
-  if (isa<LoadInst, StoreInst>(I) && !Legal->isMaskRequired(I))
-    return false;
-
+  // If predication is not needed, avoid it.
   // TODO: We can use the loop-preheader as context point here and get
-  // context sensitive reasoning
-  if (isa<BranchInst, PHINode>(I) || isSafeToSpeculativelyExecute(I))
+  // context sensitive reasoning for isSafeToSpeculativelyExecute.
+  if (!blockNeedsPredicationForAnyReason(I->getParent()) ||
+      isSafeToSpeculativelyExecute(I) ||
+      (isa<LoadInst, StoreInst, CallInst>(I) && !Legal->isMaskRequired(I)) ||
+      isa<BranchInst, PHINode>(I))
     return false;
 
   // If the instruction was executed conditionally in the original scalar loop,
-  // predication is needed.
+  // predication is needed with a mask whose lanes are all possibly inactive.
   if (Legal->blockNeedsPredication(I->getParent()))
     return true;
 
-  // Tail folding may introduce additional predication, but we're guaranteed to
-  // always have at least one active lane. If the instruction in the original
-  // scalar loop was executed unconditionally, it may not need predication,
-  // depending on its operands.
+  // All that remain are instructions with side-effects originally executed in
+  // the loop unconditionally, but now execute under a tail-fold mask (only)
+  // having at least one active lane (the first). If the side-effects of the
+  // instruction are invariant, executing it w/o (the tail-folding) mask is safe
+  // - it will cause the same side-effects as when masked.
   switch(I->getOpcode()) {
   default:
     llvm_unreachable(
-        "instruction should have been considered to not require predication "
-        "by earlier checks");
+        "instruction should have been considered by earlier checks");
+  case Instruction::Call:
+    // Side-effects of a Call are assumed to be non-invariant, needing a
+    // (fold-tail) mask.
+    assert(Legal->isMaskRequired(I) &&
+           "should have returned earlier for calls not needing a mask");
+    return true;
   case Instruction::Load:
     // If the address is loop invariant no predication is needed.
     return !Legal->isInvariant(getLoadStorePointerOperand(I));
   case Instruction::Store: {
-    // For stores, we need to prove
-    // both speculation safety (which follows from the same argument as loads),
-    // but also must prove the value being stored is correct.  The easiest
-    // form of the later is to require that all values stored are the same.
+    // For stores, we need to prove both speculation safety (which follows from
+    // the same argument as loads), but also must prove the value being stored
+    // is correct.  The easiest form of the later is to require that all values
+    // stored are the same.
     return !(Legal->isInvariant(getLoadStorePointerOperand(I)) &&
              TheLoop->isLoopInvariant(cast<StoreInst>(I)->getValueOperand()));
   }
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
index e8e34762ba238..bce2d6c14d866 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
@@ -1,5 +1,4 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; NOTE: Assertions t have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
 ; RUN: opt -p loop-vectorize -mtriple aarch64 -mcpu=neoverse-v1 -S %s | FileCheck %s
 
 ; Test case for https://github.com/llvm/llvm-project/issues/94328.



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