[llvm] [LLVM][LV] Improve UF calculation for vscale based scalar loops. (PR #146102)

via llvm-commits llvm-commits at lists.llvm.org
Fri Jun 27 09:13:07 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Paul Walker (paulwalker-arm)

<details>
<summary>Changes</summary>

Update getSmallConstantTripCount() to return scalable ElementCount values that is used to acurrately determine the maximum value for UF, namely:

  TripCount / VF ==> X * VScale / Y * VScale ==> X / Y

This improves the chances of being able to remove the scalar loop and also fixes an issue where a UF=2 is choosen for a scalar loop with exactly VF(= X * VScale) iterations.

---
Full diff: https://github.com/llvm/llvm-project/pull/146102.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+31-6) 
- (modified) llvm/test/Transforms/LoopVectorize/AArch64/sve-vscale-based-trip-counts.ll (+40-81) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index bb29e4fc6d232..8a4435eed95bf 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -423,7 +423,26 @@ static bool hasIrregularType(Type *Ty, const DataLayout &DL) {
 /// ElementCount to include loops whose trip count is a function of vscale.
 static ElementCount getSmallConstantTripCount(ScalarEvolution *SE,
                                               const Loop *L) {
-  return ElementCount::getFixed(SE->getSmallConstantTripCount(L));
+  if (unsigned ExpectedTC = SE->getSmallConstantTripCount(L))
+    return ElementCount::getFixed(ExpectedTC);
+
+  const SCEV *BTC = SE->getBackedgeTakenCount(L);
+
+  if (isa<SCEVCouldNotCompute>(BTC))
+    return ElementCount::getFixed(0);
+
+  const SCEV *ExitCount = SE->getTripCountFromExitCount(BTC, BTC->getType(), L);
+
+  if (isa<SCEVVScale>(ExitCount))
+    return ElementCount::getScalable(1);
+
+  if (auto *Mul = dyn_cast<SCEVMulExpr>(ExitCount))
+    if (Mul->getNumOperands() == 2 && isa<SCEVConstant>(Mul->getOperand(0)) &&
+        isa<SCEVVScale>(Mul->getOperand(1)))
+      return ElementCount::getScalable(
+          cast<SCEVConstant>(Mul->getOperand(0))->getValue()->getZExtValue());
+
+  return ElementCount::getFixed(0);
 }
 
 /// Returns "best known" trip count, which is either a valid positive trip count
@@ -4813,16 +4832,22 @@ LoopVectorizationCostModel::selectInterleaveCount(VPlan &Plan, ElementCount VF,
       MaxInterleaveCount = ForceTargetMaxVectorInterleaveFactor;
   }
 
-  unsigned EstimatedVF = getEstimatedRuntimeVF(VF, VScaleForTuning);
-
   // Try to get the exact trip count, or an estimate based on profiling data or
   // ConstantMax from PSE, failing that.
-  if (auto BestKnownTC = getSmallBestKnownTC(PSE, TheLoop)) {
+  auto BestKnownTC = getSmallBestKnownTC(PSE, TheLoop);
+
+  // For fixed length VFs treat a scalable trip count as unknown.
+  if (BestKnownTC && (BestKnownTC->isFixed() || VF.isScalable())) {
+    // Re-evaluate VF to be in the same numerical space as the trip count.
+    unsigned EstimatedVF = VF.getKnownMinValue();
+    if (VF.isScalable() && BestKnownTC->isFixed())
+      EstimatedVF = getEstimatedRuntimeVF(VF, VScaleForTuning);
+
     // At least one iteration must be scalar when this constraint holds. So the
     // maximum available iterations for interleaving is one less.
     unsigned AvailableTC = requiresScalarEpilogue(VF.isVector())
-                               ? BestKnownTC->getFixedValue() - 1
-                               : BestKnownTC->getFixedValue();
+                               ? BestKnownTC->getKnownMinValue() - 1
+                               : BestKnownTC->getKnownMinValue();
 
     unsigned InterleaveCountLB = bit_floor(std::max(
         1u, std::min(AvailableTC / (EstimatedVF * 2), MaxInterleaveCount)));
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/sve-vscale-based-trip-counts.ll b/llvm/test/Transforms/LoopVectorize/AArch64/sve-vscale-based-trip-counts.ll
index e2c7469a97819..dd1606c0f349a 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/sve-vscale-based-trip-counts.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/sve-vscale-based-trip-counts.ll
@@ -10,62 +10,35 @@ define void @vscale_mul_4(ptr noalias noundef readonly captures(none) %a, ptr no
 ; CHECK-NEXT:    [[TMP0:%.*]] = tail call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[TMP1:%.*]] = shl nuw nsw i64 [[TMP0]], 2
 ; CHECK-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 8
-; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP1]], [[TMP3]]
-; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
-; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 4
 ; CHECK-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP5:%.*]] = mul nuw i64 [[TMP4]], 8
+; CHECK-NEXT:    [[TMP5:%.*]] = mul nuw i64 [[TMP4]], 4
 ; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP1]], [[TMP5]]
 ; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP1]], [[N_MOD_VF]]
-; CHECK-NEXT:    [[TMP10:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP7:%.*]] = mul nuw i64 [[TMP10]], 8
-; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
-; CHECK:       [[VECTOR_BODY]]:
-; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; CHECK-NEXT:    [[TMP13:%.*]] = getelementptr inbounds nuw float, ptr [[A]], i64 [[INDEX]]
-; CHECK-NEXT:    [[TMP14:%.*]] = getelementptr inbounds nuw float, ptr [[TMP13]], i32 0
-; CHECK-NEXT:    [[TMP18:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP11:%.*]] = mul nuw i64 [[TMP18]], 4
-; CHECK-NEXT:    [[TMP26:%.*]] = getelementptr inbounds nuw float, ptr [[TMP13]], i64 [[TMP11]]
-; CHECK-NEXT:    [[WIDE_LOAD2:%.*]] = load <vscale x 4 x float>, ptr [[TMP14]], align 4
-; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <vscale x 4 x float>, ptr [[TMP26]], align 4
-; CHECK-NEXT:    [[TMP12:%.*]] = getelementptr inbounds nuw float, ptr [[B]], i64 [[INDEX]]
-; CHECK-NEXT:    [[TMP17:%.*]] = getelementptr inbounds nuw float, ptr [[TMP12]], i32 0
-; CHECK-NEXT:    [[TMP15:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP16:%.*]] = mul nuw i64 [[TMP15]], 4
-; CHECK-NEXT:    [[TMP27:%.*]] = getelementptr inbounds nuw float, ptr [[TMP12]], i64 [[TMP16]]
-; CHECK-NEXT:    [[WIDE_LOAD3:%.*]] = load <vscale x 4 x float>, ptr [[TMP17]], align 4
-; CHECK-NEXT:    [[WIDE_LOAD4:%.*]] = load <vscale x 4 x float>, ptr [[TMP27]], align 4
-; CHECK-NEXT:    [[TMP19:%.*]] = fmul <vscale x 4 x float> [[WIDE_LOAD2]], [[WIDE_LOAD3]]
-; CHECK-NEXT:    [[TMP28:%.*]] = fmul <vscale x 4 x float> [[WIDE_LOAD1]], [[WIDE_LOAD4]]
-; CHECK-NEXT:    [[TMP20:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP21:%.*]] = mul nuw i64 [[TMP20]], 4
-; CHECK-NEXT:    [[TMP22:%.*]] = getelementptr inbounds nuw float, ptr [[TMP12]], i64 [[TMP21]]
-; CHECK-NEXT:    store <vscale x 4 x float> [[TMP19]], ptr [[TMP17]], align 4
-; CHECK-NEXT:    store <vscale x 4 x float> [[TMP28]], ptr [[TMP22]], align 4
-; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP7]]
-; CHECK-NEXT:    [[TMP23:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[TMP23]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
-; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    [[TMP6:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP7:%.*]] = mul nuw i64 [[TMP6]], 4
+; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr inbounds nuw float, ptr [[A]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 4 x float>, ptr [[TMP8]], align 4
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr inbounds nuw float, ptr [[B]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <vscale x 4 x float>, ptr [[TMP9]], align 4
+; CHECK-NEXT:    [[TMP10:%.*]] = fmul <vscale x 4 x float> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-NEXT:    [[TMP11:%.*]] = getelementptr inbounds nuw float, ptr [[B]], i32 0
+; CHECK-NEXT:    store <vscale x 4 x float> [[TMP10]], ptr [[TMP11]], align 4
 ; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP1]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[CMP_N]], label %[[FOR_COND_CLEANUP:.*]], label %[[SCALAR_PH]]
-; CHECK:       [[SCALAR_PH]]:
-; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
-; CHECK-NEXT:    br label %[[FOR_BODY:.*]]
+; CHECK-NEXT:    br i1 [[CMP_N]], label %[[FOR_COND_CLEANUP:.*]], label %[[FOR_BODY:.*]]
 ; CHECK:       [[FOR_COND_CLEANUP]]:
 ; CHECK-NEXT:    ret void
 ; CHECK:       [[FOR_BODY]]:
-; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INDVARS_IV_NEXT:%.*]], %[[FOR_BODY]] ]
+; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], %[[FOR_BODY]] ], [ [[N_VEC]], %[[ENTRY]] ]
 ; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds nuw float, ptr [[A]], i64 [[INDVARS_IV]]
-; CHECK-NEXT:    [[TMP24:%.*]] = load float, ptr [[ARRAYIDX]], align 4
+; CHECK-NEXT:    [[TMP12:%.*]] = load float, ptr [[ARRAYIDX]], align 4
 ; CHECK-NEXT:    [[ARRAYIDX3:%.*]] = getelementptr inbounds nuw float, ptr [[B]], i64 [[INDVARS_IV]]
-; CHECK-NEXT:    [[TMP25:%.*]] = load float, ptr [[ARRAYIDX3]], align 4
-; CHECK-NEXT:    [[MUL4:%.*]] = fmul float [[TMP24]], [[TMP25]]
+; CHECK-NEXT:    [[TMP13:%.*]] = load float, ptr [[ARRAYIDX3]], align 4
+; CHECK-NEXT:    [[MUL4:%.*]] = fmul float [[TMP12]], [[TMP13]]
 ; CHECK-NEXT:    store float [[MUL4]], ptr [[ARRAYIDX3]], align 4
 ; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT]], [[TMP1]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
 ;
 entry:
   %0 = tail call i64 @llvm.vscale.i64()
@@ -136,7 +109,7 @@ define  void @vscale_mul_8(ptr noalias noundef readonly captures(none) %a, ptr n
 ; CHECK-NEXT:    store float [[MUL5]], ptr [[ARRAYIDX4]], align 4
 ; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT]], [[MUL1]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
 ;
 entry:
   %0 = tail call i64 @llvm.vscale.i64()
@@ -166,43 +139,30 @@ define void @vscale_mul_12(ptr noalias noundef readonly captures(none) %a, ptr n
 ; CHECK-NEXT:    [[TMP0:%.*]] = tail call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[MUL1:%.*]] = mul nuw nsw i64 [[TMP0]], 12
 ; CHECK-NEXT:    [[TMP1:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP2:%.*]] = mul nuw i64 [[TMP1]], 8
+; CHECK-NEXT:    [[TMP2:%.*]] = mul nuw i64 [[TMP1]], 4
 ; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[MUL1]], [[TMP2]]
 ; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
 ; CHECK:       [[VECTOR_PH]]:
 ; CHECK-NEXT:    [[TMP3:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 8
+; CHECK-NEXT:    [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 4
 ; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[MUL1]], [[TMP4]]
 ; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[MUL1]], [[N_MOD_VF]]
 ; CHECK-NEXT:    [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP6:%.*]] = mul nuw i64 [[TMP5]], 8
+; CHECK-NEXT:    [[TMP6:%.*]] = mul nuw i64 [[TMP5]], 4
 ; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
 ; CHECK:       [[VECTOR_BODY]]:
 ; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
 ; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr inbounds nuw float, ptr [[A]], i64 [[INDEX]]
 ; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr inbounds nuw float, ptr [[TMP7]], i32 0
-; CHECK-NEXT:    [[TMP9:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP10:%.*]] = mul nuw i64 [[TMP9]], 4
-; CHECK-NEXT:    [[TMP11:%.*]] = getelementptr inbounds nuw float, ptr [[TMP7]], i64 [[TMP10]]
-; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <vscale x 4 x float>, ptr [[TMP8]], align 4
-; CHECK-NEXT:    [[WIDE_LOAD2:%.*]] = load <vscale x 4 x float>, ptr [[TMP11]], align 4
-; CHECK-NEXT:    [[TMP12:%.*]] = getelementptr inbounds nuw float, ptr [[B]], i64 [[INDEX]]
-; CHECK-NEXT:    [[TMP13:%.*]] = getelementptr inbounds nuw float, ptr [[TMP12]], i32 0
-; CHECK-NEXT:    [[TMP14:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP15:%.*]] = mul nuw i64 [[TMP14]], 4
-; CHECK-NEXT:    [[TMP16:%.*]] = getelementptr inbounds nuw float, ptr [[TMP12]], i64 [[TMP15]]
-; CHECK-NEXT:    [[WIDE_LOAD3:%.*]] = load <vscale x 4 x float>, ptr [[TMP13]], align 4
-; CHECK-NEXT:    [[WIDE_LOAD4:%.*]] = load <vscale x 4 x float>, ptr [[TMP16]], align 4
-; CHECK-NEXT:    [[TMP18:%.*]] = fmul <vscale x 4 x float> [[WIDE_LOAD1]], [[WIDE_LOAD3]]
-; CHECK-NEXT:    [[TMP25:%.*]] = fmul <vscale x 4 x float> [[WIDE_LOAD2]], [[WIDE_LOAD4]]
-; CHECK-NEXT:    [[TMP19:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT:    [[TMP20:%.*]] = mul nuw i64 [[TMP19]], 4
-; CHECK-NEXT:    [[TMP21:%.*]] = getelementptr inbounds nuw float, ptr [[TMP12]], i64 [[TMP20]]
-; CHECK-NEXT:    store <vscale x 4 x float> [[TMP18]], ptr [[TMP13]], align 4
-; CHECK-NEXT:    store <vscale x 4 x float> [[TMP25]], ptr [[TMP21]], align 4
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 4 x float>, ptr [[TMP8]], align 4
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr inbounds nuw float, ptr [[B]], i64 [[INDEX]]
+; CHECK-NEXT:    [[TMP10:%.*]] = getelementptr inbounds nuw float, ptr [[TMP9]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD1:%.*]] = load <vscale x 4 x float>, ptr [[TMP10]], align 4
+; CHECK-NEXT:    [[TMP11:%.*]] = fmul <vscale x 4 x float> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; CHECK-NEXT:    store <vscale x 4 x float> [[TMP11]], ptr [[TMP10]], align 4
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP6]]
-; CHECK-NEXT:    [[TMP22:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[TMP22]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK-NEXT:    [[TMP12:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP12]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
 ; CHECK:       [[MIDDLE_BLOCK]]:
 ; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[MUL1]], [[N_VEC]]
 ; CHECK-NEXT:    br i1 [[CMP_N]], label %[[FOR_COND_CLEANUP:.*]], label %[[SCALAR_PH]]
@@ -214,14 +174,14 @@ define void @vscale_mul_12(ptr noalias noundef readonly captures(none) %a, ptr n
 ; CHECK:       [[FOR_BODY]]:
 ; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INDVARS_IV_NEXT:%.*]], %[[FOR_BODY]] ]
 ; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds nuw float, ptr [[A]], i64 [[INDVARS_IV]]
-; CHECK-NEXT:    [[TMP23:%.*]] = load float, ptr [[ARRAYIDX]], align 4
+; CHECK-NEXT:    [[TMP13:%.*]] = load float, ptr [[ARRAYIDX]], align 4
 ; CHECK-NEXT:    [[ARRAYIDX4:%.*]] = getelementptr inbounds nuw float, ptr [[B]], i64 [[INDVARS_IV]]
-; CHECK-NEXT:    [[TMP24:%.*]] = load float, ptr [[ARRAYIDX4]], align 4
-; CHECK-NEXT:    [[MUL5:%.*]] = fmul float [[TMP23]], [[TMP24]]
+; CHECK-NEXT:    [[TMP14:%.*]] = load float, ptr [[ARRAYIDX4]], align 4
+; CHECK-NEXT:    [[MUL5:%.*]] = fmul float [[TMP13]], [[TMP14]]
 ; CHECK-NEXT:    store float [[MUL5]], ptr [[ARRAYIDX4]], align 4
 ; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT]], [[MUL1]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
 ;
 entry:
   %0 = tail call i64 @llvm.vscale.i64()
@@ -287,7 +247,7 @@ define void @vscale_mul_31(ptr noalias noundef readonly captures(none) %a, ptr n
 ; CHECK-NEXT:    store <vscale x 4 x float> [[TMP18]], ptr [[TMP21]], align 4
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP6]]
 ; CHECK-NEXT:    [[TMP22:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[TMP22]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP22]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
 ; CHECK:       [[MIDDLE_BLOCK]]:
 ; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[MUL1]], [[N_VEC]]
 ; CHECK-NEXT:    br i1 [[CMP_N]], label %[[FOR_COND_CLEANUP:.*]], label %[[SCALAR_PH]]
@@ -306,7 +266,7 @@ define void @vscale_mul_31(ptr noalias noundef readonly captures(none) %a, ptr n
 ; CHECK-NEXT:    store float [[MUL5]], ptr [[ARRAYIDX4]], align 4
 ; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT]], [[MUL1]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
 ;
 entry:
   %0 = tail call i64 @llvm.vscale.i64()
@@ -372,7 +332,7 @@ define void @vscale_mul_64(ptr noalias noundef readonly captures(none) %a, ptr n
 ; CHECK-NEXT:    store <vscale x 4 x float> [[TMP18]], ptr [[TMP21]], align 4
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP6]]
 ; CHECK-NEXT:    [[TMP22:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[TMP22]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP22]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
 ; CHECK:       [[MIDDLE_BLOCK]]:
 ; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[MUL1]], [[N_VEC]]
 ; CHECK-NEXT:    br i1 [[CMP_N]], label %[[FOR_COND_CLEANUP:.*]], label %[[SCALAR_PH]]
@@ -391,7 +351,7 @@ define void @vscale_mul_64(ptr noalias noundef readonly captures(none) %a, ptr n
 ; CHECK-NEXT:    store float [[MUL5]], ptr [[ARRAYIDX4]], align 4
 ; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT]], [[MUL1]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_COND_CLEANUP]], label %[[FOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
 ;
 entry:
   %0 = tail call i64 @llvm.vscale.i64()
@@ -419,14 +379,13 @@ declare i64 @llvm.vscale.i64()
 attributes #0 = { vscale_range(1,16) "target-features"="+sve" }
 ;.
 ; 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]], [[META2]], [[META1]]}
+; CHECK: [[META1]] = !{!"llvm.loop.unroll.runtime.disable"}
+; CHECK: [[META2]] = !{!"llvm.loop.isvectorized", i32 1}
+; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META1]], [[META2]]}
 ; CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[META2]], [[META1]]}
 ; CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]], [[META2]]}
 ; CHECK: [[LOOP6]] = distinct !{[[LOOP6]], [[META2]], [[META1]]}
 ; CHECK: [[LOOP7]] = distinct !{[[LOOP7]], [[META1]], [[META2]]}
 ; CHECK: [[LOOP8]] = distinct !{[[LOOP8]], [[META2]], [[META1]]}
 ; CHECK: [[LOOP9]] = distinct !{[[LOOP9]], [[META1]], [[META2]]}
-; CHECK: [[LOOP10]] = distinct !{[[LOOP10]], [[META2]], [[META1]]}
 ;.

``````````

</details>


https://github.com/llvm/llvm-project/pull/146102


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