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[VPlan] Replace all uses of VF when EVL tail folding. NFCI #146339

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Jun 30, 2025
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[VPlan] Replace all uses of VF when EVL tail folding. NFCI #146339

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[VPlan] Replace all uses of VF when EVL tail folding. NFCI
lukel97 Jun 30, 2025
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Add assertion message
lukel97 Jun 30, 2025
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10 changes: 5 additions & 5 deletions llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2198,6 +2198,11 @@ static void transformRecipestoEVLRecipes(VPlan &Plan, VPValue &EVL) {
VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
VPBasicBlock *Header = LoopRegion->getEntryBasicBlock();

assert(all_of(Plan.getVF().users(),
IsaPred<VPVectorEndPointerRecipe, VPScalarIVStepsRecipe>) &&
"User of VF that we can't transform to EVL.");
Plan.getVF().replaceAllUsesWith(&EVL);

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We need to move this above the FOR transform because it introduces a trunc that uses the original VF

// Create a scalar phi to track the previous EVL if fixed-order recurrence is
// contained.
VPInstruction *PrevEVL = nullptr;
Expand All @@ -2216,11 +2221,6 @@ static void transformRecipestoEVLRecipes(VPlan &Plan, VPValue &EVL) {
PrevEVL = Builder.createScalarPhi({MaxEVL, &EVL}, DebugLoc(), "prev.evl");
}

for (VPUser *U : to_vector(Plan.getVF().users())) {
if (auto *R = dyn_cast<VPVectorEndPointerRecipe>(U))
R->setOperand(1, &EVL);
}

SmallVector<VPRecipeBase *> ToErase;

for (VPValue *HeaderMask : collectAllHeaderMasks(Plan)) {
Expand Down
7 changes: 7 additions & 0 deletions llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
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Expand Up @@ -158,6 +158,13 @@ bool VPlanVerifier::verifyEVLRecipe(const VPInstruction &EVL) const {
})
.Case<VPWidenStoreEVLRecipe, VPReductionEVLRecipe>(
[&](const VPRecipeBase *S) { return VerifyEVLUse(*S, 2); })
.Case<VPScalarIVStepsRecipe>([&](auto *R) {
if (R->getNumOperands() != 3) {
errs() << "Unrolling with EVL tail folding not yet supported\n";
return false;
}
return VerifyEVLUse(*R, 2);
})
.Case<VPWidenLoadEVLRecipe, VPVectorEndPointerRecipe>(
[&](const VPRecipeBase *R) { return VerifyEVLUse(*R, 1); })
.Case<VPInstructionWithType>(
Expand Down
27 changes: 9 additions & 18 deletions llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-call-intrinsics.ll
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Expand Up @@ -10,7 +10,6 @@ define void @vp_smax(ptr %a, ptr %b, ptr %c, i64 %N) {
; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
;
; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
; IF-EVL-NEXT: Live-in vp<[[VF:%[0-9]+]]> = VF
; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
; IF-EVL-NEXT: Live-in ir<%N> = original trip-count
Expand All @@ -24,7 +23,7 @@ define void @vp_smax(ptr %a, ptr %b, ptr %c, i64 %N) {
; IF-EVL-NEXT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI vp<[[EVL_PHI:%[0-9]+]]> = phi ir<0>, vp<[[IV_NEXT:%.+]]>
; IF-EVL-NEXT: EMIT vp<[[AVL:%.+]]> = sub ir<%N>, vp<[[EVL_PHI]]>
; IF-EVL-NEXT: EMIT vp<[[EVL:%.+]]> = EXPLICIT-VECTOR-LENGTH vp<[[AVL]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[VF]]
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[EVL]]
; IF-EVL-NEXT: CLONE ir<[[GEP1:%.+]]> = getelementptr inbounds ir<%b>, vp<[[ST]]>
; IF-EVL-NEXT: vp<[[PTR1:%[0-9]+]]> = vector-pointer ir<[[GEP1]]>
; IF-EVL-NEXT: WIDEN ir<[[LD1:%.+]]> = vp.load vp<[[PTR1]]>, vp<[[EVL]]>
Expand Down Expand Up @@ -67,7 +66,6 @@ define void @vp_smin(ptr %a, ptr %b, ptr %c, i64 %N) {
; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
;
; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
; IF-EVL-NEXT: Live-in vp<[[VF:%[0-9]+]]> = VF
; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
; IF-EVL-NEXT: Live-in ir<%N> = original trip-count
Expand All @@ -81,7 +79,7 @@ define void @vp_smin(ptr %a, ptr %b, ptr %c, i64 %N) {
; IF-EVL-NEXT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI vp<[[EVL_PHI:%[0-9]+]]> = phi ir<0>, vp<[[IV_NEXT:%.+]]>
; IF-EVL-NEXT: EMIT vp<[[AVL:%.+]]> = sub ir<%N>, vp<[[EVL_PHI]]>
; IF-EVL-NEXT: EMIT vp<[[EVL:%.+]]> = EXPLICIT-VECTOR-LENGTH vp<[[AVL]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[VF]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[EVL]]>
; IF-EVL-NEXT: CLONE ir<[[GEP1:%.+]]> = getelementptr inbounds ir<%b>, vp<[[ST]]>
; IF-EVL-NEXT: vp<[[PTR1:%[0-9]+]]> = vector-pointer ir<[[GEP1]]>
; IF-EVL-NEXT: WIDEN ir<[[LD1:%.+]]> = vp.load vp<[[PTR1]]>, vp<[[EVL]]>
Expand Down Expand Up @@ -124,7 +122,6 @@ define void @vp_umax(ptr %a, ptr %b, ptr %c, i64 %N) {
; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
;
; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
; IF-EVL-NEXT: Live-in vp<[[VF:%[0-9]+]]> = VF
; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
; IF-EVL-NEXT: Live-in ir<%N> = original trip-count
Expand All @@ -138,7 +135,7 @@ define void @vp_umax(ptr %a, ptr %b, ptr %c, i64 %N) {
; IF-EVL-NEXT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI vp<[[EVL_PHI:%[0-9]+]]> = phi ir<0>, vp<[[IV_NEXT:%.+]]>
; IF-EVL-NEXT: EMIT vp<[[AVL:%.+]]> = sub ir<%N>, vp<[[EVL_PHI]]>
; IF-EVL-NEXT: EMIT vp<[[EVL:%.+]]> = EXPLICIT-VECTOR-LENGTH vp<[[AVL]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[VF]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[EVL]]>
; IF-EVL-NEXT: CLONE ir<[[GEP1:%.+]]> = getelementptr inbounds ir<%b>, vp<[[ST]]>
; IF-EVL-NEXT: vp<[[PTR1:%[0-9]+]]> = vector-pointer ir<[[GEP1]]>
; IF-EVL-NEXT: WIDEN ir<[[LD1:%.+]]> = vp.load vp<[[PTR1]]>, vp<[[EVL]]>
Expand Down Expand Up @@ -181,7 +178,6 @@ define void @vp_umin(ptr %a, ptr %b, ptr %c, i64 %N) {
; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
;
; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
; IF-EVL-NEXT: Live-in vp<[[VF:%[0-9]+]]> = VF
; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
; IF-EVL-NEXT: Live-in ir<%N> = original trip-count
Expand All @@ -195,7 +191,7 @@ define void @vp_umin(ptr %a, ptr %b, ptr %c, i64 %N) {
; IF-EVL-NEXT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI vp<[[EVL_PHI:%[0-9]+]]> = phi ir<0>, vp<[[IV_NEXT:%.+]]>
; IF-EVL-NEXT: EMIT vp<[[AVL:%.+]]> = sub ir<%N>, vp<[[EVL_PHI]]>
; IF-EVL-NEXT: EMIT vp<[[EVL:%.+]]> = EXPLICIT-VECTOR-LENGTH vp<[[AVL]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[VF]]
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[EVL]]
; IF-EVL-NEXT: CLONE ir<[[GEP1:%.+]]> = getelementptr inbounds ir<%b>, vp<[[ST]]>
; IF-EVL-NEXT: vp<[[PTR1:%[0-9]+]]> = vector-pointer ir<[[GEP1]]>
; IF-EVL-NEXT: WIDEN ir<[[LD1:%.+]]> = vp.load vp<[[PTR1]]>, vp<[[EVL]]>
Expand Down Expand Up @@ -238,7 +234,6 @@ define void @vp_ctlz(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
;
; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
; IF-EVL-NEXT: Live-in vp<[[VF:%[0-9]+]]> = VF
; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
; IF-EVL-NEXT: Live-in ir<%N> = original trip-count
Expand All @@ -252,7 +247,7 @@ define void @vp_ctlz(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NEXT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI vp<[[EVL_PHI:%[0-9]+]]> = phi ir<0>, vp<[[IV_NEXT:%.+]]>
; IF-EVL-NEXT: EMIT vp<[[AVL:%.+]]> = sub ir<%N>, vp<[[EVL_PHI]]>
; IF-EVL-NEXT: EMIT vp<[[EVL:%.+]]> = EXPLICIT-VECTOR-LENGTH vp<[[AVL]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[VF]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[EVL]]>
; IF-EVL-NEXT: CLONE ir<[[GEP1:%.+]]> = getelementptr inbounds ir<%b>, vp<[[ST]]>
; IF-EVL-NEXT: vp<[[PTR1:%[0-9]+]]> = vector-pointer ir<[[GEP1]]>
; IF-EVL-NEXT: WIDEN ir<[[LD1:%.+]]> = vp.load vp<[[PTR1]]>, vp<[[EVL]]>
Expand Down Expand Up @@ -290,7 +285,6 @@ define void @vp_cttz(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
;
; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
; IF-EVL-NEXT: Live-in vp<[[VF:%[0-9]+]]> = VF
; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
; IF-EVL-NEXT: Live-in ir<%N> = original trip-count
Expand All @@ -304,7 +298,7 @@ define void @vp_cttz(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NEXT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI vp<[[EVL_PHI:%[0-9]+]]> = phi ir<0>, vp<[[IV_NEXT:%.+]]>
; IF-EVL-NEXT: EMIT vp<[[AVL:%.+]]> = sub ir<%N>, vp<[[EVL_PHI]]>
; IF-EVL-NEXT: EMIT vp<[[EVL:%.+]]> = EXPLICIT-VECTOR-LENGTH vp<[[AVL]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[VF]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[EVL]]>
; IF-EVL-NEXT: CLONE ir<[[GEP1:%.+]]> = getelementptr inbounds ir<%b>, vp<[[ST]]>
; IF-EVL-NEXT: vp<[[PTR1:%[0-9]+]]> = vector-pointer ir<[[GEP1]]>
; IF-EVL-NEXT: WIDEN ir<[[LD1:%.+]]> = vp.load vp<[[PTR1]]>, vp<[[EVL]]>
Expand Down Expand Up @@ -342,7 +336,6 @@ define void @vp_lrint(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
;
; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
; IF-EVL-NEXT: Live-in vp<[[VF:%[0-9]+]]> = VF
; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
; IF-EVL-NEXT: Live-in ir<%N> = original trip-count
Expand All @@ -356,7 +349,7 @@ define void @vp_lrint(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NEXT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI vp<[[EVL_PHI:%[0-9]+]]> = phi ir<0>, vp<[[IV_NEXT:%.+]]>
; IF-EVL-NEXT: EMIT vp<[[AVL:%.+]]> = sub ir<%N>, vp<[[EVL_PHI]]>
; IF-EVL-NEXT: EMIT vp<[[EVL:%.+]]> = EXPLICIT-VECTOR-LENGTH vp<[[AVL]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[VF]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[EVL]]>
; IF-EVL-NEXT: CLONE ir<[[GEP1:%.+]]> = getelementptr inbounds ir<%b>, vp<[[ST]]>
; IF-EVL-NEXT: vp<[[PTR1:%[0-9]+]]> = vector-pointer ir<[[GEP1]]>
; IF-EVL-NEXT: WIDEN ir<[[LD1:%.+]]> = vp.load vp<[[PTR1]]>, vp<[[EVL]]>
Expand Down Expand Up @@ -398,7 +391,6 @@ define void @vp_llrint(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
;
; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
; IF-EVL-NEXT: Live-in vp<[[VF:%[0-9]+]]> = VF
; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
; IF-EVL-NEXT: Live-in ir<%N> = original trip-count
Expand All @@ -412,7 +404,7 @@ define void @vp_llrint(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NEXT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI vp<[[EVL_PHI:%[0-9]+]]> = phi ir<0>, vp<[[IV_NEXT:%.+]]>
; IF-EVL-NEXT: EMIT vp<[[AVL:%.+]]> = sub ir<%N>, vp<[[EVL_PHI]]>
; IF-EVL-NEXT: EMIT vp<[[EVL:%.+]]> = EXPLICIT-VECTOR-LENGTH vp<[[AVL]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[VF]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[EVL]]>
; IF-EVL-NEXT: CLONE ir<[[GEP1:%.+]]> = getelementptr inbounds ir<%b>, vp<[[ST]]>
; IF-EVL-NEXT: vp<[[PTR1:%[0-9]+]]> = vector-pointer ir<[[GEP1]]>
; IF-EVL-NEXT: WIDEN ir<[[LD1:%.+]]> = vp.load vp<[[PTR1]]>, vp<[[EVL]]>
Expand Down Expand Up @@ -454,7 +446,6 @@ define void @vp_abs(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
;
; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
; IF-EVL-NEXT: Live-in vp<[[VF:%[0-9]+]]> = VF
; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
; IF-EVL-NEXT: Live-in ir<%N> = original trip-count
Expand All @@ -468,7 +459,7 @@ define void @vp_abs(ptr %a, ptr %b, i64 %N) {
; IF-EVL-NEXT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI vp<[[EVL_PHI:%[0-9]+]]> = phi ir<0>, vp<[[IV_NEXT:%.+]]>
; IF-EVL-NEXT: EMIT vp<[[AVL:%.+]]> = sub ir<%N>, vp<[[EVL_PHI]]>
; IF-EVL-NEXT: EMIT vp<[[EVL:%.+]]> = EXPLICIT-VECTOR-LENGTH vp<[[AVL]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[VF]]>
; IF-EVL-NEXT: vp<[[ST:%[0-9]+]]> = SCALAR-STEPS vp<[[EVL_PHI]]>, ir<1>, vp<[[EVL]]>
; IF-EVL-NEXT: CLONE ir<[[GEP1:%.+]]> = getelementptr inbounds ir<%b>, vp<[[ST]]>
; IF-EVL-NEXT: vp<[[PTR1:%[0-9]+]]> = vector-pointer ir<[[GEP1]]>
; IF-EVL-NEXT: WIDEN ir<[[LD1:%.+]]> = vp.load vp<[[PTR1]]>, vp<[[EVL]]>
Expand Down
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