[LV][EVL] Skip tryAddExplicitVectorLength for plans with scalar VF. #125497

Mel-Chen · 2025-02-03T13:50:10Z

The plans with scalar VF should not be transformed the plans folded by EVL.
For this, this patch introduces VPlan::hasScalarVF() to check if a plan includes a scalar VF.

TODO: Move the scalar VF checking into LoopVectorizationCostModel ::foldTailWithEVL().

llvmbot · 2025-02-03T13:51:09Z

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-vectorizers

Author: Mel Chen (Mel-Chen)

Changes

The plans with scalar VF should not be transformed the plans folded by EVL.
For this, this patch introduces VPlan::hasScalarVF() to check if a plan includes a scalar VF.

TODO: Move the scalar VF checking into LoopVectorizationCostModel ::foldTailWithEVL().

Full diff: https://github.com/llvm/llvm-project/pull/125497.diff

7 Files Affected:

(modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+1-1)
(modified) llvm/lib/Transforms/Vectorize/VPlan.h (+4)
(modified) llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-call-intrinsics.ll (+27)
(modified) llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-cast-intrinsics.ll (+30)
(modified) llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics-reduction.ll (+5-2)
(modified) llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics.ll (+3)
(modified) llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-select-intrinsics.ll (+5)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index f88c13525421c8..bc0f611587749d 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -8925,7 +8925,7 @@ void LoopVectorizationPlanner::buildVPlansWithVPRecipes(ElementCount MinVF,
       VPlanTransforms::optimize(*Plan);
       // TODO: try to put it close to addActiveLaneMask().
       // Discard the plan if it is not EVL-compatible
-      if (CM.foldTailWithEVL() &&
+      if (CM.foldTailWithEVL() && !Plan->hasScalarVF() &&
           !VPlanTransforms::runPass(VPlanTransforms::tryAddExplicitVectorLength,
                                     *Plan, CM.getMaxSafeElements()))
         break;
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index fac207287e0bcc..6a997218e6a5a3 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -3678,6 +3678,10 @@ class VPlan {
     return {VFs.begin(), VFs.end()};
   }
 
+  bool hasScalarVF() const {
+    return any_of(VFs, [](ElementCount VF) { return VF.isScalar(); });
+  }
+
   bool hasScalarVFOnly() const { return VFs.size() == 1 && VFs[0].isScalar(); }
 
   bool hasUF(unsigned UF) const { return UFs.empty() || UFs.contains(UF); }
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-call-intrinsics.ll b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-call-intrinsics.ll
index 05c687a2053533..81a2675dc65832 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-call-intrinsics.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-call-intrinsics.ll
@@ -6,6 +6,9 @@
 ; RUN: -mtriple=riscv64 -mattr=+v -riscv-v-vector-bits-max=128 -disable-output < %s 2>&1 | FileCheck --check-prefix=IF-EVL %s
 
 define void @vp_smax(ptr %a, ptr %b, ptr %c, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -59,6 +62,9 @@ exit:
 }
 
 define void @vp_smin(ptr %a, ptr %b, ptr %c, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -112,6 +118,9 @@ exit:
 }
 
 define void @vp_umax(ptr %a, ptr %b, ptr %c, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -165,6 +174,9 @@ exit:
 }
 
 define void @vp_umin(ptr %a, ptr %b, ptr %c, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -218,6 +230,9 @@ exit:
 }
 
 define void @vp_ctlz(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -266,6 +281,9 @@ exit:
 }
 
 define void @vp_cttz(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -314,6 +332,9 @@ exit:
 }
 
 define void @vp_lrint(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -366,6 +387,9 @@ exit:
 }
 
 define void @vp_llrint(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -418,6 +442,9 @@ exit:
 }
 
 define void @vp_abs(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-cast-intrinsics.ll b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-cast-intrinsics.ll
index f4acfd6185644d..40cf02c4663fee 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-cast-intrinsics.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-cast-intrinsics.ll
@@ -5,6 +5,9 @@
 ; RUN: -mtriple=riscv64 -mattr=+v -riscv-v-vector-bits-max=128 -disable-output < %s 2>&1 | FileCheck --check-prefix=IF-EVL %s
 
 define void @vp_sext(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
+;
 ; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2},UF={1}' {
 ; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -55,6 +58,9 @@ exit:
 }
 
 define void @vp_zext(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
+;
 ; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2},UF={1}' {
 ; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -103,6 +109,9 @@ exit:
 }
 
 define void @vp_trunc(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -151,6 +160,9 @@ exit:
 }
 
 define void @vp_fpext(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
+;
 ; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2},UF={1}' {
 ; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -199,6 +211,9 @@ exit:
 }
 
 define void @vp_fptrunc(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
+;
 ; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2},UF={1}' {
 ; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -247,6 +262,9 @@ exit:
 }
 
 define void @vp_sitofp(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -295,6 +313,9 @@ exit:
 }
 
 define void @vp_uitofp(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -343,6 +364,9 @@ exit:
 }
 
 define void @vp_fptosi(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -391,6 +415,9 @@ exit:
 }
 
 define void @vp_fptoui(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
@@ -439,6 +466,9 @@ exit:
 }
 
 define void @vp_inttoptr(ptr %a, ptr %b, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
+;
 ; IF-EVL: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2},UF={1}' {
 ; IF-EVL-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics-reduction.ll b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics-reduction.ll
index cd1d734f00eaa5..0daf15d04af358 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics-reduction.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics-reduction.ll
@@ -3,13 +3,13 @@
 ; RUN: opt -passes=loop-vectorize -debug-only=loop-vectorize \
 ; RUN: -force-tail-folding-style=data-with-evl \
 ; RUN: -prefer-predicate-over-epilogue=predicate-dont-vectorize \
-; RUN: -mtriple=riscv64 -mattr=+v -riscv-v-vector-bits-max=128 -disable-output < %s 2>&1 | FileCheck --check-prefixes=IF-EVL-OUTLOOP %s
+; RUN: -mtriple=riscv64 -mattr=+v -riscv-v-vector-bits-max=128 -disable-output < %s 2>&1 | FileCheck --check-prefixes=IF-EVL-OUTLOOP,IF-EVL %s
 
 ; RUN: opt -passes=loop-vectorize -debug-only=loop-vectorize \
 ; RUN: -prefer-inloop-reductions \
 ; RUN: -force-tail-folding-style=data-with-evl \
 ; RUN: -prefer-predicate-over-epilogue=predicate-dont-vectorize \
-; RUN: -mtriple=riscv64 -mattr=+v -riscv-v-vector-bits-max=128 -disable-output < %s 2>&1 | FileCheck --check-prefixes=IF-EVL-INLOOP %s
+; RUN: -mtriple=riscv64 -mattr=+v -riscv-v-vector-bits-max=128 -disable-output < %s 2>&1 | FileCheck --check-prefixes=IF-EVL-INLOOP,IF-EVL %s
 
 ; RUN: opt -passes=loop-vectorize -debug-only=loop-vectorize \
 ; RUN: -force-tail-folding-style=none \
@@ -24,6 +24,9 @@
 
 
 define i32 @reduction(ptr %a, i64 %n, i32 %start) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; IF-EVL-NOT: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
+
 ; IF-EVL-OUTLOOP: VPlan 'Initial VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
 ; IF-EVL-OUTLOOP-NEXT: Live-in vp<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-OUTLOOP-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics.ll b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics.ll
index 706b6f88829848..e64ea387d4582c 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-intrinsics.ll
@@ -11,6 +11,9 @@
 ; RUN: -mtriple=riscv64 -mattr=+v -riscv-v-vector-bits-max=128 -disable-output < %s 2>&1 | FileCheck --check-prefixes=NO-VP,CHECK %s
 
 define void @foo(ptr noalias %a, ptr noalias %b, ptr noalias %c, i64 %N) {
+; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+; 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<[[VFUF:%[0-9]+]]> = VF * UF
 ; IF-EVL-NEXT: Live-in vp<[[VTC:%[0-9]+]]> = vector-trip-count
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-select-intrinsics.ll b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-select-intrinsics.ll
index 53c9fb0c604daa..90de5b6bfd1d3d 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-select-intrinsics.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/vplan-vp-select-intrinsics.ll
@@ -6,6 +6,11 @@
  ; RUN: -mtriple=riscv64 -mattr=+v -riscv-v-vector-bits-max=128 -disable-output < %s 2>&1 | FileCheck --check-prefix=IF-EVL %s
 
  define void @vp_select(ptr noalias %a, ptr noalias %b, ptr noalias %c, i64 %N) {
+ ; IF-EVL: VPlan 'Initial VPlan for VF={1},UF>=1'
+ ; 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: EXPLICIT-VECTOR-LENGTH-BASED-IV-PHI
+ ;
  ; IF-EVL: VPlan 'Final VPlan for VF={vscale x 1,vscale x 2,vscale x 4},UF={1}' {
  ; IF-EVL-NEXT: Live-in ir<[[VFUF:%.+]]> = VF * UF
  ; IF-EVL-NEXT: Live-in ir<[[VTC:%.+]]> = vector-trip-count

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

alexey-bataev · 2025-02-03T14:01:54Z

Better to modify setTailFoldingStyles() and add a check to bool EVLIsLegal:

bool EVLIsLegal = IsScalableVF && UserIC <= 1 && ...

which was removed accidentally

…h scalar VF. NFC (#125499) Pre-commit for #125497.

Mel-Chen · 2025-02-04T12:59:18Z

Better to modify setTailFoldingStyles() and add a check to bool EVLIsLegal:
bool EVLIsLegal = IsScalableVF && UserIC <= 1 && ...
which was removed accidentally

It looks like another issue. I fixed it at #125678.

alexey-bataev

LG

lukel97

LGTM

lukel97 · 2025-02-04T15:20:17Z

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -8933,14 +8933,15 @@ void LoopVectorizationPlanner::buildVPlansWithVPRecipes(ElementCount MinVF,
  for (ElementCount VF = MinVF; ElementCount::isKnownLT(VF, MaxVFTimes2);) {
    VFRange SubRange = {VF, MaxVFTimes2};
    if (auto Plan = tryToBuildVPlanWithVPRecipes(SubRange)) {
+      bool HasScalarVF = Plan->hasVF(ElementCount::getFixed(1));


Is it possible to have a plan with both scalar and non scalar VFs? Could we use Plan->hasScalarVFOnly()

I think there's nothing that completely rules it out at the moment, but I couldn't find a test case, although some of the unit tests did have such plans. I'll look a bit more, but for now probably best to be conservative and keep it as is.

fhahn

LGTM, thanks

fhahn · 2025-02-04T21:46:34Z

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -8933,14 +8933,15 @@ void LoopVectorizationPlanner::buildVPlansWithVPRecipes(ElementCount MinVF,
  for (ElementCount VF = MinVF; ElementCount::isKnownLT(VF, MaxVFTimes2);) {
    VFRange SubRange = {VF, MaxVFTimes2};
    if (auto Plan = tryToBuildVPlanWithVPRecipes(SubRange)) {
+      bool HasScalarVF = Plan->hasVF(ElementCount::getFixed(1));


I think there's nothing that completely rules it out at the moment, but I couldn't find a test case, although some of the unit tests did have such plans. I'll look a bit more, but for now probably best to be conservative and keep it as is.

…h scalar VF. NFC (llvm#125499) Pre-commit for llvm#125497.

…lvm#125497) The plans with scalar VF should not be transformed the plans folded by EVL. TODO: Move the scalar VF checking into `LoopVectorizationCostModel ::foldTailWithEVL()`.

Mel-Chen requested review from fhahn, lukel97, arcbbb, alexey-bataev, ayalz and david-arm February 3, 2025 13:50

llvmbot added vectorizers llvm:transforms labels Feb 3, 2025

Mel-Chen mentioned this pull request Feb 3, 2025

[LV][EVL] Pre-commit test cases for preventing to transform plans with scalar VF. NFC #125499

Merged

david-arm reviewed Feb 3, 2025

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llvm/lib/Transforms/Vectorize/LoopVectorize.cpp Outdated Show resolved Hide resolved

Mel-Chen added a commit that referenced this pull request Feb 4, 2025

[LV][EVL] Pre-commit test cases for preventing to transform plans wit…

b9fa35f

…h scalar VF. NFC (#125499) Pre-commit for #125497.

Mel-Chen added 2 commits February 4, 2025 01:24

[LV][EVL] Skip tryAddExplicitVectorLength for plans with scalar VF

3ec0118

Extract the scalar vf checking

1524daf

Mel-Chen force-pushed the evl-scalar-vf branch from 91cc51c to 1524daf Compare February 4, 2025 12:36

Mel-Chen requested a review from david-arm February 4, 2025 12:57

alexey-bataev approved these changes Feb 4, 2025

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lukel97 approved these changes Feb 4, 2025

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fhahn approved these changes Feb 4, 2025

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Mel-Chen merged commit 8d037b9 into llvm:main Feb 5, 2025
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Icohedron pushed a commit to Icohedron/llvm-project that referenced this pull request Feb 11, 2025

[LV][EVL] Pre-commit test cases for preventing to transform plans wit…

90cd054

…h scalar VF. NFC (llvm#125499) Pre-commit for llvm#125497.

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[LV][EVL] Skip tryAddExplicitVectorLength for plans with scalar VF. #125497

[LV][EVL] Skip tryAddExplicitVectorLength for plans with scalar VF. #125497

Mel-Chen commented Feb 3, 2025

llvmbot commented Feb 3, 2025 •

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fhahn Feb 4, 2025

[LV][EVL] Skip tryAddExplicitVectorLength for plans with scalar VF. #125497

[LV][EVL] Skip tryAddExplicitVectorLength for plans with scalar VF. #125497

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Mel-Chen commented Feb 3, 2025

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llvmbot commented Feb 3, 2025 •

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