[llvm] b7a8d95 - [VectorCombine] Combine scalar fneg with insert/extract to vector fneg when length is different (#115209)
via llvm-commits
llvm-commits at lists.llvm.org
Tue Dec 17 23:47:45 PST 2024
Author: hanbeom
Date: 2024-12-18T07:47:42Z
New Revision: b7a8d9584c787b95ddf6931e915fb643b28f91e1
URL: https://github.com/llvm/llvm-project/commit/b7a8d9584c787b95ddf6931e915fb643b28f91e1
DIFF: https://github.com/llvm/llvm-project/commit/b7a8d9584c787b95ddf6931e915fb643b28f91e1.diff
LOG: [VectorCombine] Combine scalar fneg with insert/extract to vector fneg when length is different (#115209)
insertelt DestVec, (fneg (extractelt SrcVec, Index)), Index
-> shuffle DestVec, (shuffle (fneg SrcVec), poison, SrcMask), Mask
Original combining left the combine between vectors of different lengths as a TODO.
Added:
Modified:
llvm/lib/Transforms/Vectorize/VectorCombine.cpp
llvm/test/Transforms/VectorCombine/X86/extract-fneg-insert.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
index 791006c48b5ddf..5254fab1cdc914 100644
--- a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
+++ b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
@@ -666,9 +666,10 @@ bool VectorCombine::foldInsExtFNeg(Instruction &I) {
m_ExtractElt(m_Value(SrcVec), m_SpecificInt(Index))))))
return false;
- // TODO: We could handle this with a length-changing shuffle.
auto *VecTy = cast<FixedVectorType>(I.getType());
- if (SrcVec->getType() != VecTy)
+ auto *ScalarTy = VecTy->getScalarType();
+ auto *SrcVecTy = dyn_cast<FixedVectorType>(SrcVec->getType());
+ if (!SrcVecTy || ScalarTy != SrcVecTy->getScalarType())
return false;
// Ignore bogus insert/extract index.
@@ -682,8 +683,6 @@ bool VectorCombine::foldInsExtFNeg(Instruction &I) {
SmallVector<int> Mask(NumElts);
std::iota(Mask.begin(), Mask.end(), 0);
Mask[Index] = Index + NumElts;
-
- Type *ScalarTy = VecTy->getScalarType();
InstructionCost OldCost =
TTI.getArithmeticInstrCost(Instruction::FNeg, ScalarTy, CostKind) +
TTI.getVectorInstrCost(I, VecTy, CostKind, Index);
@@ -698,14 +697,33 @@ bool VectorCombine::foldInsExtFNeg(Instruction &I) {
TTI.getArithmeticInstrCost(Instruction::FNeg, VecTy, CostKind) +
TTI.getShuffleCost(TargetTransformInfo::SK_Select, VecTy, Mask, CostKind);
+ bool NeedLenChg = SrcVecTy->getNumElements() != NumElts;
+ // If the lengths of the two vectors are not equal,
+ // we need to add a length-change vector. Add this cost.
+ SmallVector<int> SrcMask;
+ if (NeedLenChg) {
+ SrcMask.assign(NumElts, PoisonMaskElem);
+ SrcMask[Index] = Index;
+ NewCost += TTI.getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc,
+ SrcVecTy, SrcMask, CostKind);
+ }
+
if (NewCost > OldCost)
return false;
- // insertelt DestVec, (fneg (extractelt SrcVec, Index)), Index -->
- // shuffle DestVec, (fneg SrcVec), Mask
+ Value *NewShuf;
+ // insertelt DestVec, (fneg (extractelt SrcVec, Index)), Index
Value *VecFNeg = Builder.CreateFNegFMF(SrcVec, FNeg);
- Value *Shuf = Builder.CreateShuffleVector(DestVec, VecFNeg, Mask);
- replaceValue(I, *Shuf);
+ if (NeedLenChg) {
+ // shuffle DestVec, (shuffle (fneg SrcVec), poison, SrcMask), Mask
+ Value *LenChgShuf = Builder.CreateShuffleVector(SrcVec, SrcMask);
+ NewShuf = Builder.CreateShuffleVector(DestVec, LenChgShuf, Mask);
+ } else {
+ // shuffle DestVec, (fneg SrcVec), Mask
+ NewShuf = Builder.CreateShuffleVector(DestVec, VecFNeg, Mask);
+ }
+
+ replaceValue(I, *NewShuf);
return true;
}
diff --git a/llvm/test/Transforms/VectorCombine/X86/extract-fneg-insert.ll b/llvm/test/Transforms/VectorCombine/X86/extract-fneg-insert.ll
index df5fcdb7beb656..83f94ba46a072f 100644
--- a/llvm/test/Transforms/VectorCombine/X86/extract-fneg-insert.ll
+++ b/llvm/test/Transforms/VectorCombine/X86/extract-fneg-insert.ll
@@ -18,6 +18,19 @@ define <4 x float> @ext0_v4f32(<4 x float> %x, <4 x float> %y) {
ret <4 x float> %r
}
+define <4 x float> @ext0_v2f32v4f32(<2 x float> %x, <4 x float> %y) {
+; CHECK-LABEL: @ext0_v2f32v4f32(
+; CHECK-NEXT: [[E:%.*]] = extractelement <2 x float> [[X:%.*]], i32 0
+; CHECK-NEXT: [[N:%.*]] = fneg float [[E]]
+; CHECK-NEXT: [[R:%.*]] = insertelement <4 x float> [[Y:%.*]], float [[N]], i32 0
+; CHECK-NEXT: ret <4 x float> [[R]]
+;
+ %e = extractelement <2 x float> %x, i32 0
+ %n = fneg float %e
+ %r = insertelement <4 x float> %y, float %n, i32 0
+ ret <4 x float> %r
+}
+
; Eliminating extract/insert is profitable.
define <4 x float> @ext2_v4f32(<4 x float> %x, <4 x float> %y) {
@@ -32,6 +45,19 @@ define <4 x float> @ext2_v4f32(<4 x float> %x, <4 x float> %y) {
ret <4 x float> %r
}
+define <4 x float> @ext2_v2f32v4f32(<2 x float> %x, <4 x float> %y) {
+; CHECK-LABEL: @ext2_v2f32v4f32(
+; CHECK-NEXT: [[TMP1:%.*]] = fneg <2 x float> [[X:%.*]]
+; CHECK-NEXT: [[TMP2:%.*]] = shufflevector <2 x float> [[X]], <2 x float> poison, <4 x i32> <i32 poison, i32 poison, i32 2, i32 poison>
+; CHECK-NEXT: [[R:%.*]] = shufflevector <4 x float> [[Y:%.*]], <4 x float> [[TMP2]], <4 x i32> <i32 0, i32 1, i32 6, i32 3>
+; CHECK-NEXT: ret <4 x float> [[R]]
+;
+ %e = extractelement <2 x float> %x, i32 2
+ %n = fneg float %e
+ %r = insertelement <4 x float> %y, float %n, i32 2
+ ret <4 x float> %r
+}
+
; Eliminating extract/insert is still profitable. Flags propagate.
define <2 x double> @ext1_v2f64(<2 x double> %x, <2 x double> %y) {
@@ -46,6 +72,25 @@ define <2 x double> @ext1_v2f64(<2 x double> %x, <2 x double> %y) {
ret <2 x double> %r
}
+define <4 x double> @ext1_v2f64v4f64(<2 x double> %x, <4 x double> %y) {
+; SSE-LABEL: @ext1_v2f64v4f64(
+; SSE-NEXT: [[E:%.*]] = extractelement <2 x double> [[X:%.*]], i32 1
+; SSE-NEXT: [[N:%.*]] = fneg nsz double [[E]]
+; SSE-NEXT: [[R:%.*]] = insertelement <4 x double> [[Y:%.*]], double [[N]], i32 1
+; SSE-NEXT: ret <4 x double> [[R]]
+;
+; AVX-LABEL: @ext1_v2f64v4f64(
+; AVX-NEXT: [[TMP1:%.*]] = fneg nsz <2 x double> [[X:%.*]]
+; AVX-NEXT: [[TMP2:%.*]] = shufflevector <2 x double> [[X]], <2 x double> poison, <4 x i32> <i32 poison, i32 1, i32 poison, i32 poison>
+; AVX-NEXT: [[R:%.*]] = shufflevector <4 x double> [[Y:%.*]], <4 x double> [[TMP2]], <4 x i32> <i32 0, i32 5, i32 2, i32 3>
+; AVX-NEXT: ret <4 x double> [[R]]
+;
+ %e = extractelement <2 x double> %x, i32 1
+ %n = fneg nsz double %e
+ %r = insertelement <4 x double> %y, double %n, i32 1
+ ret <4 x double> %r
+}
+
; The vector fneg would cost twice as much as the scalar op with SSE,
; so we don't transform there (the shuffle would also be more expensive).
@@ -67,6 +112,19 @@ define <8 x float> @ext7_v8f32(<8 x float> %x, <8 x float> %y) {
ret <8 x float> %r
}
+define <8 x float> @ext7_v4f32v8f32(<4 x float> %x, <8 x float> %y) {
+; CHECK-LABEL: @ext7_v4f32v8f32(
+; CHECK-NEXT: [[E:%.*]] = extractelement <4 x float> [[X:%.*]], i32 3
+; CHECK-NEXT: [[N:%.*]] = fneg float [[E]]
+; CHECK-NEXT: [[R:%.*]] = insertelement <8 x float> [[Y:%.*]], float [[N]], i32 7
+; CHECK-NEXT: ret <8 x float> [[R]]
+;
+ %e = extractelement <4 x float> %x, i32 3
+ %n = fneg float %e
+ %r = insertelement <8 x float> %y, float %n, i32 7
+ ret <8 x float> %r
+}
+
; Same as above with an extra use of the extracted element.
define <8 x float> @ext7_v8f32_use1(<8 x float> %x, <8 x float> %y) {
@@ -91,6 +149,21 @@ define <8 x float> @ext7_v8f32_use1(<8 x float> %x, <8 x float> %y) {
ret <8 x float> %r
}
+define <8 x float> @ext7_v4f32v8f32_use1(<4 x float> %x, <8 x float> %y) {
+; CHECK-LABEL: @ext7_v4f32v8f32_use1(
+; CHECK-NEXT: [[E:%.*]] = extractelement <4 x float> [[X:%.*]], i32 3
+; CHECK-NEXT: call void @use(float [[E]])
+; CHECK-NEXT: [[N:%.*]] = fneg float [[E]]
+; CHECK-NEXT: [[R:%.*]] = insertelement <8 x float> [[Y:%.*]], float [[N]], i32 3
+; CHECK-NEXT: ret <8 x float> [[R]]
+;
+ %e = extractelement <4 x float> %x, i32 3
+ call void @use(float %e)
+ %n = fneg float %e
+ %r = insertelement <8 x float> %y, float %n, i32 3
+ ret <8 x float> %r
+}
+
; Negative test - the transform is likely not profitable if the fneg has another use.
define <8 x float> @ext7_v8f32_use2(<8 x float> %x, <8 x float> %y) {
@@ -108,6 +181,21 @@ define <8 x float> @ext7_v8f32_use2(<8 x float> %x, <8 x float> %y) {
ret <8 x float> %r
}
+define <8 x float> @ext7_v4f32v8f32_use2(<4 x float> %x, <8 x float> %y) {
+; CHECK-LABEL: @ext7_v4f32v8f32_use2(
+; CHECK-NEXT: [[E:%.*]] = extractelement <4 x float> [[X:%.*]], i32 3
+; CHECK-NEXT: [[N:%.*]] = fneg float [[E]]
+; CHECK-NEXT: call void @use(float [[N]])
+; CHECK-NEXT: [[R:%.*]] = insertelement <8 x float> [[Y:%.*]], float [[N]], i32 3
+; CHECK-NEXT: ret <8 x float> [[R]]
+;
+ %e = extractelement <4 x float> %x, i32 3
+ %n = fneg float %e
+ call void @use(float %n)
+ %r = insertelement <8 x float> %y, float %n, i32 3
+ ret <8 x float> %r
+}
+
; Negative test - can't convert variable index to a shuffle.
define <2 x double> @ext_index_var_v2f64(<2 x double> %x, <2 x double> %y, i32 %index) {
@@ -123,6 +211,19 @@ define <2 x double> @ext_index_var_v2f64(<2 x double> %x, <2 x double> %y, i32 %
ret <2 x double> %r
}
+define <4 x double> @ext_index_var_v2f64v4f64(<2 x double> %x, <4 x double> %y, i32 %index) {
+; CHECK-LABEL: @ext_index_var_v2f64v4f64(
+; CHECK-NEXT: [[E:%.*]] = extractelement <2 x double> [[X:%.*]], i32 [[INDEX:%.*]]
+; CHECK-NEXT: [[N:%.*]] = fneg nsz double [[E]]
+; CHECK-NEXT: [[R:%.*]] = insertelement <4 x double> [[Y:%.*]], double [[N]], i32 [[INDEX]]
+; CHECK-NEXT: ret <4 x double> [[R]]
+;
+ %e = extractelement <2 x double> %x, i32 %index
+ %n = fneg nsz double %e
+ %r = insertelement <4 x double> %y, double %n, i32 %index
+ ret <4 x double> %r
+}
+
; Negative test - require same extract/insert index for simple shuffle.
; TODO: We could handle this by adjusting the cost calculation.
@@ -139,6 +240,33 @@ define <2 x double> @ext1_v2f64_ins0(<2 x double> %x, <2 x double> %y) {
ret <2 x double> %r
}
+; Negative test - extract from an index greater than the vector width of the destination
+define <2 x double> @ext3_v4f64v2f64(<4 x double> %x, <2 x double> %y) {
+; CHECK-LABEL: @ext3_v4f64v2f64(
+; CHECK-NEXT: [[E:%.*]] = extractelement <4 x double> [[X:%.*]], i32 3
+; CHECK-NEXT: [[N:%.*]] = fneg nsz double [[E]]
+; CHECK-NEXT: [[R:%.*]] = insertelement <2 x double> [[Y:%.*]], double [[N]], i32 1
+; CHECK-NEXT: ret <2 x double> [[R]]
+;
+ %e = extractelement <4 x double> %x, i32 3
+ %n = fneg nsz double %e
+ %r = insertelement <2 x double> %y, double %n, i32 1
+ ret <2 x double> %r
+}
+
+define <4 x double> @ext1_v2f64v4f64_ins0(<2 x double> %x, <4 x double> %y) {
+; CHECK-LABEL: @ext1_v2f64v4f64_ins0(
+; CHECK-NEXT: [[E:%.*]] = extractelement <2 x double> [[X:%.*]], i32 1
+; CHECK-NEXT: [[N:%.*]] = fneg nsz double [[E]]
+; CHECK-NEXT: [[R:%.*]] = insertelement <4 x double> [[Y:%.*]], double [[N]], i32 0
+; CHECK-NEXT: ret <4 x double> [[R]]
+;
+ %e = extractelement <2 x double> %x, i32 1
+ %n = fneg nsz double %e
+ %r = insertelement <4 x double> %y, double %n, i32 0
+ ret <4 x double> %r
+}
+
; Negative test - avoid changing poison ops
define <4 x float> @ext12_v4f32(<4 x float> %x, <4 x float> %y) {
@@ -154,6 +282,19 @@ define <4 x float> @ext12_v4f32(<4 x float> %x, <4 x float> %y) {
ret <4 x float> %r
}
+define <4 x float> @ext12_v2f32v4f32(<2 x float> %x, <4 x float> %y) {
+; CHECK-LABEL: @ext12_v2f32v4f32(
+; CHECK-NEXT: [[E:%.*]] = extractelement <2 x float> [[X:%.*]], i32 6
+; CHECK-NEXT: [[N:%.*]] = fneg float [[E]]
+; CHECK-NEXT: [[R:%.*]] = insertelement <4 x float> [[Y:%.*]], float [[N]], i32 12
+; CHECK-NEXT: ret <4 x float> [[R]]
+;
+ %e = extractelement <2 x float> %x, i32 6
+ %n = fneg float %e
+ %r = insertelement <4 x float> %y, float %n, i32 12
+ ret <4 x float> %r
+}
+
; This used to crash because we assumed matching a true, unary fneg instruction.
define <2 x float> @ext1_v2f32_fsub(<2 x float> %x) {
@@ -181,3 +322,16 @@ define <2 x float> @ext1_v2f32_fsub_fmf(<2 x float> %x, <2 x float> %y) {
%r = insertelement <2 x float> %y, float %s, i32 1
ret <2 x float> %r
}
+
+define <4 x float> @ext1_v2f32v4f32_fsub_fmf(<2 x float> %x, <4 x float> %y) {
+; CHECK-LABEL: @ext1_v2f32v4f32_fsub_fmf(
+; CHECK-NEXT: [[TMP1:%.*]] = fneg nnan nsz <2 x float> [[X:%.*]]
+; CHECK-NEXT: [[TMP2:%.*]] = shufflevector <2 x float> [[X]], <2 x float> poison, <4 x i32> <i32 poison, i32 1, i32 poison, i32 poison>
+; CHECK-NEXT: [[R:%.*]] = shufflevector <4 x float> [[Y:%.*]], <4 x float> [[TMP2]], <4 x i32> <i32 0, i32 5, i32 2, i32 3>
+; CHECK-NEXT: ret <4 x float> [[R]]
+;
+ %e = extractelement <2 x float> %x, i32 1
+ %s = fsub nsz nnan float 0.0, %e
+ %r = insertelement <4 x float> %y, float %s, i32 1
+ ret <4 x float> %r
+}
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