[llvm] b331a7e - [InstCombine] canonicalize fneg after shuffle
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Fri May 6 13:30:35 PDT 2022
Author: Sanjay Patel
Date: 2022-05-06T16:30:26-04:00
New Revision: b331a7ebc1e02f9939d1a4a1509e7eb6cdda3d38
URL: https://github.com/llvm/llvm-project/commit/b331a7ebc1e02f9939d1a4a1509e7eb6cdda3d38
DIFF: https://github.com/llvm/llvm-project/commit/b331a7ebc1e02f9939d1a4a1509e7eb6cdda3d38.diff
LOG: [InstCombine] canonicalize fneg after shuffle
For the unary shuffle pattern, this is opposite to what we try
to do with binops, but it seems better to keep it consistent
with the motivating binary shuffle pattern. On that, it is
clearly better on the usual no-extra uses case.
There is a chance that this will pull an fneg away from some
other binop and cause a regression in codegen, but that should
be invertible in the backend. The transform is birectional:
https://alive2.llvm.org/ce/z/kKaKCU
https://alive2.llvm.org/ce/z/3Desfw
Fixes #45631
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
llvm/test/Transforms/InstCombine/vec_shuffle-inseltpoison.ll
llvm/test/Transforms/InstCombine/vec_shuffle.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
index 066fbbaaaaa86..8908739b37727 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -2242,6 +2242,39 @@ static Instruction *narrowVectorSelect(ShuffleVectorInst &Shuf,
return SelectInst::Create(NarrowCond, NarrowX, NarrowY);
}
+/// Canonicalize FP negate after shuffle.
+static Instruction *foldFNegShuffle(ShuffleVectorInst &Shuf,
+ InstCombiner::BuilderTy &Builder) {
+ Instruction *FNeg0;
+ Value *X;
+ if (!match(Shuf.getOperand(0), m_CombineAnd(m_Instruction(FNeg0),
+ m_FNeg(m_Value(X)))))
+ return nullptr;
+
+ // shuffle (fneg X), Mask --> fneg (shuffle X, Mask)
+ if (FNeg0->hasOneUse() && match(Shuf.getOperand(1), m_Undef())) {
+ Value *NewShuf = Builder.CreateShuffleVector(X, Shuf.getShuffleMask());
+ return UnaryOperator::CreateFNegFMF(NewShuf, FNeg0);
+ }
+
+ Instruction *FNeg1;
+ Value *Y;
+ if (!match(Shuf.getOperand(1), m_CombineAnd(m_Instruction(FNeg1),
+ m_FNeg(m_Value(Y)))))
+ return nullptr;
+
+ // shuffle (fneg X), (fneg Y), Mask --> fneg (shuffle X, Y, Mask)
+ if (FNeg0->hasOneUse() || FNeg1->hasOneUse()) {
+ Value *NewShuf = Builder.CreateShuffleVector(X, Y, Shuf.getShuffleMask());
+ Instruction *NewFNeg = UnaryOperator::CreateFNeg(NewShuf);
+ NewFNeg->copyIRFlags(FNeg0);
+ NewFNeg->andIRFlags(FNeg1);
+ return NewFNeg;
+ }
+
+ return nullptr;
+}
+
/// Try to fold an extract subvector operation.
static Instruction *foldIdentityExtractShuffle(ShuffleVectorInst &Shuf) {
Value *Op0 = Shuf.getOperand(0), *Op1 = Shuf.getOperand(1);
@@ -2537,6 +2570,9 @@ Instruction *InstCombinerImpl::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
if (Instruction *I = narrowVectorSelect(SVI, Builder))
return I;
+ if (Instruction *I = foldFNegShuffle(SVI, Builder))
+ return I;
+
APInt UndefElts(VWidth, 0);
APInt AllOnesEltMask(APInt::getAllOnes(VWidth));
if (Value *V = SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
diff --git a/llvm/test/Transforms/InstCombine/vec_shuffle-inseltpoison.ll b/llvm/test/Transforms/InstCombine/vec_shuffle-inseltpoison.ll
index fe57994e37703..00d5cffb08dd0 100644
--- a/llvm/test/Transforms/InstCombine/vec_shuffle-inseltpoison.ll
+++ b/llvm/test/Transforms/InstCombine/vec_shuffle-inseltpoison.ll
@@ -749,8 +749,8 @@ define <8 x i8> @pr19730(<16 x i8> %in0) {
define i32 @pr19737(<4 x i32> %in0) {
; CHECK-LABEL: @pr19737(
-; CHECK-NEXT: [[RV:%.*]] = extractelement <4 x i32> [[IN0:%.*]], i64 0
-; CHECK-NEXT: ret i32 [[RV]]
+; CHECK-NEXT: [[TMP1:%.*]] = extractelement <4 x i32> [[IN0:%.*]], i64 0
+; CHECK-NEXT: ret i32 [[TMP1]]
;
%shuffle.i = shufflevector <4 x i32> zeroinitializer, <4 x i32> %in0, <4 x i32> <i32 0, i32 4, i32 2, i32 6>
%neg.i = xor <4 x i32> %shuffle.i, <i32 -1, i32 -1, i32 -1, i32 -1>
@@ -1277,8 +1277,8 @@ define <2 x float> @fsub_splat_constant1(<2 x float> %x) {
define <2 x float> @fneg(<2 x float> %x) {
; CHECK-LABEL: @fneg(
-; CHECK-NEXT: [[TMP1:%.*]] = fneg <2 x float> [[X:%.*]]
-; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <2 x float> [[X:%.*]], <2 x float> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT: [[R:%.*]] = fneg <2 x float> [[TMP1]]
; CHECK-NEXT: ret <2 x float> [[R]]
;
%splat = shufflevector <2 x float> %x, <2 x float> poison, <2 x i32> zeroinitializer
diff --git a/llvm/test/Transforms/InstCombine/vec_shuffle.ll b/llvm/test/Transforms/InstCombine/vec_shuffle.ll
index 0a556642a77a6..32a02a73cf6c6 100644
--- a/llvm/test/Transforms/InstCombine/vec_shuffle.ll
+++ b/llvm/test/Transforms/InstCombine/vec_shuffle.ll
@@ -1278,8 +1278,8 @@ define <2 x float> @fsub_splat_constant1(<2 x float> %x) {
define <2 x float> @fneg(<2 x float> %x) {
; CHECK-LABEL: @fneg(
-; CHECK-NEXT: [[TMP1:%.*]] = fneg <2 x float> [[X:%.*]]
-; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <2 x float> [[X:%.*]], <2 x float> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT: [[R:%.*]] = fneg <2 x float> [[TMP1]]
; CHECK-NEXT: ret <2 x float> [[R]]
;
%splat = shufflevector <2 x float> %x, <2 x float> undef, <2 x i32> zeroinitializer
@@ -1791,8 +1791,8 @@ define <4 x i32> @PR46872(<4 x i32> %x) {
define <2 x float> @fneg_unary_shuf(<2 x float> %x) {
; CHECK-LABEL: @fneg_unary_shuf(
-; CHECK-NEXT: [[NX:%.*]] = fneg nnan nsz <2 x float> [[X:%.*]]
-; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[NX]], <2 x float> poison, <2 x i32> <i32 1, i32 0>
+; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <2 x float> [[X:%.*]], <2 x float> poison, <2 x i32> <i32 1, i32 0>
+; CHECK-NEXT: [[R:%.*]] = fneg nnan nsz <2 x float> [[TMP1]]
; CHECK-NEXT: ret <2 x float> [[R]]
;
%nx = fneg nsz nnan <2 x float> %x
@@ -1802,8 +1802,8 @@ define <2 x float> @fneg_unary_shuf(<2 x float> %x) {
define <4 x half> @fneg_unary_shuf_widen(<2 x half> %x) {
; CHECK-LABEL: @fneg_unary_shuf_widen(
-; CHECK-NEXT: [[NX:%.*]] = fneg ninf <2 x half> [[X:%.*]]
-; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x half> [[NX]], <2 x half> poison, <4 x i32> <i32 1, i32 0, i32 0, i32 undef>
+; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <2 x half> [[X:%.*]], <2 x half> poison, <4 x i32> <i32 1, i32 0, i32 0, i32 undef>
+; CHECK-NEXT: [[R:%.*]] = fneg ninf <4 x half> [[TMP1]]
; CHECK-NEXT: ret <4 x half> [[R]]
;
%nx = fneg ninf <2 x half> %x
@@ -1813,8 +1813,8 @@ define <4 x half> @fneg_unary_shuf_widen(<2 x half> %x) {
define <2 x double> @fneg_unary_shuf_narrow(<4 x double> %x) {
; CHECK-LABEL: @fneg_unary_shuf_narrow(
-; CHECK-NEXT: [[NX:%.*]] = fneg nsz <4 x double> [[X:%.*]]
-; CHECK-NEXT: [[R:%.*]] = shufflevector <4 x double> [[NX]], <4 x double> poison, <2 x i32> <i32 3, i32 0>
+; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <4 x double> [[X:%.*]], <4 x double> poison, <2 x i32> <i32 3, i32 0>
+; CHECK-NEXT: [[R:%.*]] = fneg nsz <2 x double> [[TMP1]]
; CHECK-NEXT: ret <2 x double> [[R]]
;
%nx = fneg nsz <4 x double> %x
@@ -1822,6 +1822,8 @@ define <2 x double> @fneg_unary_shuf_narrow(<4 x double> %x) {
ret <2 x double> %r
}
+; negative test - extra use prevents canonicalization
+
define <2 x float> @fneg_unary_shuf_use(<2 x float> %x) {
; CHECK-LABEL: @fneg_unary_shuf_use(
; CHECK-NEXT: [[NX:%.*]] = fneg nsz <2 x float> [[X:%.*]]
@@ -1835,11 +1837,12 @@ define <2 x float> @fneg_unary_shuf_use(<2 x float> %x) {
ret <2 x float> %r
}
+; intersect FMF
+
define <4 x float> @fneg_shuf(<4 x float> %x, <4 x float> %y) {
; CHECK-LABEL: @fneg_shuf(
-; CHECK-NEXT: [[NX:%.*]] = fneg ninf nsz <4 x float> [[X:%.*]]
-; CHECK-NEXT: [[NY:%.*]] = fneg nnan ninf <4 x float> [[Y:%.*]]
-; CHECK-NEXT: [[R:%.*]] = shufflevector <4 x float> [[NX]], <4 x float> [[NY]], <4 x i32> <i32 0, i32 1, i32 4, i32 5>
+; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <4 x float> [[X:%.*]], <4 x float> [[Y:%.*]], <4 x i32> <i32 0, i32 1, i32 4, i32 5>
+; CHECK-NEXT: [[R:%.*]] = fneg ninf <4 x float> [[TMP1]]
; CHECK-NEXT: ret <4 x float> [[R]]
;
%nx = fneg nsz ninf <4 x float> %x
@@ -1848,12 +1851,14 @@ define <4 x float> @fneg_shuf(<4 x float> %x, <4 x float> %y) {
ret <4 x float> %r
}
+; length-changing shuffle and extra use are ok
+
define <4 x float> @fneg_shuf_widen_use1(<2 x float> %x, <2 x float> %y) {
; CHECK-LABEL: @fneg_shuf_widen_use1(
; CHECK-NEXT: [[NX:%.*]] = fneg nnan <2 x float> [[X:%.*]]
; CHECK-NEXT: call void @use(<2 x float> [[NX]])
-; CHECK-NEXT: [[NY:%.*]] = fneg nnan <2 x float> [[Y:%.*]]
-; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[NX]], <2 x float> [[NY]], <4 x i32> <i32 undef, i32 1, i32 2, i32 3>
+; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <2 x float> [[X]], <2 x float> [[Y:%.*]], <4 x i32> <i32 undef, i32 1, i32 2, i32 3>
+; CHECK-NEXT: [[R:%.*]] = fneg nnan <4 x float> [[TMP1]]
; CHECK-NEXT: ret <4 x float> [[R]]
;
%nx = fneg nnan <2 x float> %x
@@ -1863,12 +1868,14 @@ define <4 x float> @fneg_shuf_widen_use1(<2 x float> %x, <2 x float> %y) {
ret <4 x float> %r
}
+; length-changing shuffle and extra use still ok
+
define <2 x float> @fneg_shuf_narrow_use2(<4 x float> %x, <4 x float> %y) {
; CHECK-LABEL: @fneg_shuf_narrow_use2(
-; CHECK-NEXT: [[NX:%.*]] = fneg nnan nsz <4 x float> [[X:%.*]]
; CHECK-NEXT: [[NY:%.*]] = fneg nnan nsz <4 x float> [[Y:%.*]]
; CHECK-NEXT: call void @use4(<4 x float> [[NY]])
-; CHECK-NEXT: [[R:%.*]] = shufflevector <4 x float> [[NX]], <4 x float> [[NY]], <2 x i32> <i32 3, i32 5>
+; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <4 x float> [[X:%.*]], <4 x float> [[Y]], <2 x i32> <i32 3, i32 5>
+; CHECK-NEXT: [[R:%.*]] = fneg nnan nsz <2 x float> [[TMP1]]
; CHECK-NEXT: ret <2 x float> [[R]]
;
%nx = fneg nsz nnan <4 x float> %x
@@ -1878,6 +1885,8 @@ define <2 x float> @fneg_shuf_narrow_use2(<4 x float> %x, <4 x float> %y) {
ret <2 x float> %r
}
+; negative test - too many extra uses
+
define <2 x float> @fneg_shuf_use3(<2 x float> %x, <2 x float> %y) {
; CHECK-LABEL: @fneg_shuf_use3(
; CHECK-NEXT: [[NX:%.*]] = fneg nnan <2 x float> [[X:%.*]]
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