[VectorCombine] foldShuffleToIdentity - peek through bitcasts to see if they come from the same value to form identity sequence #98334
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@llvm/pr-subscribers-llvm-transforms Author: Simon Pilgrim (RKSimon) ChangesWorkaround until I can get #96884 fixed properly - when trying to find identity sequences, peek through any bitcasts to see if the values all came from the same source. We don't run CSE frequently enough to merge all the bitcasts that we end up with. Full diff: https://github.com/llvm/llvm-project/pull/98334.diff 2 Files Affected:
diff --git a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
index 4896b8ed2595b..3a49f95d3f117 100644
--- a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
+++ b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
@@ -1859,13 +1859,19 @@ bool VectorCombine::foldShuffleToIdentity(Instruction &I) {
if (!FrontU)
return false;
+ // Helper to peek through bitcasts to the same value.
+ auto IsEquiv = [&](Value *X, Value *Y) {
+ return X->getType() == Y->getType() &&
+ peekThroughBitcasts(X) == peekThroughBitcasts(Y);
+ };
+
// Look for an identity value.
if (FrontLane == 0 &&
cast<FixedVectorType>(FrontU->get()->getType())->getNumElements() ==
Ty->getNumElements() &&
- all_of(drop_begin(enumerate(Item)), [Item](const auto &E) {
+ all_of(drop_begin(enumerate(Item)), [IsEquiv, Item](const auto &E) {
Value *FrontV = Item.front().first->get();
- return !E.value().first || (E.value().first->get() == FrontV &&
+ return !E.value().first || (IsEquiv(E.value().first->get(), FrontV) &&
E.value().second == (int)E.index());
})) {
IdentityLeafs.insert(FrontU);
diff --git a/llvm/test/Transforms/PhaseOrdering/X86/blendv-select.ll b/llvm/test/Transforms/PhaseOrdering/X86/blendv-select.ll
index 011d51600b51f..c2ed7b9c84523 100644
--- a/llvm/test/Transforms/PhaseOrdering/X86/blendv-select.ll
+++ b/llvm/test/Transforms/PhaseOrdering/X86/blendv-select.ll
@@ -88,20 +88,10 @@ define <4 x i64> @x86_pblendvb_v8i32_v4i32(<4 x i64> %a, <4 x i64> %b, <4 x i64>
; CHECK-NEXT: [[C_BC:%.*]] = bitcast <4 x i64> [[C:%.*]] to <8 x i32>
; CHECK-NEXT: [[D_BC:%.*]] = bitcast <4 x i64> [[D:%.*]] to <8 x i32>
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <8 x i32> [[C_BC]], [[D_BC]]
-; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <8 x i1> [[CMP]], <8 x i1> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
-; CHECK-NEXT: [[TMP2:%.*]] = bitcast <4 x i64> [[A:%.*]] to <8 x i32>
-; CHECK-NEXT: [[TMP3:%.*]] = shufflevector <8 x i32> [[TMP2]], <8 x i32> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
-; CHECK-NEXT: [[TMP4:%.*]] = bitcast <4 x i64> [[B:%.*]] to <8 x i32>
-; CHECK-NEXT: [[TMP5:%.*]] = shufflevector <8 x i32> [[TMP4]], <8 x i32> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
-; CHECK-NEXT: [[TMP6:%.*]] = select <4 x i1> [[TMP1]], <4 x i32> [[TMP5]], <4 x i32> [[TMP3]]
-; CHECK-NEXT: [[TMP7:%.*]] = shufflevector <8 x i1> [[CMP]], <8 x i1> poison, <4 x i32> <i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP8:%.*]] = bitcast <4 x i64> [[A]] to <8 x i32>
-; CHECK-NEXT: [[TMP9:%.*]] = shufflevector <8 x i32> [[TMP8]], <8 x i32> poison, <4 x i32> <i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP10:%.*]] = bitcast <4 x i64> [[B]] to <8 x i32>
-; CHECK-NEXT: [[TMP11:%.*]] = shufflevector <8 x i32> [[TMP10]], <8 x i32> poison, <4 x i32> <i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP12:%.*]] = select <4 x i1> [[TMP7]], <4 x i32> [[TMP11]], <4 x i32> [[TMP9]]
-; CHECK-NEXT: [[TMP13:%.*]] = shufflevector <4 x i32> [[TMP6]], <4 x i32> [[TMP12]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[RES:%.*]] = bitcast <8 x i32> [[TMP13]] to <4 x i64>
+; CHECK-NEXT: [[TMP1:%.*]] = bitcast <4 x i64> [[A:%.*]] to <8 x i32>
+; CHECK-NEXT: [[TMP2:%.*]] = bitcast <4 x i64> [[B:%.*]] to <8 x i32>
+; CHECK-NEXT: [[TMP3:%.*]] = select <8 x i1> [[CMP]], <8 x i32> [[TMP2]], <8 x i32> [[TMP1]]
+; CHECK-NEXT: [[RES:%.*]] = bitcast <8 x i32> [[TMP3]] to <4 x i64>
; CHECK-NEXT: ret <4 x i64> [[RES]]
;
%a.bc = bitcast <4 x i64> %a to <32 x i8>
@@ -129,20 +119,10 @@ define <4 x i64> @x86_pblendvb_v16i16_v8i16(<4 x i64> %a, <4 x i64> %b, <4 x i64
; CHECK-NEXT: [[C_BC:%.*]] = bitcast <4 x i64> [[C:%.*]] to <16 x i16>
; CHECK-NEXT: [[D_BC:%.*]] = bitcast <4 x i64> [[D:%.*]] to <16 x i16>
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <16 x i16> [[C_BC]], [[D_BC]]
-; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <16 x i1> [[CMP]], <16 x i1> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP2:%.*]] = bitcast <4 x i64> [[A:%.*]] to <16 x i16>
-; CHECK-NEXT: [[TMP3:%.*]] = shufflevector <16 x i16> [[TMP2]], <16 x i16> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP4:%.*]] = bitcast <4 x i64> [[B:%.*]] to <16 x i16>
-; CHECK-NEXT: [[TMP5:%.*]] = shufflevector <16 x i16> [[TMP4]], <16 x i16> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP6:%.*]] = select <8 x i1> [[TMP1]], <8 x i16> [[TMP5]], <8 x i16> [[TMP3]]
-; CHECK-NEXT: [[TMP7:%.*]] = shufflevector <16 x i1> [[CMP]], <16 x i1> poison, <8 x i32> <i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[TMP8:%.*]] = bitcast <4 x i64> [[A]] to <16 x i16>
-; CHECK-NEXT: [[TMP9:%.*]] = shufflevector <16 x i16> [[TMP8]], <16 x i16> poison, <8 x i32> <i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[TMP10:%.*]] = bitcast <4 x i64> [[B]] to <16 x i16>
-; CHECK-NEXT: [[TMP11:%.*]] = shufflevector <16 x i16> [[TMP10]], <16 x i16> poison, <8 x i32> <i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[TMP12:%.*]] = select <8 x i1> [[TMP7]], <8 x i16> [[TMP11]], <8 x i16> [[TMP9]]
-; CHECK-NEXT: [[TMP13:%.*]] = shufflevector <8 x i16> [[TMP6]], <8 x i16> [[TMP12]], <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[RES:%.*]] = bitcast <16 x i16> [[TMP13]] to <4 x i64>
+; CHECK-NEXT: [[TMP1:%.*]] = bitcast <4 x i64> [[A:%.*]] to <16 x i16>
+; CHECK-NEXT: [[TMP2:%.*]] = bitcast <4 x i64> [[B:%.*]] to <16 x i16>
+; CHECK-NEXT: [[TMP3:%.*]] = select <16 x i1> [[CMP]], <16 x i16> [[TMP2]], <16 x i16> [[TMP1]]
+; CHECK-NEXT: [[RES:%.*]] = bitcast <16 x i16> [[TMP3]] to <4 x i64>
; CHECK-NEXT: ret <4 x i64> [[RES]]
;
%a.bc = bitcast <4 x i64> %a to <32 x i8>
@@ -276,20 +256,10 @@ define <8 x i64> @x86_pblendvb_v16i32_v8i32(<8 x i64> %a, <8 x i64> %b, <8 x i64
; CHECK-NEXT: [[C_BC:%.*]] = bitcast <8 x i64> [[C:%.*]] to <16 x i32>
; CHECK-NEXT: [[D_BC:%.*]] = bitcast <8 x i64> [[D:%.*]] to <16 x i32>
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <16 x i32> [[C_BC]], [[D_BC]]
-; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <16 x i1> [[CMP]], <16 x i1> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP2:%.*]] = bitcast <8 x i64> [[A:%.*]] to <16 x i32>
-; CHECK-NEXT: [[TMP3:%.*]] = shufflevector <16 x i32> [[TMP2]], <16 x i32> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP4:%.*]] = bitcast <8 x i64> [[B:%.*]] to <16 x i32>
-; CHECK-NEXT: [[TMP5:%.*]] = shufflevector <16 x i32> [[TMP4]], <16 x i32> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP6:%.*]] = select <8 x i1> [[TMP1]], <8 x i32> [[TMP5]], <8 x i32> [[TMP3]]
-; CHECK-NEXT: [[TMP7:%.*]] = shufflevector <16 x i1> [[CMP]], <16 x i1> poison, <8 x i32> <i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[TMP8:%.*]] = bitcast <8 x i64> [[A]] to <16 x i32>
-; CHECK-NEXT: [[TMP9:%.*]] = shufflevector <16 x i32> [[TMP8]], <16 x i32> poison, <8 x i32> <i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[TMP10:%.*]] = bitcast <8 x i64> [[B]] to <16 x i32>
-; CHECK-NEXT: [[TMP11:%.*]] = shufflevector <16 x i32> [[TMP10]], <16 x i32> poison, <8 x i32> <i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[TMP12:%.*]] = select <8 x i1> [[TMP7]], <8 x i32> [[TMP11]], <8 x i32> [[TMP9]]
-; CHECK-NEXT: [[TMP13:%.*]] = shufflevector <8 x i32> [[TMP6]], <8 x i32> [[TMP12]], <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[RES:%.*]] = bitcast <16 x i32> [[TMP13]] to <8 x i64>
+; CHECK-NEXT: [[TMP1:%.*]] = bitcast <8 x i64> [[A:%.*]] to <16 x i32>
+; CHECK-NEXT: [[TMP2:%.*]] = bitcast <8 x i64> [[B:%.*]] to <16 x i32>
+; CHECK-NEXT: [[TMP3:%.*]] = select <16 x i1> [[CMP]], <16 x i32> [[TMP2]], <16 x i32> [[TMP1]]
+; CHECK-NEXT: [[RES:%.*]] = bitcast <16 x i32> [[TMP3]] to <8 x i64>
; CHECK-NEXT: ret <8 x i64> [[RES]]
;
%a.bc = bitcast <8 x i64> %a to <64 x i8>
@@ -317,20 +287,10 @@ define <8 x i64> @x86_pblendvb_v32i16_v16i16(<8 x i64> %a, <8 x i64> %b, <8 x i6
; CHECK-NEXT: [[C_BC:%.*]] = bitcast <8 x i64> [[C:%.*]] to <32 x i16>
; CHECK-NEXT: [[D_BC:%.*]] = bitcast <8 x i64> [[D:%.*]] to <32 x i16>
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <32 x i16> [[C_BC]], [[D_BC]]
-; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <32 x i1> [[CMP]], <32 x i1> poison, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[TMP2:%.*]] = bitcast <8 x i64> [[A:%.*]] to <32 x i16>
-; CHECK-NEXT: [[TMP3:%.*]] = shufflevector <32 x i16> [[TMP2]], <32 x i16> poison, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[TMP4:%.*]] = bitcast <8 x i64> [[B:%.*]] to <32 x i16>
-; CHECK-NEXT: [[TMP5:%.*]] = shufflevector <32 x i16> [[TMP4]], <32 x i16> poison, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT: [[TMP6:%.*]] = select <16 x i1> [[TMP1]], <16 x i16> [[TMP5]], <16 x i16> [[TMP3]]
-; CHECK-NEXT: [[TMP7:%.*]] = shufflevector <32 x i1> [[CMP]], <32 x i1> poison, <16 x i32> <i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31>
-; CHECK-NEXT: [[TMP8:%.*]] = bitcast <8 x i64> [[A]] to <32 x i16>
-; CHECK-NEXT: [[TMP9:%.*]] = shufflevector <32 x i16> [[TMP8]], <32 x i16> poison, <16 x i32> <i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31>
-; CHECK-NEXT: [[TMP10:%.*]] = bitcast <8 x i64> [[B]] to <32 x i16>
-; CHECK-NEXT: [[TMP11:%.*]] = shufflevector <32 x i16> [[TMP10]], <32 x i16> poison, <16 x i32> <i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31>
-; CHECK-NEXT: [[TMP12:%.*]] = select <16 x i1> [[TMP7]], <16 x i16> [[TMP11]], <16 x i16> [[TMP9]]
-; CHECK-NEXT: [[TMP13:%.*]] = shufflevector <16 x i16> [[TMP6]], <16 x i16> [[TMP12]], <32 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31>
-; CHECK-NEXT: [[RES:%.*]] = bitcast <32 x i16> [[TMP13]] to <8 x i64>
+; CHECK-NEXT: [[TMP1:%.*]] = bitcast <8 x i64> [[A:%.*]] to <32 x i16>
+; CHECK-NEXT: [[TMP2:%.*]] = bitcast <8 x i64> [[B:%.*]] to <32 x i16>
+; CHECK-NEXT: [[TMP3:%.*]] = select <32 x i1> [[CMP]], <32 x i16> [[TMP2]], <32 x i16> [[TMP1]]
+; CHECK-NEXT: [[RES:%.*]] = bitcast <32 x i16> [[TMP3]] to <8 x i64>
; CHECK-NEXT: ret <8 x i64> [[RES]]
;
%a.bc = bitcast <8 x i64> %a to <64 x i8>
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davemgreen
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Jul 14, 2024
RKSimon
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Don't rely on phaseordering tests alone
…if they come from the same value to form identity sequence Workaround until I can get llvm#96884 fixed properly - when trying to find identity sequences, peek through any bitcasts to see if the values all came from the same source. We don't run CSE frequently enough to merge all the bitcasts that we end up with.
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/17/builds/858 Here is the relevant piece of the build log for the reference: |
yuxuanchen1997
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Jul 25, 2024
…if they come from the same value to form identity sequence (#98334) Summary: Workaround until I can get #96884 fixed properly - when trying to find identity sequences, peek through any bitcasts to see if the values all came from the same source. We don't run CSE frequently enough to merge all the bitcasts that we end up with. Test Plan: Reviewers: Subscribers: Tasks: Tags: Differential Revision: https://phabricator.intern.facebook.com/D60251606
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Workaround until I can get #96884 fixed properly - when trying to find identity sequences, peek through any bitcasts to see if the values all came from the same source. We don't run CSE frequently enough to merge all the bitcasts that we end up with.