[PATCH] D102404: [InstCombine] Add instcombine fold for extractelement + splat for scalable vectors
Caroline via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Jun 8 02:45:41 PDT 2021
This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG6fd1604d1433: [InstCombine] Add instcombine fold for extractelement + splat for scalable… (authored by CarolineConcatto).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D102404/new/
https://reviews.llvm.org/D102404
Files:
llvm/lib/Analysis/InstructionSimplify.cpp
llvm/test/Transforms/InstCombine/gep-vector-indices.ll
llvm/test/Transforms/InstCombine/vscale_extractelement-inseltpoison.ll
llvm/test/Transforms/InstCombine/vscale_extractelement.ll
Index: llvm/test/Transforms/InstCombine/vscale_extractelement.ll
===================================================================
--- llvm/test/Transforms/InstCombine/vscale_extractelement.ll
+++ llvm/test/Transforms/InstCombine/vscale_extractelement.ll
@@ -55,13 +55,9 @@
ret i8 %r
}
-; TODO: Instcombine could optimize to return %v.
define i32 @extractelement_shuffle_in_range(i32 %v) {
; CHECK-LABEL: @extractelement_shuffle_in_range(
-; CHECK-NEXT: [[IN:%.*]] = insertelement <vscale x 4 x i32> undef, i32 [[V:%.*]], i32 0
-; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <vscale x 4 x i32> [[IN]], <vscale x 4 x i32> undef, <vscale x 4 x i32> zeroinitializer
-; CHECK-NEXT: [[R:%.*]] = extractelement <vscale x 4 x i32> [[SPLAT]], i32 1
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: ret i32 %v
;
%in = insertelement <vscale x 4 x i32> undef, i32 %v, i32 0
%splat = shufflevector <vscale x 4 x i32> %in, <vscale x 4 x i32> undef, <vscale x 4 x i32> zeroinitializer
Index: llvm/test/Transforms/InstCombine/vscale_extractelement-inseltpoison.ll
===================================================================
--- llvm/test/Transforms/InstCombine/vscale_extractelement-inseltpoison.ll
+++ llvm/test/Transforms/InstCombine/vscale_extractelement-inseltpoison.ll
@@ -55,13 +55,9 @@
ret i8 %r
}
-; TODO: Instcombine could optimize to return %v.
define i32 @extractelement_shuffle_in_range(i32 %v) {
; CHECK-LABEL: @extractelement_shuffle_in_range(
-; CHECK-NEXT: [[IN:%.*]] = insertelement <vscale x 4 x i32> poison, i32 [[V:%.*]], i32 0
-; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <vscale x 4 x i32> [[IN]], <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
-; CHECK-NEXT: [[R:%.*]] = extractelement <vscale x 4 x i32> [[SPLAT]], i32 1
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: ret i32 %v
;
%in = insertelement <vscale x 4 x i32> poison, i32 %v, i32 0
%splat = shufflevector <vscale x 4 x i32> %in, <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
Index: llvm/test/Transforms/InstCombine/gep-vector-indices.ll
===================================================================
--- llvm/test/Transforms/InstCombine/gep-vector-indices.ll
+++ llvm/test/Transforms/InstCombine/gep-vector-indices.ll
@@ -61,10 +61,7 @@
define i32* @vector_splat_ptrs_nxv2i64_ext0(i32* %a, i64 %index) {
; CHECK-LABEL: @vector_splat_ptrs_nxv2i64_ext0(
-; CHECK-NEXT: [[TMP:%.*]] = insertelement <vscale x 2 x i32*> poison, i32* [[A:%.*]], i32 0
-; CHECK-NEXT: [[SPLATOFA:%.*]] = shufflevector <vscale x 2 x i32*> [[TMP]], <vscale x 2 x i32*> poison, <vscale x 2 x i32> zeroinitializer
-; CHECK-NEXT: [[TMP0:%.*]] = extractelement <vscale x 2 x i32*> [[SPLATOFA]], i32 0
-; CHECK-NEXT: [[RES:%.*]] = getelementptr i32, i32* [[TMP0]], i64 [[INDEX:%.*]]
+; CHECK-NEXT: [[RES:%.*]] = getelementptr i32, i32* [[A:%.*]], i64 [[INDEX:%.*]]
; CHECK-NEXT: ret i32* [[RES]]
;
%tmp = insertelement <vscale x 2 x i32*> poison, i32* %a, i32 0
Index: llvm/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/lib/Analysis/InstructionSimplify.cpp
+++ llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4495,9 +4495,13 @@
// find a previously computed scalar that was inserted into the vector.
if (auto *IdxC = dyn_cast<ConstantInt>(Idx)) {
// For fixed-length vector, fold into undef if index is out of bounds.
- if (isa<FixedVectorType>(VecVTy) &&
- IdxC->getValue().uge(cast<FixedVectorType>(VecVTy)->getNumElements()))
+ unsigned MinNumElts = VecVTy->getElementCount().getKnownMinValue();
+ if (isa<FixedVectorType>(VecVTy) && IdxC->getValue().uge(MinNumElts))
return PoisonValue::get(VecVTy->getElementType());
+ // Handle case where an element is extracted from a splat.
+ if (IdxC->getValue().ult(MinNumElts))
+ if (auto *Splat = getSplatValue(Vec))
+ return Splat;
if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
return Elt;
}
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