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-rw-r--r--llvm/lib/Analysis/InstructionSimplify.cpp20
-rw-r--r--llvm/test/Transforms/InstSimplify/shufflevector.ll77
2 files changed, 91 insertions, 6 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 807bbd20ac0..0e522cb4e49 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4085,8 +4085,9 @@ Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
static Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
Type *RetTy, const Query &Q,
unsigned MaxRecurse) {
+ Type *InVecTy = Op0->getType();
unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
- unsigned InVecNumElts = Op0->getType()->getVectorNumElements();
+ unsigned InVecNumElts = InVecTy->getVectorNumElements();
auto *Op0Const = dyn_cast<Constant>(Op0);
auto *Op1Const = dyn_cast<Constant>(Op1);
@@ -4108,11 +4109,22 @@ static Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
MaskSelects1 = true;
}
if (!MaskSelects0 && Op1Const)
- return ConstantFoldShuffleVectorInstruction(UndefValue::get(Op0->getType()),
+ return ConstantFoldShuffleVectorInstruction(UndefValue::get(InVecTy),
Op1Const, Mask);
if (!MaskSelects1 && Op0Const)
- return ConstantFoldShuffleVectorInstruction(
- Op0Const, UndefValue::get(Op0->getType()), Mask);
+ return ConstantFoldShuffleVectorInstruction(Op0Const,
+ UndefValue::get(InVecTy), Mask);
+
+ // A shuffle of a splat is always the splat itself. Legal if the shuffle's
+ // value type is same as the input vectors' type.
+ if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0))
+ if (!MaskSelects1 && RetTy == InVecTy &&
+ OpShuf->getMask()->getSplatValue())
+ return Op0;
+ if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op1))
+ if (!MaskSelects0 && RetTy == InVecTy &&
+ OpShuf->getMask()->getSplatValue())
+ return Op1;
return nullptr;
}
diff --git a/llvm/test/Transforms/InstSimplify/shufflevector.ll b/llvm/test/Transforms/InstSimplify/shufflevector.ll
index e4c2c23923e..c6d180da293 100644
--- a/llvm/test/Transforms/InstSimplify/shufflevector.ll
+++ b/llvm/test/Transforms/InstSimplify/shufflevector.ll
@@ -29,14 +29,87 @@ define <4 x i32> @const_folding_negative(<3 x i32> %x) {
define <4 x i32> @splat_operand(<4 x i32> %x) {
; CHECK-LABEL: @splat_operand(
; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> undef, <4 x i32> zeroinitializer
-; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <4 x i32> [[SPLAT]], <4 x i32> undef, <4 x i32> <i32 0, i32 3, i32 2, i32 1>
-; CHECK-NEXT: ret <4 x i32> [[SHUF]]
+; CHECK-NEXT: ret <4 x i32> [[SPLAT]]
;
%splat = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> zeroinitializer
%shuf = shufflevector <4 x i32> %splat, <4 x i32> undef, <4 x i32> <i32 0, i32 3, i32 2, i32 1>
ret <4 x i32> %shuf
}
+define <4 x i32> @splat_operand1(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @splat_operand1(
+; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> [[Y:%.*]], <4 x i32> zeroinitializer
+; CHECK-NEXT: ret <4 x i32> [[SPLAT]]
+;
+ %splat = shufflevector <4 x i32> %x, <4 x i32> %y, <4 x i32> zeroinitializer
+ %shuf = shufflevector <4 x i32> %splat, <4 x i32> undef, <4 x i32> <i32 0, i32 3, i32 2, i32 1>
+ ret <4 x i32> %shuf
+}
+
+define <4 x i32> @splat_operand2(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @splat_operand2(
+; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> undef, <4 x i32> zeroinitializer
+; CHECK-NEXT: ret <4 x i32> [[SPLAT]]
+;
+ %splat = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> zeroinitializer
+ %shuf = shufflevector <4 x i32> %splat, <4 x i32> %y, <4 x i32> <i32 0, i32 3, i32 2, i32 1>
+ ret <4 x i32> %shuf
+}
+
+define <4 x i32> @splat_operand3(<4 x i32> %x) {
+; CHECK-LABEL: @splat_operand3(
+; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> undef, <4 x i32> zeroinitializer
+; CHECK-NEXT: ret <4 x i32> [[SPLAT]]
+;
+ %splat = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> zeroinitializer
+ %shuf = shufflevector <4 x i32> zeroinitializer, <4 x i32> %splat, <4 x i32> <i32 7, i32 6, i32 5, i32 5>
+ ret <4 x i32> %shuf
+}
+
+define <8 x i32> @splat_operand_negative(<4 x i32> %x) {
+; CHECK-LABEL: @splat_operand_negative(
+; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> undef, <4 x i32> zeroinitializer
+; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <4 x i32> [[SPLAT]], <4 x i32> undef, <8 x i32> <i32 0, i32 3, i32 2, i32 1, i32 undef, i32 undef, i32 undef, i32 undef>
+; CHECK-NEXT: ret <8 x i32> [[SHUF]]
+;
+ %splat = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> zeroinitializer
+ %shuf = shufflevector <4 x i32> %splat, <4 x i32> undef, <8 x i32> <i32 0, i32 3, i32 2, i32 1, i32 undef, i32 undef, i32 undef, i32 undef>
+ ret <8 x i32> %shuf
+}
+
+define <4 x i32> @splat_operand_negative2(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @splat_operand_negative2(
+; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> undef, <4 x i32> zeroinitializer
+; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <4 x i32> [[SPLAT]], <4 x i32> [[Y:%.*]], <4 x i32> <i32 0, i32 3, i32 4, i32 1>
+; CHECK-NEXT: ret <4 x i32> [[SHUF]]
+;
+ %splat = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> zeroinitializer
+ %shuf = shufflevector <4 x i32> %splat, <4 x i32> %y, <4 x i32> <i32 0, i32 3, i32 4, i32 1>
+ ret <4 x i32> %shuf
+}
+
+define <4 x i32> @splat_operand_negative3(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @splat_operand_negative3(
+; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> undef, <4 x i32> zeroinitializer
+; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <4 x i32> [[Y:%.*]], <4 x i32> [[SPLAT]], <4 x i32> <i32 0, i32 3, i32 4, i32 1>
+; CHECK-NEXT: ret <4 x i32> [[SHUF]]
+;
+ %splat = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> zeroinitializer
+ %shuf = shufflevector <4 x i32> %y, <4 x i32> %splat, <4 x i32> <i32 0, i32 3, i32 4, i32 1>
+ ret <4 x i32> %shuf
+}
+
+define <4 x i32> @splat_operand_negative4(<4 x i32> %x) {
+; CHECK-LABEL: @splat_operand_negative4(
+; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> undef, <4 x i32> <i32 2, i32 undef, i32 2, i32 undef>
+; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <4 x i32> [[SPLAT]], <4 x i32> undef, <4 x i32> <i32 0, i32 2, i32 undef, i32 undef>
+; CHECK-NEXT: ret <4 x i32> [[SHUF]]
+;
+ %splat = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> <i32 2, i32 undef, i32 2, i32 undef>
+ %shuf = shufflevector <4 x i32> %splat, <4 x i32> undef, <4 x i32> <i32 0, i32 2, i32 undef, i32 undef>
+ ret <4 x i32> %shuf
+}
+
define <4 x i32> @undef_mask(<4 x i32> %x) {
; CHECK-LABEL: @undef_mask(
; CHECK-NEXT: ret <4 x i32> undef
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