Fix type of shuffle obtained from reordering with binary operation

In transformation:
    BinOp(shuffle(v1,undef), shuffle(v2,undef)) -> shuffle(BinOp(v1, v2),undef)
type of the undef argument must be same as type of BinOp.

llvm-svn: 208531

2 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 90ca8863e8c..8c0a249aee1 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1125,7 +1125,7 @@ Value *InstCombiner::SimplifyVectorOp(BinaryOperator &Inst) {
       BinaryOperator *NewBO = CreateBinOpAsGiven(Inst, LShuf->getOperand(0),
           RShuf->getOperand(0), Builder);
       Value *Res = Builder->CreateShuffleVector(NewBO,
-          UndefValue::get(Inst.getType()), LShuf->getMask());
+          UndefValue::get(NewBO->getType()), LShuf->getMask());
       return Res;
     }
   }
diff --git a/llvm/test/Transforms/InstCombine/vec_shuffle.ll b/llvm/test/Transforms/InstCombine/vec_shuffle.ll
index 79377a18765..a3f7f79624d 100644
--- a/llvm/test/Transforms/InstCombine/vec_shuffle.ll
+++ b/llvm/test/Transforms/InstCombine/vec_shuffle.ll
@@ -375,3 +375,14 @@ define <2 x i32> @pr19717(<4 x i32> %in0, <2 x i32> %in1) {
   %mul = mul <2 x i32> %shuffle, %shuffle4
   ret <2 x i32> %mul
 }
+
+define <4 x i16> @pr19717a(<8 x i16> %in0, <8 x i16> %in1) {
+; CHECK-LABEL: @pr19717a(
+; CHECK: [[VAR1:%[a-zA-Z0-9.]+]] = mul <8 x i16> %in0, %in1
+; CHECK: [[VAR2:%[a-zA-Z0-9.]+]] = shufflevector <8 x i16> [[VAR1]], <8 x i16> undef, <4 x i32> <i32 5, i32 5, i32 5, i32 5>
+; CHECK: ret <4 x i16> [[VAR2]]
+  %shuffle = shufflevector <8 x i16> %in0, <8 x i16> %in0, <4 x i32> <i32 5, i32 5, i32 5, i32 5>
+  %shuffle1 = shufflevector <8 x i16> %in1, <8 x i16> %in1, <4 x i32> <i32 5, i32 5, i32 5, i32 5>
+  %mul = mul <4 x i16> %shuffle, %shuffle1
+  ret <4 x i16> %mul
+}