Fix reordering of shuffles and binary operations

Do not apply transformation:

    BinOp(shuffle(v1), shuffle(v2)) -> shuffle(BinOp(v1, v2))

if operands v1 and v2 are of different size.
This change fixes PR19717, which was caused by r208488.
    

llvm-svn: 208518

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -1120,6 +1120,7 @@ Value *InstCombiner::SimplifyVectorOp(BinaryOperator &Inst) {
     ShuffleVectorInst *RShuf = cast<ShuffleVectorInst>(RHS);
     if (isa<UndefValue>(LShuf->getOperand(1)) &&
         isa<UndefValue>(RShuf->getOperand(1)) &&
+        LShuf->getOperand(0)->getType() == RShuf->getOperand(0)->getType() &&
         LShuf->getMask() == RShuf->getMask()) {
       BinaryOperator *NewBO = CreateBinOpAsGiven(Inst, LShuf->getOperand(0),
           RShuf->getOperand(0), Builder);

llvm/test/Transforms/InstCombine/vec_shuffle.ll

@@ -363,3 +363,15 @@ define <4 x i32> @shuffle_17mulsplat(<4 x i32> %v) {
                       <4 x i32> <i32 1, i32 1, i32 1, i32 1>
   ret <4 x i32> %s2
 }
+
+; Do not reorder shuffle and binop if LHS of shuffles are of different size
+define <2 x i32> @pr19717(<4 x i32> %in0, <2 x i32> %in1) {
+; CHECK-LABEL: @pr19717(
+; CHECK: shufflevector
+; CHECK: shufflevector
+; CHECK: mul
+  %shuffle = shufflevector <4 x i32> %in0, <4 x i32> %in0, <2 x i32> zeroinitializer
+  %shuffle4 = shufflevector <2 x i32> %in1, <2 x i32> %in1, <2 x i32> zeroinitializer
+  %mul = mul <2 x i32> %shuffle, %shuffle4
+  ret <2 x i32> %mul
+}