[X86] Use DAG.getConstant instead of getZeroVector in combinePMULDQ.

getZeroVector canonicalizes the type to vXi32, but that's a
legalization action. We should use the most correct type if
possible.

llvm-svn: 371345

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index c784422..3950b29 100644 (file)
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -44768,7 +44768,7 @@ static SDValue combinePMULDQ(SDNode *N, SelectionDAG &DAG,
   // Multiply by zero.
   // Don't return RHS as it may contain UNDEFs.
   if (ISD::isBuildVectorAllZeros(RHS.getNode()))
-    return getZeroVector(N->getSimpleValueType(0), Subtarget, DAG, SDLoc(N));
+    return DAG.getConstant(0, SDLoc(N), N->getValueType(0));
 
   // PMULDQ/PMULUDQ only uses lower 32 bits from each vector element.
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();