1 files changed, 13 insertions, 3 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index ad68ddbeaa8b..eecf34902ddc 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -5059,6 +5059,14 @@ bool X86TargetLowering::shouldFoldMaskToVariableShiftPair(SDValue Y) const {
   return true;
 }
 
+bool X86TargetLowering::shouldExpandShift(SelectionDAG &DAG,
+                                          SDNode *N) const {
+  if (DAG.getMachineFunction().getFunction().hasMinSize() &&
+      !Subtarget.isOSWindows())
+    return false;
+  return true;
+}
+
 bool X86TargetLowering::shouldSplatInsEltVarIndex(EVT VT) const {
   // Any legal vector type can be splatted more efficiently than
   // loading/spilling from memory.
@@ -44096,7 +44104,8 @@ static SDValue combineScalarToVector(SDNode *N, SelectionDAG &DAG) {
 
 // Simplify PMULDQ and PMULUDQ operations.
 static SDValue combinePMULDQ(SDNode *N, SelectionDAG &DAG,
-                             TargetLowering::DAGCombinerInfo &DCI) {
+                             TargetLowering::DAGCombinerInfo &DCI,
+                             const X86Subtarget &Subtarget) {
   SDValue LHS = N->getOperand(0);
   SDValue RHS = N->getOperand(1);
 
@@ -44106,8 +44115,9 @@ static SDValue combinePMULDQ(SDNode *N, SelectionDAG &DAG,
     return DAG.getNode(N->getOpcode(), SDLoc(N), N->getValueType(0), RHS, LHS);
 
   // Multiply by zero.
+  // Don't return RHS as it may contain UNDEFs.
   if (ISD::isBuildVectorAllZeros(RHS.getNode()))
-    return RHS;
+    return getZeroVector(N->getSimpleValueType(0), Subtarget, DAG, SDLoc(N));
 
   // Aggressively peek through ops to get at the demanded low bits.
   APInt DemandedMask = APInt::getLowBitsSet(64, 32);
@@ -44315,7 +44325,7 @@ SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
   case X86ISD::PCMPEQ:
   case X86ISD::PCMPGT:      return combineVectorCompare(N, DAG, Subtarget);
   case X86ISD::PMULDQ:
-  case X86ISD::PMULUDQ:     return combinePMULDQ(N, DAG, DCI);
+  case X86ISD::PMULUDQ:     return combinePMULDQ(N, DAG, DCI, Subtarget);
   }
 
   return SDValue();