[X86] combinePMULDQ - add op back to worklist if SimplifyDemandedBits succeeds on either operand

Prevents missing other simplifications that may occur deep in the operand chain where CommitTargetLoweringOpt won't add the PMULDQ back to the worklist itself

llvm-svn: 343922

1 files changed, 6 insertions, 2 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index cb4eea7d009..e113dbc6760 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -40317,10 +40317,14 @@ static SDValue combinePMULDQ(SDNode *N, SelectionDAG &DAG,
   APInt DemandedMask(APInt::getLowBitsSet(64, 32));
 
   // PMULQDQ/PMULUDQ only uses lower 32 bits from each vector element.
-  if (TLI.SimplifyDemandedBits(LHS, DemandedMask, DCI))
+  if (TLI.SimplifyDemandedBits(LHS, DemandedMask, DCI)) {
+    DCI.AddToWorklist(N);
     return SDValue(N, 0);
-  if (TLI.SimplifyDemandedBits(RHS, DemandedMask, DCI))
+  }
+  if (TLI.SimplifyDemandedBits(RHS, DemandedMask, DCI)) {
+    DCI.AddToWorklist(N);
     return SDValue(N, 0);
+  }
 
   return SDValue();
 }