[X86] Return SDValue(N, 0) instead of an SDValue() after a successful combine.

Returning SDValue() means nothing changed, SDValue(N,0) means there was a change but the worklist management was taken care of.

I don't know if this has a real effect other than making sure the combine counter in the DAG combiner gets updated, but it is the correct thing to do.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321463 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 321bc0e..ae5100e 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -31003,8 +31003,8 @@ static SDValue combineExtractVectorElt(SDNode *N, SelectionDAG &DAG,
     DAG.ReplaceAllUsesOfValueWith(SDValue(Extract, 0), Vals[IdxVal]);
   }
 
-  // The replacement was made in place; don't return anything.
-  return SDValue();
+  // The replacement was made in place; return N so it won't be revisited.
+  return SDValue(N, 0);
 }
 
 /// If a vector select has an operand that is -1 or 0, try to simplify the