[llvm] [SelectionDAG][X86] Fix the assertion failure in Release build after #91747 (PR #93434)

[Shengchen Kan via llvm-commits]

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@@ -49253,8 +49253,10 @@ static SDValue combineX86SubCmpForFlags(SDNode *N, SDValue Flag,
     return SDValue();
 
   SDValue X = SetCC.getOperand(1);
-  // Replace API is called manually here b/c the number of results may change.
-  DAG.ReplaceAllUsesOfValueWith(Flag, X);
+  // sub has two results while X only have one. DAG combine assumes the value
+  // type matches.
+  if (N->getNumValues() > 1)
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KanRobert wrote:

`N` can be a `X86ISD::CMP` or `X86ISD::SUB`. When `N` is `CMP`, it only has one result.

https://github.com/llvm/llvm-project/pull/93434