[llvm] [DAG] narrowExtractedVectorBinOp - ensure we limit late node creation to LegalOperations only (PR #72130)

[Matt Arsenault via llvm-commits]

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@@ -41371,8 +41371,18 @@ bool X86TargetLowering::SimplifyDemandedVectorEltsForTargetNode(
     case X86ISD::UNPCKH:
     case X86ISD::BLENDI:
       // Integer ops.
+    case X86ISD::PCMPEQ:
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arsenm wrote:

Don't know enough about x86 but seems like there would need to be more tests hitting these cases?

https://github.com/llvm/llvm-project/pull/72130