[llvm] [X86] SimplifyDemandedVectorEltsForTargetNode - reduce width of X86 conversions nodes when upper elements are not demanded. (PR #102882)

[Phoebe Wang via llvm-commits]

================
@@ -42518,6 +42518,25 @@ bool X86TargetLowering::SimplifyDemandedVectorEltsForTargetNode(
       SDValue Insert =
           insertSubVector(UndefVec, ExtOp, 0, TLO.DAG, DL, ExtSizeInBits);
       return TLO.CombineTo(Op, Insert);
+    }
+      // Conversions.
----------------
phoebewang wrote:

Do we need to consider other conversion nodes like `CVTP2SI/CVTP2UI/CVTSI2P/VFPROUND...`?

https://github.com/llvm/llvm-project/pull/102882