[llvm] [SDAG] Handle insert_subvector in isKnownNeverNaN (PR #131989)

[Simon Pilgrim via llvm-commits]

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@@ -5727,6 +5730,9 @@ bool SelectionDAG::isKnownNeverNaN(SDValue Op, bool SNaN, unsigned Depth) const
   case ISD::EXTRACT_SUBVECTOR: {
     return isKnownNeverNaN(Op.getOperand(0), SNaN, Depth + 1);
   }
+  case ISD::INSERT_SUBVECTOR:
+    return isKnownNeverNaN(Op.getOperand(0), SNaN, Depth + 1) &&
+           isKnownNeverNaN(Op.getOperand(1), SNaN, Depth + 1);
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RKSimon wrote:

@tclin914 I've created #135952 to add DemandedElts handling to isKnownNeverNaN

https://github.com/llvm/llvm-project/pull/131989