[llvm] [X86] Combine LRINT/LLRINT and TRUNC when nuw/nsw (PR #126217)

[Craig Topper via llvm-commits]

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@@ -53919,6 +53919,11 @@ static SDValue combineTruncate(SDNode *N, SelectionDAG &DAG,
       return DAG.getNode(X86ISD::MMX_MOVD2W, DL, MVT::i32, BCSrc);
   }
 
+  if ((N->getFlags().hasNoUnsignedWrap() || N->getFlags().hasNoSignedWrap()) &&
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topperc wrote:

alive2 says this isn't valid for nsw https://alive2.llvm.org/ce/z/wPyHGQ
I had to reduce bitwidths to avoid timeouts.

https://github.com/llvm/llvm-project/pull/126217