[llvm] [LLVM][CodeGen] When expanding ISD::LRINT, non-deterministic results should be frozen. (PR #197435)

[Paul Walker via llvm-commits]

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@@ -4636,9 +4636,11 @@ bool SelectionDAGLegalize::ExpandNode(SDNode *Node) {
     SDValue Arg = Node->getOperand(0);
     EVT ArgVT = Arg.getValueType();
     EVT ResVT = Node->getValueType(0);
-    SDLoc dl(Node);
-    SDValue RoundNode = DAG.getNode(ISD::FRINT, dl, ArgVT, Arg);
-    Results.push_back(DAG.getNode(ISD::FP_TO_SINT, dl, ResVT, RoundNode));
+    SDLoc DL(Node);
+    SDValue RoundNode = DAG.getNode(ISD::FRINT, DL, ArgVT, Arg);
+    SDValue ConvertNode = DAG.getNode(ISD::FP_TO_SINT, DL, ResVT, RoundNode);
+    // Non-deterministic results are equivalent to freeze poison.
+    Results.push_back(DAG.getFreeze(ConvertNode));
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paulwalker-arm wrote:

ISD::FP_TO_SINT is the operation that can generate a poison result.

https://github.com/llvm/llvm-project/pull/197435