[llvm] SelectionDAG/expandFMINIMUMNUM_FMAXIMUMNUM: FCANONICALIZE is needed only for sNaN (PR #108180)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-selectiondag

Author: YunQiang Su (wzssyqa)

<details>
<summary>Changes</summary>

If we are sure that it is not sNaN, even it may be qNaN, we can use it directly.

---
Full diff: https://github.com/llvm/llvm-project/pull/108180.diff


1 Files Affected:

- (modified) llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp (+2-2) 


``````````diff
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 03010c1df00145..042661af1c8f96 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -8614,8 +8614,8 @@ SDValue TargetLowering::expandFMINIMUMNUM_FMAXIMUMNUM(SDNode *Node,
   SDValue MinMax =
       DAG.getSelectCC(DL, LHS, RHS, LHS, RHS, IsMax ? ISD::SETGT : ISD::SETLT);
   // If MinMax is NaN, let's quiet it.
-  if (!Flags.hasNoNaNs() && !DAG.isKnownNeverNaN(LHS) &&
-      !DAG.isKnownNeverNaN(RHS)) {
+  if (!Flags.hasNoNaNs() && !DAG.isKnownNeverSNaN(LHS) &&
+      !DAG.isKnownNeverSNaN(RHS)) {
     MinMax = DAG.getNode(ISD::FCANONICALIZE, DL, VT, MinMax, Flags);
   }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/108180