[llvm] [DAGCombiner] Remove `UnsafeFPMath` usage in `visitFSUBForFMACombine` etc. (PR #145637)

[Matt Arsenault via llvm-commits]

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@@ -17167,7 +17167,7 @@ SDValue DAGCombiner::visitFSUBForFMACombine(SDNode *N) {
   }
 
   auto isReassociable = [&Options](SDNode *N) {
-    return Options.UnsafeFPMath || N->getFlags().hasAllowReassociation();
+    return N->getFlags().hasAllowReassociation();
   };
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arsenm wrote:

Can now drop the lambda and just directly check the flags

https://github.com/llvm/llvm-project/pull/145637