[llvm] [LLVM][DAGCombine] Remove combiner-vector-fcopysign-extend-round. (PR #129878)

[Paul Walker via llvm-commits]

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@@ -18011,7 +18007,8 @@ static inline bool CanCombineFCOPYSIGN_EXTEND_ROUND(EVT XTy, EVT YTy) {
   if (YTy == MVT::f128)
     return false;
 
-  return !YTy.isVector() || EnableVectorFCopySignExtendRound;
+  // Avoid mismatched vector operand types, for better instruction selection.
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paulwalker-arm wrote:

This was the original comment that I've pulled from https://reviews.llvm.org/D128642.

https://github.com/llvm/llvm-project/pull/129878