[llvm] [SLP]Flatten fsub/fneg chains into fadd reductions with per-operand signs (PR #215840)

[Ryan Buchner via llvm-commits]

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@@ -14643,7 +14662,8 @@ void BoUpSLP::reorderGatherNode(TreeEntry &TE) {
 }
 
 /// Check if we can convert fadd/fsub sequence to FMAD.
-/// \returns Cost of the FMAD, if conversion is possible, invalid cost otherwise.
+/// \returns Cost of the FMAD, if conversion is possible, invalid cost
+/// otherwise.
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bababuck wrote:

why changed?

https://github.com/llvm/llvm-project/pull/215840