[PATCH] D59356: [SelectionDAGBuilder] Use accumulator value in VECREDUCE_FADD/FMUL

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

See also https://bugs.llvm.org/show_bug.cgi?id=36734 and https://reviews.llvm.org/D45336. According to @aemerson this is intended behavior.

Imho we should definitely make this change, and consider also making it for undef -- it seems like a bad idea to special-case it, because it may negatively affect optimization.

If there are concerns about backwards compatibility for experimental intrinsics, we should rename and autoupgrade them. (Updrade fast fadd to fadd.acc with 0.0 argument, the original one being ignored per current semantics).


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  https://reviews.llvm.org/D59356/new/

https://reviews.llvm.org/D59356