[PATCH] D111555: [LoopVectorize] Add vector reduction support for fmuladd intrinsic

[Mindong Chen via Phabricator via llvm-commits]

mdchen added a comment.

Thanks for your reply!

> There's this line in the semantics for `llvm.fma`:
>
>   When specified with the fast-math-flag ‘afn’, the result may be approximated using a less accurate calculation.
>
> My reading is the underlying operation must be maintained (i.e. a fused multiply-add)

This is probably not the case, for example in D71706 <https://reviews.llvm.org/D71706> `pow` is allowed to be transformed to `sqrt` if `afn` exits. But I agree it depends on the interpretation since the text now is opaque. Maybe we can raise this question up in the dev mailist? Thanks again!


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https://reviews.llvm.org/D111555