[PATCH] D115429: [Clang] Implement the rest of __builtin_elementwise_* functions.

[Jun Zhang via Phabricator via cfe-commits]

junaire added a comment.

Hi, @aaron.ballman  I'm sorry for not updating the patch in time because I'm preparing for my school final exam :-(
One thing I want to mention is that `__builtin_elementwise_roundeven` is actually been added in the RFC during the code review. You can find it in D111529 <https://reviews.llvm.org/D111529>.

> "Prevailing rounding mode" is not super-useful, other than as a spelling for round-to-nearest-ties-to-even (IEEE 754 default rounding). Outside of a FENV_ACCESS ON context, there's not even really a notion of "prevailing rounding mode" to appeal to. I assume the intent is for this to lower to e.g. x86 ROUND* with the dynamic rounding-mode immediate.
>
> I would recommend adding __builtin_elementwise_roundeven(T x) instead, which would statically bind IEEE default rounding (following TS 18661-1 naming) without having to appeal to prevailing rounding mode, and can still lower to ROUND* on x86 outside of FENV_ACCESS ON contexts, which is the norm for vector code (and FRINTN unconditionally on armv8). I think we can punt on rint/nearbyint for now, and add them in the future if there's a need.




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  https://reviews.llvm.org/D115429/new/

https://reviews.llvm.org/D115429