[PATCH] D135097: Remove redundant option '-menable-unsafe-fp-math'.

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman accepted this revision.
aaron.ballman added a comment.
This revision is now accepted and ready to land.

LGTM!



================
Comment at: clang/docs/ReleaseNotes.rst:410-412
+- The driver option ``-menable-unsafe-fp-math`` has been removed. Passing it, will
+result in a hard error. To enable unsafe floating-point optimizations, the compiler
+options ``-funsafe-math-optimizations`` and ``-ffast-math`` are used instead.
----------------
zahiraam wrote:
> MaskRay wrote:
> > aaron.ballman wrote:
> > > zahiraam wrote:
> > > > aaron.ballman wrote:
> > > > > Because we diagnose unknown driver flags as an error (https://godbolt.org/z/4xjzKh4Ej) and there's no deprecation period, I think we should put this under the potentially breaking changes section. In this case, I'm specifically worried about proprietary projects using the flag for optimization purposes (a lot of numerical analysis code is behind closed doors).
> > > > > 
> > > > > CC @MaskRay just to make sure there's agreement (we're still trying to figure out what constitutes a breaking change we want to be loud about in terms of driver flags).
> > > > > 
> > > > > Assuming Fangrui doesn't disagree, once this lands, please post an announcement about it into https://discourse.llvm.org/c/announce/46 with the `clang` and `potentially-breaking` tags (an example of such a post is: https://discourse.llvm.org/t/clang-16-notice-of-potentially-breaking-changes/65562/ though you wouldn't need all that lead-in text). 
> > > > @aaron.ballman would it be worth adding a diagnostic for the option we are removing?
> > > If we're going to deprecate rather than remove, sure. But I think we're okay removing, and I think the default error diagnostic behavior will be sufficient.
> > Since -menable-unsafe-fp-math was only accidentally exposed in 2020 and it's clear not used in the wild, placing this under "Potentially Breaking Changes" seems overkill to me (lengthy entries in release notes also discourage readers).
> > 
> > > The driver option ``-menable-unsafe-fp-math`` has been removed. Passing it, will result in a hard error. 
> > 
> > I think `Passing it, will result in a hard error. ` can be removed as the removal clearly indicates that passing it is an error:)
> > 
> > > the compiler options ``-funsafe-math-optimizations`` and ``-ffast-math`` are used instead.
> > 
> > Use xxx or xxx instead.
> @MaskRay Thanks! 
> I tend to agree about the "Potentially Breaking changes". 
Great, that works for me. Thank you @MaskRay!


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D135097/new/

https://reviews.llvm.org/D135097