[PATCH] D30415: Fix -mno-altivec cannot overwrite -maltivec option

Eric Christopher via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Sat Mar 18 16:27:03 PDT 2017

echristo added a comment.

In https://reviews.llvm.org/D30415#703652, @uweigand wrote:

> In https://reviews.llvm.org/D30415#703442, @hfinkel wrote:
> > In https://reviews.llvm.org/D30415#703398, @echristo wrote:
> >
> > > Different suggestion:
> > >
> > > Remove the faltivec option. Even gcc doesn't support it anymore afaict.
> >
> >
> > What are you suggesting? Always having the language extensions on? Or explicitly tying the language extensions to the underlying target feature?
> I'm a bit confused by this discussion.  -faltivec and -maltivec are simply aliases, they do exactly the same thing; the clang-internal variable OPT_faltivec indicates the use of either -faltivec or -maltivec.

They didn't used to, I arranged it so that they did (technically breaking gcc compatibility) a while ago.

> Is the suggestion to remove that flag completely, i.e. both -maltivec and -faltivec?   This seems strange to me since -maltivec is used in many Makefiles etc. that would break if clang suddenly refused to accept the option.

No, just faltivec.

> Or is the suggestion to simply remove the alias -faltivec, and leave -maltivec as-is?  I'd be less opposed to this since it probably breaks fewer users ... but I'm still not quite sure what it actually buys us.   And in any case the patch currently under discussion here would still be necessary then, to fix -maltivec -mno-altivec ...

No, remove faltivec and move forward with -maltivec/-mno-altivec but you should be able to remove a lot of the special handling at that point.


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