documentation of powerpc64{,le}-linux-gnu as primary platform

[Segher Boessenkool]

On Thu, Jul 09, 2020 at 08:18:56PM -0500, Bill Schmidt via Gcc wrote:
> >>>No, I don't leave this alone.  The little endian target is dropped in
> >>GCC 9 and
> >>>GCC 10.  Is this really what you intended to do?
> >>No, it's not dropped.  Some people are being pedantic about the name,
> >>which is why Bill added {,le}.  powerpc64-unknown-linux-gnu means
> >>everything.  If you want to add {,le} back, that's fine.  But there
> >>always is some variant omitted, and that doesn't mean it is ignored.
> >>The more that one over-specifies and enumerates some variants, the
> >>more that it implies the other variants intentionally are ignored.
> >>
> >>I would appreciate that we would separate the discussion about
> >>explicit reference to {,le} from the discussion about dropping the big
> >>endian platform.
> >I think for primary platforms it is important to be as specific as 
> >possible since certain regressions are supposed to block a release. That's 
> >less of an issue for secondary platforms but it's still a valid concern 
> >there as well for build issues.
> 
> Sorry, I've been on vacation and am a little late to this discussion.  I 
> obviously agree with specifying both, since I did that for GCC 8 (and 
> assumed it would be propagated forward).  I had forgotten I did this 
> when I subsequently noticed for GCC 9 that it was only 
> powerpc64-unknown-linux-gnu.  I brought it up then and, IIRC, was told 
> by the maintainers that "LE is implied as well, don't worry about it."  

Yes, that is exactly my recollection as well.

> It looks like thoughts on this have changed, so certainly I would agree 
> with putting "{,le}" back at this time.
> 
> I agree with David that BE isn't going anywhere anytime soon, so 
> anything that implies it should be a secondary platform is wrong. We 
> continue to support it and test it.

And the same is true for powerpc-linux (the 32-bit one).  It is used and
maintained *much* more than some primary targets, but we aren't even
secondary anymore.  It does not matter one bit, because we make very
sure it works anyway, is in order before stage4 (or any time really),
and we scream bloody murder if it is broken during stage4.

32-bit PowerPC Linux isn't super important as a deployment target now,
but it is the center of cohesion of the whole port.  Keeping both word
sizes and endiannesses working well is important, for many reasons.


Primary / secondary / tertiary / imaginary only matters for targets that
are not actively maintained, in practice.


Segher