[Bug target/56010] Powerpc, -mcpu=native and -mtune=native use the wrong name for target 7450

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56010

--- Comment #10 from Segher Boessenkool <segher at gcc dot gnu.org> ---
(In reply to Peter Bergner from comment #9)
> (In reply to Segher Boessenkool from comment #8)
> >> This kernel AT_PLATFORM name should strip the '+' off:
> >>   .platform = "power7+", -> "power7"
> >
> > We probably should have a -mcpu=power7+, we have power5+ as well etc.
> 
> Well, we have a -mcpu=power5+ because power5+ added a few new instructions
> over and above what power5 has.  That is not the case with power7+.  It
> implements the exact same instructions that power7 does, so power7+ doesn't
> really buy us anything.

It makes life simpler for users who do not know that -- like the compiler
itself with -mcpu=native :-)  (Compare with 740 vs. 750, although you could
call that historical accident).

power7 and power7+ have different cache sizes, if we ever bother to get that
right, too.

> >> These kernel AT_PLATFORM names should strip their prefix and suffix off:
> >>   .platform = "ppc440gp", -> "440"
> >>   .platform = "ppc-cell-be", -> "cell"
> >> 
> >> These kernel AT_PLATFORM names should strip the 'ppc' prefix off, as
> >> well as test the AT_HWCAP for PPC_FEATURE_HAS_FPU:
> >>   .platform = "ppc405", -> "405" | "405fp"
> >>   .platform = "ppc440", -> "440" | "440fp"
> >> 
> >> This kernel AT_PLATFORM name should strip the 'ppc' prefix off, change
> >> 470 to 476 as well as test the AT_HWCAP for PPC_FEATURE_HAS_FPU:
> >>   .platform = "ppc470", -> "476" | "476fp"
> > 
> > We could also decide not to support those for "native" (except cell?),
> > they all have problems and no one will try to build on those anyway.
> > I hope.
> 
> Well, it was easy enough to add support for them in case some did try in the
> future.  Up to you though if you want to leave them out.

The "fp" ones are not so easy.  I don't know if 440gp is the same core.

> > Could use 970 for pa6t, if we care.
> 
> Its up to you if you want me to map that to 970.  Let me know what you want
> me to do.

I don't think we care.