[Bug target/108981] New: Raise errors for cpu type without powerpc64 support.

["linkw at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108981

            Bug ID: 108981
           Summary: Raise errors for cpu type without powerpc64 support.
           Product: gcc
           Version: 13.0
               URL: https://gcc.gnu.org/pipermail/gcc-patches/2023-January
                    /609492.html
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: linkw at gcc dot gnu.org
                CC: bergner at gcc dot gnu.org, linkw at gcc dot gnu.org,
                    marxin at gcc dot gnu.org, segher at gcc dot gnu.org
        Depends on: 108240
            Blocks: 108415
  Target Milestone: ---
            Target: powerpc

+++ This bug was initially created as a clone of Bug #108240 +++

Currently for the explicitly given option -m64 and the cpu type without
powerpc64 support like cpu 401, we just go with -m64 and powerpc64 enabled and
there is no any warnings or errors. Without any explicit option -m64 or -m32
but it's set as 64bit env from TARGET_DEFAULT, for the cpu type without
powerpc64 support like cpu 401, we will emit errors on Linux and warnings on
aix and darwin.

As Segher pointed out in PR108240, we've better to make them be handled
consistently, that is to raise errors and prevent this non-sense usage, open
this for further tracking.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108240
[Bug 108240] [13 Regression] Error message missing since
r13-4894-gacc727cf02a144 (then make concealed ICE exposed)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108415
[Bug 108415] ICE in emit_library_call_value_1 at gcc/calls.cc:4181