[Bug target/108240] [13 Regression] ICE in emit_library_call_value_1 at gcc/calls.cc:4181 since r13-4894-gacc727cf02a144

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108240

--- Comment #5 from Kewen Lin <linkw at gcc dot gnu.org> ---
(In reply to Segher Boessenkool from comment #4)
> (In reply to Kewen Lin from comment #3)
> > With the culprit commit r13-4894, we always implicitly enable powerpc64 for
> > both explicit and implicit 64 bit, it's the same as before for the explicit
> > 64 bit case, but for the implicit 64 bit case, there is no chance for the
> > used cpu to unset powerpc64 (like this case). To keep it consistent with the
> > previous, the fix can be to only enable powerpc64 implicitly for explicit 64
> > bit, while let it be for implicit 64 bit.
> 
> No?  If the user says to use a CPU without 64-bit instructions, while the
> user also says we require 64-bit insns (via -m64), we should just error.

But both the previous behavior (before r13-4894) and the current behavior
(starting from r13-4894) honour the given explicit -m64, it would always enable
-mpowerpc64 at the same time without any errors/warnings.

> Not hide the problem (and cause many more problems!)
> 

The behavior change is for the case without any explicit -m64 but the
TARGET_DEFAULT has 64 bit set (implicit -m64).  And yes, different from the
previous behavior, the current behavior hides the error/warning and force the
-mpower64, so I posted one patch at:

https://gcc.gnu.org/pipermail/gcc-patches/2023-January/609492.html

It would allow that powerpc64 gets unset if the user says to use a CPU without
64-bit instructions and with implicit 64 bit.