https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67291
Peter Bergner <bergner at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |bergner at gcc dot gnu.org,
| |meissner at gcc dot gnu.org
--- Comment #3 from Peter Bergner <bergner at gcc dot gnu.org> ---
(In reply to Alan Modra from comment #2)
> I think this is a user error.
>
> The "ww" constraint is for the single precision vsx insns, like xsaddsp.
> This constraint is only enabled for vsx regs when compiling with
> -mcpu=power8 (or when you compiler defaults to -mcpu=power8), or when
> explicitly enabled with -mupper-regs-sf. So if your compiler defaults to
> -mcpu=power7, you'll get the "impossible constraints" message.
Agreed. Looking at the configure options above, this is a big-endian build
that did not use --with-cpu=..., so the -mcpu= default is much older than
power8. IIRC, it's even a pre-power4 ISA.
