[Bug target/67291] error: 'asm' operand has impossible constraints when compiling gromacs 5.1 testsuite on PPC64 and PPC64LE with VSX SIMD

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

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.