Re: [PATCH v2, rs6000] Change insn condition from TARGET_64BIT to TARGET_POWERPC64 for VSX scalar extract/insert instructions

[Segher Boessenkool <segher@kernel.crashing.org>]

Hi!

On Mon, Sep 05, 2022 at 02:36:30PM +0800, HAO CHEN GUI wrote:
> On 2/9/2022 下午 11:56, Segher Boessenkool wrote:
> >> -  const signed long __builtin_vsx_scalar_extract_exp (double);
> >> +  const unsigned long long __builtin_vsx_scalar_extract_exp (double);
> >>      VSEEDP xsxexpdp {}
> >>
> >> -  const signed long __builtin_vsx_scalar_extract_sig (double);
> >> +  const unsigned long long __builtin_vsx_scalar_extract_sig (double);
> >>      VSESDP xsxsigdp {}
> > This also brings these legacy builtins in line with the vec_ versions,
> > which are the preferred builtins (they are defined in the PVIPR).
> 
> The return type of vec_ version built-ins are different than their definition
> in PVIPR. In PVIPR, they're vector unsigned int or vector unsigned long long.
> Shall we correct them?
> 
>   const vd __builtin_vsx_extract_exp_dp (vd);
>     VEEDP xvxexpdp {}
> 
>   const vf __builtin_vsx_extract_exp_sp (vf);
>     VEESP xvxexpsp {}
> 
>   const vd __builtin_vsx_extract_sig_dp (vd);
>     VESDP xvxsigdp {}
> 
>   const vf __builtin_vsx_extract_sig_sp (vf);
>     VESSP xvxsigsp {}

Those are the vsx_ versions.  I'm not sure what you're asking.

It won't be easy at all to change types from vector integer to vector
float, it will break all over.  A compatibility nightmare.  It is better
if you can show the current stuff cannot ever work, it's not a problem
to replace it in that case.

> >> --- a/gcc/testsuite/gcc.target/powerpc/bfp/scalar-extract-exp-0.c
> >> +++ b/gcc/testsuite/gcc.target/powerpc/bfp/scalar-extract-exp-0.c
> >> @@ -1,7 +1,8 @@
> >> -/* { dg-do compile { target { powerpc*-*-* } } } */
> >> -/* { dg-require-effective-target lp64 } */
> >> -/* { dg-require-effective-target powerpc_p9vector_ok } */
> >> +/* { dg-do compile { target { powerpc*-*-linux* } } } */
> > Why?
> The powerpc*-*-linux* is no need as bfp.exp excludes AIX and Darwin.
> I will modify it.

And powerpc*-*-* is guaranteed in all of gcc.target/powerpc/, so you
need no target clause at all here.

> >>  /* { dg-options "-mdejagnu-cpu=power9" } */
> >> +/* { dg-additional-options "-mpowerpc64" } */
> >> +/* { dg-require-effective-target has_arch_ppc64 } */
> > This is guaranteed already by that -mpowerpc64.
> > 
> > It probably is best if you do not add -mpowerpc64 at all.  That solves
> > both problems, is simpler, and gives better coverage as well :-)
> > 
> > So just use has_arch_ppc64 instead of lp64.  That makes it run on a
> > strict superset of cases :-)
> We commonly do regression test with -m32 and -m64. So if -mpowerpc64 is
> not added, the combination of "-m32/-mpowerpc64" is not tested.

make -k -j60 check RUNTESTFLAGS="--target_board=unix'{-m64,-m32,-m32/-mpowerpc64}'"

It is fine to not test -m32/-mpowerpc64 so often, and certaionly not
something I will ask everyone to always do :-)


Segher