Re: [PATCH] i386: Sync tune_string with arch_string for target attribute arch=*

[Hongyu Wang <wwwhhhyyy333@gmail.com>]

Thanks, I'll backport it down to GCC10 after this passed all bootstrap/regtest.

Uros Bizjak via Gcc-patches <gcc-patches@gcc.gnu.org> 于2023年6月26日周一 14:05写道：
>
> On Mon, Jun 26, 2023 at 4:31 AM Hongyu Wang <hongyu.wang@intel.com> wrote:
> >
> > Hi,
> >
> > For function with target attribute arch=*, current logic will set its
> > tune to -mtune from command line so all target_clones will get same
> > tuning flags which would affect the performance for each clone. Override
> > tune with arch if tune was not explicitly specified to get proper tuning
> > flags for target_clones.
> >
> > Bootstrapped/regtested on x86_64-pc-linux-gnu{-m32,}
> >
> > Ok for trunk and backport to active release branches?
> >
> > gcc/ChangeLog:
> >
> >         * config/i386/i386-options.cc (ix86_valid_target_attribute_tree):
> >         Override tune_string with arch_string if tune_string is not
> >         explicitly specified.
> >
> > gcc/testsuite/ChangeLog:
> >
> >         * gcc.target/i386/mvc17.c: New test.
>
> LGTM.
>
> Thanks,
> Uros.
>
> > ---
> >  gcc/config/i386/i386-options.cc       |  6 +++++-
> >  gcc/testsuite/gcc.target/i386/mvc17.c | 11 +++++++++++
> >  2 files changed, 16 insertions(+), 1 deletion(-)
> >  create mode 100644 gcc/testsuite/gcc.target/i386/mvc17.c
> >
> > diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
> > index 2cb0bddcd35..7f593cebe76 100644
> > --- a/gcc/config/i386/i386-options.cc
> > +++ b/gcc/config/i386/i386-options.cc
> > @@ -1400,7 +1400,11 @@ ix86_valid_target_attribute_tree (tree fndecl, tree args,
> >        if (option_strings[IX86_FUNCTION_SPECIFIC_TUNE])
> >         opts->x_ix86_tune_string
> >           = ggc_strdup (option_strings[IX86_FUNCTION_SPECIFIC_TUNE]);
> > -      else if (orig_tune_defaulted)
> > +      /* If we have explicit arch string and no tune string specified, set
> > +        tune_string to NULL and later it will be overriden by arch_string
> > +        so target clones can get proper optimization.  */
> > +      else if (option_strings[IX86_FUNCTION_SPECIFIC_ARCH]
> > +              || orig_tune_defaulted)
> >         opts->x_ix86_tune_string = NULL;
> >
> >        /* If fpmath= is not set, and we now have sse2 on 32-bit, use it.  */
> > diff --git a/gcc/testsuite/gcc.target/i386/mvc17.c b/gcc/testsuite/gcc.target/i386/mvc17.c
> > new file mode 100644
> > index 00000000000..2c7cc2fdace
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/mvc17.c
> > @@ -0,0 +1,11 @@
> > +/* { dg-do compile } */
> > +/* { dg-require-ifunc "" } */
> > +/* { dg-options "-O2" } */
> > +/* { dg-final { scan-assembler-times "rep mov" 1 } } */
> > +
> > +__attribute__((target_clones("default","arch=icelake-server")))
> > +void
> > +foo (char *a, char *b, int size)
> > +{
> > +  __builtin_memcpy (a, b, size & 0x7F);
> > +}
> > --
> > 2.31.1
> >