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

[Hongyu Wang <wwwhhhyyy333@gmail.com>]

The testcase fails with --with-arch=native build on cascadelake, here
is the patch to adjust it

gcc/testsuite/ChangeLog:

* gcc.target/i386/mvc17.c: Add -march=x86-64 to dg-options.
---
 gcc/testsuite/gcc.target/i386/mvc17.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.target/i386/mvc17.c
b/gcc/testsuite/gcc.target/i386/mvc17.c
index 2c7cc2fdace..8b83c1aecb3 100644
--- a/gcc/testsuite/gcc.target/i386/mvc17.c
+++ b/gcc/testsuite/gcc.target/i386/mvc17.c
@@ -1,6 +1,6 @@
 /* { dg-do compile } */
 /* { dg-require-ifunc "" } */
-/* { dg-options "-O2" } */
+/* { dg-options "-O2 -march=x86-64" } */
 /* { dg-final { scan-assembler-times "rep mov" 1 } } */

 __attribute__((target_clones("default","arch=icelake-server")))
---

Will push it as an obvious fix, also will apply to the pending backports.

Hongyu Wang <wwwhhhyyy333@gmail.com> 于2023年6月27日周二 13:43写道：
>
> 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
> > >