> -----Original Message-----
> From: Richard Sandiford <richard.sandif...@arm.com>
> Sent: Wednesday, January 15, 2025 3:23 PM
> To: Tamar Christina <tamar.christ...@arm.com>
> Cc: gcc-patches@gcc.gnu.org; nd <n...@arm.com>; Richard Earnshaw
> <richard.earns...@arm.com>; ktkac...@gcc.gnu.org
> Subject: Re: [PATCH]AArch64: have -mcpu=native detect architecture extensions
> for unknown non-homogenous systems [PR113257]
>
> Tamar Christina <tamar.christ...@arm.com> writes:
> > Ok for master? and how do you feel about a backport for the two patches to
> > help
> > distros?
>
> Backporting to GCC 14 & GCC 13 sounds good. Not so sure about GCC 12,
> since I think we should be extra cautious with the "most stable" branch,
> but let's see what others think.
>
> OK for trunk, and for GCC 14 & 13 after a grace period, with one
> trivial nit below:
Thanks, I should have indicated that I'm not pushing for GCC 12.
So I'm happy with just GCC 13 and 14.
Cheers,
Tamar
>
> >
> > Thanks,
> > Tamar
> >
> > gcc/ChangeLog:
> >
> > PR target/113257
> > * config/aarch64/driver-aarch64.cc (get_cpu_from_id, DEFAULT_CPU):
> New.
> > (host_detect_local_cpu): Use it.
> >
> > gcc/testsuite/ChangeLog:
> >
> > PR target/113257
> > * gcc.target/aarch64/cpunative/info_34: New test.
> > * gcc.target/aarch64/cpunative/native_cpu_34.c: New test.
> > * gcc.target/aarch64/cpunative/info_35: New test.
> > * gcc.target/aarch64/cpunative/native_cpu_35.c: New test.
> >
> > -- inline patch --
> >
> > diff --git a/gcc/config/aarch64/driver-aarch64.cc
> > b/gcc/config/aarch64/driver-
> aarch64.cc
> > index
> 45fce67a646351b848b7cd7d0fd35d343731c0d1..731b5e486879d3670ad0feb
> 02906c6d6bdbb1f01 100644
> > --- a/gcc/config/aarch64/driver-aarch64.cc
> > +++ b/gcc/config/aarch64/driver-aarch64.cc
> > @@ -60,6 +60,7 @@ struct aarch64_core_data
> > #define ALL_VARIANTS ((unsigned)-1)
> > /* Default architecture to use if -mcpu=native did not detect a known CPU.
> > */
> > #define DEFAULT_ARCH "8A"
> > +#define DEFAULT_CPU "generic-armv8-a"
> >
> > #define AARCH64_CORE(CORE_NAME, CORE_IDENT, SCHED, ARCH, FLAGS,
> COSTS, IMP, PART, VARIANT) \
> > { CORE_NAME, #ARCH, IMP, PART, VARIANT, feature_deps::cpu_##CORE_IDENT
> },
> > @@ -106,6 +107,21 @@ get_arch_from_id (const char* id)
> > return NULL;
> > }
> >
> > +/* Return an aarch64_core_data for the cpu described
> > + by ID, or NULL if ID describes something we don't know about. */
> > +
> > +static const aarch64_core_data *
> > +get_cpu_from_id (const char* name)
> > +{
> > + for (unsigned i = 0; aarch64_cpu_data[i].name != NULL; i++)
> > + {
> > + if (strcmp (name, aarch64_cpu_data[i].name) == 0)
> > + return &aarch64_cpu_data[i];
> > + }
>
> Redundant braces, should be:
>
> for (unsigned i = 0; aarch64_cpu_data[i].name != NULL; i++)
> if (strcmp (name, aarch64_cpu_data[i].name) == 0)
> return &aarch64_cpu_data[i];
>
> Thanks,
> Richard
>
> > +
> > + return NULL;
> > +}
> > +
> > /* Check wether the CORE array is the same as the big.LITTLE BL_CORE.
> > For an example CORE={0xd08, 0xd03} and
> > BL_CORE=AARCH64_BIG_LITTLE (0xd08, 0xd03) will return true. */
> > @@ -405,12 +421,12 @@ host_detect_local_cpu (int argc, const char **argv)
> >
> > if (aarch64_cpu_data[i].name == NULL)
> > {
> > - auto arch_info = get_arch_from_id (DEFAULT_ARCH);
> > + auto cpu_info = get_cpu_from_id (DEFAULT_CPU);
> >
> > - gcc_assert (arch_info);
> > + gcc_assert (cpu_info);
> >
> > - res = concat ("-march=", arch_info->name, NULL);
> > - default_flags = arch_info->flags;
> > + res = concat ("-mcpu=", cpu_info->name, NULL);
> > + default_flags = cpu_info->flags;
> > }
> > else if (arch)
> > {
> > @@ -449,6 +465,20 @@ host_detect_local_cpu (int argc, const char **argv)
> > break;
> > }
> > }
> > +
> > + /* On big.LITTLE if we find any unknown CPUs we can still pick arch
> > + features as the cores should have the same features. So just pick
> > + the feature flags from any of the cpus. */
> > + if (aarch64_cpu_data[i].name == NULL)
> > + {
> > + auto cpu_info = get_cpu_from_id (DEFAULT_CPU);
> > +
> > + gcc_assert (cpu_info);
> > +
> > + res = concat ("-mcpu=", cpu_info->name, NULL);
> > + default_flags = cpu_info->flags;
> > + }
> > +
> > if (!res)
> > goto not_found;
> > }
> > diff --git a/gcc/testsuite/gcc.target/aarch64/cpunative/info_34
> b/gcc/testsuite/gcc.target/aarch64/cpunative/info_34
> > new file mode 100644
> > index
> 0000000000000000000000000000000000000000..61cb254785a4b9ec19ebe3
> 88402223c9a82af7ed
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/aarch64/cpunative/info_34
> > @@ -0,0 +1,18 @@
> > +processor : 0
> > +BogoMIPS : 100.00
> > +Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 asimddp sve sve2
> fphp asimdhp fcma
> > +CPU implementer : 0xfe
> > +CPU architecture: 8
> > +CPU variant : 0x0
> > +CPU part : 0xd08
> > +CPU revision : 2
> > +
> > +processor : 0
> > +BogoMIPS : 100.00
> > +Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 asimddp sve sve2
> fphp asimdhp fcma
> > +CPU implementer : 0xfe
> > +CPU architecture: 8
> > +CPU variant : 0x0
> > +CPU part : 0xd09
> > +CPU revision : 2
> > +
> > diff --git a/gcc/testsuite/gcc.target/aarch64/cpunative/info_35
> b/gcc/testsuite/gcc.target/aarch64/cpunative/info_35
> > new file mode 100644
> > index
> 0000000000000000000000000000000000000000..61cb254785a4b9ec19ebe3
> 88402223c9a82af7ed
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/aarch64/cpunative/info_35
> > @@ -0,0 +1,18 @@
> > +processor : 0
> > +BogoMIPS : 100.00
> > +Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 asimddp sve sve2
> fphp asimdhp fcma
> > +CPU implementer : 0xfe
> > +CPU architecture: 8
> > +CPU variant : 0x0
> > +CPU part : 0xd08
> > +CPU revision : 2
> > +
> > +processor : 0
> > +BogoMIPS : 100.00
> > +Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 asimddp sve sve2
> fphp asimdhp fcma
> > +CPU implementer : 0xfe
> > +CPU architecture: 8
> > +CPU variant : 0x0
> > +CPU part : 0xd09
> > +CPU revision : 2
> > +
> > diff --git a/gcc/testsuite/gcc.target/aarch64/cpunative/native_cpu_34.c
> b/gcc/testsuite/gcc.target/aarch64/cpunative/native_cpu_34.c
> > new file mode 100644
> > index
> 0000000000000000000000000000000000000000..168140002a0f0205c0f552
> de0cce9b2d356e09e2
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/aarch64/cpunative/native_cpu_34.c
> > @@ -0,0 +1,12 @@
> > +/* { dg-do compile { target { { aarch64*-*-linux*} && native } } } */
> > +/* { dg-set-compiler-env-var GCC_CPUINFO
> "$srcdir/gcc.target/aarch64/cpunative/info_34" } */
> > +/* { dg-additional-options "-mcpu=native" } */
> > +
> > +int main()
> > +{
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler {\.arch
> > armv8-a\+dotprod\+crc\+crypto\+sve2\n}
> } } */
> > +
> > +/* Test a normal looking procinfo. */
> > diff --git a/gcc/testsuite/gcc.target/aarch64/cpunative/native_cpu_35.c
> b/gcc/testsuite/gcc.target/aarch64/cpunative/native_cpu_35.c
> > new file mode 100644
> > index
> 0000000000000000000000000000000000000000..8c3bd6111c77c63541c49e
> 8085ee79deea7a8a54
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/aarch64/cpunative/native_cpu_35.c
> > @@ -0,0 +1,13 @@
> > +/* { dg-do compile { target { { aarch64*-*-linux*} && native } } } */
> > +/* { dg-set-compiler-env-var GCC_CPUINFO
> "$srcdir/gcc.target/aarch64/cpunative/info_34" } */
> > +/* { dg-additional-options "-march=armv8.8-a+sve -mcpu=native" } */
> > +
> > +int main()
> > +{
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler {\.arch armv8.8-a\+crc\+sve\n} } } */
> > +/* { dg-excess-errors "" } */
> > +
> > +/* Test a normal looking procinfo. */
