You can't make an omelette without breaking eggs, as they say. New
architectures need new assemblers.
However, I wonder if there's anything in v9-a that significantly affects
the quality of the base multilib code needed for building the libraries.
It might be that we can deal with v9-a by just mapping it to the v8-a
equivalents. That would then avoid the need for an updated assembler,
and reduce the build time and install footprint.
R.
On 16/11/2021 08:03, Christophe Lyon via Gcc-patches wrote:
Hi,
On Tue, Nov 9, 2021 at 12:36 PM Przemyslaw Wirkus via Gcc-patches <
gcc-patches@gcc.gnu.org> wrote:
-----Original Message-----
From: Przemyslaw Wirkus
Sent: 18 October 2021 10:37
To: gcc-patches@gcc.gnu.org
Cc: Richard Earnshaw <richard.earns...@arm.com>; Ramana
Radhakrishnan <ramana.radhakrish...@arm.com>; Kyrylo Tkachov
<kyrylo.tkac...@arm.com>; ni...@redhat.com
Subject: [PATCH][GCC] arm: add armv9-a architecture to -march
Hi,
This patch is adding `armv9-a` to -march in Arm GCC.
In this patch:
+ Add `armv9-a` to -march.
+ Update multilib with armv9-a and armv9-a+simd.
After this patch three additional multilib directories are available:
$ arm-none-eabi-gcc --print-multi-lib .; [...vanilla multi-lib
dirs...] thumb/v9-a/nofp;@mthumb@march=armv9-a@mfloat-abi=soft
thumb/v9-a+simd/softfp;@mthumb@march=armv9-a+simd@mfloat-
abi=softfp
thumb/v9-a+simd/hard;@mthumb@march=armv9-a+simd@mfloat-
abi=hard
This is causing a GCC build failure when using "old" binutils (I'm using
2.36.1),
because the new -march=armv9-a option is not supported. This breaks the
multilib support.
I don't remember how we handled similar cases in the past? Is that just
"expected", and
"current" GCC needs "current" binutils, or should we have a multilib list
dependent on
the actual binutils support? (I think this is not the case, and it sounds
like an undesirable
extra complication in an already overcrowded mutilib-Makefile)
Christophe
New multi-lib directories under
$GCC_INSTALL_DIE/lib/gcc/arm-none-eabi/12.0.0/thumb are created:
thumb/
+--- v9-a
| |--- nofp
|
+--- v9-a+simd
|--- hard
|--- softfp
Regtested on arm-none-eabi cross and no issues.
OK for master?
Thanks.
commit 32ba7860ccaddd5219e6dae94a3d0653e124c9dd
Ok.
Thanks,
Kyrill
gcc/ChangeLog:
* config/arm/arm-cpus.in (armv9): New define.
(ARMv9a): New group.
(armv9-a): New arch definition.
* config/arm/arm-tables.opt: Regenerate.
* config/arm/arm.h (BASE_ARCH_9A): New arch enum value.
* config/arm/t-aprofile: Added armv9-a and armv9+simd.
* config/arm/t-arm-elf: Added arm9-a, v9_fps and all_v9_archs
to MULTILIB_MATCHES.
* config/arm/t-multilib: Added v9_a_nosimd_variants and
v9_a_simd_variants to MULTILIB_MATCHES.
* doc/invoke.texi: Update docs.
gcc/testsuite/ChangeLog:
* gcc.target/arm/multilib.exp: Update test with armv9-a entries.
* lib/target-supports.exp (v9a): Add new armflag.
(__ARM_ARCH_9A__): Add new armdef.
--
kind regards,
Przemyslaw Wirkus
