On Thu, 6 Mar 2025 at 11:03, Christophe Lyon <christophe.l...@linaro.org> wrote:
>
> On Wed, 5 Mar 2025 at 12:59, Richard Earnshaw <rearn...@arm.com> wrote:
> >
> > The header file arm_neon.h provides the Advanced SIMD intrinsics that
> > are available on armv7 or later A & R profile cores. However, they
> > are not compatible with M-profile and we also need to ensure that the
> > FP instructions are enabled (with -mfloat-abi=softfp/hard). That
> > leads to some complicated checking as arm_neon.h includes stdint.h
> > and, at least on linux, that can require that the appropriate ABI
> > bits/ headers are also installed.
> >
> > This patch adds a new check to target-supports.exp to establish the
> > minimal set of option overrides needed to enable use of this header in
> > a test.
> >
> > gcc/testsuite:
> > * lib/target-supports.exp
> > (check_effective_target_arm_neon_h_ok_nocache): New function.
> > (check_effective_target_arm_neon_h_ok): Likewise.
> > (add_options_for_arm_neon_h): Likewise.
Sorry forgot to ask: do these new functions need an entry in sourcebuild.texi?
> > (check_effective_target_arm_libc_fp_abi_ok_nocache): Allow any
> > Arm target, not just arm32.
> > * gcc.target/arm/attr-neon-builtin-fail.c: Use it.
> > * gcc.target/arm/attr-neon-builtin-fail2.c: Likewise.
> > * gcc.target/arm/attr-neon-fp16.c: Likewise.
> > * gcc.target/arm/attr-neon2.c: Likewise.
> > ---
> >
> > I'm going to wait 24 hrs before committing this as I'd like to see the
> > results of the CI first.
> >
>
> I've manually started precommit tests which are not executed by
> default (targeting arm-none-eabi with runtest flags overridden), and
> results look good:
>
> * NO CHANGE (except for line number change in attr-neon-builtin-fail.c):
> v7a_softfp_eabi -marm/-march=armv7-a/-mfpu=vfpv3-d16/-mfloat-abi=softfp
> thumb_m33_hard
> -mthumb/-march=armv8-m.main+dsp+fp/-mtune=cortex-m33/-mfloat-abi=hard/-mfpu=auto
>
> * UNSUPPORTED -> PASS:
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-builtin-fail.c
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-fp16.c
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon2.c
> default flags ""
> thumb_m3_softfp
> -mthumb/-march=armv7-m/-mtune=cortex-m3/-mfloat-abi=softfp/-mfpu=auto
> thumb_m7_hard
> -mthumb/-march=armv7e-m+fp.dp/-mtune=cortex-m7/-mfloat-abi=hard/-mfpu=auto
> thumb_v8a_hard -mthumb/-march=armv8-a+simd/-mfpu=auto/-mfloat-abi=hard
>
> * UNSUPPORTED -> PASS:
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-builtin-fail.c
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-builtin-fail2.c
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-fp16.c
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon2.c
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/pr68620.c
> thumb_m0_soft
> -mthumb/-march=armv6s-m/-mtune=cortex-m0/-mfloat-abi=soft/-mfpu=auto
> thumb_m23_soft
> -mthumb/-march=armv8-m.base/-mtune=cortex-m23/-mfloat-abi=soft/-mfpu=auto
>
> * FAIL / UNRESOLVED -> PASS:
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-builtin-fail.c
> (test for excess errors)
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-builtin-fail.c
> (test for warnings, line 14)
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-builtin-fail.c
> at line 17 (test for errors, line )
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-builtin-fail2.c
> (test for errors, line 13)
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-builtin-fail2.c
> (test for excess errors)
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon-fp16.c (test
> for excess errors)
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon2.c (test for
> excess errors)
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon2.c
> check-function-bodies my
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon2.c
> check-function-bodies my1
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon2.c
> scan-assembler .fpu\\s+neon\n
> gcc:gcc.target/arm/arm.exp=gcc.target/arm/attr-neon2.c
> scan-assembler .fpu\\s+vfp\n
> thumb_m55_hard
> -mthumb/-march=armv8.1-m.main+mve.fp+fp.dp/-mtune=cortex-m55/-mfloat-abi=hard/-mfpu=auto
>
> so we actually get more coverage, which is nice, thanks!
>
> > R.
> >
> > .../gcc.target/arm/attr-neon-builtin-fail.c | 6 +--
> > .../gcc.target/arm/attr-neon-builtin-fail2.c | 5 +-
> > gcc/testsuite/gcc.target/arm/attr-neon-fp16.c | 4 +-
> > gcc/testsuite/gcc.target/arm/attr-neon2.c | 5 +-
> > gcc/testsuite/lib/target-supports.exp | 53 ++++++++++++++++++-
> > 5 files changed, 60 insertions(+), 13 deletions(-)
> >
> > diff --git a/gcc/testsuite/gcc.target/arm/attr-neon-builtin-fail.c
> > b/gcc/testsuite/gcc.target/arm/attr-neon-builtin-fail.c
> > index fb6e0b9cd66..645d708f005 100644
> > --- a/gcc/testsuite/gcc.target/arm/attr-neon-builtin-fail.c
> > +++ b/gcc/testsuite/gcc.target/arm/attr-neon-builtin-fail.c
> > @@ -1,9 +1,8 @@
> > /* Check that calling a neon builtin from a function compiled with vfp
> > fails. */
> > /* { dg-do compile } */
> > -/* { dg-require-effective-target arm_fp_ok } */
> > -/* { dg-require-effective-target arm_neon_ok } */
> > +/* { dg-require-effective-target arm_neon_h_ok } */
> > /* { dg-options "-O2" } */
> > -/* { dg-add-options arm_fp } */
> > +/* { dg-add-options arm_neon_h } */
> >
> > #include <arm_neon.h>
> >
> > @@ -15,4 +14,3 @@ foo (uint8x16_t *p)
> > }
> >
> > /* { dg-error "inlining failed in call to 'always_inline'" "" { target
> > *-*-* } 0 } */
> > -
> > diff --git a/gcc/testsuite/gcc.target/arm/attr-neon-builtin-fail2.c
> > b/gcc/testsuite/gcc.target/arm/attr-neon-builtin-fail2.c
> > index 9cb5a2ebb90..ed0c4634b77 100644
> > --- a/gcc/testsuite/gcc.target/arm/attr-neon-builtin-fail2.c
> > +++ b/gcc/testsuite/gcc.target/arm/attr-neon-builtin-fail2.c
> > @@ -1,8 +1,8 @@
> > /* Check that calling a neon builtin from a function compiled with vfp
> > fails. */
> > /* { dg-do compile } */
> > -/* { dg-require-effective-target arm_vfp_ok } */
> > +/* { dg-require-effective-target arm_neon_h_ok } */
> > /* { dg-options "-O2" } */
> > -/* { dg-add-options arm_vfp } */
> > +/* { dg-add-options arm_neon_h } */
> >
> > extern __simd64_int8_t a, b;
> >
> > @@ -13,4 +13,3 @@ foo (__simd128_int16_t *p)
> > *p = (__simd128_int16_t)__builtin_neon_vaddlsv8qi (a, b); /* { dg-error
> > "You must enable NEON instructions .*" } */
> >
> > }
> > -
> > diff --git a/gcc/testsuite/gcc.target/arm/attr-neon-fp16.c
> > b/gcc/testsuite/gcc.target/arm/attr-neon-fp16.c
> > index d7b75645bc4..a5982604f9e 100644
> > --- a/gcc/testsuite/gcc.target/arm/attr-neon-fp16.c
> > +++ b/gcc/testsuite/gcc.target/arm/attr-neon-fp16.c
> > @@ -1,8 +1,8 @@
> > /* { dg-do compile } */
> > /* { dg-skip-if "-mpure-code supports M-profile only and without Neon" {
> > *-*-* } { "-mpure-code" } } */
> > -/* { dg-require-effective-target arm_fp_ok } */
> > +/* { dg-require-effective-target arm_neon_h_ok } */
> > /* { dg-options "-mfp16-format=ieee" } */
> > -/* { dg-add-options arm_fp } */
> > +/* { dg-add-options arm_neon_h } */
> >
> > #include "arm_neon.h"
> >
> > diff --git a/gcc/testsuite/gcc.target/arm/attr-neon2.c
> > b/gcc/testsuite/gcc.target/arm/attr-neon2.c
> > index a7a72dac379..c0f7667c2dc 100644
> > --- a/gcc/testsuite/gcc.target/arm/attr-neon2.c
> > +++ b/gcc/testsuite/gcc.target/arm/attr-neon2.c
> > @@ -1,8 +1,7 @@
> > /* { dg-do compile } */
> > -/* { dg-require-effective-target arm_neon_ok } */
> > -/* { dg-require-effective-target arm_fp_ok } */
> > +/* { dg-require-effective-target arm_neon_h_ok } */
> > /* { dg-options "-Ofast" } */
> > -/* { dg-add-options arm_fp } */
> > +/* { dg-add-options arm_neon_h } */
> >
> > /* Reset fpu to a value compatible with the next pragmas. */
> > #pragma GCC target ("fpu=vfp")
> > diff --git a/gcc/testsuite/lib/target-supports.exp
> > b/gcc/testsuite/lib/target-supports.exp
> > index d02d1fa9bec..ca0bd1bc8a2 100644
> > --- a/gcc/testsuite/lib/target-supports.exp
> > +++ b/gcc/testsuite/lib/target-supports.exp
> > @@ -5127,7 +5127,7 @@ proc add_options_for_arm_fp { flags } {
> > proc check_effective_target_arm_libc_fp_abi_ok_nocache { } {
> > global et_arm_libc_fp_abi_flags
> > set et_arm_libc_fp_abi_flags ""
> > - if { [check_effective_target_arm32] } {
> > + if { [istarget arm*-*-*] } {
> > foreach flags {"-mfloat-abi=hard" "-mfloat-abi=softfp"} {
> > if { [check_no_compiler_messages_nocache arm_libc_fp_abi_ok
> > object {
> > #include <stdint.h>
> > @@ -5155,6 +5155,57 @@ proc add_options_for_arm_libc_fp_abi { flags } {
> > return "$flags $et_arm_libc_fp_abi_flags"
> > }
> >
> > +# Try to find the minimal set of flags needed to make the header file
> > +# arm_neon.h compatible with this compilation. The is complicated due
> > +# to the fact that this header doesn't work properly on m-profile cores
> > +# and also won't work correctly if the wrong floating-point ABI is used
> > +# on the platfrom (since arm_neon.h can include stdint.h, which on Linux
> typo "platform"
>
> > +# will pull in stub headers that aren't installed).
> > +# Note: This will not necessarily enable Neon instructions, just provide
> > +# something where the header will not cause errors.
> > +
> > +proc check_effective_target_arm_neon_h_ok_nocache { } {
> > + # none-arm or thumb1 cannot support neon, so there's no point in
> I'm not sure what "none-arm" means here? "not arm" ?
>
>
> Thanks,
>
> Christophe
>
> > + # looking further.
> > + if { [istarget arm*-*-*] } {
> > + global et_arm_neon_h_flags
> > + set base_flags [add_options_for_arm_libc_fp_abi ""]
> > + foreach flags {"" "-mfpu=auto" "-marm" "-marm -mfpu=auto" \
> > + "-mcpu=unset -march=armv7-a+fp -mfpu=auto" } {
> > + if { [check_no_compiler_messages_nocache arm_neon_h_ok assembly
> > {
> > + #if __ARM_ARCH < 5
> > + #error architecture too low for FP
> > + #endif
> > + #if __ARM_ARCH < 7
> > + #if !defined(__arm__) || (defined(__thumb__) &&
> > !defined(__thumb2__))
> > + #error incompatible arch or mode
> > + #endif
> > + #endif
> > + #if __ARM_ARCH_PROFILE == 'M'
> > + #error incompatible profile
> > + #endif
> > + } "$base_flags $flags" ] } {
> > + set et_arm_neon_h_flags "$base_flags $flags"
> > + return 1
> > + }
> > + }
> > + }
> > + return 0
> > +}
> > +
> > +proc check_effective_target_arm_neon_h_ok { } {
> > + return [check_cached_effective_target arm_neon_h_ok \
> > + check_effective_target_arm_neon_h_ok_nocache]
> > +}
> > +
> > +proc add_options_for_arm_neon_h { flags } {
> > + if { ! [check_effective_target_arm_neon_h_ok] } {
> > + return "$flags"
> > + }
> > + global et_arm_neon_h_flags
> > + return "$flags $et_arm_neon_h_flags"
> > +}
> > +
> > # Return 1 if this is an ARM target defining __ARM_FP with
> > # double-precision support. We may need -mfloat-abi=softfp or
> > # equivalent options. Some multilibs may be incompatible with these
> > --
> > 2.34.1
> >
