On 06/11/2024 13:50, Torbjorn SVENSSON wrote:
>
>
> On 2024-11-06 14:04, Richard Earnshaw (lists) wrote:
>> On 06/11/2024 12:23, Torbjorn SVENSSON wrote:
>>>
>>>
>>> On 2024-11-06 12:26, Richard Earnshaw (lists) wrote:
>>>> On 06/11/2024 07:44, Christophe Lyon wrote:
>>>>> On Wed, 6 Nov 2024 at 07:20, Torbjörn SVENSSON
>>>>> <torbjorn.svens...@foss.st.com> wrote:
>>>>>>
>>>>>> While the regression was reported on GCC15, I'm sure that same
>>>>>> regression will be seen on GCC14 when it's tested in the
>>>>>> arm-linux-gnueabihf configuration.
>>>>>>
>>>>>> Ok for trunk and releases/gcc-14?
>>>>>>
>>>>>> --
>>>>>>
>>>>>> This fixes reported regression at
>>>>>> https://linaro.atlassian.net/browse/GNU-1407.
>>>>>>
>>>>>> gcc/testsuite/ChangeLog:
>>>>>>
>>>>>> * gcc.target/arm/pr68620.c: Use effective-target arm_fp.
>>>>>>
>>>>>> Signed-off-by: Torbjörn SVENSSON <torbjorn.svens...@foss.st.com>
>>>>>> ---
>>>>>> gcc/testsuite/gcc.target/arm/pr68620.c | 4 +++-
>>>>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/gcc/testsuite/gcc.target/arm/pr68620.c
>>>>>> b/gcc/testsuite/gcc.target/arm/pr68620.c
>>>>>> index 6e38671752f..1ed84f4ac75 100644
>>>>>> --- a/gcc/testsuite/gcc.target/arm/pr68620.c
>>>>>> +++ b/gcc/testsuite/gcc.target/arm/pr68620.c
>>>>>> @@ -1,8 +1,10 @@
>>>>>> /* { dg-do compile } */
>>>>>> /* { dg-skip-if "-mpure-code supports M-profile without Neon only" {
>>>>>> *-*-* } { "-mpure-code" } } */
>>>>>> /* { dg-require-effective-target arm_arch_v7a_ok } */
>>>>>> -/* { dg-options "-mfp16-format=ieee -mfpu=auto -mfloat-abi=softfp" } */
>>>>>> +/* { dg-require-effective-target arm_fp_ok } */
>>>>>> +/* { dg-options "-mfp16-format=ieee -mfpu=auto" } */
>>>>>> /* { dg-add-options arm_arch_v7a } */
>>>>>> +/* { dg-add-options arm_fp } */
>>>>>>
>>>>>
>>>>> So... this partially reverts your previous patch (bringing back
>>>>> arm_fp). What is the problem now?
>>>>>
>>>>
>>>> Yeah, that sounds wrong. arm_fp_ok tries to find options to add to the
>>>> basic testsuite options, but it can't be combined with arm_arch_v7a as
>>>> that picks a totally different set of flags for the architecture.
>>>
>>> The problem is that for arm-linux-gnueabihf, we cannot use
>>> -mfloat-abi=softfp as there is no multilib available for that ABI, or at
>>> least that's my interpretation of below error message.
>>>
>>> This is the output from the CI run:
>>>
>>> Executing on host:
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/bin/armv8l-unknown-linux-gnueabihf-gcc
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/gcc.target/arm/pr68620.c
>>> -fdiagnostics-plain-output -mfp16-format=ieee -mfpu=auto
>>> -mfloat-abi=softfp -mcpu=unset -march=armv7-a+fp -S -o pr68620.s (timeout =
>>> 600)
>>> spawn -ignore SIGHUP
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/bin/armv8l-unknown-linux-gnueabihf-gcc
>>>
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/gcc.target/arm/pr68620.c
>>> -fdiagnostics-plain-output -mfp16-format=ieee -mfpu=auto
>>> -mfloat-abi=softfp -mcpu=unset -march=armv7-a+fp -S -o pr68620.s
>>> In file included from /usr/include/features.h:510,
>>> from
>>> /usr/include/arm-linux-gnueabihf/bits/libc-header-start.h:33,
>>> from /usr/include/stdint.h:26,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/lib/gcc/armv8l-unknown-linux-gnueabihf/15.0.0/include/stdint.h:11,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/lib/gcc/armv8l-unknown-linux-gnueabihf/15.0.0/include/arm_fp16.h:34,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/lib/gcc/armv8l-unknown-linux-gnueabihf/15.0.0/include/arm_neon.h:41,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/gcc.target/arm/pr68620.c:7:
>>> /usr/include/arm-linux-gnueabihf/gnu/stubs.h:7:11: fatal error:
>>> gnu/stubs-soft.h: No such file or directory
>>> compilation terminated.
>>> compiler exited with status 1
>>> output is:
>>> In file included from /usr/include/features.h:510,
>>> from
>>> /usr/include/arm-linux-gnueabihf/bits/libc-header-start.h:33,
>>> from /usr/include/stdint.h:26,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/lib/gcc/armv8l-unknown-linux-gnueabihf/15.0.0/include/stdint.h:11,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/lib/gcc/armv8l-unknown-linux-gnueabihf/15.0.0/include/arm_fp16.h:34,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/lib/gcc/armv8l-unknown-linux-gnueabihf/15.0.0/include/arm_neon.h:41,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/gcc.target/arm/pr68620.c:7:
>>> /usr/include/arm-linux-gnueabihf/gnu/stubs.h:7:11: fatal error:
>>> gnu/stubs-soft.h: No such file or directory
>>> compilation terminated.
>>>
>>> comp_output (pruned) is:
>>> In file included from /usr/include/features.h:510,
>>> from
>>> /usr/include/arm-linux-gnueabihf/bits/libc-header-start.h:33,
>>> from /usr/include/stdint.h:26,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/lib/gcc/armv8l-unknown-linux-gnueabihf/15.0.0/include/stdint.h:11,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/lib/gcc/armv8l-unknown-linux-gnueabihf/15.0.0/include/arm_fp16.h:34,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/builds/destdir/armv8l-unknown-linux-gnueabihf/lib/gcc/armv8l-unknown-linux-gnueabihf/15.0.0/include/arm_neon.h:41,
>>> from
>>> /home/tcwg-buildslave/workspace/tcwg_gnu_1/abe/snapshots/gcc.git~master/gcc/testsuite/gcc.target/arm/pr68620.c:7:
>>> /usr/include/arm-linux-gnueabihf/gnu/stubs.h:7:11: fatal error:
>>> gnu/stubs-soft.h: No such file or directory
>>> compilation terminated.
>>>
>>> FAIL: gcc.target/arm/pr68620.c (test for excess errors)
>>>
>>> So, if we cannot use arm_fp, what can we use instead to check if it needs
>>> -mfloat-abi=softfp or -mfloat-abi=hard?
>>>
>>> Kind regards,
>>> Torbjörn
>>
>> Ah, got you. Interestingly my ubuntu armhf instalation has booth
>> stubs-soft.h and stubs-hard.h even though it's a hard-float environment, so
>> I wouldn't see this error. I'm not sure if that's something ubuntu has
>> fixed, or whether it's because the tcwg install is slightly non-standard.
>>
>> Technically this isn't a multilib - because we aren't linking, but I see
>> where you're coming from. I need to think a bit about this one. What we
>> really need is some way of checking if stdint.h works in a soft-fp
>> environment; we might need a new check for this in target-supports.exp.
>
> An alternative is to add an entry in the list that is arm_arch_v7a_softfp and
> then do dg-require-effective-target on it, but then it will not be tested for
> HF only-targets. Is this a good enough compromise? We could also go the other
> way and do the "hard" way, but either way, one of them would not be tested in
> that case.
>
> Let me know what you think.
>
> It's the same problem in the attr-neon* patch that I have in parallell to
> this one, but I'll wait for this one to have a way forward before working
> more on that one.
>
> Kind regards,
> Torbjörn
I think the attached is probably a better approach here. It tries to find just
the correct ABI flags to add while remaining compatible with the platform.
It's not perfect: the compiler doesn't really support -mfloat-abi=softfp
correctly when generating thumb1 code, but that's a different bug.
R.
diff --git a/gcc/testsuite/gcc.target/arm/pr68620.c b/gcc/testsuite/gcc.target/arm/pr68620.c
index 6e38671752f..3ffaa5c5a9c 100644
--- a/gcc/testsuite/gcc.target/arm/pr68620.c
+++ b/gcc/testsuite/gcc.target/arm/pr68620.c
@@ -1,8 +1,10 @@
/* { dg-do compile } */
/* { dg-skip-if "-mpure-code supports M-profile without Neon only" { *-*-* } { "-mpure-code" } } */
/* { dg-require-effective-target arm_arch_v7a_ok } */
-/* { dg-options "-mfp16-format=ieee -mfpu=auto -mfloat-abi=softfp" } */
+/* { dg-require-effective-target arm_libc_fp_abi_ok } */
+/* { dg-options "-mfp16-format=ieee -mfpu=auto" } */
/* { dg-add-options arm_arch_v7a } */
+/* { dg-add-options arm_libc_fp_abi } */
#include "arm_neon.h"
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index 75703ddca60..0c2fd83f45c 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -4950,6 +4950,41 @@ proc add_options_for_arm_fp { flags } {
return "$flags $et_arm_fp_flags"
}
+# Some libc headers will only compile correctly if the correct ABI flags
+# are picked for the target environment. Try to find an ABI setting
+# that works. Glibc falls into this category. This test is intended
+# to enable FP as far as possible, so does not try -mfloat-abi=soft.
+proc check_effective_target_arm_libc_fp_abi_ok_nocache { } {
+ global et_arm_libc_fp_abi_flags
+ set et_arm_libc_fp_abi_flags ""
+ if { [check_effective_target_arm32] } {
+ foreach flags {"-mfloat-abi=hard" "-mfloat-abi=softfp"} {
+ if { [check_no_compiler_messages_nocache arm_libc_fp_abi_ok object {
+ #include <stdint.h>
+ } "$flags"] } {
+ set et_arm_libc_fp_abi_flags $flags
+ return 1
+ }
+ }
+ }
+ return 0
+}
+
+proc check_effective_target_arm_libc_fp_abi_ok { } {
+ return [check_cached_effective_target arm_libc_fp_abi_ok \
+ check_effective_target_arm_libc_fp_abi_ok_nocache]
+}
+
+# Add flags that pick the right ABI for the supported libc headers on
+# this platform.
+proc add_options_for_arm_libc_fp_abi { flags } {
+ if { ! [check_effective_target_arm_libc_fp_abi_ok] } {
+ return "$flags"
+ }
+ global et_arm_libc_fp_abi_flags
+ return "$flags $et_arm_libc_fp_abi_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
