Re: [Linaro-TCWG-CI] gcc-17-2325-g4302e16581b4: 10 regressions on arm

On Wed, Jul 15, 2026 at 7:46=E2=80=AFPM Andrea Pinski via Gcc <[email protected].=
org> wrote:
>
> On Wed, Jul 15, 2026 at 10:10=E2=80=AFAM <[email protected]> wrote:
> >
> > Dear contributor,
> >
> > Our automatic CI has detected problems related to your patch(es). Pleas=
e find some details below.
> >
> > In  armv8l-unknown-linux-gnueabihf native, after:
> >   | commit gcc-17-2325-g4302e16581b4
> >   | Author: Andrew Pinski <[email protected]>
> >   | Date:   Fri Jul 10 16:55:19 2026 -0700
> >   |
> >   |     vect: Add back testcases for trapping math with comparisons [PR=
36190]
> >   |
> >   |     These were originally renamed to no-trapping-math-vect-*.c in r=
0-87196-g04b03edb56633f
> >   |     but were fixed in r0-107313-gf9613c9a919462 but never added bac=
k to the
> >   |     trapping versions.
> >   | ... 17 lines of the commit log omitted.
> >
> > Produces 10 regressions:
> >   |
> >   | regressions.sum:
> >   | Running gcc:gcc.dg/vect/vect.exp ...
> >   | FAIL: gcc.dg/vect/vect-111.c (test for excess errors)
> >   | FAIL: gcc.dg/vect/vect-111.c -flto -ffat-lto-objects (test for exce=
ss errors)
> >   | FAIL: gcc.dg/vect/vect-ifcvt-12.c (test for excess errors)
> >   | FAIL: gcc.dg/vect/vect-ifcvt-12.c -flto -ffat-lto-objects (test for=
 excess errors)
> >   | ... and 6 more
>
> FAIL: gcc.dg/vect/vect-111.c (test for excess errors)
> Excess errors:
> cc1: warning: '-fassociative-math' disabled; other options take precedenc=
e
>
> This is caused by an interaction with -ftrapping-math added by the new
> testcases and this from check_vect_support_and_set_flags:
> ```
>     } elseif [is-effective-target arm_neon_ok] {
>         eval lappend DEFAULT_VECTCFLAGS [add_options_for_arm_neon ""]
>         # NEON does not support denormals, so is not used for vectorizati=
on by
>         # default to avoid loss of precision.  We must pass -ffast-math t=
o test
>         # vectorization of float operations.
>         lappend DEFAULT_VECTCFLAGS "-ffast-math"
>         if [is-effective-target arm_neon_hw] {
>             set dg-do-what-default run
>         } else {
>             set dg-do-what-default compile
>         }
> ```
> I am not sure what the best way of solving this. Do we just not test
> these testcases on arm neon?
> or something else?

If it's only denormals, can we do with -funsafe-math-optimizations only?
Or does that have the same issue wrt -ftrapping-math?

>
>
> >
> > Used configuration :
> >  *CI config* tcwg_gcc_check armv8l-unknown-linux-gnueabihf
> >  *configure and test flags:* none, autodetected on armv8l-unknown-linux=
-gnueabihf--disable-multilib --with-float=3Dhard --with-mode=3Dthumb --with=
-tune=3Dcortex-a9 --with-arch=3Darmv7-a --with-fpu=3Dneon-fp-armv8
> >
> > We track this bug report under https://linaro.atlassian.net/browse/GNU-=
1969. (Require Linaro login) Please let us know if you have a fix.
> >
> > If you have any questions regarding this report, please ask on linaro-t=
[email protected] mailing list.
> >
> > -----------------8<--------------------------8<------------------------=
--8<--------------------------
> >
> > The information below contains the details of the failures, and the way=
s to reproduce a debug environment:
> >
> > You can find the failure logs in *.log.1.xz files in
> >  * http://54.172.246.49:9090/jobs/tcwg_gcc_check--master-arm-build/buil=
ds/10423/archive/artifacts/00-sumfiles/
> > The full lists of regressions and improvements as well as configure and=
 make commands are in
> >  * http://54.172.246.49:9090/jobs/tcwg_gcc_check--master-arm-build/buil=
ds/10423/archive/artifacts/notify/
> > The list of [ignored] baseline and flaky failures are in
> >  * http://54.172.246.49:9090/jobs/tcwg_gcc_check--master-arm-build/buil=
ds/10423/archive/artifacts/sumfiles/xfails.xfail
> >
> > Current build   : http://54.172.246.49:9090/jobs/tcwg_gcc_check--master=
-arm-build/builds/10423/archive/artifacts/
> > Reference build : http://54.172.246.49:9090/jobs/tcwg_gcc_check--master=
-arm-build/builds/10422/archive/artifacts/
> >
> > Instruction to reproduce the build : https://gitlab.com/LinaroLtd/tcwg/=
ci/interesting-commits/-/raw/master/gcc/sha1/4302e16581b490a196a11de3a54a42=
4f52e27340/tcwg_gcc_check/master-arm/reproduction_instructions.txt
> >
> > Full commit : See in git+ssh://[email protected]/git/gcc.git