Hm, this is weird, as it really seems to depend on the
-march=.... So if there is really a difference
between those structs which make them incompatible on
some archs, we should not consider them to be
compatible in general.
struct g { int a[n]; int b; } *y;
{ struct g { int a[4]; int b; } *y2 = y; }
But I do not see what could go wrong here as
sizeof / alignment is the same for n = 4. So there
is something else I missed....
Am Freitag, dem 22.12.2023 um 05:07 +0800 schrieb haochen.jiang:
> On Linux/x86_64,
>
> 23fee88f84873b0b8b41c8e5a9b229d533fb4022 is the first bad commit
> commit 23fee88f84873b0b8b41c8e5a9b229d533fb4022
> Author: Martin Uecker <uec...@tugraz.at>
> Date: Tue Aug 15 14:58:32 2023 +0200
>
> c23: tag compatibility rules for struct and unions
>
> caused
>
> FAIL: gcc.dg/gnu23-tag-4.c (test for excess errors)
>
> with GCC configured with
>
> ../../gcc/configure
> --prefix=/export/users/haochenj/src/gcc-bisect/master/master/r14-6770/usr
> --enable-clocale=gnu --with-system-zlib --with-demangler-in-ld
> --with-fpmath=sse --enable-languages=c,c++,fortran --enable-cet --without-isl
> --enable-libmpx x86_64-linux --disable-bootstrap
>
> To reproduce:
>
> $ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gcc.dg/gnu23-tag-4.c
> --target_board='unix{-m32\ -march=cascadelake}'"
> $ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gcc.dg/gnu23-tag-4.c
> --target_board='unix{-m64\ -march=cascadelake}'"
>
> (Please do not reply to this email, for question about this report, contact
> me at haochen dot jiang at intel.com.)
> (If you met problems with cascadelake related, disabling AVX512F in command
> line might save that.)
> (However, please make sure that there is no potential problems with AVX512.)
