Jakub Jelinek <ja...@redhat.com> writes:
> On Thu, Sep 04, 2025 at 09:58:14AM +0200, Richard Biener wrote:
>> I'm in favor of disabling but I also fear the code will bitrot quickly if so?
>> We might also want to have a set of testcases for the -fcompare-debug
>> issues that are fixed by the change of defaults?
>>
>> Otherwise I defer to Jakub who will better remember why we didn't
>> do this earlier.
>
> I remember a lot of fallout, but trying this patch (I've just applied
> it,
Yes, I was mildly terrified I'd missed something so checked several
extra times to try reproduce those past issues you mentioned, but
couldn't with trunk. I was waiting for your testing :)
> rebuilt stage3 cc1/cc1plus/f951/lto1 and did make check-{gcc,g++} for
> dwarf2.exp and guality.exp) I'm getting just
> -FAIL: gcc.dg/guality/pr36728-4.c -O3 -g -DPREVENT_OPTIMIZATION line 14 y
> == 2
> -FAIL: gcc.dg/guality/pr43051-1.c -O3 -fomit-frame-pointer -funroll-loops
> -fpeel-loops -ftracer -finline-functions -DPREVENT_OPTIMIZATION line 34 c
> == &a[0]
> +FAIL: gcc.dg/guality/pr43479.c -O2 -flto -fno-use-linker-plugin
> -flto-partition=none -DPREVENT_OPTIMIZATION line 18 j == 8
> +FAIL: gcc.dg/guality/pr43479.c -O2 -flto -fuse-linker-plugin
> -fno-fat-lto-objects -DPREVENT_OPTIMIZATION line 18 j == 8
> +FAIL: g++.dg/guality/pr55665.C -O2 -flto -fuse-linker-plugin
> -fno-fat-lto-objects line 23 p == 40
> on x86_64-linux and
> -FAIL: gcc.dg/guality/pr36728-4.c -O3 -g -DPREVENT_OPTIMIZATION line 14 y
> == 2
> on i686-linux, so I agree in guality it is a wash.
>
> So as you said, I'd suggest to enable -gstatement-frontiers and/or
> -gvariable-location-views on a few copies of guality tests (both C and C++)
> and on say 20-30 randomly chosen other tests (perhaps torture ones such that
> it is tested at different optimization levels; but in a form of
> dg-additional-options if the test doesn't contain dg-options already).
I'll work on that. Thanks.
>
> Jakub
sam
