[Bug target/101104] test case gcc.c-torture/execute/ieee/cdivchkld.c fails

["patrick.mcgehearty at oracle dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101104

--- Comment #8 from Patrick McGehearty <patrick.mcgehearty at oracle dot com> ---
Thanks for the run.

On the plus side, I would expect FAIL or PASS to be consistent
for all optimization levels, so that's actually good that
they all match now.

I'm either I'm mistaken about the root cause of the failure
or I've made some goof in my fix.

... break to reexamine the tests I did...

got back on gcc135.fsffrance.org and looked carefully at the
tests I ran.  I see where I went wrong. In my manual testing,
I set RBIG, RMIN, RMIN2, RMINSCAL and RMAX2 all to double
precision values instead of long double precision values.
When I modified the libgcc2.c file, I only changed the
RMINSCAL and RMAX2 (which depended DBL_EPSILON).
I just created and ran a new manual test which only changes
RMINSCAL and RMAX2. It fails. Oops...
I'm pretty sure of the fix, but I will take the time to be
careful and submit a revised patch (V6) soon.

My challenge is that the very old glibc on gcc135.fsffrance.org
does not know about _TF_ vs _KF_ and _IF_. It refused to
build the new libgcc/config/rs6000/_divkc3.c file.
That's why I did not test the result in place.

It just occurred to me that if I remove _KF_ references in that
file and build a test compiler, that will give me a way to
test the ibm doubledouble code generated by libgcc/libgcc2.c

Thanks again for helping this fix move forward.

- patrick




On 9/29/2021 4:46 PM, bergner at gcc dot gnu.org wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101104
>
> --- Comment #7 from Peter Bergner <bergner at gcc dot gnu.org> ---
> (In reply to Peter Bergner from comment #6)
>> Ah, the v5 patch.  I'll bootstrap and regtest the patch and report back.
> Building with and without the patch, I'm seeing:
>
> +FAIL: gcc.c-torture/execute/ieee/cdivchkld.c execution,  -O0
>   FAIL: gcc.c-torture/execute/ieee/cdivchkld.c execution,  -O1
>   FAIL: gcc.c-torture/execute/ieee/cdivchkld.c execution,  -O2
>   FAIL: gcc.c-torture/execute/ieee/cdivchkld.c execution,  -O2 -flto
> -fno-use-linker-plugin -flto-partition=none
>   FAIL: gcc.c-torture/execute/ieee/cdivchkld.c execution,  -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects
>   FAIL: gcc.c-torture/execute/ieee/cdivchkld.c execution,  -O3
> -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-fu
> nctions
>   FAIL: gcc.c-torture/execute/ieee/cdivchkld.c execution,  -O3 -g
> +FAIL: gcc.c-torture/execute/ieee/cdivchkld.c execution,  -Og -g
>   FAIL: gcc.c-torture/execute/ieee/cdivchkld.c execution,  -Os
>
> So 2 new FAILs and no new PASSes with the patch. :-(
> Is there anything you want me to check?
>