Re: Tests of gcc development beyond its testsuite (in this case, for gfortran)

[Andrew Pinski <pinskia@gmail.com>]

On Mon, May 6, 2024 at 2:27 PM Toon Moene <toon@moene.org> wrote:
>
> I have now, for some time, ran LAPACK's test programs on my gcc/gfortran
> builds on both on the x86_64-linux-gnu architecture, as well as the
> aarch64-linux-gnu one (see, e.g.,
> http://moene.org/~toon/lapack-amd64-gfortran13-O3).
>
> The results are rather alarming - this is r15-202 for aarch64 vs r15-204
> for x86_64 (compiled with -O3):

Did you test x86_64 with -march=native (or with -mfma) or just -O3?
The reason why I am asking is aarch64 includes FMA by default while
x86_64 does not.
Most recent x86_64 includes an FMA instruction but since the base ISA
does not include it, it is not enabled by default.
I am suspect the aarch64 "excessive exceeding the threshold for
errors" are all caused by the more use of FMA rather than anything
else.

Thanks,
Andrew Pinski

>
> diff lapack-amd64-gfortran15-O3 lapack-aarch64-gfortran15-O3
>
> 3892,3895c3928,3931
> < REAL                  1327023         0       (0.000%)        0       (0.000%)
> < DOUBLE PRECISION      1300917         6       (0.000%)        0       (0.000%)
> < COMPLEX               786775          0       (0.000%)        0       (0.000%)
> < COMPLEX16             787842          0       (0.000%)        0       (0.000%)
> ---
>  > REAL                 1317063         71      (0.005%)        0       (0.000%)
>  > DOUBLE PRECISION     1318331         54      (0.004%)        4       (0.000%)
>  > COMPLEX              767023          390     (0.051%)        0       (0.000%)
>  > COMPLEX16            772338          305     (0.039%)        0       (0.000%)
> 3897c3933
> < --> ALL PRECISIONS    4202557         6       (0.000%)        0       (0.000%)
> ---
>  > --> ALL PRECISIONS   4174755         820     (0.020%)        4       (0.000%)
>
> Note the excessive exceeding the threshold for errors on the aarch64
> side (>).
>
> Of course, this is only an excerpt of the full log file - there is more
> information in it to zoom in on the errors on the aarch64 side (note
> that the x86_64 side is not faultless).
>
> Is there a way to pass this information to our websites, so that we do
> not "forget" this - or in the alternative, follow the progress in
> solving this ?
>
> Kind regards,
>
> --
> Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
> Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands