Re: [PATCH 3/3] vect: inbranch SIMD clones

[Jakub Jelinek <jakub@redhat.com>]

On Fri, Jan 06, 2023 at 12:20:33PM +0000, Andrew Stubbs wrote:
> > > +/* Ensure the the in-branch simd clones are used on targets that support
> > > +   them.  These counts include all call and definitions.  */
> > > +
> > > +/* { dg-skip-if "" { x86_64-*-* } { "-flto" } { "" } } */
> > 
> > Drop lines line above.
> 
> I don't want to drop the comment because I get so frustrated by testcases
> that fail when something changes and it's not obvious what the original
> author was actually trying to test.
> 
> I've tried to fix the -flto thing and I can't figure out how. The problem
> seems to be that there are two dump files from the two compiler invocations
> and it scans the wrong one. Aarch64 has the same problem.

Two dumps are because it is in a dg-do run test.
I think it would be better to separate it, have for all cases one
test with defaulted dg-do (in vect.exp that is either dg-do run or dg-do
compile:
# If the target system supports vector instructions, the default action
# for a test is 'run', otherwise it's 'compile'.
) without the dg-final and then another one with the same TYPE which would
be forcibly dg-do compile with dg-final and
dg-additional-options "-ffat-lto-objects", then you get a single dump only.

> > > +/* { dg-final { scan-tree-dump-times "simdclone" 18 "optimized" { target x86_64-*-* } } } */
> > > +/* { dg-final { scan-tree-dump-times "simdclone" 7 "optimized" { target amdgcn-*-* } } } */
> > 
> > And scan-tree-dump-times " = foo.simdclone" 2 "optimized"; I'd think that
> > should be the right number for all of x86_64, amdgcn and aarch64.  And
> > please don't forget about i?86-*-* too.
> 
> I've switched the pattern and changed to using the "vect" dump (instead of
> "optimized") so that the later transformations don't mess up the counts.
> However there are still other reasons why the count varies. It might be that
> those can be turned off by options somehow, but probably testing those cases
> is valuable too. The values are 2, 3, or 4, now, instead of 18, so that's an
> improvement.

But still varries between the architectures, so it is an extra maintainance
nightmare.

> > > +/* TODO: aarch64 */
> > 
> > For aarch64, one would need to include it in check_effective_target_vect_simd_clones
> > first...
> 
> I've done so and tested it, but that's not included in the patch because
> there were other testcases that started reporting fails. None of the new
> testcases fail for Aarch64.

Sure, that would be for a separate patch.

Anyway, if you want, commit the patch as is and tweak the testcases if
possible incrementally.

	Jakub