On Tue, 28 Sep 2021, Hongtao Liu wrote:
> On Tue, Sep 28, 2021 at 2:59 PM Richard Biener via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > On Mon, 27 Sep 2021, sunil.k.pandey wrote:
> >
> > > On Linux/x86_64,
> > >
> > > 6390c5047adb75960f86d56582e6322aaa4d9281 is the first bad commit
> > > commit 6390c5047adb75960f86d56582e6322aaa4d9281
> > > Author: Richard Biener <rguent...@suse.de>
> > > Date: Wed Nov 18 09:36:57 2020 +0100
> > >
> > > Allow different vector types for stmt groups
> > >
> > > caused
> > >
> > > FAIL: gcc.dg/vect/bb-slp-17.c -flto -ffat-lto-objects
> > > scan-tree-dump-times slp2 "optimized: basic block" 1
> > > FAIL: gcc.dg/vect/bb-slp-17.c scan-tree-dump-times slp2 "optimized: basic
> > > block" 1
> >
> > This shows that it is maybe a bad idea to support V2SImode vectorization
> > with -m32 when we refuse to implement even plus.
> >
> > OTOH it's just the mode that's available, autovectorize_vector_modes
> > doesn't include the corresponding mode but we still pick it up via
> > the related vector mode for group-size == 2.
It looks like we could define the vectorize.related_mode hook to
reject V2SImode when !TARGET_MMX_WITH_SSE - the default implementation
just checks for vector_mode_supported_p.
> > > FAIL: gcc.dg/vect/bb-slp-pr65935.c -flto -ffat-lto-objects
> > > scan-tree-dump-times slp1 "optimized: basic block" 10
> > > FAIL: gcc.dg/vect/bb-slp-pr65935.c scan-tree-dump-times slp1 "optimized:
> > > basic block" 10
> >
> > We are now vectorizing the SSE tail when vectorizing with AVX. I'll
> > adjust the testcase to prefer SSE.
> >
> > > FAIL: gcc.target/i386/vect-pr97352.c scan-assembler-times vmov.pd 4
> >
> > With -mach=cascadelake we get
> >
> > vpermpd $68, c, %ymm0
> > vpermpd $238, c, %ymm0
> >
> > instead of
> >
> > vmovapd c, %ymm1
> > vinsertf128 $1, %xmm1, %ymm1, %ymm0
> > vperm2f128 $49, %ymm1, %ymm1, %ymm0
> >
> > what's a way to disallow additional -march= from taking effect? It's
> I usually add -mno-{avx,avx512f} and -mtune=generic or sometimes
> -mprefer-vector-width=* to the testcases.
OK, I will try this route then.
Thanks,
Richard.
