Re: [r12-3893 Regression] FAIL: gcc.target/i386/vect-pr97352.c scan-assembler-times vmov.pd 4 on Linux/x86_64
On Tue, 28 Sep 2021, Richard Biener wrote:
> On Tue, 28 Sep 2021, Hongtao Liu wrote:
>
> > On Tue, Sep 28, 2021 at 2:59 PM Richard Biener via Gcc-patches
> > 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
> > > > 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.
Meh, that doesn't work. We then fall through
else if (SCALAR_INT_MODE_P (prevailing_mode)
|| !related_vector_mode (prevailing_mode,
inner_mode, nunits).exists
(_mode))
{
/* Fall back to using mode_for_vector, mostly in the hope of being
able to use an integer mode. */
if (known_eq (nunits, 0U)
&& !multiple_p (GET_MODE_SIZE (prevailing_mode), nbytes,
))
return NULL_TREE;
if (!mode_for_vector (inner_mode, nunits).exists (_mode))
return NULL_TREE;
and return V2SImode anyway from mode_for_vector ...
So - should we only allow integer modes here as the comment suggests?
With that, thus
if (!mode_for_vector (inner_mode, nunits).exists (_mode)
|| GET_MODE_CLASS (simd_mode) != MODE_INT)
return NULL_TREE;
we "properly" _not_ use V2SImode for vectorization on x86 when
!TARGET_MMX_WITH_SSE. Note that will also not use V2SImode
for vectorizing copies (which are properly supported). So I'm
not sure rejecting V2SImode outright is "proper" ...
Richard.
Re: [r12-3893 Regression] FAIL: gcc.target/i386/vect-pr97352.c scan-assembler-times vmov.pd 4 on Linux/x86_64
On Tue, 28 Sep 2021, Hongtao Liu wrote:
> On Tue, Sep 28, 2021 at 2:59 PM Richard Biener via Gcc-patches
> 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
> > > 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.
Re: [r12-3893 Regression] FAIL: gcc.target/i386/vect-pr97352.c scan-assembler-times vmov.pd 4 on Linux/x86_64
On Tue, Sep 28, 2021 at 2:59 PM Richard Biener via Gcc-patches
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
> > 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.
>
> > 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.
or use (?:vinsertf128|vpermpd) for alternative instructions.
> really impossible to cater for all possible ISA variants in these kind
> of testcases.
Additional option -march=cascadelake sometimes can find real regression.
>
> Richard.
--
BR,
Hongtao
Re: [r12-3893 Regression] FAIL: gcc.target/i386/vect-pr97352.c scan-assembler-times vmov.pd 4 on Linux/x86_64
On Mon, 27 Sep 2021, sunil.k.pandey wrote: > On Linux/x86_64, > > 6390c5047adb75960f86d56582e6322aaa4d9281 is the first bad commit > commit 6390c5047adb75960f86d56582e6322aaa4d9281 > Author: Richard Biener > 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. > 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 really impossible to cater for all possible ISA variants in these kind of testcases. Richard.
[r12-3893 Regression] FAIL: gcc.target/i386/vect-pr97352.c scan-assembler-times vmov.pd 4 on Linux/x86_64
On Linux/x86_64,
6390c5047adb75960f86d56582e6322aaa4d9281 is the first bad commit
commit 6390c5047adb75960f86d56582e6322aaa4d9281
Author: Richard Biener
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
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
FAIL: gcc.target/i386/vect-pr97352.c scan-assembler-times vmov.pd 4
with GCC configured with
../../gcc/configure
--prefix=/local/skpandey/gccwork/toolwork/gcc-bisect-master/master/r12-3893/usr
--enable-clocale=gnu --with-system-zlib --with-demangler-in-ld
--with-fpmath=sse --enable-languages=c,c++,fortran --enable-cet --without-isl
--enable-libmpx x86_64-linux --disable-bootstrap
To reproduce:
$ cd {build_dir}/gcc && make check
RUNTESTFLAGS="vect.exp=gcc.dg/vect/bb-slp-17.c --target_board='unix{-m32}'"
$ cd {build_dir}/gcc && make check
RUNTESTFLAGS="vect.exp=gcc.dg/vect/bb-slp-17.c --target_board='unix{-m32\
-march=cascadelake}'"
$ cd {build_dir}/gcc && make check
RUNTESTFLAGS="vect.exp=gcc.dg/vect/bb-slp-pr65935.c --target_board='unix{-m32\
-march=cascadelake}'"
$ cd {build_dir}/gcc && make check
RUNTESTFLAGS="vect.exp=gcc.dg/vect/bb-slp-pr65935.c --target_board='unix{-m64\
-march=cascadelake}'"
$ cd {build_dir}/gcc && make check
RUNTESTFLAGS="i386.exp=gcc.target/i386/vect-pr97352.c
--target_board='unix{-m32\ -march=cascadelake}'"
(Please do not reply to this email, for question about this report, contact me
at skpgkp2 at gmail dot com)
