[Bug testsuite/96109] New: gcc.dg/vect/slp-47.c etc. FAIL

[Bug testsuite/96109] New: gcc.dg/vect/slp-47.c etc. FAIL

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

            Bug ID: 96109
           Summary: gcc.dg/vect/slp-47.c etc. FAIL
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: testsuite
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: rguenth at gcc dot gnu.org
  Target Milestone: ---
            Target: sparc-sun-solaris2.11, arm*-*-*, ia64-suse-linux-gnu

The new gcc.dg/vect/slp-47.c and gcc.dg/vect/slp-48.c tests FAIL on various
targets, e.g. sparc-sun-solaris2.11 (both 32 and 64-bit):

+FAIL: gcc.dg/vect/slp-47.c -flto -ffat-lto-objects  scan-tree-dump-times vect
"vectorizing stmts using SLP" 2
+FAIL: gcc.dg/vect/slp-47.c scan-tree-dump-times vect "vectorizing stmts using
SLP" 2
+FAIL: gcc.dg/vect/slp-48.c -flto -ffat-lto-objects  scan-tree-dump-times vect
"vectorizing stmts using SLP" 2
+FAIL: gcc.dg/vect/slp-48.c scan-tree-dump-times vect "vectorizing stmts using
SLP" 2

IIUC the failure on SPARC is due to

/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/slp-47.c:12:19: missed: 
 not vectorized: unsupported unaligned load: y[_5]
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/slp-47.c:20:17: missed: 
 not vectorized: unsupported unaligned load: y[_2]

I'm attaching the dump for reference.

[Bug testsuite/96109] gcc.dg/vect/slp-47.c etc. FAIL

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

--- Comment #1 from Rainer Orth <ro at gcc dot gnu.org> ---
Created attachment 48844
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48844&action=edit
32-bit sparc-sun-solaris2.11 slp-47.c.163t.vect

[Bug testsuite/96109] gcc.dg/vect/slp-47.c etc. FAIL

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

Rainer Orth <ro at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.0

[Bug testsuite/96109] gcc.dg/vect/slp-47.c etc. FAIL

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-07-08

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Hmm, the loads should be all aligned ... but maybe we're not figuring they are.
Ah, so this is confusion in vect_compute_data_ref_alignment which does

  /* If this is a backward running DR then first access in the larger
     vectype actually is N-1 elements before the address in the DR.
     Adjust misalign accordingly.  */
  if (tree_int_cst_sgn (drb->step) < 0)
    /* PLUS because STEP is negative.  */
    misalignment += ((TYPE_VECTOR_SUBPARTS (vectype) - 1)
                     * -TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE
(vectype))));

but that's of course not the ideal place to do this because the actual
DRs alignment is _not_ different.  And in fact for SLP the above is even
bogus - I suppose we might even end up with wrong code in case the above
would make the access appear aligned.

[Bug testsuite/96109] gcc.dg/vect/slp-47.c etc. FAIL

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, it's indeed wrong which means we'd fall through the checks that prevent
SPARC from vectorizing here but then we'll create an unaligned access
anyway (because VMAT_STRIDED_SLP is too lazy to figure out appropriate
alignment).  We're also assuming element alignment there.

static double x[1024], y[1024];

void __attribute__((noipa))
foo ()
{
  for (int i = 0; i < 511; ++i)
    {
      x[2*i] = y[1022 - 2*i - 1];
      x[2*i+1] = y[1022 - 2*i];
    }
}

int main()
{
  for (int i = 0; i < 1024; ++i)
    x[i] = 0, y[i] = i;
  foo ();
  for (int i = 0; i < 1022; ++i)
    if (x[i] != y[1022 - (i^1)])
      __builtin_abort ();
  if (x[1022] != 0 || x[1023] != 0)
    __builtin_abort ();
  return 0;
}

[Bug testsuite/96109] gcc.dg/vect/slp-47.c etc. FAIL

[clyon at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

Christophe Lyon <clyon at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clyon at gcc dot gnu.org
             Target|sparc-sun-solaris2.11,      |sparc-sun-solaris2.11,
                   |arm*-*-*,                   |arm*-*-*,
                   |ia64-suse-linux-gnu         |ia64-suse-linux-gnu,
                   |                            |aarch64*elf

--- Comment #4 from Christophe Lyon <clyon at gcc dot gnu.org> ---
Also seen on aarch64-elf (aarch64-linux-gnu is OK)

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rsandifo at gcc dot gnu.org

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #3)
> OK, it's indeed wrong which means we'd fall through the checks that prevent
> SPARC from vectorizing here but then we'll create an unaligned access
> anyway (because VMAT_STRIDED_SLP is too lazy to figure out appropriate
> alignment).  We're also assuming element alignment there.
> 
> static double x[1024], y[1024];
> 
> void __attribute__((noipa))
> foo ()
> {
>   for (int i = 0; i < 511; ++i)
>     {
>       x[2*i] = y[1022 - 2*i - 1];
>       x[2*i+1] = y[1022 - 2*i];
>     }
> }
> 
> int main()
> {
>   for (int i = 0; i < 1024; ++i)
>     x[i] = 0, y[i] = i;
>   foo ();
>   for (int i = 0; i < 1022; ++i)
>     if (x[i] != y[1022 - (i^1)])
>       __builtin_abort ();
>   if (x[1022] != 0 || x[1023] != 0)
>     __builtin_abort ();
>   return 0;
> }

So for example on aarch64-linux with -O3 -mstrict-align -fno-vect-cost-model
we analyze this as

x.c:6:21: note:   vect_model_load_cost: aligned.
x.c:6:21: note:   vect_model_load_cost: inside_cost = 3, prologue_cost = 0 .

but correctly emit an unaligned load (dump with -gimple to see the alignment)

  _20 = &y + 8168ul;
...
  _19 = __PHI (__BB5: _16, __BB2: _20);
...
  _15 = __MEM <vector(2) double, 64> ((double *)_19);

and correctly (but not optimal) expand it via extract-bit-field to

;; _15 = MEM <vector(2) double> [(double *)ivtmp_19];

(insn 12 11 13 (clobber (reg:V2DF 95 [ _15 ])) "x.c":8:17 -1
     (nil))

(insn 13 12 14 (set (subreg:DI (reg:V2DF 95 [ _15 ]) 0)
        (mem:DI (reg:DI 92 [ ivtmp.13 ]) [1 MEM <vector(2) double> [(double
*)ivtmp_19]+0 S8 A64])) "x.c":8:17 -1
     (nil))

(insn 14 13 0 (set (subreg:DI (reg:V2DF 95 [ _15 ]) 8)
        (mem:DI (plus:DI (reg:DI 92 [ ivtmp.13 ])
                (const_int 8 [0x8])) [1 MEM <vector(2) double> [(double
*)ivtmp_19]+8 S8 A64])) "x.c":8:17 -1
     (nil))

so we're not getting a runtime fail here but clearly the vectorizers idea
of alignment of the access is bogus (and if VMAT_STRIDED_SLP were less
lazy and trusted the computed alignment info we'd miscompile).  I guess
we're getting away with this because RTL expansion has fallback code
to correctly expand misaligned accesses on strict-align targets.  But
clearly it's not what the vectorizer costs (it also oddly costs a
vec_construct when you enable the cost model but doesn't emit any in the end).

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
So the question is whether we can make vect_compute_data_ref_alignment
vectype agnostic (to also fix the required same vectype for multi SLP nodes
covering the same DRs) and instead make DR_MISALIGNMENT a function
we pass vectype (and an element offset?) to, computing whether the step
maintains alignment on the fly (and have the offset specify that
"N-1 elements before the address" we do for negative step)?  Basically
only record info for the scalar access.  Specifically I wonder whether this
will work to determine the base_misaligned info and realigning the base.

[Bug testsuite/96109] [11/12 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.0                        |11.2

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 11.1 has been released, retargeting bugs to GCC 11.2.

[Bug testsuite/96109] [11/12 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.2                        |11.3

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 11.2 is being released, retargeting bugs to GCC 11.3

[Bug testsuite/96109] [11/12 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:94f28340513753ba94ab483e93ce1d096842a5ad

commit r12-4706-g94f28340513753ba94ab483e93ce1d096842a5ad
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Oct 25 13:39:07 2021 +0200

    Move negative stride bias out of dr_misalignment

    This moves applying of a bias for negative stride accesses out of
    dr_misalignment in favor of a more general optional offset argument.
    The negative bias is now computed by get_load_store_type and applied
    accordingly to determine the alignment support scheme.  Likewise
    the peeling/versioning code is adjusted albeit that still assumes
    we'll end up with VMAT_CONTIGUOUS_DOWN or VMAT_CONTIGUOUS_REVERSE
    but at least when not so (VMAT_STRIDED_SLP is one possibility) then
    get_load_store_type will _not_ falsely report an aligned access but
    instead an access with known misalignment.

    This fixes PR96109.

    2021-10-25  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/96109
            * tree-vectorizer.h (dr_misalignment): Add optional offset
            parameter.
            * tree-vect-data-refs.c (dr_misalignment): Likewise.  Remove
            offset applied for negative stride accesses.
            (vect_enhance_data_refs_alignment): Compute negative stride
            access offset and pass it to dr_misalignment.
            * tree-vect-stmts.c (get_negative_load_store_type): Pass
            negative offset to dr_misalignment.
            (get_group_load_store_type): Likewise.
            (get_load_store_type): Likewise.
            (vectorizable_store): Remove asserts about alignment.
            (vectorizable_load): Likewise.

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[11/12 Regression]          |[11 Regression]
                   |gcc.dg/vect/slp-47.c etc.   |gcc.dg/vect/slp-47.c etc.
                   |FAIL                        |FAIL
      Known to fail|                            |11.2.0
      Known to work|                            |12.0

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Should be fixed on trunk, backporting the whole series of changes is likely not
a good idea.

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.3                        |11.4

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 11.3 is being released, retargeting bugs to GCC 11.4.

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.4                        |11.5

--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 11.4 is being released, retargeting bugs to GCC 11.5.

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

David Binderman <dcb314 at hotmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dcb314 at hotmail dot com

--- Comment #13 from David Binderman <dcb314 at hotmail dot com> ---
The bug first seems to appear sometime between g:93f803d53b5ccaab
and g:68f7cb6cf9e8b9f2, some 39 commits.

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

--- Comment #14 from David Binderman <dcb314 at hotmail dot com> ---
Sorry wrong bug report.

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

--- Comment #15 from Rainer Orth <ro at gcc dot gnu.org> ---
Created attachment 57507
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57507&action=edit
current sparc-sun-solaris2.11 dumps

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

--- Comment #16 from Rainer Orth <ro at gcc dot gnu.org> ---
The two tests still/again? FAIL on 32 and 64-bit Solaris/SPARC.

If I understand the dumps correctly

/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/slp-47.c:9:21: note:  
==> examining statement: _3 = y[_2];
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/slp-47.c:9:21: missed:  
unsupported vect permute { 1 0 3 2 5 4 }
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/slp-47.c:9:21: missed:  
unsupported load permutation
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/slp-47.c:11:17: missed: 
 not vectorized: relevant stmt not supported: _3 = y[_2];

the tests should also require vect_perm?

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

--- Comment #17 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Rainer Orth <ro@gcc.gnu.org>:

https://gcc.gnu.org/g:96b63fa255e343bb9b3e7f77302213a91ce96293

commit r14-9427-g96b63fa255e343bb9b3e7f77302213a91ce96293
Author: Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
Date:   Mon Mar 11 15:45:17 2024 +0100

    testsuite: vect: Require vect_perm in several tests [PR114071, PR113557,
PR96109]

    Several vectorization tests FAIL on 32 and 64-bit Solaris/SPARC:

    FAIL: gcc.dg/vect/pr37027.c -flto -ffat-lto-objects scan-tree-dump-times
    vect "vectorized 1 loops" 1
    FAIL: gcc.dg/vect/pr37027.c -flto -ffat-lto-objects scan-tree-dump-times
    vect "vectorizing stmts using SLP" 1
    FAIL: gcc.dg/vect/pr37027.c scan-tree-dump-times vect "vectorized 1 loops"
1
    FAIL: gcc.dg/vect/pr37027.c scan-tree-dump-times vect "vectorizing stmts
    using SLP" 1
    FAIL: gcc.dg/vect/pr67790.c -flto -ffat-lto-objects scan-tree-dump vect
    "vectorizing stmts using SLP"
    FAIL: gcc.dg/vect/pr67790.c scan-tree-dump vect "vectorizing stmts using
SLP"
    FAIL: gcc.dg/vect/slp-47.c -flto -ffat-lto-objects scan-tree-dump-times
    vect "vectorizing stmts using SLP" 2
    FAIL: gcc.dg/vect/slp-47.c scan-tree-dump-times vect "vectorizing stmts
    using SLP" 2
    FAIL: gcc.dg/vect/slp-48.c -flto -ffat-lto-objects scan-tree-dump-times
    vect "vectorizing stmts using SLP" 2
    FAIL: gcc.dg/vect/slp-48.c scan-tree-dump-times vect "vectorizing stmts
    using SLP" 2
    FAIL: gcc.dg/vect/slp-reduc-1.c -flto -ffat-lto-objects
    scan-tree-dump-times vect "vectorized 1 loops" 1
    FAIL: gcc.dg/vect/slp-reduc-1.c -flto -ffat-lto-objects
    scan-tree-dump-times vect "vectorizing stmts using SLP" 1
    FAIL: gcc.dg/vect/slp-reduc-1.c scan-tree-dump-times vect "vectorized 1
loops" 1
    FAIL: gcc.dg/vect/slp-reduc-1.c scan-tree-dump-times vect "vectorizing
    stmts using SLP" 1
    FAIL: gcc.dg/vect/slp-reduc-2.c -flto -ffat-lto-objects
    scan-tree-dump-times vect "vectorized 1 loops" 1
    FAIL: gcc.dg/vect/slp-reduc-2.c -flto -ffat-lto-objects
    scan-tree-dump-times vect "vectorizing stmts using SLP" 1
    FAIL: gcc.dg/vect/slp-reduc-2.c scan-tree-dump-times vect "vectorized 1
loops" 1
    FAIL: gcc.dg/vect/slp-reduc-2.c scan-tree-dump-times vect "vectorizing
    stmts using SLP" 1
    FAIL: gcc.dg/vect/slp-reduc-7.c -flto -ffat-lto-objects
    scan-tree-dump-times vect "vectorized 1 loops" 1
    FAIL: gcc.dg/vect/slp-reduc-7.c -flto -ffat-lto-objects
    scan-tree-dump-times vect "vectorizing stmts using SLP" 1
    FAIL: gcc.dg/vect/slp-reduc-7.c scan-tree-dump-times vect "vectorized 1
loops" 1
    FAIL: gcc.dg/vect/slp-reduc-7.c scan-tree-dump-times vect "vectorizing
    stmts using SLP" 1
    FAIL: gcc.dg/vect/slp-reduc-8.c -flto -ffat-lto-objects scan-tree-dump vect
    "vectorized 1 loops"
    FAIL: gcc.dg/vect/slp-reduc-8.c scan-tree-dump vect "vectorized 1 loops"
    FAIL: gcc.dg/vect/vect-multi-peel-gaps.c -flto -ffat-lto-objects
    scan-tree-dump vect "LOOP VECTORIZED"
    FAIL: gcc.dg/vect/vect-multi-peel-gaps.c scan-tree-dump vect "LOOP
VECTORIZED"

    The dumps show variations of

    /vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/pr37027.c:24:17:
    note: ==> examining statement: _4 = a[i_19].f2;
    /vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/pr37027.c:24:17:
    missed: unsupported vect permute { 1 0 3 2 5 4 }
    /vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/pr37027.c:24:17:
    missed: unsupported load permutation
    /vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/vect/pr37027.c:27:17:
    missed: not vectorized: relevant stmt not supported: _4 = a[i_19].f2;

    so I think the tests should require vect_perm.  This is what this patch
does

    Tested on sparc-sun-solaris2.11 and i386-pc-solaris2.11.

    2024-02-22  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

            gcc/testsuite:
            PR tree-optimization/114071
            * gcc.dg/vect/pr37027.c: Require vect_perm.
            * gcc.dg/vect/pr67790.c: Likewise.
            * gcc.dg/vect/slp-reduc-1.c: Likewise.
            * gcc.dg/vect/slp-reduc-2.c: Likewise.
            * gcc.dg/vect/slp-reduc-7.c: Likewise.
            * gcc.dg/vect/slp-reduc-8.c: Likewise.

            PR tree-optimization/113557
            * gcc.dg/vect/vect-multi-peel-gaps.c (scan-tree-dump): Also
            require vect_perm.

            PR testsuite/96109
            * gcc.dg/vect/slp-47.c: Require vect_perm.
            * gcc.dg/vect/slp-48.c: Likewise.

[Bug testsuite/96109] [11 Regression] gcc.dg/vect/slp-47.c etc. FAIL

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96109

--- Comment #18 from Rainer Orth <ro at gcc dot gnu.org> ---
SPARC testsuite failures fixed for GCC 14.0.1.