[Bug testsuite/116784] New: [15 regression] gcc.dg/vect/slp-perm-9.c fails after r15-3715-g77bd23a3e24755

[Bug testsuite/116784] New: [15 regression] gcc.dg/vect/slp-perm-9.c fails after r15-3715-g77bd23a3e24755

[seurer at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116784

            Bug ID: 116784
           Summary: [15 regression] gcc.dg/vect/slp-perm-9.c fails after
                    r15-3715-g77bd23a3e24755
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: testsuite
          Assignee: unassigned at gcc dot gnu.org
          Reporter: seurer at gcc dot gnu.org
  Target Milestone: ---

g:77bd23a3e247555ba427d01af8e5713934be8d5b, r15-3715-g77bd23a3e24755

Do these test cases need adjusting after this change?

make  -k check-gcc RUNTESTFLAGS="vect.exp=gcc.dg/vect/slp-perm-9.c"
FAIL: gcc.dg/vect/slp-perm-9.c scan-tree-dump-times vect "vectorizing stmts
using SLP" 0
FAIL: gcc.dg/vect/slp-perm-9.c -flto -ffat-lto-objects  scan-tree-dump-times
vect "vectorizing stmts using SLP" 0

commit 77bd23a3e247555ba427d01af8e5713934be8d5b (HEAD, refs/bisect/bad)
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Sep 18 12:41:25 2024 +0200

    Fall back to single-lane SLP before falling back to no SLP

[Bug testsuite/116784] [15 regression] gcc.dg/vect/slp-perm-9.c fails after r15-3715-g77bd23a3e24755

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116784

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2024-09-20
   Target Milestone|---                         |15.0
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |ASSIGNED
           Keywords|                            |testsuite-fail

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
It looks like powerpc supports the 3-lane interleaving scheme we use for SLP.

It might fit vect_strided3 (but powerpc isn't amongst that).

In particular we use the following V8HImode permutes:

  _39 = VEC_PERM_EXPR <vect_a_13.25_22, vect_a_13.26_8, { 2, 2, 5, 5, 8, 8, 11,
11 }>;
  _40 = VEC_PERM_EXPR <vect_a_13.26_8, vect_a_13.27_6, { 6, 6, 9, 9, 12, 12,
15, 15 }>;
  _41 = VEC_PERM_EXPR <_39, _40, { 0, 2, 4, 6, 8, 10, 12, 14 }>;
  _35 = VEC_PERM_EXPR <vect_a_13.25_22, vect_a_13.26_8, { 1, 1, 4, 4, 7, 7, 10,
10 }>;
  _36 = VEC_PERM_EXPR <vect_a_13.26_8, vect_a_13.27_6, { 5, 5, 8, 8, 11, 11,
14, 14 }>;
  _37 = VEC_PERM_EXPR <_35, _36, { 0, 2, 4, 6, 8, 10, 12, 14 }>;
  _32 = VEC_PERM_EXPR <vect_a_13.25_22, vect_a_13.26_8, { 0, 0, 3, 3, 6, 6, 9,
9 }>;
  _33 = VEC_PERM_EXPR <vect_a_13.26_8, vect_a_13.27_6, { 4, 4, 7, 7, 10, 10,
13, 13 }>;
  _34 = VEC_PERM_EXPR <_32, _33, { 0, 2, 4, 6, 8, 10, 12, 14 }>;

  _45 = VEC_PERM_EXPR <vect__3.30_43, vect__4.31_44, { 0, 8, 0, 1, 9, 1, 2, 10
}>;
  _46 = VEC_PERM_EXPR <vect__3.30_43, vect__4.31_44, { 2, 3, 11, 3, 4, 12, 4, 5
}>;
  _47 = VEC_PERM_EXPR <vect__4.31_44, vect__3.30_43, { 5, 13, 14, 6, 14, 15, 7,
15 }>;
  _49 = VEC_PERM_EXPR <_45, vect__5.32_48, { 0, 1, 8, 3, 4, 9, 6, 7 }>;
  _50 = VEC_PERM_EXPR <vect__5.32_48, _46, { 2, 9, 10, 3, 12, 13, 4, 15 }>;
  _51 = VEC_PERM_EXPR <_47, vect__5.32_48, { 0, 13, 2, 3, 14, 5, 6, 15 }>;

Note the testcase has the "obvious" problem that the vectorized test uses
vect_perm_short while the SLP check uses vect_perm3_short.  In general
we should now be able to always SLP when we vectorize, so the checks should
match up (or be removed alltogether).

I'll see if matching up causes problems elsewhere.

[Bug testsuite/116784] [15 regression] gcc.dg/vect/slp-perm-9.c fails after r15-3715-g77bd23a3e24755

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116784

--- Comment #2 from GCC 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:fd83474b2fee54697f27719a4631a21d68cb4ab6

commit r15-3727-gfd83474b2fee54697f27719a4631a21d68cb4ab6
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Sep 20 08:53:53 2024 +0200

    testsuite/116784 - match up SLP scan and vectorized scan

    The test used vect_perm_short for the vectorized scanning but
    vect_perm3_short for whether that's done with SLP.  We're now
    generally expecting SLP to be used - even as fallback, so the
    following adjusts both to match up, fixing the powerpc64 reported
    testsuite issue.

            PR testsuite/116784
            * gcc.dg/vect/slp-perm-9.c: Use vect_perm_short also for
            the SLP check.

[Bug testsuite/116784] [15 regression] gcc.dg/vect/slp-perm-9.c fails after r15-3715-g77bd23a3e24755

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116784

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Should be fixed.