[Bug other/97299] New: [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[Bug other/97299] New: [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[seurer at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

            Bug ID: 97299
           Summary: [11 regression] gcc.dg/vect/slp-reduc-3.c fails after
                    r11-3563
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: seurer at gcc dot gnu.org
  Target Milestone: ---

g:9ff2bcd9df8f189dcc94e3bef33f7f282dcaa780, r11-3563
make  -k check-gcc RUNTESTFLAGS="vect.exp=gcc.dg/vect/slp-reduc-3.c"
FAIL: gcc.dg/vect/slp-reduc-3.c scan-tree-dump-times vect "VEC_PERM_EXPR" 0
FAIL: gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects  scan-tree-dump-times
vect "VEC_PERM_EXPR" 0
# of expected passes            6
# of unexpected failures        2

commit 9ff2bcd9df8f189dcc94e3bef33f7f282dcaa780 (HEAD, refs/bisect/bad)
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Sep 30 16:12:20 2020 +0200


Executing on host: /home/seurer/gcc/git/build/gcc-test/gcc/xgcc
-B/home/seurer/gcc/git/build/gcc-test/gcc/ exceptions_enabled346952.cc   
-fdiagnostics-plain-output  -S -o exceptions_enabled346952.s    (timeout = 300)
spawn -ignore SIGHUP /home/seurer/gcc/git/build/gcc-test/gcc/xgcc
-B/home/seurer/gcc/git/build/gcc-test/gcc/ exceptions_enabled346952.cc
-fdiagnostics-plain-output -S -o exceptions_enabled346952.s
PASS: gcc.dg/vect/slp-reduc-3.c (test for excess errors)
Setting LD_LIBRARY_PATH to
:/home/seurer/gcc/git/build/gcc-test/gcc::/home/seurer/gcc/git/build/gcc-test/gcc:/home/seurer/gcc/git/build/gcc-test/./gmp/.libs:/home/seurer/gcc/git/build/gcc-test/./prev-gmp/.libs:/home/seurer/gcc/git/build/gcc-test/./mpfr/src/.libs:/home/seurer/gcc/git/build/gcc-test/./prev-mpfr/src/.libs:/home/seurer/gcc/git/build/gcc-test/./mpc/src/.libs:/home/seurer/gcc/git/build/gcc-test/./prev-mpc/src/.libs:/home/seurer/gcc/git/build/gcc-test/./isl/.libs:/home/seurer/gcc/git/build/gcc-test/./prev-isl/.libs
Execution timeout is: 300
spawn [open ...]
PASS: gcc.dg/vect/slp-reduc-3.c execution test
gcc.dg/vect/slp-reduc-3.c: pattern found 0 times
XFAIL: gcc.dg/vect/slp-reduc-3.c scan-tree-dump-times vect
"vect_recog_dot_prod_pattern: detected" 1
PASS: gcc.dg/vect/slp-reduc-3.c scan-tree-dump-times vect "vectorized 1 loops"
2
gcc.dg/vect/slp-reduc-3.c: pattern found 0 times
XFAIL: gcc.dg/vect/slp-reduc-3.c scan-tree-dump-times vect "vectorizing stmts
using SLP" 1
gcc.dg/vect/slp-reduc-3.c: pattern found 12 times
FAIL: gcc.dg/vect/slp-reduc-3.c scan-tree-dump-times vect "VEC_PERM_EXPR" 0
Executing on host: /home/seurer/gcc/git/build/gcc-test/gcc/xgcc
-B/home/seurer/gcc/git/build/gcc-test/gcc/
/home/seurer/gcc/git/gcc-test/gcc/testsuite/gcc.dg/vect/slp-reduc-3.c   
-fdiagnostics-plain-output  -flto -ffat-lto-objects -maltivec -mpower8-vector
-ftree-vectorize -fno-tree-loop-distribute-patterns -fno-vect-cost-model
-fno-common -O2 -fdump-tree-vect-details --param=vect-epilogues-nomask=0  -lm 
-o ./slp-reduc-3.exe    (timeout = 300)
spawn -ignore SIGHUP /home/seurer/gcc/git/build/gcc-test/gcc/xgcc
-B/home/seurer/gcc/git/build/gcc-test/gcc/
/home/seurer/gcc/git/gcc-test/gcc/testsuite/gcc.dg/vect/slp-reduc-3.c
-fdiagnostics-plain-output -flto -ffat-lto-objects -maltivec -mpower8-vector
-ftree-vectorize -fno-tree-loop-distribute-patterns -fno-vect-cost-model
-fno-common -O2 -fdump-tree-vect-details --param=vect-epilogues-nomask=0 -lm -o
./slp-reduc-3.exe
PASS: gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects (test for excess
errors)
Setting LD_LIBRARY_PATH to
:/home/seurer/gcc/git/build/gcc-test/gcc::/home/seurer/gcc/git/build/gcc-test/gcc:/home/seurer/gcc/git/build/gcc-test/./gmp/.libs:/home/seurer/gcc/git/build/gcc-test/./prev-gmp/.libs:/home/seurer/gcc/git/build/gcc-test/./mpfr/src/.libs:/home/seurer/gcc/git/build/gcc-test/./prev-mpfr/src/.libs:/home/seurer/gcc/git/build/gcc-test/./mpc/src/.libs:/home/seurer/gcc/git/build/gcc-test/./prev-mpc/src/.libs:/home/seurer/gcc/git/build/gcc-test/./isl/.libs:/home/seurer/gcc/git/build/gcc-test/./prev-isl/.libs
Execution timeout is: 300
spawn [open ...]
PASS: gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects execution test
gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects : pattern found 0 times
XFAIL: gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects  scan-tree-dump-times
vect "vect_recog_dot_prod_pattern: detected" 1
PASS: gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects  scan-tree-dump-times
vect "vectorized 1 loops" 2
gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects : pattern found 0 times
XFAIL: gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects  scan-tree-dump-times
vect "vectorizing stmts using SLP" 1
gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects : pattern found 12 times
FAIL: gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects  scan-tree-dump-times
vect "VEC_PERM_EXPR" 0
testcase /home/seurer/gcc/git/gcc-test/gcc/testsuite/gcc.dg/vect/vect.exp
completed in 2 seconds

                === gcc Summary ===

# of expected passes            6
# of unexpected failures        2

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

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
          Component|other                       |testsuite
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-10-06
   Target Milestone|---                         |11.0

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I will have a look.

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Just noting that while gcc-testresults has almost daily results of GCC 8,9,10
branches for ppc64le-linux trunk is only daily tested on ppc64-aix

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, so this is a bad interaction of pattern detection and SLP reduction
vectorization.  We're detecting

/home/rguenther/src/trunk/gcc/testsuite/gcc.dg/vect/slp-reduc-3.c:26:14: note: 
 widen_sum pattern recognized: patt_47 = prod_24 w+ res2_31;

which in turn empties LOOP_VINFO_REDUCTIONS via

  /* Patterns cannot be vectorized using SLP, because they change the order of
     computation.  */
  if (loop_vinfo)
    {
      unsigned ix, ix2;
      stmt_vec_info *elem_ptr;
      VEC_ORDERED_REMOVE_IF (LOOP_VINFO_REDUCTIONS (loop_vinfo), ix, ix2,
                             elem_ptr, *elem_ptr == stmt_info);
    }

which means we're ending up with interleaving (and worse code).
The sentence above should only apply to reduction ops performing lane
reduction (SAD_EXPR, but also WIDEN_SUM_EXPR).

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

--- Comment #4 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:104304cd246e9e8cd874f6cef7e2a5cd4bb0114d

commit r11-6767-g104304cd246e9e8cd874f6cef7e2a5cd4bb0114d
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Jan 18 14:51:00 2021 +0100

    testsuite/97299 - fix test condition of gcc.dg/vect/slp-reduc-3.c

    This avoids looking for permute optimization when SLP cannot be applied.

    2021-01-18  Richard Biener  <rguenther@suse.de>

            PR testsuite/97299
            * gcc.dg/vect/slp-reduc-3.c: Guard VEC_PERM_EXPR scan.

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

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

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

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|FIXED                       |---
             Status|RESOLVED                    |REOPENED
                 CC|                            |ro at gcc dot gnu.org

--- Comment #6 from Rainer Orth <ro at gcc dot gnu.org> ---
This patch has caused

+XPASS: gcc.dg/vect/slp-reduc-3.c -flto -ffat-lto-objects  scan-tree-dump-times
vect "VEC_PERM_EXPR" 0
+XPASS: gcc.dg/vect/slp-reduc-3.c scan-tree-dump-times vect "VEC_PERM_EXPR" 0

on sparc-sun-solaris2.11 (32 and 64-bit) and, according to gcc-testresults, on
armeb-none-linux-gnueabihf, aarch64-suse-linux-gnu

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 50017
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50017&action=edit
patch

OK, so the arm fails are because they use load_lanes.  Which means adjusting
like

/* { dg-final { scan-tree-dump-times "VEC_PERM_EXPR" 0 "vect" { xfail { {
vect_widen_sum_hi_to_si_pattern || { ! vect_unpack } } && { ! vect_load_lanes }
} } } } */

should work there.  Then we have solaris which likely does not vectorize this
at all which means we need to condition all scans on the 'vectorized 1 loops'
scan.  Meh, complicated target selectors :/

Rainer, can you test the attached patch?

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[ro at CeBiTec dot Uni-Bielefeld.DE]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

--- Comment #8 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
> --- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
> Created attachment 50017
>   --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50017&action=edit
> patch
[...]
> Rainer, can you test the attached patch?

Sure, just did on sparc-sun-solaris2.11 and (for good measure)
i386-pc-solaris2.11: worked fine on both.  Thanks.

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

--- 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:f46a40112caa7e039d949beda94386ff4e436a35

commit r11-6831-gf46a40112caa7e039d949beda94386ff4e436a35
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Jan 21 10:57:18 2021 +0100

    testsuite/97299 - more gcc.dg/vect/slp-reduc-3.c massaging

    This adds more guards to the VEC_PERM_EXPR scan, namely that
    we also could end up with load-lanes and of course no vectorization
    at all.  Need dependent scans (scan-if-scan-X PASSed ...).

    2021-01-21  Richard Biener  <rguenther@suse.de>

            PR testsuite/97299
            * gcc.dg/vect/slp-reduc-3.c: Amend target selectors.

[Bug testsuite/97299] [11 regression] gcc.dg/vect/slp-reduc-3.c fails after r11-3563

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97299

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

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

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed again (fingers crossing...)