[Bug c/97862] New: [11 Regression] ICE in expand_omp_for_init_vars, at omp-expand.c:2524

[Bug c/97862] New: [11 Regression] ICE in expand_omp_for_init_vars, at omp-expand.c:2524

[gscfq@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97862

            Bug ID: 97862
           Summary: [11 Regression] ICE in expand_omp_for_init_vars, at
                    omp-expand.c:2524
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gscfq@t-online.de
  Target Milestone: ---

Changed between 20200705 and 20200712 :


$ cat z1.c
void f ()
{
  int i, j;
#pragma omp for collapse(2)
  for (i = 0; i < 1; ++i)
    for (j = 0; j < i; ++j);
}


$ gcc-11-20200705 -c z1.c -fopenmp
$
$ gcc-11-20201115 -c z1.c -fopenmp
during GIMPLE pass: ompexp
z1.c: In function 'f':
z1.c:4:9: internal compiler error: Segmentation fault
    4 | #pragma omp for collapse(2)
      |         ^~~
0xb3b52f crash_signal
        ../../gcc/toplev.c:330
0x145ebc6 expand_omp_for_init_vars
        ../../gcc/omp-expand.c:2524
0x146be17 expand_omp_for_static_nochunk
        ../../gcc/omp-expand.c:5261
0x1474b6c expand_omp_for
        ../../gcc/omp-expand.c:8006
0x147537a expand_omp
        ../../gcc/omp-expand.c:9883
0x147725d execute_expand_omp
        ../../gcc/omp-expand.c:10115

[Bug c/97862] [11 Regression] ICE in expand_omp_for_init_vars, at omp-expand.c:2524

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97862

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
                 CC|                            |jakub at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
   Target Milestone|---                         |11.0
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org
   Last reconfirmed|                            |2020-11-16

[Bug middle-end/97862] [11 Regression] ICE in expand_omp_for_init_vars, at omp-expand.c:2524

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97862

Martin Liška <marxin at gcc dot gnu.org> changed:

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

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with r6-4544-ge01d41e553aae245.

[Bug middle-end/97862] [11 Regression] ICE in expand_omp_for_init_vars, at omp-expand.c:2524

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97862

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
With r11-1967-g5acef69f9d3d9f3c537b5e5157519edf02f86c4d actually.
The version you've mentioned started (properly) rejecting it, this wasn't valid
in OpenMP 4.5, but is valid in 5.0 and for GCC11 the support has been added.

[Bug middle-end/97862] [11 Regression] ICE in expand_omp_for_init_vars, at omp-expand.c:2524

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97862

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

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

[Bug middle-end/97862] [11 Regression] ICE in expand_omp_for_init_vars, at omp-expand.c:2524

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97862

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 49576
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49576&action=edit
gcc11-pr97862.patch

Untested fix.

[Bug middle-end/97862] [11 Regression] ICE in expand_omp_for_init_vars, at omp-expand.c:2524

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97862

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:ba009860aec4619f2424f5bdee812f14572dc3cc

commit r11-5121-gba009860aec4619f2424f5bdee812f14572dc3cc
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Nov 18 09:40:45 2020 +0100

    openmp: Fix ICE on non-rectangular loop with known 0 iterations

    The loops in the testcase are non-rectangular and have 0 iterations
    (the outer loop iterates, but the inner one never).  In this case we
    just have the overall number of iterations computed (0), and don't have
    factor and other values computed.  We never need to map logical iterations
    to the individual iterations in that case, and we were crashing during
    expansion of that code.

    2020-11-18  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/97862
            * omp-expand.c (expand_omp_for_init_vars): Don't use the sqrt path
            if number of iterations is constant 0.

            * c-c++-common/gomp/pr97862.c: New test.

[Bug middle-end/97862] [11 Regression] ICE in expand_omp_for_init_vars, at omp-expand.c:2524

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97862

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

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

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.