[Bug tree-optimization/97486] New: [11 Regression] ICE in vect_create_constant_vectors, at tree-vect-slp.c:4513 since r11-4005-g6c6e0cafa38cee83

[Bug tree-optimization/97486] New: [11 Regression] ICE in vect_create_constant_vectors, at tree-vect-slp.c:4513 since r11-4005-g6c6e0cafa38cee83

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97486

            Bug ID: 97486
           Summary: [11 Regression] ICE in vect_create_constant_vectors,
                    at tree-vect-slp.c:4513 since
                    r11-4005-g6c6e0cafa38cee83
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: rguenth at gcc dot gnu.org
  Target Milestone: ---

It's reduced from emacs:

$ cat emacs.i
struct {
  int *end_info;
  int *fp;
} png_load_body_c;

int *png_set_longjmp_fn();

void setjmp();

void png_load_body() {
  int *fp;
  int png_ptr, info_ptr, *end_info;
  if (!fp)
    return;
  if (png_ptr) {
    info_ptr = 0;
    end_info = png_set_longjmp_fn();
  }
  png_load_body_c.end_info = end_info;
  png_load_body_c.fp = fp;
  if (png_ptr)
    png_set_longjmp_fn();
  setjmp(info_ptr);
}

$ gcc emacs.i -c -O3
during GIMPLE pass: slp
emacs.i: In function ‘png_load_body’:
emacs.i:10:6: internal compiler error: in vect_create_constant_vectors, at
tree-vect-slp.c:4513
   10 | void png_load_body() {
      |      ^~~~~~~~~~~~~
0x736046 vect_create_constant_vectors
        /home/marxin/Programming/gcc/gcc/tree-vect-slp.c:4513
0x736046 vect_schedule_slp_instance
        /home/marxin/Programming/gcc/gcc/tree-vect-slp.c:5032
0x1045d47 vect_schedule_slp_instance
        /home/marxin/Programming/gcc/gcc/tree-vect-slp.c:5041
0x1047a92 vect_schedule_slp(vec_info*, vec<_slp_instance*, va_heap, vl_ptr>)
        /home/marxin/Programming/gcc/gcc/tree-vect-slp.c:5299
0x104905d vect_slp_region
        /home/marxin/Programming/gcc/gcc/tree-vect-slp.c:4046
0x104905d vect_slp_bbs
        /home/marxin/Programming/gcc/gcc/tree-vect-slp.c:4164
0x1049afc vect_slp_function(function*)
        /home/marxin/Programming/gcc/gcc/tree-vect-slp.c:4215
0x104b76d execute
        /home/marxin/Programming/gcc/gcc/tree-vectorizer.c:1430
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

[Bug tree-optimization/97486] [11 Regression] ICE in vect_create_constant_vectors, at tree-vect-slp.c:4513 since r11-4005-g6c6e0cafa38cee83

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97486

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
      Known to fail|                            |11.0
   Last reconfirmed|                            |2020-10-19
      Known to work|                            |10.2.0
           Priority|P3                          |P1
   Target Milestone|---                         |11.0
             Status|UNCONFIRMED                 |NEW

[Bug tree-optimization/97486] [11 Regression] ICE in vect_create_constant_vectors, at tree-vect-slp.c:4513 since r11-4005-g6c6e0cafa38cee83

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97486

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, so we insert on the edge 4->5

<bb 4> [local count: 290235635]:
info_ptr_14(ab) = 0;
_16 = png_set_longjmp_fn ();

<bb 5> [local count: 290197324]:
# info_ptr_1(ab) = PHI <info_ptr_14(ab)(4)>
png_load_body_c.end_info = _16;
png_load_body_c.fp = fp_9(D);
png_set_longjmp_fn ();

where gimple_find_edge_insert_loc has

  /* If the destination has one predecessor which has no PHI nodes,
     insert there.  Except for the exit block.

     The requirement for no PHI nodes could be relaxed.  Basically we
     would have to examine the PHIs to prove that none of them used
     the value set by the statement we want to insert on E.  That
     hardly seems worth the effort.  */
 restart:
  if (single_pred_p (dest)
      && gimple_seq_empty_p (phi_nodes (dest))
      && dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
    {

so the single-arg PHI confuses us here.

So we now either have to restrict the BB region or convince ourselves that
splitting the edge is OK at the above point (I think it is) ...

I'm tending to keep regions small for now.

[Bug tree-optimization/97486] [11 Regression] ICE in vect_create_constant_vectors, at tree-vect-slp.c:4513 since r11-4005-g6c6e0cafa38cee83

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97486

--- Comment #2 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:361c378dda1f17435ecc364ab246978784df2482

commit r11-4068-g361c378dda1f17435ecc364ab246978784df2482
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Oct 19 11:30:46 2020 +0200

    tree-optimization/97486 - avoid edge insertion in SLP vectorizing

    This avoids edge inserting and eventual splitting during BB SLP
    vectorization for now.

    2020-10-19  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/97486
            * tree-vect-slp.c (vect_slp_function): Split after stmts
            ending a BB.

            * gcc.dg/vect/bb-slp-pr97486.c: New testcase.

[Bug tree-optimization/97486] [11 Regression] ICE in vect_create_constant_vectors, at tree-vect-slp.c:4513 since r11-4005-g6c6e0cafa38cee83

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97486

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> ---
Fixed.