[Bug c++/95272] New: ice in vectorizable_reduction, at tree-vect-loop.c:6197

[Bug c++/95272] New: ice in vectorizable_reduction, at tree-vect-loop.c:6197

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95272

            Bug ID: 95272
           Summary: ice in vectorizable_reduction, at
                    tree-vect-loop.c:6197
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

For this C++ code:

enum { a = 5, b };
typedef struct {
  int c[b];
} d;
extern d e[];
int f;
int g[6];
void h() {
  int i;
  for (; f; f++) {
    i = 0;
    for (; i < b; i++)
      if (e[f].c[i])
        g[i] = e[f].c[i];
  }
}

compiled by recent gcc trunk and compiler flags -w -c -O3 -march=cooperlake,
I get:

during GIMPLE pass: vect
bug613.cc: In function ‘void h()’:
bug613.cc:8:6: internal compiler error: in vectorizable_reduction, at
tree-vect-
loop.c:6197
    8 | void h() {
      |      ^
0x11e91f5 vectorizable_reduction(_loop_vec_info*, _stmt_vec_info*, _slp_tree*,
_
slp_instance*, vec<stmt_info_for_cost, va_heap, vl_ptr>*)
        ../../trunk.git/gcc/tree-vect-loop.c:6197
0x11bb55d vect_analyze_stmt(vec_info*, _stmt_vec_info*, bool*, _slp_tree*,
_slp_
instance*, vec<stmt_info_for_cost, va_heap, vl_ptr>*)
        ../../trunk.git/gcc/tree-vect-stmts.c:11067
0x120767d vect_slp_analyze_node_operations_1(vec_info*, _slp_tree*,
_slp_instanc
e*, vec<stmt_info_for_cost, va_heap, vl_ptr>*)
        ../../trunk.git/gcc/tree-vect-slp.c:2676
0x120767d vect_slp_analyze_node_operations(vec_info*, _slp_tree*,
_slp_instance*
, hash_set<_slp_tree*, false, default_hash_traits<_slp_tree*> >&,
hash_set<_slp_
tree*, false, default_hash_traits<_slp_tree*> >&, vec<stmt_info_for_cost,
va_hea
p, vl_ptr>*)
        ../../trunk.git/gcc/tree-vect-slp.c:2844


The problem first seems to occur sometime between dates 20200521 and
20200522. git hashes f094665d465..e740f3d7314

[Bug tree-optimization/95272] ice in vectorizable_reduction, at tree-vect-loop.c:6197

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95272

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |tree-optimization
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2020-05-25
     Ever confirmed|0                           |1
            Version|unknown                     |11.0
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Mine.

[Bug tree-optimization/95272] ice in vectorizable_reduction, at tree-vect-loop.c:6197 since r11-564-g79f0451c67e8ed56

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95272

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
static void
vect_slp_rearrange_stmts (slp_tree node, unsigned int group_size,
                          vec<unsigned> permutation,
                          hash_set<slp_tree> &visited)
{     
...
      /* ???  Computation nodes are isomorphic and need no rearrangement.
         This is a quick hack to cover those where rearrangement breaks
         semantics because only the first stmt is guaranteed to have the
         correct operation code due to others being swapped or inverted.  */
      stmt_vec_info first = SLP_TREE_SCALAR_STMTS (node)[0];
      if (is_gimple_assign (first->stmt)
          && gimple_assign_rhs_code (first->stmt) == COND_EXPR)
        return;

bites back.  This leaves us with an inconsistent SLP tree (harmless before
the change exposing the ICE).

[Bug tree-optimization/95272] ice in vectorizable_reduction, at tree-vect-loop.c:6197 since r11-564-g79f0451c67e8ed56

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95272

--- Comment #3 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:c735929a2503a7d03ac4739bba5b25336bf954c3

commit r11-718-gc735929a2503a7d03ac4739bba5b25336bf954c3
Author: Richard Biener <rguenther@suse.de>
Date:   Fri May 29 12:00:00 2020 +0200

    tree-optimization/95272 - add SLP_TREE_REPRESENTATIVE

    This adds SLP_TREE_REPRESENTATIVE - a representative stmt-info that
    is used by SLP analysis and code generation.  This avoids the need
    for the hack in vect_slp_rearrange_stmts which previously avoided
    to re-arrange stmts that might not have been isomorphic because
    of operand swapping.  It also plays nice with future directions of SLP
    and for the forseeable future is easier than replicating more and
    more info in the SLP node as long as non-SLP is in-tree.

    2020-05-29  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/95272
            * tree-vectorizer.h (_slp_tree::representative): Add.
            (SLP_TREE_REPRESENTATIVE): Likewise.
            * tree-vect-loop.c (vectorizable_reduction): Adjust SLP
            node gathering.
            (vectorizable_live_operation): Use the representative to
            attach the reduction info to.
            * tree-vect-slp.c (_slp_tree::_slp_tree): Initialize
            SLP_TREE_REPRESENTATIVE.
            (vect_create_new_slp_node): Likewise.
            (slp_copy_subtree): Copy it.
            (vect_slp_rearrange_stmts): Re-arrange even COND_EXPR stmts.
            (vect_slp_analyze_node_operations_1): Pass the representative
            to vect_analyze_stmt.
            (vect_schedule_slp_instance): Pass the representative to
            vect_transform_stmt.

            * gcc.dg/vect/pr95272.c: New testcase.

[Bug tree-optimization/95272] ice in vectorizable_reduction, at tree-vect-loop.c:6197 since r11-564-g79f0451c67e8ed56

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95272

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

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

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Finally fixed.  Sorry for the delay.