[Bug c/104445] New: [12 Regression] ICE in vect_create_partial_epilog, at tree-vect-loop.cc:5098

["gscfq@t-online.de" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104445

            Bug ID: 104445
           Summary: [12 Regression] ICE in vect_create_partial_epilog, at
                    tree-vect-loop.cc:5098
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gscfq@t-online.de
  Target Milestone: ---

Changed between 20210711 and 20210718, at -O3 or -Ofast :


$ cat z1.c
signed char a;
signed char f (int i, int j)
{
  signed char c;
  while (i != 0)
  {
    a ^= j;
    ++c;
    ++i;
  }
  return c;
}


$ gcc-12-20220206 -c z1.c -m32 -O3 -mavx -mno-mmx
during GIMPLE pass: vect
z1.c: In function 'f':
z1.c:2:13: internal compiler error: in vect_create_partial_epilog, at
tree-vect-loop.cc:5098
    2 | signed char f (int i, int j)
      |             ^
0xe32e69 vect_create_partial_epilog
        ../../gcc/tree-vect-loop.cc:5095
0xe3bd5f vect_transform_cycle_phi(_loop_vec_info*, _stmt_vec_info*, gimple**,
_slp_tree*, _slp_instance*)
        ../../gcc/tree-vect-loop.cc:7795
0x190fcad vect_transform_stmt(vec_info*, _stmt_vec_info*,
gimple_stmt_iterator*, _slp_tree*, _slp_instance*)
        ../../gcc/tree-vect-stmts.cc:11276
0xe4b65f vect_transform_loop(_loop_vec_info*, gimple*)
        ../../gcc/tree-vect-loop.cc:9799
0xe7d565 vect_transform_loops
        ../../gcc/tree-vectorizer.cc:1004
0xe7d713 vect_transform_loops
        ../../gcc/tree-vectorizer.cc:1022
0xe7db86 try_vectorize_loop_1
        ../../gcc/tree-vectorizer.cc:1133
0xe7db86 try_vectorize_loop
        ../../gcc/tree-vectorizer.cc:1164
0xe7e0c4 execute
        ../../gcc/tree-vectorizer.cc:1278