[Bug c/95108] New: [10/11 Regression] ICE in tree_fits_uhwi_p, at tree.c:7292

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95108

            Bug ID: 95108
           Summary: [10/11 Regression] ICE in tree_fits_uhwi_p, at
                    tree.c:7292
           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 20190811 and 20190818, with -fno-tree-ccp :
(test case derived from pr88588.c)


$ cat z1.c
int *v;

#pragma omp declare simd
void
foo (int x)
{
  int *a = &x + 1;

  for (;;)
    {
      *v = *a;
      a = v;
    }
}


$ gcc-10-20190811 -c z1.c -O2 -fopenmp -fno-tree-ccp
$
$ gcc-11-20200510 -c z1.c -O2 -fopenmp -fno-tree-ccp
during GIMPLE pass: alias
z1.c: In function 'foo.simdclone.0':
z1.c:5:1: internal compiler error: Segmentation fault
    5 | foo (int x)
      | ^~~
0xb0ed8f crash_signal
        ../../gcc/toplev.c:328
0xd62e47 tree_fits_uhwi_p(tree_node const*)
        ../../gcc/tree.c:7292
0xcb74ad create_variable_info_for_1
        ../../gcc/tree-ssa-structalias.c:6068
0xcb7c43 create_variable_info_for
        ../../gcc/tree-ssa-structalias.c:6251
0xcb7c43 get_vi_for_tree
        ../../gcc/tree-ssa-structalias.c:2939
0xcb839f get_constraint_for_ssa_var
        ../../gcc/tree-ssa-structalias.c:3031
0xcb8902 get_constraint_for_1
        ../../gcc/tree-ssa-structalias.c:3611
0xcb97c4 get_constraint_for_ptr_offset
        ../../gcc/tree-ssa-structalias.c:3166
0xcb8939 get_constraint_for_1
        ../../gcc/tree-ssa-structalias.c:3544
0xcb9172 get_constraint_for_address_of
        ../../gcc/tree-ssa-structalias.c:3462
0xcb8b6b get_constraint_for_1
        ../../gcc/tree-ssa-structalias.c:3530
0xcbce95 find_func_aliases
        ../../gcc/tree-ssa-structalias.c:5017
0xcbdafe compute_points_to_sets
        ../../gcc/tree-ssa-structalias.c:7380
0xcbdafe compute_may_aliases()
        ../../gcc/tree-ssa-structalias.c:7861
0xa4524e execute_function_todo
        ../../gcc/passes.c:1957
0xa46192 execute_todo
        ../../gcc/passes.c:2039


A test version (configured with --enable-checking=yes)
does not need that extra option :

$ gcc-11-20200510-chk -c z1.c -O2 -fopenmp
z1.c: In function 'foo.simdclone.7':
z1.c:14:1: error: definition in block 6 follows the use
   14 | }
      | ^
for SSA_NAME: _8 in statement:
_9 = &MEM <int> [(void *)_8 + 4B];
during IPA pass: simdclone
z1.c:14:1: internal compiler error: verify_ssa failed
0xf3faab verify_ssa(bool, bool)
        ../../gcc/tree-ssa.c:1208
0xbe8827 execute_function_todo
        ../../gcc/passes.c:1992
0xbe952d do_per_function
        ../../gcc/passes.c:1647
0xbe9592 execute_todo
        ../../gcc/passes.c:2039