[Bug tree-optimization/81744] [8 Regression] ICE: verify_ssa failed, at tree-ssa.c:1186

["trippels at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81744

Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-08-07
                 CC|                            |trippels at gcc dot gnu.org
            Summary|ICE: verify_ssa failed, at  |[8 Regression] ICE:
                   |tree-ssa.c:1186             |verify_ssa failed, at
                   |                            |tree-ssa.c:1186
     Ever confirmed|0                           |1

--- Comment #1 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
trippels@gcc2-power8 ~ % cat test.i
typedef struct {
  int a, b;
} CompandSegment;
int a;
CompandSegment *b;
void fn1() {
  for (; a; a++)
    b[a].a = b[a].b = b[a - 1].a = b[a - 1].b = 0;
}

trippels@gcc2-power8 ~ % gcc -c -O3 test.i
test.i: In function ‘fn1’:
test.i:6:6: error: definition in block 6 follows the use
 void fn1() {
      ^~~
for SSA_NAME: _30 in statement:
_8 = (unsigned int) _30;
during GIMPLE pass: pcom
test.i:6:6: internal compiler error: verify_ssa failed
0x10bd7fcb verify_ssa(bool, bool)
        ../../gcc/gcc/tree-ssa.c:1186
0x10800bdf execute_function_todo
        ../../gcc/gcc/passes.c:1997
0x108017e3 do_per_function
        ../../gcc/gcc/passes.c:1655
0x10801a63 execute_todo
        ../../gcc/gcc/passes.c:2044