[Bug tree-optimization/50767] [4.7 Regression] ICE: in refs_may_alias_p_1, at tree-ssa-alias.c:1004 with -O2 -fno-tree-copy-prop -fno-tree-dominator-opts

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50767

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-10-18 
09:51:17 UTC ---
PRE produces

<bb 2>:
  # VUSE <.MEM_4(D)>
  pretmp.5_8 = 0B;

<bb 3>:
  # .MEM_3 = PHI <.MEM_4(D)(2), .MEM_6(4)>
  # VUSE <.MEM_3>
  s.0_1 = s;
  ss.1_2 = pretmp.5_8;
  # .MEM_5 = VDEF <.MEM_3>
  s.0_1->s = ss.1_2;
  # .MEM_6 = VDEF <.MEM_5>
  bar ();

<bb 4>:
  goto <bb 3>;

which happens to fold ss->s for the first time, to the above but it misses
to call update_stmt.