[Bug tree-optimization/54498] [4.6/4.7/4.8 Regression] incorrect code generation from g++ -O

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54498

--- Comment #7 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-09-06 15:20:29 UTC ---
Author: rguenth
Date: Thu Sep  6 15:20:24 2012
New Revision: 191031

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191031
Log:
2012-09-06  Richard Guenther  <rguenther@suse.de>

    PR tree-optimization/54498
    * tree-ssa-alias.h (get_continuation_for_phi): Add flag to
    abort when reaching an already visited region.
    * tree-ssa-alias.c (maybe_skip_until): Likewise.  And do it.
    (get_continuation_for_phi_1): Likewise.
    (walk_non_aliased_vuses): When we translated the reference,
    abort when we re-visit a region.
    * tree-ssa-pre.c (translate_vuse_through_block): Adjust.

Modified:
    branches/gcc-4_7-branch/gcc/ChangeLog
    branches/gcc-4_7-branch/gcc/tree-ssa-alias.c
    branches/gcc-4_7-branch/gcc/tree-ssa-alias.h
    branches/gcc-4_7-branch/gcc/tree-ssa-pre.c