[Bug tree-optimization/47271] [4.6 Regression] if-conversion removes a test (if), the function generates invalid outputs

[spop at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47271

--- Comment #16 from Sebastian Pop <spop at gcc dot gnu.org> 2011-01-25 
14:51:28 UTC ---
Author: spop
Date: Tue Jan 25 14:51:23 2011
New Revision: 169233

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=169233
Log:
Fix PR47271: only if-convert full writes.

2011-01-25  Sebastian Pop  <sebastian....@amd.com>
        Jakub Jelinek  <ja...@redhat.com>

    PR tree-optimization/47271
    * tree-if-conv.c (bb_postdominates_preds): New.
    (if_convertible_bb_p): Call bb_postdominates_preds.
    (if_convertible_loop_p_1): Compute CDI_POST_DOMINATORS.
    (predicate_scalar_phi): Call bb_postdominates_preds.

    * gcc.dg/tree-ssa/ifc-pr47271.c: New.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ifc-pr47271.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-if-conv.c