[Bug middle-end/52756] [4.8 Regression] 255.vortex in SPEC CPU 2000 failed to build

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52756

--- Comment #8 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-04-02 15:13:50 UTC ---
Author: rguenth
Date: Mon Apr  2 15:13:45 2012
New Revision: 186085

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186085
Log:
2012-04-02  Richard Guenther  <rguenther@suse.de>

    PR tree-optimization/52756
    * tree-ssa-threadupdate.c (def_split_header_continue_p): New function.
    (thread_through_loop_header): After threading through the loop latch
    remove the split part from the loop and clear further threading
    opportunities that would create a multiple entry loop.

    * gcc.dg/torture/pr52756.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr52756.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-threadupdate.c