[Bug tree-optimization/55875] [4.8 Regression] IVopts caused miscompilation

[hubicka at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55875

--- Comment #10 from Jan Hubicka <hubicka at gcc dot gnu.org> 2013-01-09 15:10:55 UTC ---
Author: hubicka
Date: Wed Jan  9 15:10:43 2013
New Revision: 195054

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=195054
Log:
    PR tree-optimiation/55875
    * gcc.c-torture/execute/pr55875.c: New testcase.
    * g++.dg/torture/pr55875.C: New testcase.

    * tree-ssa-loop-niter.c (number_of_iterations_cond): Add
    EVERY_ITERATION parameter.
    (number_of_iterations_exit): Check if exit is executed every
    iteration.
    (idx_infer_loop_bounds): Similarly here.
    (n_of_executions_at_most): Simplify
    to only test for cases where statement is dominated by the
    particular bound; handle correctly the "postdominance"
    test.
    (scev_probably_wraps_p): Use max loop iterations info
    as a global bound first.


Added:
    trunk/gcc/testsuite/g++.dg/torture/pr55875.C
    trunk/gcc/testsuite/gcc.c-torture/execute/pr55875.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-loop-niter.c