[Bug target/82271] [5/6/7 Regression] loop gets miscompiled on powerpc at -O2

[sirl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82271

--- Comment #3 from Franz Sirl <sirl at gcc dot gnu.org> ---
The bug was introduced with r195054:

2013-01-09  Jan Hubicka  <jh@suse.cz>

        PR tree-optimiation/55875
        * 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.

BTW, -fno-tree-vrp also suppresses the bug.