[Bug tree-optimization/79489] Strange static branch prediction for n != 0

["marxin at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79489

--- Comment #7 from Martin Liška <marxin at gcc dot gnu.org> ---
Author: marxin
Date: Wed Jun 21 12:51:46 2017
New Revision: 249450

URL: https://gcc.gnu.org/viewcvs?rev=249450&root=gcc&view=rev
Log:
Make early return predictor more precise.

2017-06-21  Martin Liska  <mliska@suse.cz>

        PR tree-optimization/79489
        * gimplify.c (maybe_add_early_return_predict_stmt): New
        function.
        (gimplify_return_expr): Call the function.
        * predict.c (tree_estimate_probability_bb): Remove handling
        of early return.
        * predict.def: Update comment about early return predictor.
        * gimple-predict.h (is_gimple_predict): New function.
        * predict.def: Change default value of early return to 66.
        * tree-tailcall.c (find_tail_calls): Skip GIMPLE_PREDICT
        statements.
        * passes.def: Put pass_strip_predict_hints to the beginning of
        IPA passes.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-low.c
    trunk/gcc/gimple-predict.h
    trunk/gcc/gimplify.c
    trunk/gcc/passes.def
    trunk/gcc/predict.c
    trunk/gcc/predict.def
    trunk/gcc/tree-tailcall.c