[Bug tree-optimization/68541] [6 Regression] Path splitting causes if-conversion miss

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68541

--- Comment #6 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Author: law
Date: Fri Feb  5 23:49:08 2016
New Revision: 233191

URL: https://gcc.gnu.org/viewcvs?rev=233191&root=gcc&view=rev
Log:
        PR tree-optimization/68541
        * gimple-ssa-split-paths.c: Include tree-cfg.h and params.h.
        (count_stmts_in_block): New function.
        (poor_ifcvt_candidate_code): Likewise.
        (is_feasible_trace): Add some heuristics to determine when path
        splitting is profitable.
        (find_block_to_duplicate_for_splitting_paths): Make sure the graph
        is a diamond with a single exit.

        PR tree-optimization/68541
        * gcc.dg/tree-ssa/split-path-2.c: New test.
        * gcc.dg/tree-ssa/split-path-3.c: New test.
        * gcc.dg/tree-ssa/split-path-4.c: New test.
        * gcc.dg/tree-ssa/split-path-5.c: New test.
        * gcc.dg/tree-ssa/split-path-6.c: New test.
        * gcc.dg/tree-ssa/split-path-7.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/split-path-2.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/split-path-3.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/split-path-4.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/split-path-5.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/split-path-6.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/split-path-7.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-ssa-split-paths.c
    trunk/gcc/testsuite/ChangeLog