[Bug tree-optimization/54742] Switch elimination in FSM loop

[spop at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54742

--- Comment #39 from Sebastian Pop <spop at gcc dot gnu.org> ---
Author: spop
Date: Sat Dec  6 19:19:37 2014
New Revision: 218451

URL: https://gcc.gnu.org/viewcvs?rev=218451&root=gcc&view=rev
Log:
extend jump thread for finite state automata

    PR tree-optimization/54742
    * params.def (max-fsm-thread-path-insns, max-fsm-thread-length,
    max-fsm-thread-paths): New.

    * doc/invoke.texi (max-fsm-thread-path-insns, max-fsm-thread-length,
    max-fsm-thread-paths): Documented.

    * tree-cfg.c (split_edge_bb_loc): Export.
    * tree-cfg.h (split_edge_bb_loc): Declared extern.

    * tree-ssa-threadedge.c (simplify_control_stmt_condition): Restore the
    original value of cond when simplification fails.
    (fsm_find_thread_path): New.
    (fsm_find_control_statement_thread_paths): New.
    (thread_through_normal_block): Call find_control_statement_thread_paths.

    * tree-ssa-threadupdate.c (dump_jump_thread_path): Pretty print
    EDGE_FSM_THREAD.
    (verify_seme): New.
    (duplicate_seme_region): New.
    (thread_through_all_blocks): Generate code for EDGE_FSM_THREAD edges
    calling duplicate_seme_region.

    * tree-ssa-threadupdate.h (jump_thread_edge_type): Add EDGE_FSM_THREAD.

    * testsuite/gcc.dg/tree-ssa/ssa-dom-thread-6.c: New test.
    * testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-6.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/doc/invoke.texi
    trunk/gcc/params.def
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-cfg.c
    trunk/gcc/tree-cfg.h
    trunk/gcc/tree-ssa-threadedge.c
    trunk/gcc/tree-ssa-threadupdate.c
    trunk/gcc/tree-ssa-threadupdate.h