[Bug tree-optimization/78496] [7/8 Regression] Missed opportunities for jump threading

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78496

--- Comment #12 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Author: law
Date: Mon Dec  4 16:14:24 2017
New Revision: 255387

URL: https://gcc.gnu.org/viewcvs?rev=255387&root=gcc&view=rev
Log:
        PR tree-optimizatin/78496
        * gimple-ssa-evrp-analyze.h
        (evrp_range_analyzer::get_vr_values): Simplify.
        * gimple-ssa-evrp-analyze.c: Corresponding changes.
        * tree-ssa-dom.c: Include alloc-pool.h, tree-vrp.h, vr-values.h
        and gimple-ssa-evrp-analyze.h.
        (dom_opt_dom_walker class): Add evrp_range_analyzer member.
        (simplify_stmt_for_jump_threading): Copy a blob of code from
        tree-vrp.c to use ranges to simplify statements.
        (dom_opt_dom_walker::before_dom_children): Call
        evrp_range_analyzer::{enter,record_ranges_from_stmt} methods.
        (dom_opt_dom_walker::after_dom_children): Similarly for
        evrp_range_analyzer::leave.
        (dom_opt_dom_walker::optimize_stmt): Use EVRP ranges to optimize
        conditionals.

        PR tree-optimization/78496
        * gcc.dg/builtin-unreachable-6.c: Disable DOM.
        * gcc.dg/builtin-unreachable-6a.c: New test.
        * gcc.dg/tree-ssa/20030922-1.c: No longer XFAIL.
        * gcc.dg/ssa-dom-branch-1.c: Tweak expected output.

Added:
    trunk/gcc/testsuite/gcc.dg/builtin-unreachable-6a.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-ssa-evrp-analyze.h
    trunk/gcc/gimple-ssa-evrp.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/builtin-unreachable-6.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/20030922-2.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-branch-1.c
    trunk/gcc/tree-ssa-dom.c