[Bug tree-optimization/68619] [6 Regression] error: loop with header 6 not in loop tree

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68619

--- Comment #5 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Author: law
Date: Thu Dec 10 16:34:43 2015
New Revision: 231527

URL: https://gcc.gnu.org/viewcvs?rev=231527&root=gcc&view=rev
Log:
2015-12-10  Jeff Law  <law@redhat.com>

        PR tree-optimization/68619
        * tree-ssa-dom.c (dom_opt_dom_walker::before_dom_children): Propgate
        return value from optimize_stmt.
        (dom_opt_dom_walker): Add new argument to dom_walker constructor.
        (pass_dominator:execute): If a block has an unreachable edge,
        remove all jump threads through any successor of the affected block.
        (record_equivalences_from_phis): Ignore alternative if the edge
        does not have EDGE_EXECUTABLE set.
        (single_incoming_edge_ignoring_loop_edges): Similarly.
        (optimize_stmt): If a gimple_code has a compile-time constant
        condition, return the edge taken for that constant value.  Also
        change the condition to true/false as necessary.
        * domwalk.h (dom_walker::dom_walker): Add new argument
        skip_unreachable_blocks.  Don't provide empty constructor body.
        (dom_walker::before_dom_children): Change return type.
        (dom_walker::bb_reachable): Declare new private method.
        (dom_walker::propagate_unreachable_to_edges): Likewise.
        (dom_walker::m_unreachable_dom): Declare new private data member.
        (dom_walker::m_skip_unreachable_blocks): Likewise.
        * domwalk.c: Include dumpfile.h.
        (dom_walker::dom_walker): New constructor.  Initialize private data
        members.  If needed, set EDGE_EXECUTABLE for all edges in the CFG,
        extracted from tree-ssa-sccvn.c.
        (dom_walker::bb_reachable): New method extracted from tree-ssa-sccvn.c
        (dom_walker::propagate_unreachable_to_edges): Likewise.
        (dom_walker::walk): Only call before_dom_children on reachable
        blocks.  If before_dom_children returns an edge, then clear
        EDGE_EXECUTABLE for all other outgoing edges from the same block.
        For unreachable blocks, call propagate_unreachable_to_edges.
        Similarly, only call after_dom_children on reachable blocks.  For
        unreachable blocks, conditionally clear m_unreachable_dom.
        * tree-ssa-sccvn.c (sccvn_dom_walker::unreachable_dom): Remove
        private data member.
        (sccvn_dom_walker::after_dom_children): Use methods from dom_walker
        class.
        (run_scc_vn): Likewise.
        (sccvn_dom_walker::before_dom_children): Likewise.  Return the taken
        outgoing edge if a COND, SWITCH, or GOTO are optimized.
        * compare-elim.c (find_comparison_dom_walker::before_dom_children):
        Change return type to an edge.  Always return NULL.
        * fwprop.c (single_def_use_dom_walker::before_dom_children): Likewise.
        * gimple-ssa-strength-reduction.c
        (find_candidates_dom_walker::before_dom_children): Likewise.
        * ipa-prop.c (analysis_dom_walker::before_dom_children): Likewise.
        (ipcp_modif_dom_walker::before_dom_children): Likewise.
        * tree-into-ssa.c (rewrite_dom_walker::before_dom_children): Likewise.
        (rewrite_update_dom_walker::before_dom_children): Likewise.
        (mark_def_dom_children::before_dom_children): Likewise.
        * tree-ssa-dse.c (dse_dom_walker::before_dom_children): Likewise.
        * tree-ssa-loop-im.c
        (invariantness_dom_walker::before_dom_children): Likewise.
        (move_computations_dom_walker::before_dom_walker): Likewise.
        * tree-ssa-phiopt.c
        (nontrapping_dom_walker::before_dom_children): Likewise.
        * tree-ssa-pre.c
        (eliminate_dom_walker::before_dom_children): Likewise.
        * tree-ssa-propagate.c
        (substitute_and_fold_dom_walker::before_dom_children): Likewise.
        * tree-ssa-strlen.c
        (strlen_dom_walker::before_dom_children): Likewise.
        * tree-ssa-uncprop.c
        (uncprop_dom_walker::before_dom_children): Likewise.

        PR tree-optimization/68619
        * gcc.dg/tree-ssa/pr68619-1.c: New test.
        * gcc.dg/tree-ssa/pr68619-2.c: New test.
        * gcc.dg/tree-ssa/pr68619-3.c: New test.
        * gcc.dg/tree-ssa/pr68619-4.c: New test.
        * gcc.dg/tree-ssa/pr68619-5.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr68619-1.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr68619-2.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr68619-3.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr68619-4.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr68619-5.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/compare-elim.c
    trunk/gcc/domwalk.c
    trunk/gcc/domwalk.h
    trunk/gcc/fwprop.c
    trunk/gcc/gimple-ssa-strength-reduction.c
    trunk/gcc/ipa-prop.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-into-ssa.c
    trunk/gcc/tree-ssa-dom.c
    trunk/gcc/tree-ssa-dse.c
    trunk/gcc/tree-ssa-loop-im.c
    trunk/gcc/tree-ssa-phiopt.c
    trunk/gcc/tree-ssa-pre.c
    trunk/gcc/tree-ssa-propagate.c
    trunk/gcc/tree-ssa-sccvn.c
    trunk/gcc/tree-ssa-strlen.c
    trunk/gcc/tree-ssa-uncprop.c