[Bug middle-end/61409] [5/6/7 regression] -Wmaybe-uninitialized false-positive with -O2

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61409

--- Comment #25 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
Author: aldyh
Date: Sun Nov 20 18:34:06 2016
New Revision: 242639

URL: https://gcc.gnu.org/viewcvs?rev=242639&root=gcc&view=rev
Log:
        PR middle-end/61409
        * tree-ssa-uninit.c: Define new global max_phi_args.
        (compute_uninit_opnds_pos): Use max_phi_args.
        (prune_uninit_phi_opnds): Same.
        (use_pred_not_overlap_with_undef_path_pred): Remove reference to
        missing NUM_PREDS in function comment.
        (can_one_predicate_be_invalidated_p): New.
        (can_chain_union_be_invalidated_p): New.
        (flatten_out_predicate_chains): New.
        (uninit_ops_invalidate_phi_use): New.
        (is_use_properly_guarded): Call uninit_ops_invalidate_phi_use.

Added:
    trunk/gcc/testsuite/gcc.dg/uninit-pr61409.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-uninit.c