[Bug tree-optimization/91178] [9 Regression] Infinite recursion in split_constant_offset in slp after r260289

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91178

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Wed Jul 17 11:21:49 2019
New Revision: 273550

URL: https://gcc.gnu.org/viewcvs?rev=273550&root=gcc&view=rev
Log:
2019-07-17  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/91178
        * tree-ssa.c (release_defs_bitset): Iterate from higher to
        lower SSA names to avoid quadratic behavior in the common case.
        * tree-data-ref.c (split_constant_offset): Add limit argument
        and pass it down.  Initialize it from PARAM_SSA_NAME_DEF_CHAIN_LIMIT.
        (split_constant_offset_1): Add limit argument and use it to
        limit SSA def walking.  Optimize the common plus/minus case.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-data-ref.c
    trunk/gcc/tree-ssa.c