[Bug tree-optimization/76490] [5/6/7 Regression] when use -O2 -fcheck-founds compiler appears to hang and consumes all memory

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=76490

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Wed Aug 17 11:51:51 2016
New Revision: 239529

URL: https://gcc.gnu.org/viewcvs?rev=239529&root=gcc&view=rev
Log:
2016-08-17  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/76490
        * tree-vrp.c (update_value_range): Preserve overflow infinities
        when intersecting with ranges from get_range_info.
        (operand_less_p): Handle overflow infinities correctly.
        (value_range_constant_singleton): Use vrp_operand_equal_p
        to handle overflow max/min correctly.
        (vrp_valueize): Likewise.
        (union_ranges): Likewise.
        (intersect_ranges): Likewise.
        (vrp_visit_phi_node): Improve iteration limitation to only
        apply when we'll possibly re-visit the PHI via a changed argument
        on the backedge.

        * gfortran.fortran-torture/compile/pr76490.f90: New testcase.
        * gcc.dg/pr52904.c: XFAIL.

Added:
    trunk/gcc/testsuite/gfortran.fortran-torture/compile/pr76490.f90
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/pr52904.c
    trunk/gcc/tree-vrp.c