[Bug middle-end/61725] [4.9/4.10 Regression] __builtin_ffs(0) leads to wrong code generation

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61725

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Tue Jul  8 09:39:57 2014
New Revision: 212353

URL: https://gcc.gnu.org/viewcvs?rev=212353&root=gcc&view=rev
Log:
    PR tree-optimization/61725
    * tree-vrp.c (extract_range_basic): Don't assume vr0 is unsigned
    range, use range_includes_zerop_p instead of integer_zerop on
    vr0->min, only use log2 of max if min is not negative.

    * gcc.dg/tree-ssa/vrp93.c: New test.
    * gcc.c-torture/execute/pr61725.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr61725.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/vrp93.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vrp.c