[Bug tree-optimization/31605] [4.2/4.3 Regression] VRP eliminates a useful test due with conversion from unsigned int to int

[ian at gcc dot gnu dot org]

------- Comment #6 from ian at gcc dot gnu dot org  2007-04-24 23:24 -------
Subject: Bug 31605

Author: ian
Date: Tue Apr 24 23:24:01 2007
New Revision: 124128

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=124128
Log:
./:
        PR tree-optimization/31605
        * tree-vrp.c (set_value_range): Check that min and max are not
        both overflow infinities.
        (set_value_range_to_value): New static function.
        (extract_range_from_binary_expr): Call set_value_range_to_value.
        (extract_range_from_cond_expr): Likewise.
        (extract_range_from_expr): Likewise.
        (extract_range_from_unary_expr): Likewise.  Don't create a range
        which overflows on both sides.
        (vrp_meet): Check for a useless range.
        (vrp_visit_phi_node): If we see a constant which looks like an
        overflow infinity, turn off the TREE_OVERFLOW flag.
testsuite/:
        PR tree-optimizatoin/31605
        * gcc.c-torture/execute/pr31605.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr31605.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vrp.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31605