r144808 - in /branches/no-undefined-overflow/gc...

[rguenth@gcc.gnu.org]

Author: rguenth
Date: Thu Mar 12 10:03:26 2009
New Revision: 144808

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=144808
Log:
2009-03-12  Richard Guenther  <rguenther@suse.de>

	* fold-const.c (may_negate_without_overflow_p): Unsigned zero
	can be negated without overflow.
	(negate_expr_p): Handle *NV_EXPR.
	(fold_negate_expr): Likewise.
	(fold_binary): Avoid loosing non-overflow flag during
	A - B -> A + (-B) folding with constant B.

Modified:
    branches/no-undefined-overflow/gcc/ChangeLog.overflow
    branches/no-undefined-overflow/gcc/fold-const.c