2006-06-08  Richard Guenther  <rguenther@suse.de>

	PR middle-end/27116
	* fold-const.c (negate_expr_p): We can negate BIT_NOT_EXPR
	only, if overflow is defined and not trapping.
	(negate_expr): Likewise.

	* gcc.dg/torture/pr27116.c: New testcase.
	* gcc.dg/pr15785-1.c: Remove test for invalid transformation.

From-SVN: r114483