2007-01-05 Manuel Lopez-Ibanez <manu@gcc.gnu.org>

2007-01-05  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR c/19978
	* tree.h (TREE_OVERFLOW_P): New.
	* c-typeck.c (parser_build_unary_op): Warn only if result
	overflowed and operands did not.
	(parser_build_binary_op): Likewise.
	(convert_for_assignment): Remove redundant overflow_warning.
	* c-common.c (overflow_warning): Don't check or set TREE_OVERFLOW.

cp/
	* semantics.c (finish_unary_op_expr): Warn only if result
	overflowed and operands did not.

testsuite/
	* gcc.dg/multiple-overflow-warn-1.c: New.
	* gcc.dg/multiple-overflow-warn-2.c: New.
	* gcc.dg/overflow-warn-6.c: New.
	* g++.dg/warn/multiple-overflow-warn-1.C: New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@120505 138bc75d-0d04-0410-961f-82ee72b054a4