2008-01-16  Richard Guenther  <rguenther@suse.de>

	PR middle-end/32628
	* fold-const.c (fold_convert_const_int_from_int): Do not
	set overflow if that occured only because of a sign extension
	change when converting from/to a sizetype with the same
	precision and signedness.

	* gcc.dg/overflow-warn-7.c: New testcase.

From-SVN: r131579