re PR middle-end/11968 (Array reference is incorrectly computed for POINTERS_EXTEND_UNSIGNED)

	PR middle-end/11968
	* expr.c (expand_expr <MULT_EXPR>): Remove inappropriate and
	confusing comment; distributivity isn't handled in expand_expr.
	* fold-const.c (extract_muldiv_1 <PLUS_EXPR>):  Allow overflow
	in distributivity, if wrap-around semantics are specified with
	-fwrapv.

From-SVN: r73166