* expr.c (get_def_for_expr): New function.
	(expand_expr_real_1) <PLUS_EXPR, MINUS_EXPR>: Adjust to work with
	SSA rather than trees.
	<MULT_EXPR>: Likewise.  Use subexp0 and subexp1 instead of
	TREE_OPERAND (exp, 0) and TREE_OPERAND (exp, 1).

Co-Authored-By: Richard Guenther <rguenther@suse.de>

From-SVN: r147078