simplify-rtx.c (simplifi_binary_operation): If DIV has narrower mode than op0, only return the bits in DIV's mode.

	* simplify-rtx.c (simplifi_binary_operation) [DIV]: If DIV has
	narrower mode than op0, only return the bits in DIV's mode.

	* gcc.c-torture/compile/20011219-2.c: New test.

From-SVN: r48199