PR middle-end/48335
	* expr.c (expand_assignment): Handle all possibilities
	if TO_RTX is CONCAT.
	* expmed.c (store_bit_field_1): Avoid trying to create
	invalid SUBREGs.
	(store_split_bit_field): If SUBREG_REG (op0) or
	op0 itself has smaller mode than word, return it
	for offset 0 and const0_rtx for out-of-bounds stores.
	If word is const0_rtx, skip it.

	* gcc.c-torture/compile/pr48335-1.c: New test.
	* gcc.dg/pr48335-1.c: New test.
	* gcc.dg/pr48335-2.c: New test.
	* gcc.dg/pr48335-3.c: New test.
	* gcc.dg/pr48335-4.c: New test.
	* gcc.dg/pr48335-5.c: New test.
	* gcc.dg/pr48335-6.c: New test.
	* gcc.dg/pr48335-7.c: New test.
	* gcc.dg/pr48335-8.c: New test.
	* gcc.target/i386/pr48335-1.c: New test.

From-SVN: r171855