poly_int: store_bit_field bitrange

poly_int: store_bit_field bitrange

This patch changes the bitnum and bitsize arguments to
store_bit_field from unsigned HOST_WIDE_INTs to poly_uint64s.
The later part of store_bit_field_1 still needs to operate
on constant bit positions and sizes, so the patch splits
it out into a subfunction (store_integral_bit_field).

2017-12-20  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* expmed.h (store_bit_field): Take bitsize and bitnum as
	poly_uint64s rather than unsigned HOST_WIDE_INTs.
	* expmed.c (simple_mem_bitfield_p): Likewise.  Add a parameter
	that returns the byte size.
	(store_bit_field_1): Take bitsize and bitnum as
	poly_uint64s rather than unsigned HOST_WIDE_INTs.  Update call
	to simple_mem_bitfield_p.  Split the part that can only handle
	constant bitsize and bitnum out into...
	(store_integral_bit_field): ...this new function.
	(store_bit_field): Take bitsize and bitnum as poly_uint64s rather
	than unsigned HOST_WIDE_INTs.
	(extract_bit_field_1): Update call to simple_mem_bitfield_p.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@255877 138bc75d-0d04-0410-961f-82ee72b054a4