poly_int: alter_reg

poly_int: alter_reg

This patch makes alter_reg cope with polynomial mode sizes.

2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* reload1.c (spill_stack_slot_width): Change element type
	from unsigned int to poly_uint64_pod.
	(alter_reg): Treat mode sizes as polynomial.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r256160