poly_int: reload<->ira interface

poly_int: reload<->ira interface

This patch uses poly_int64 for:

- ira_reuse_stack_slot
- ira_mark_new_stack_slot
- ira_spilled_reg_stack_slot::width

all of which are part of the IRA/reload interface.

2017-12-21  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* ira-int.h (ira_spilled_reg_stack_slot::width): Change from
	an unsigned int to a poly_uint64.
	* ira.h (ira_reuse_stack_slot, ira_mark_new_stack_slot): Take the
	sizes as poly_uint64s rather than unsigned ints.
	* ira-color.c (ira_reuse_stack_slot, ira_mark_new_stack_slot):
	Likewise.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r255924