This patch changes the type of the reg_attrs offset field
from HOST_WIDE_INT to poly_int64 and updates uses accordingly.
This includes changing reg_attr_hasher::hash to use inchash.
(Doing this has no effect on code generation since the only
use of the hasher is to avoid creating duplicate objects.)

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

gcc/
	* rtl.h (reg_attrs::offset): Change from HOST_WIDE_INT to poly_int64.
	(gen_rtx_REG_offset): Take the offset as a poly_int64.
	* inchash.h (inchash::hash::add_poly_hwi): New function.
	* gengtype.c (main): Register poly_int64.
	* emit-rtl.c (reg_attr_hasher::hash): Use inchash.  Treat the
	offset as a poly_int.
	(reg_attr_hasher::equal): Use must_eq to compare offsets.
	(get_reg_attrs, update_reg_offset, gen_rtx_REG_offset): Take the
	offset as a poly_int64.
	(set_reg_attrs_from_value): Treat the offset as a poly_int64.
	* print-rtl.c (print_poly_int): New function.
	(rtx_writer::print_rtx_operand_code_r): Treat REG_OFFSET as
	a poly_int.
	* var-tracking.c (track_offset_p, get_tracked_reg_offset): New
	functions.
	(var_reg_set, var_reg_delete_and_set, var_reg_delete): Use them.
	(same_variable_part_p, track_loc_p): Take the offset as a poly_int64.
	(vt_get_decl_and_offset): Return the offset as a poly_int64.
	Enforce track_offset_p for parts of a PARALLEL.
	(vt_add_function_parameter): Use const_offset for the final
	offset to track.  Use get_tracked_reg_offset for the parts
	of a PARALLEL.

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

From-SVN: r255867