poly_int: pointer_may_wrap_p

poly_int: pointer_may_wrap_p

This patch changes the bitpos argument to pointer_may_wrap_p from
HOST_WIDE_INT to poly_int64.  A later patch makes the callers track
polynomial offsets.

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

gcc/
	* fold-const.c (pointer_may_wrap_p): Take the offset as a
	HOST_WIDE_INT rather than a poly_int64.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r255890