poly_int: instantiate_virtual_regs

poly_int: instantiate_virtual_regs

This patch makes the instantiate virtual regs pass track offsets
as poly_ints.

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

gcc/
	* function.c (in_arg_offset, var_offset, dynamic_offset)
	(out_arg_offset, cfa_offset): Change from int to poly_int64.
	(instantiate_new_reg): Return the new offset as a poly_int64_pod
	rather than a HOST_WIDE_INT.
	(instantiate_virtual_regs_in_rtx): Track polynomial offsets.
	(instantiate_virtual_regs_in_insn): Likewise.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r255920