poly_int: omp-simd-clone.c

This patch adds a wrapper around TYPE_VECTOR_SUBPARTS for omp-simd-clone.c.
Supporting SIMD clones for variable-length vectors is post GCC8 work.

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

gcc/
	* omp-simd-clone.c (simd_clone_subparts): New function.
	(simd_clone_init_simd_arrays): Use it instead of TYPE_VECTOR_SUBPARTS.
	(ipa_simd_modify_function_body): Likewise.

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

From-SVN: r256145