* config/nvptx/nvptx.c: Include gimple headers.
	(worker_red_size, worker_red_align, worker_red_name,
	worker_red_sym): New.
	(nvptx_option_override): Initialize worker reduction buffer.
	(nvptx_file_end): Write out worker reduction buffer var.
	(nvptx_expand_shuffle, nvptx_expand_worker_addr,
	nvptx_expand_cmp_swap): New builtin expanders.
	(enum nvptx_builtins): New.
	(nvptx_builtin_decls): New.
	(nvptx_builtin_decl, nvptx_init_builtins, nvptx_expand_builtin): New
	(PTX_VECTOR_LENGTH, PTX_WORKER_LENGTH): New.
	(nvptx_get_worker_red_addr, nvptx_generate_vector_shuffle,
	nvptx_lockless_update): New helpers.
	(nvptx_goacc_reduction_setup, nvptx_goacc_reduction_init,
	nvptx_goacc_reduction_fini, nvptx_goacc_reduction_teaddown): New.
	(nvptx_goacc_reduction): New.
	(TARGET_INIT_BUILTINS, TARGET_EXPAND_BUILTIN,
	TARGET_BUILTIN_DECL): Override.
	(TARGET_GOACC_REDUCTION): Override.

Co-Authored-By: Cesar Philippidis <cesar@codesourcery.com>

From-SVN: r229768