[AArch64] Separate shrink wrapping hooks implementation

[AArch64] Separate shrink wrapping hooks implementation

	* config/aarch64/aarch64.h (machine_function): Add
	reg_is_wrapped_separately field.
	* config/aarch64/aarch64.md (LAST_SAVED_REGNUM): Define new constant.
	* config/aarch64/aarch64.c (emit_set_insn): Change return type to
	rtx_insn *.
	(aarch64_save_callee_saves): Don't save registers that are wrapped
	separately.
	(aarch64_restore_callee_saves): Don't restore registers that are
	wrapped separately.
	(offset_9bit_signed_unscaled_p, offset_12bit_unsigned_scaled_p,
	aarch64_offset_7bit_signed_scaled_p): Move earlier in the file.
	(aarch64_get_separate_components): New function.
	(aarch64_get_next_set_bit): Likewise.
	(aarch64_components_for_bb): Likewise.
	(aarch64_disqualify_components): Likewise.
	(aarch64_emit_prologue_components): Likewise.
	(aarch64_emit_epilogue_components): Likewise.
	(aarch64_set_handled_components): Likewise.
	(aarch64_process_components): Likewise.
	(TARGET_SHRINK_WRAP_GET_SEPARATE_COMPONENTS,
	TARGET_SHRINK_WRAP_COMPONENTS_FOR_BB,
	TARGET_SHRINK_WRAP_DISQUALIFY_COMPONENTS,
	TARGET_SHRINK_WRAP_EMIT_PROLOGUE_COMPONENTS,
	TARGET_SHRINK_WRAP_EMIT_EPILOGUE_COMPONENTS,
	TARGET_SHRINK_WRAP_SET_HANDLED_COMPONENTS): Define.

From-SVN: r243200