gcc/
	* common/config/rs6000/rs6000-common.c (TARGET_SUPPORTS_SPLIT_STACK):
	Define.
	(rs6000_supports_split_stack): New function.
	* gcc/config/rs6000/rs6000.c (machine_function): Add
	split_stack_arg_pointer.
	(TARGET_EXTRA_LIVE_ON_ENTRY, TARGET_INTERNAL_ARG_POINTER): Define.
	(setup_incoming_varargs): Use crtl->args.internal_arg_pointer
	rather than virtual_incoming_args_rtx.
	(rs6000_va_start): Likewise.
	(split_stack_arg_pointer_used_p): New function.
	(rs6000_emit_prologue): Set up arg pointer for -fsplit-stack.
	(morestack_ref): New var.
	(gen_add3_const, rs6000_expand_split_stack_prologue,
	rs6000_internal_arg_pointer, rs6000_live_on_entry,
	rs6000_split_stack_space_check): New functions.
	(rs6000_elf_file_end): Call file_end_indicate_split_stack.
	* gcc/config/rs6000/rs6000.md (UNSPEC_STACK_CHECK): Define.
	(UNSPECV_SPLIT_STACK_RETURN): Define.
	(split_stack_prologue, load_split_stack_limit,
	load_split_stack_limit_di, load_split_stack_limit_si,
	split_stack_return, split_stack_space_check): New expands and insns.
	* gcc/config/rs6000/rs6000-protos.h
	(rs6000_expand_split_stack_prologue): Declare.
	(rs6000_split_stack_space_check): Declare.
libgcc/
	* config/rs6000/morestack.S: New.
	* config/rs6000/t-stack-rs6000: New.
	* config.host (powerpc*-*-linux*): Add t-stack and t-stack-rs6000
	to tmake_file.
	* generic-morestack.c: Don't build for powerpc 32-bit.

From-SVN: r223426