* config/bfin/bfin.opt (mstack-check-l1): New.
	* doc/invoke.texi (Blackfin Options): Document it.
	* config/bfin/bfin.c (bfin_expand_prologue): Generate code to use
	stack bounds in L1 memory if the new option is enabled.
	(override_options): Don't allow combinations of -fstack-limit and
	-mstack-check-l1.
	(add_to_reg): Renamed from add_to_sp.  All callers changed.  Lose some
	dead code.

From-SVN: r119049