Replace BB_HEAD et al macros with functions

Replace BB_HEAD et al macros with functions

gcc/
2014-08-19  David Malcolm  <dmalcolm@redhat.com>

	* basic-block.h (BB_HEAD): Convert to a function.  Strengthen the
	return type from rtx to rtx_insn *.
	(BB_END): Likewise.
	(BB_HEADER): Likewise.
	(BB_FOOTER): Likewise.
	(SET_BB_HEAD): Convert to a function.
	(SET_BB_END): Likewise.
	(SET_BB_HEADER): Likewise.
	(SET_BB_FOOTER): Likewise.

	* cfgrtl.c (BB_HEAD): New function, from macro of same name.
	Strengthen the return type from rtx to rtx_insn *.  For now, this
	is done by adding a checked cast, but this will eventually
	become a field lookup.
	(BB_END): Likewise.
	(BB_HEADER): Likewise.
	(BB_FOOTER): Likewise.
	(SET_BB_HEAD): New function, from macro of same name.  This is
	intended for use as an lvalue, and so returns an rtx& to allow
	in-place modification.
	(SET_BB_END): Likewise.
	(SET_BB_HEADER): Likewise.
	(SET_BB_FOOTER): Likewise.

From-SVN: r214126