Prologue/epilogue using STRD/LDRD in ARM mode

Prologue/epilogue using STRD/LDRD in ARM mode

2013-04-16  Greta Yorsh  <Greta.Yorsh at arm.com>

	* config/arm/arm.c (emit_multi_reg_push): New declaration
	for an existing function.
	(arm_emit_strd_push): New function.
	(arm_expand_prologue): Used here.
	(arm_emit_ldrd_pop): New function.
	(arm_expand_epilogue): Used here.
	(arm_get_frame_offsets): Update condition.
	(arm_emit_multi_reg_pop): Add a special case for load of a single
	register with writeback.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@198004 138bc75d-0d04-0410-961f-82ee72b054a4