arm: Convert thumb1 prologue to rtl.

arm: Convert thumb1 prologue to rtl.

	* config/arm/arm.c (arm_output_function_prologue): Don't call
	thumb1_output_function_prologue.
	(arm_expand_prologue): Avoid dead store.
	(number_of_first_bit_set): Use ctz_hwi.
	(thumb1_emit_multi_reg_push): New.
	(thumb1_expand_prologue): Merge thumb1_output_function_prologue
	to emit the entire prologue as rtl.
	(thumb1_output_interwork): Split out from
	thumb1_output_function_prologue.
	(thumb1_output_function_prologue): Remove.
	(arm_attr_length_push_multi): Handle thumb1.
	* config/arm/arm.md (VUNSPEC_THUMB1_INTERWORK): New.
	(prologue_thumb1_interwork): New.
	(*push_multi): Allow thumb1; use push_mult_memory_operand.
	* config/arm/predicates.md (push_mult_memory_operand): New.

From-SVN: r175605