Add initial support for prefixed/PC-relative addressing.

Add initial support for prefixed/PC-relative addressing.

2019-09-30  Michael Meissner  <meissner@linux.ibm.com>

	* config/rs6000/predicates.md (pcrel_address): Delete predicate.
	(pcrel_local_address): Replace pcrel_address predicate, use the
	new function address_to_insn_form.
	(pcrel_external_address): Replace with new implementation using
	address_to_insn_form..
	(prefixed_mem_operand): Delete predicate which is now unused.
	(pcrel_external_mem_operand): Delete predicate which is now
	unused.
	* config/rs6000/rs6000-protos.h (enum insn_form): New
	enumeration.
	(enum non_prefixed): New enumeration.
	(address_to_insn_form): New declaration.
	(prefixed_load_p): New declaration.
	(prefixed_store_p): New declaration.
	(prefixed_paddi_p): New declaration.
	(rs6000_asm_output_opcode): New declaration.
	(rs6000_final_prescan_insn): Move declaration and update calling
	signature.
	(address_is_prefixed): New helper inline function.
	* config/rs6000/rs6000.c(print_operand_address): Check for either
	PC-relative local symbols or PC-relative external symbols.
	(rs6000_emit_move): Support loading PC-relative addresses.
	(mode_supports_prefixed_address_p): Delete, no longer used.
	(rs6000_prefixed_address_mode_p): Delete, no longer used.
	(address_to_insn_form): New function to decode an address format.
	(reg_to_non_prefixed): New function to identify what the
	non-prefixed memory instruction format is for a register.
	(prefixed_load_p): New function to identify prefixed loads.
	(prefixed_store_p): New function to identify prefixed stores.
	(prefixed_paddi_p): New function to identify prefixed load
	immediates.
	(next_insn_prefixed_p): New static state variable.
	(rs6000_final_prescan_insn): New function to determine if an insn
	uses a prefixed instruction.
	(rs6000_asm_output_opcode): New function to emit 'p' in front of a
	prefixed instruction.
	* config/rs6000/rs6000.h (FINAL_PRESCAN_INSN): New target hook.
	(ASM_OUTPUT_OPCODE): New target hook.
	* config/rs6000/rs6000.md (prefixed): New insn attribute for
	prefixed instructions.
	(prefixed_length): New insn attribute for the size of prefixed
	instructions.
	(non_prefixed_length): New insn attribute for the size of
	non-prefixed instructions.
	(pcrel_local_addr): New insn to load up a local PC-relative
	address.
	(pcrel_extern_addr): New insn to load up an external PC-relative
	address.
	(mov<mode>_64bit_dm): Split the alternatives for loading 0.0 to a
	GPR and loading a 128-bit floating point type to a GPR.

From-SVN: r276300