* config/rx/rx.opt (mallow-string-insns): New option.
	* config/rx/rx.c (RX_BUILTIN_RMPA): Disable the use of this
	builtin if string instructions are denied.
	* config/rx/rx.h (TARGET_CPU_CPP_BUILTINS): Define
	__RX_ALLOW_STRING_INSNS__ or __RX_DISALLOW_STRING_INSNS__, as
	appropriate.
	(ASM_SPEC): Pass -mno-allow-string-insns on to the assembler.
	* config/rx/rx.md (movstr): Enable pattern only if string
	instructions are allowed.
	(rx_movstr, rx_strend, movmemsi, rx_movmem): Likewise.
	(cmpstrnsi, cmpstrsi, rx_cmpstrn, rmpa): Likewise.
	* config/rx/t-rx (MULTILIB_OPTIONS): Add mno-allow-string-insns.
	(MULTILIB_DIRNAMES): Add no-strings.
	* doc/invoke.texi: Document -mno-allow-string-insns.

	* gcc.target/rx/builtins.c: Disable RMPA test if string
	instructions are not allowed.

From-SVN: r222116