nios2.opt (march, mbmx, mcdx): New options.

nios2.opt (march, mbmx, mcdx): New options.

2015-07-14  Sandra Loosemore  <sandra@codesourcery.com>
	    Cesar Philippidis  <cesar@codesourcery.com>
	    Chung-Lin Tang  <cltang@codesourcery.com>

	gcc/
	* config/nios2/nios2.opt (march, mbmx, mcdx): New options.
	* config/nios2/nios2-opts.h (enum nios2_arch_type): New enum for
	Nios II architecture level.
	* config/nios2/nios2.h (TARGET_ARCH_R2): New define.
	(TARGET_CPU_CPP_BUILTINS): Add definition of __nios2_arch__ symbol.
	(OPTION_DEFAULT_SPECS): Define.
	(ASM_SPEC): Add -march= spec strings.
	* config/nios2/nios2.c (nios2_option_override): Check for
	conflicts involving new options.
	* config.gcc (nios2*-*-*): Support --with-arch=.
	* doc/invoke.texi (Option Summary, Nios II Options): Document
	-march=, -mbmx,	and -mcdx.

Co-Authored-By: Cesar Philippidis <cesar@codesourcery.com>
Co-Authored-By: Chung-Lin Tang <cltang@codesourcery.com>
From-SVN: r225791