re PR target/70738 (Add -mgeneral-regs-only option)

	PR target/70738
	* common/config/i386/i386-common.c
	(OPTION_MASK_ISA_GENERAL_REGS_ONLY_UNSET): New.
	(ix86_handle_option) <case OPT_mgeneral_regs_only>: Disable
	MPX, MMX, SSE and x87 instructions for -mgeneral-regs-only.
	* config/i386/i386.opt (ix86_target_flags): Add new Variable.
	(-mgeneral-regs-only): Add new option.
	* config/i386/i386.c (ix86_option_override_internal): Don't enable
	x87 instructions if only general registers are allowed.
	(ix86_target_string): Add ix86_flags argument. Handle additional
	flags options through ix86_flags argument.  Update all callers.
	* doc/invoke.texi: Document -mgeneral-regs-only.

testsuite/ChangeLog:

	PR target/70738
	* gcc.target/i386/pr70738-1.c: New test.
	* gcc.target/i386/pr70738-2.c: Likewise.
	* gcc.target/i386/pr70738-3.c: Likewise.
	* gcc.target/i386/pr70738-4.c: Likewise.
	* gcc.target/i386/pr70738-5.c: Likewise.
	* gcc.target/i386/pr70738-6.c: Likewise.
	* gcc.target/i386/pr70738-7.c: Likewise.
	* gcc.target/i386/pr70738-8.c: Likewise.
	* gcc.target/i386/pr70738-9.c: Likewise.

From-SVN: r236738