* pa.c (fix_range): New function to mark a range(s) of registers as
	fixed registers.
	(override_options): Call fix_range if the -mfixed-range option string
	is not empty.
	* pa.h (TARGET_OPTIONS): Add -mfixed-range option.
	* doc/invoke.texi (-mfixed-range): Document new option.

From-SVN: r84690