* rtl.def (PREFETCH): New rtx code.
	* doc/rtl.texi (PREFETCH): Add documentation.
	* function.c (instantiate_virtual_regs_1): Handle PREFETCH rtx.
	* rtlanal.c (reg_referenced_p): Ditto.
	* sched-vis.c (print_exp):  Ditto.
	* ssa-dce.c (find_inherently_necessary):  Ditto.

From-SVN: r47580