* rtlanal.c (set_noop_p): Return true for noop jumps.

	* expr.c (emit_single_push_insn): Add call to push expander.
	* expr.h (optab_index): Add OTI_push
	(push_optab): New constant.
	* genopinit.c (optabs): Add push_optab.
	* optabs.c (init_optab): Init push optab.
	* md.texi (push??1): Document

From-SVN: r44210