PR middle-end/55030
	* builtins.c (expand_builtin_setjmp_receiver): Update comment
	regarding purpose of blockage.
	* emit-rtl.c [!HAVE_blockage] (gen_blockage): Similarly for
	the head comment.
	* rtlanal.c (volatile_insn_p): Ditto.
	* doc/md.texi (blockage): Update similarly.  Change wording to
	require one of two forms, rather than implying a wider choice.
	* cse.c (cse_insn): Where checking for blocking insns, use
	volatile_insn_p instead of manual check for volatile ASM.
	* dse.c (scan_insn): Ditto.
	* cselib.c (cselib_process_insn): Ditto.

From-SVN: r193802