basic-block.h: Improve comments.

basic-block.h: Improve comments.

	* basic-block.h: Improve comments.
	* except.c (expand_eh_region_end_allowed): Remove redundant call
	to do_pending_stack_adjust.
	* flow.c (life_analysis): Fix typo in comment.
	(calculate_global_regs_live): Add documentation.
	(mark_set_1): Likewise.
	(debug_regset): Likewise.
	* doc/rtl.texi (cond_exec): Document it.

From-SVN: r43049