re PR rtl-optimization/40761 (IRA memory hog for insanely nested loops)

2010-03-04  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/40761
	* tree-ssa-pre.c (compute_antic): Walk reverse postorder
	in reverse order.
	(my_rev_post_order_compute): New function.
	(init_pre): Call it.

From-SVN: r157225