re PR tree-optimization/26854 (Inordinate compile times on large routines)

re PR tree-optimization/26854 (Inordinate compile times on large routines)

2008-01-18  Kenneth Zadeck  <zadeck@naturalbridge.com>
	    Steven Bosscher  <stevenb.gcc@gmail.com>

	PR rtl-optimization/26854
	PR rtl-optimization/34400
	* df-problems.c (df_live_scratch): New scratch bitmap.
	(df_live_alloc): Allocate df_live_scratch when doing df_live.
	(df_live_reset): Clear the proper bitmaps.
	(df_live_bb_local_compute): Only process the artificial defs once
	since the order is not important.
	(df_live_init): Init the df_live sets only with the variables
	found live by df_lr.
	(df_live_transfer_function): Use the df_lr sets to prune the
	df_live sets as they are being computed.
	(df_live_free): Free df_live_scratch.

Co-Authored-By: Steven Bosscher <stevenb.gcc@gmail.com>
From-SVN: r131649