re PR rtl-optimization/34035 (ICE in calc_dfs_tree with -O2 -fnon-call-exceptions -ffast-math -fno-gcse)

	PR rtl-optimization/34035
	* cse.c (cse_cfg_altered): New global variable.
	(cse_jumps_altered): Make boolean.
	(recorded_label_ref): Likewise.
	(cse_insn): Adjust for above changes.
	(cse_extended_basic_block): Likewise.  Set cse_cfg_altered
	if dead edges have been purged.
	(cse_main): Change return value specification and adjust code.
	(rest_of_handle_cse): Adjust for above change.
	(rest_of_handle_cse2): Likewise.
	* gcse.c (rest_of_handle_gcse): Likewise.

From-SVN: r130122