re PR tree-optimization/46590 (long compile time with -O2 and many loops)

2012-09-05  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/46590
	* tree-ssa-loop-ivcanon.c (try_unroll_loop_completely): Do not
	update SSA form here.
	(canonicalize_induction_variables): Assert we do not need to
	update SSA form.
	(tree_unroll_loops_completely): Update SSA form here.
	* tree-ssa-loop-manip.c (gimple_duplicate_loop_to_header_edge):
	Do not verify loop-closed SSA form if SSA form is not up-to-date.

From-SVN: r190978