Add rewrite_virtuals_into_loop_closed_ssa

Add rewrite_virtuals_into_loop_closed_ssa

2015-07-07  Tom de Vries  <tom@codesourcery.com>

	* tree-cfg.c (get_virtual_phi): New function.
	* tree-cfg.h (get_virtual_phi): Declare.
	* tree-ssa-loop-manip.c (replace_uses_in_dominated_bbs)
	(rewrite_virtuals_into_loop_closed_ssa): New function.
	* tree-ssa-loop-manip.h (rewrite_virtuals_into_loop_closed_ssa):
	Declare.
	* tree-parloops.c (replace_uses_in_bbs_by): Remove.
	(transform_to_exit_first_loop_alt): Use
	rewrite_virtuals_into_loop_closed_ssa.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@225520 138bc75d-0d04-0410-961f-82ee72b054a4