Don't split non-critical edges in crited

Don't split non-critical edges in crited

gcc/ChangeLog:

        * tree-cfg.h (split_critical_edges): Add for_edge_insertion_p
	parameter with default value false to declaration.
        (split_edges_for_insertion): New inline function.  Wrapper for
	split_critical_edges with for_edge_insertion_p = true.
        * tree-cfg.c (split_critical_edges): Don't split non-critical
	edges if for_edge_insertion_p is false.  Fix whitespace.
        * tree-ssa-pre.c (pass_pre::execute): Call
	split_edges_for_insertion instead of split_critical_edges.
        * gcc/tree-ssa-tail-merge.c (tail_merge_optimize): Ditto.
        * gcc/tree-ssa-sink.c (pass_sink_code::execute): Ditto.
	(pass_data_sink_code): Update function name in the comment.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@271461 138bc75d-0d04-0410-961f-82ee72b054a4