* invoke.texi (max-loop-headers-insns): Document.
	* params.def (PARAM_MAX_LOOP_HEADER_INSNS): New.
	* tree-ssa-loop-ch.c (should_duplicate_loop_header_p): Update comment.
	(ch_base::copy_headers): Use PARAM_MAX_LOOP_HEADER_INSNS.

From-SVN: r237219