re PR middle-end/39157 (Code that compiles fine in 1GB of memory with 4.1.2 requires > 20GB in 4.2.* and higher)

	PR middle-end/39157
	* Makefile.in (loop-invariant.o): Depend on $(PARAMS_H).
	* params.h (LOOP_INVARIANT_MAX_BBS_IN_LOOP): Define.
	* params.def (loop-invariant-max-bbs-in-loop): New parameter.
	* opts.c (decode_options): Set loop-invariant-max-bbs-in-loop
	parameter to 1000 for -O1 by default.
	* doc/invoke.texi (loop-invariant-max-bbs-in-loop): Document new
	parameter.
	* loop-invariant.c: Include params.h.
	(move_loop_invariants): Don't call move_single_loop_invariants on
	very large loops.

From-SVN: r144320