ddg.h, [...]: New files.

 	* ddg.h, ddg.c, modulo-sched.c: New files.
 	* cfglayout.c (duplicate_insn_chain): Remove "static" and push
 	internals to "dupicate_insn".
 	(duplicate_insn): New function.
 	* cfglayout.h (duplicate_insn_chain, duplicate_insn): New
 	declarations.
 	* common.opt (fmodulo-sched): New flag.
 	* df.c (df_bb_regno_last_use_find, df_bb_regno_first_def_find):
 	Remove static and forward declaration.
 	(df_find_def, df_reg_used, df_bb_regno_last_def_find): New
 	functions.
 	* df.h (df_bb_regno_last_use_find, df_bb_regno_first_def_find,
 	df_bb_regno_last_def_find, df_find_def, df_reg_used): New
 	declarations.
 	* flags.h (flag_modulo_sched): New flag.
 	* opts.c (common_handle_option): Handle modulo-sched flag.
 	* params.def (max-sms-loop-number, sms-max-ii-factor,
 	sms-dfa-history, sms-loop-average-count-threshold): New
 	parameters.
	* params.h (MAX_SMS_LOOP_NUMBER, SMS_MAX_II_FACTOR,
 	SMS_DFA_HISTORY, SMS_LOOP_AVERAGE_COUNT_THRESHOLD): New
 	parameters.
 	* passes.c ("sms", "sms-vcg"): New dumps.
 	(rest_of_handle_sched): Call sms_schedule.
 	* rtl.h (sms_schedule): New declaration.
 	* timevar.def (TV_SMS): New.
 	* toplev.c (flag_modulo_sched): Initialize.
 	(f_options): Handle -fmodulo-sched option.
 	* docs/invoke.texi: Document -fmodulo-sched & -dm options.
 	* docs/passes.texi: Document new SMS pass.f toplev.c doc/invoke.texi doc/passes.texi

Co-Authored-By: Mostafa Hagog <mustafa@il.ibm.com>

From-SVN: r82235