params.def (PARAM_IRA_LOOP_RESERVED_REGS): New.

2009-09-26  Vladimir Makarov  <vmakarov@redhat.com>

	* params.def (PARAM_IRA_LOOP_RESERVED_REGS): New.
	* params.h (IRA_LOOP_RESERVED_REGS): New
	* tree-pass.h (pass_subregs_of_mode_init,
	pass_subregs_of_mode_finish): Remove.
	* passes.c (pass_subregs_of_mode_init,
	pass_subregs_of_mode_finish): Remove.
	(pass_reginfo_init): Move before loop optimizations.
	* config/i386/i386.h (STACK_REG_COVER_CLASS): Define.
	* common.opt (fira-loop-pressure): New.
	* toplev.h (flag_ira_loop_pressure): New.
	* rtl.h (init_subregs_of_mode, finish_subregs_of_mode): New
	externals.
	* reginfo.c (init_subregs_of_mode, finish_subregs_of_mode):
	Make external and void type functions.
	(gate_subregs_of_mode_init, pass_subregs_of_mode_init,
	pass_subregs_of_mode_finish): Remove.
	* ira-costs.c (init_costs): Call init_subregs_of_mode.
	* regmove.c: Include ira.h.
	(regmove_optimize): Call ira_set_pseudo_classes after IRA based
	register pressure calculation in loops.
	* loop-invariant.c: Include REGS_H and ira.h.
	(struct loop_data): New members max_reg_pressure, regs_ref, and
	regs_live.
	(struct invariant): New member orig_regno.
	(curr_loop): New variable.
	(find_exits): Initialize regs_ref and regs_live.
	(create_new_invariant): Initialize orig_regno.
	(get_cover_class_and_nregs): New.
	(get_inv_cost): Make aregs_needed an array.  Use regs_needed as an
	array.  Add code for flag_ira_loop_pressure.
	(gain_for_invariant): Make new_regs an array.  Add code for
	flag_ira_loop_pressure.
	(best_gain_for_invariant): Ditto.
	(set_move_mark): New parameter gain.  Use it for debugging output.
	(find_invariants_to_move): Make regs_needed and new_regs an array.
	Add code for flag_ira_loop_pressure.
	(move_invariant_reg): Set up orig_regno.
	(move_invariants): Set up reg classes for pseudos for
	flag_ira_loop_pressure.
	(free_loop_data): Clear regs_ref and regs_live.
	(curr_regs_live, curr_reg_pressure, regs_set, n_regs_set,
	get_regno_cover_class, change_pressure, mark_regno_live,
	mark_regno_death, mark_reg_store, mark_reg_clobber,
	mark_reg_death, mark_ref_regs, calculate_loop_reg_pressure): New.
	(move_loop_invariants): Calculate pressure.  Initialize curr_loop.
	* ira.c (ira): Call ira_set_pseudo_classes after IRA based
	register pressure calculation in loops if new regs were added.
	Call finish_subregs_of_mode.
	* opts.c (decode_options): Set up flag_ira_loop_pressure.
	* Makefile.in (loop-invariant.o): Add ira.h.
	(regmove.o): Ditto.
	* doc/invoke.texi (-fira-loop-pressure, ira-loop-reserved-regs):
	Describe.
	* doc/tm.texi (STACK_REG_COVER_CLASS): Describe.

From-SVN: r152770

2 files changed, 25 insertions, 2 deletions

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 3f131fd..ddcde71 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -346,7 +346,8 @@ Objective-C and Objective-C++ Dialects}.
 -finline-small-functions -fipa-cp -fipa-cp-clone -fipa-matrix-reorg -fipa-pta @gol
 -fipa-pure-const -fipa-reference -fipa-struct-reorg @gol
 -fipa-type-escape -fira-algorithm=@var{algorithm} @gol
--fira-region=@var{region} -fira-coalesce -fno-ira-share-save-slots @gol
+-fira-region=@var{region} -fira-coalesce @gol
+-fira-loop-pressure -fno-ira-share-save-slots @gol
 -fno-ira-share-spill-slots -fira-verbose=@var{n} @gol
 -fivopts -fkeep-inline-functions -fkeep-static-consts @gol
 -floop-block -floop-interchange -floop-strip-mine -fgraphite-identity @gol
@@ -5719,7 +5720,8 @@ invoking @option{-O2} on programs that use computed gotos.
 Optimize yet more.  @option{-O3} turns on all optimizations specified
 by @option{-O2} and also turns on the @option{-finline-functions},
 @option{-funswitch-loops}, @option{-fpredictive-commoning},
-@option{-fgcse-after-reload} and @option{-ftree-vectorize} options.
+@option{-fgcse-after-reload}, @option{-ftree-vectorize} and
+@option{-fira-loop-pressure} options.
 
 @item -O0
 @opindex O0
@@ -6216,6 +6218,14 @@ give the best results in most cases and for most architectures.
 Do optimistic register coalescing.  This option might be profitable for
 architectures with big regular register files.
 
+@item -fira-loop-pressure
+@opindex fira-loop-pressure
+Use IRA to evaluate register pressure in loops for decision to move
+loop invariants.  Usage of this option usually results in generation
+of faster and smaller code but can slow compiler down.
+
+This option is enabled at level @option{-O3}.
+
 @item -fno-ira-share-save-slots
 @opindex fno-ira-share-save-slots
 Switch off sharing stack slots used for saving call used hard
@@ -8387,6 +8397,14 @@ lower quality register allocation algorithm will be used.  The
 algorithm do not use pseudo-register conflicts.  The default value of
 the parameter is 2000.
 
+@item ira-loop-reserved-regs
+IRA can be used to evaluate more accurate register pressure in loops
+for decision to move loop invariants (see @option{-O3}).  The number
+of available registers reserved for some other purposes is described
+by this parameter.  The default value of the parameter is 2 which is
+minimal number of registers needed for execution of typical
+instruction.  This value is the best found from numerous experiments.
+
 @item loop-invariant-max-bbs-in-loop
 Loop invariant motion can be very expensive, both in compile time and
 in amount of needed compile time memory, with very large loops.  Loops
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 8588852..57e2b76 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -2349,6 +2349,11 @@ with it, as well as defining these macros.
 Define this if the machine has any stack-like registers.
 @end defmac
 
+@defmac STACK_REG_COVER_CLASS
+This is a cover class containing the stack registers.  Define this if
+the machine has any stack-like registers.
+@end defmac
+
 @defmac FIRST_STACK_REG
 The number of the first stack-like register.  This one is the top
 of the stack.