Functions
static void	make_hard_regno_born ()
static void	make_hard_regno_dead ()
static void	make_object_born ()
static void	update_allocno_pressure_excess_length ()
static void	make_object_dead ()
static void	inc_register_pressure ()
static void	dec_register_pressure ()
static bool	pseudo_regno_single_word_and_live_p ()
static void	mark_pseudo_regno_live ()
static void	mark_pseudo_regno_subword_live ()
static void	mark_hard_reg_live ()
static void	mark_pseudo_reg_live ()
static void	mark_ref_live ()
static void	mark_pseudo_regno_dead ()
static void	mark_pseudo_regno_subword_dead ()
static void	mark_hard_reg_dead ()
static void	mark_pseudo_reg_dead ()
static void	mark_ref_dead ()
static bool	make_pseudo_conflict (rtx reg, enum reg_class cl, rtx dreg, rtx orig_dreg, bool advance_p)
static bool	check_and_make_def_use_conflict (rtx dreg, rtx orig_dreg, enum reg_class def_cl, int use, enum reg_class use_cl, bool advance_p)
static void	check_and_make_def_conflict ()
static void	make_early_clobber_and_input_conflicts ()
static bool	mark_hard_reg_early_clobbers ()
static enum reg_class	single_reg_class ()
static enum reg_class	single_reg_operand_class ()
void	ira_implicitly_set_insn_hard_regs ()
static void	process_single_reg_class_operands ()
static bool	bb_has_abnormal_call_pred ()
static rtx	find_call_crossed_cheap_reg ()
static void	process_bb_node_lives ()
static void	create_start_finish_chains ()
void	ira_rebuild_start_finish_chains ()
static void	remove_some_program_points_and_update_live_ranges ()
void	ira_print_live_range_list ()
DEBUG_FUNCTION void	debug ()
void	ira_debug_live_range_list ()
static void	print_object_live_ranges ()
static void	print_allocno_live_ranges ()
void	ira_debug_allocno_live_ranges ()
static void	print_live_ranges ()
void	ira_debug_live_ranges ()
void	ira_create_allocno_live_ranges ()
void	ira_compress_allocno_live_ranges ()
void	ira_finish_allocno_live_ranges ()

Variables
int	ira_max_point
live_range_t *	ira_start_point_ranges
live_range_t *	ira_finish_point_ranges
static int	curr_point
static int	high_pressure_start_point [N_REG_CLASSES]
static sparseset	objects_live
static sparseset	allocnos_processed
static HARD_REG_SET	hard_regs_live
static ira_loop_tree_node_t	curr_bb_node
static int	last_call_num
static int *	allocno_saved_at_call
static int	curr_reg_pressure [N_REG_CLASSES]

Function Documentation

static bool bb_has_abnormal_call_pred ( )

static

   Return true when one of the predecessor edges of BB is marked with
   EDGE_ABNORMAL_CALL or EDGE_EH.

References modified_between_p(), and pseudo_regno_single_word_and_live_p().

static void check_and_make_def_conflict ( )

static

   Check and make if necessary conflicts for definition DEF of class
   DEF_CL of the current insn with input operands.  Process only
   constraints of alternative ALT.

         If there's any alternative that allows USE to match DEF, do not
         record a conflict.  If that causes us to create an invalid
         instruction due to the earlyclobber, reload must fix it up.

static bool check_and_make_def_use_conflict	(	rtx	dreg,
		rtx	orig_dreg,
		enum reg_class	def_cl,
		int	use,
		enum reg_class	use_cl,
		bool	advance_p
	)

static

   Check and make if necessary conflicts for pseudo DREG of class
   DEF_CL of the current insn with input operand USE of class USE_CL.
   ORIG_DREG is the rtx actually accessed, it may be identical to
   DREG or a subreg of it.  Advance the current program point before
   making the conflict if ADVANCE_P.  Return TRUE if we will need to
   advance the current program point.

     Reload may end up swapping commutative operands, so you
     have to take both orderings into account.  The
     constraints for the two operands can be completely
     different.  (Indeed, if the constraints for the two
     operands are the same for all alternatives, there's no
     point marking them as commutative.)

static void create_start_finish_chains ( )

static

   Create and set up IRA_START_POINT_RANGES and
   IRA_FINISH_POINT_RANGES.

DEBUG_FUNCTION void debug ( )

static void dec_register_pressure ( )

static

   Record that register pressure for PCLASS has decreased by NREGS
   registers; update current register pressure, start point of the
   register pressure excess, and register pressure excess length for
   living allocnos.

References high_pressure_start_point, ira_object_id_map, and update_allocno_pressure_excess_length().

Referenced by mark_pseudo_regno_subword_dead().

static rtx find_call_crossed_cheap_reg ( )

static

   Look through the CALL_INSN_FUNCTION_USAGE of a call insn INSN, and see if
   we find a SET rtx that we can use to deduce that a register can be cheaply
   caller-saved.  Return such a register, or NULL_RTX if none is found.

References ira_loop_tree_node::bb, df_get_live_out(), eliminable_regset, hard_regs_live, high_pressure_start_point, last_call_num, mark_pseudo_regno_live(), ira_loop_tree_node::reg_pressure, and sparseset_clear().

Referenced by process_bb_node_lives().

static void inc_register_pressure ( )

static

   Record that register pressure for PCLASS increased by N registers.
   Update the current register pressure, maximal register pressure for
   the current BB and the start point of the register pressure
   excess.

References high_pressure_start_point.

Referenced by mark_pseudo_regno_live().

void ira_compress_allocno_live_ranges ( void )

   Compress allocno live ranges.

void ira_create_allocno_live_ranges ( void )

   The main entry function creates live ranges, set up
   CONFLICT_HARD_REGS and TOTAL_CONFLICT_HARD_REGS for objects, and
   calculate register pressure info.

     Clean up.

void ira_debug_allocno_live_ranges ( )

   Print live ranges of allocno A to stderr.

void ira_debug_live_range_list ( )

   Print live ranges R to stderr.

References internal_flag_ira_verbose, ira_dump_file, ira_rebuild_start_finish_chains(), and remove_some_program_points_and_update_live_ranges().

void ira_debug_live_ranges ( void )

   Print live ranges of all allocnos to stderr.

void ira_finish_allocno_live_ranges ( void )

   Free arrays IRA_START_POINT_RANGES and IRA_FINISH_POINT_RANGES.

void ira_implicitly_set_insn_hard_regs ( )

   The function sets up hard register set *SET to hard registers which
   might be used by insn reloads because the constraints are too
   strict.

                         There is no register pressure problem if all of the
                         regs in this class are fixed.

Referenced by undo_transformations().

void ira_print_live_range_list ( )

   Print live ranges R to file F.

References ira_objects_num, and sparseset_alloc().

void ira_rebuild_start_finish_chains ( void )

   Rebuild IRA_START_POINT_RANGES and IRA_FINISH_POINT_RANGES after
   new live ranges and program points were added as a result if new
   insn generation.

Referenced by ira_debug_live_range_list().

static void make_early_clobber_and_input_conflicts ( )

static

   Make conflicts of early clobber pseudo registers of the current
   insn with its inputs.  Avoid introducing unnecessary conflicts by
   checking classes of the constraints and pseudos because otherwise
   significant code degradation is possible for some targets.

Referenced by process_bb_node_lives().

static void make_hard_regno_born ( )

static

   Record the birth of hard register REGNO, updating hard_regs_live and
   hard reg conflict information for living allocnos.

References hard_regs_live.

static void make_hard_regno_dead ( )

static

   Process the death of hard register REGNO.  This updates
   hard_regs_live.

Referenced by mark_pseudo_regno_subword_dead().

static void make_object_born ( )

static

   Record the birth of object OBJ.  Set a bit for it in objects_live,
   start a new live range for it if necessary and update hard register
   conflicts.

References high_pressure_start_point.

Referenced by mark_pseudo_regno_live().

static void make_object_dead ( )

static

   Process the death of object OBJ, which is associated with allocno
   A.  This finishes the current live range for it.

static bool make_pseudo_conflict	(	rtx	reg,
		enum reg_class	cl,
		rtx	dreg,
		rtx	orig_dreg,
		bool	advance_p
	)

static

   If REG is a pseudo or a subreg of it, and the class of its allocno
   intersects CL, make a conflict with pseudo DREG.  ORIG_DREG is the
   rtx actually accessed, it may be identical to DREG or a subreg of it.
   Advance the current program point before making the conflict if
   ADVANCE_P.  Return TRUE if we will need to advance the current
   program point.

static void mark_hard_reg_dead ( )

static

   Mark the hard register REG as dead.  Store a 0 in hard_regs_live for the
   register.

static bool mark_hard_reg_early_clobbers ( )

static

   Mark early clobber hard registers of the current INSN as live (if
   LIVE_P) or dead.  Return true if there are such registers.

           Hard register clobbers are believed to be early clobber
           because there is no way to say that non-operand hard
           register clobbers are not early ones.

Referenced by process_bb_node_lives().

static void mark_hard_reg_live ( )

static

   Mark the register REG as live.  Store a 1 in hard_regs_live for
   this register, record how many consecutive hardware registers it
   actually needs.

References df_read_modify_subreg_p(), mark_pseudo_regno_live(), mark_pseudo_regno_subword_live(), and subreg_lowpart_p().

static void mark_pseudo_reg_dead ( )

static

   Mark a pseudo, or one of its subwords, as dead.  REGNO is the pseudo's
   register number; ORIG_REG is the access in the insn, which may be a
   subreg.

static void mark_pseudo_reg_live ( )

static

   Mark a pseudo, or one of its subwords, as live.  REGNO is the pseudo's
   register number; ORIG_REG is the access in the insn, which may be a
   subreg.

References allocno_saved_at_call, and ira_curr_regno_allocno_map.

static void mark_pseudo_regno_dead ( )

static

   Mark the pseudo register REGNO as dead.  Update all information about
   live ranges and register pressure.

     Invalidate because it is referenced.

         We track every subobject separately.

static void mark_pseudo_regno_live ( )

static

   Mark the pseudo register REGNO as live.  Update all information about
   live ranges and register pressure.

     Invalidate because it is referenced.

         We track every subobject separately.

References inc_register_pressure(), make_object_born(), and sparseset_bit_p().

Referenced by find_call_crossed_cheap_reg(), and mark_hard_reg_live().

static void mark_pseudo_regno_subword_dead ( )

static

   Like mark_pseudo_regno_dead, but called when we know that only part of the
   register dies.  SUBWORD indicates which; a value of 0 indicates the low part.

     Invalidate because it is referenced.

       The allocno as a whole doesn't die in this case.

References dec_register_pressure(), hard_regs_live, and make_hard_regno_dead().

static void mark_pseudo_regno_subword_live ( )

static

   Like mark_pseudo_regno_live, but try to only mark one subword of
   the pseudo as live.  SUBWORD indicates which; a value of 0
   indicates the low part.

     Invalidate because it is referenced.

Referenced by mark_hard_reg_live().

static void mark_ref_dead ( )

static

   Mark the register referenced by definition DEF as dead, if the
   definition is a total one.

Referenced by process_bb_node_lives().

static void mark_ref_live ( )

static

   Mark the register referenced by use or def REF as live.

Referenced by process_bb_node_lives().

static void print_allocno_live_ranges ( )

static

   Print live ranges of allocno A to file F.

References ira_free().

static void print_live_ranges ( )

static

   Print live ranges of all allocnos to file F.

Referenced by print_object_live_ranges().

static void print_object_live_ranges ( )

static

   Print live ranges of object OBJ to file F.

References ira_dump_file, and print_live_ranges().

static void process_bb_node_lives ( )

static

   Process insns of the basic block given by its LOOP_TREE_NODE to
   update allocno live ranges, allocno hard register conflicts,
   intersected calls, and register pressure info for allocnos for the
   basic block for and regions containing the basic block.

         Invalidate all allocno_saved_at_call entries.

         Scan the code of this basic block, noting which allocnos and
         hard regs are born or die.

         Note that this loop treats uninitialized values as live until
         the beginning of the block.  For example, if an instruction
         uses (reg:DI foo), and only (subreg:SI (reg:DI foo) 0) is ever
         set, FOO will remain live until the beginning of the block.
         Likewise if FOO is not set at all.  This is unnecessarily
         pessimistic, but it probably doesn't matter much in practice.

             Mark each defined value as live.  We need to do this for
             unused values because they still conflict with quantities
             that are live at the time of the definition.

             Ignore DF_REF_MAY_CLOBBERs on a call instruction.  Such
             references represent the effect of the called function
             on a call-clobbered register.  Marking the register as
             live would stop us from allocating it to a call-crossing
             allocno.

             If INSN has multiple outputs, then any value used in one
             of the outputs conflicts with the other outputs.  Model this
             by making the used value live during the output phase.

             It is unsafe to use !single_set here since it will ignore
             an unused output.  Just because an output is unused does
             not mean the compiler can assume the side effect will not
             occur.  Consider if ALLOCNO appears in the address of an
             output and we reload the output.  If we allocate ALLOCNO
             to the same hard register as an unused output we could
             set the hard register before the output reload insn.

                           After the previous loop, this is a no-op if
                           REG is contained within SET_DEST (SET).

             See which defined values die here.

                 Try to find a SET in the CALL_INSN_FUNCTION_USAGE, and from
                 there, try to find a pseudo that is live across the call but
                 can be cheaply reconstructed from the return value.

                 The current set of live allocnos are live across the call.

                     Don't allocate allocnos that cross setjmps or any
                     call, if this function receives a nonlocal
                     goto.

                       Here we are mimicking caller-save.c behaviour
                       which does not save hard register at a call if
                       it was saved on previous call in the same basic
                       block and the hard register was not mentioned
                       between the two calls.

                     Mark it as saved at the next call.

             Mark each used value as live.

                 Mark each hard reg as live again.  For example, a
                 hard register can be in clobber and in an insn
                 input.

         Allocnos can't go in stack regs at the start of a basic block
         that is reached by an abnormal edge. Likewise for call
         clobbered regs, because caller-save, fixup_abnormal_edges and
         possibly the table driven EH machinery are not quite ready to
         handle such allocnos live across such edges.

             No need to record conflicts for call clobbered regs if we
             have nonlocal labels around, as we don't ever try to
             allocate such regs in this case.

     Propagate register pressure to upper loop tree nodes:

References add_reg_note(), allocno_saved_at_call, can_throw_internal(), cfun, curr_point, DF_REF_MAY_CLOBBER, extract_insn(), find_call_crossed_cheap_reg(), find_reg_note(), function::has_nonlocal_label, internal_flag_ira_verbose, ira_dump_file, ira_object_id_map, last_call_num, ira_loop_tree_node::loop_num, make_early_clobber_and_input_conflicts(), mark_hard_reg_early_clobbers(), mark_ref_dead(), mark_ref_live(), multiple_sets(), ira_loop_tree_node::parent, preprocess_constraints(), process_single_reg_class_operands(), reg_overlap_mentioned_p(), SET, sparseset_bit_p(), sparseset_clear(), and sparseset_set_bit().

static void process_single_reg_class_operands ( )

static

   Processes input operands, if IN_P, or output operands otherwise of
   the current insn with FREQ to find allocno which can use only one
   hard register and makes other currently living allocnos conflicting
   with the hard register.

                 View the desired allocation of OPERAND as:

                    (REG:YMODE YREGNO),

                 a simplification of:

                    (subreg:YMODE (reg:XMODE XREGNO) OFFSET).

                 We could increase costs of A instead of making it
                 conflicting with the hard register.  But it works worse
                 because it will be spilled in reload in anyway.

References ira_allocate_and_set_costs(), and ira_init_register_move_cost_if_necessary().

Referenced by process_bb_node_lives().

static bool pseudo_regno_single_word_and_live_p ( )

static

   Determine from the objects_live bitmap whether REGNO is currently live,
   and occupies only one object.  Return false if we have no information.

Referenced by bb_has_abnormal_call_pred().

static void remove_some_program_points_and_update_live_ranges ( )

static

   Compress allocno live ranges by removing program points where
   nothing happens.

Referenced by ira_debug_live_range_list().

static enum reg_class single_reg_class ( )

static

   Checks that CONSTRAINTS permits to use only one hard register.  If
   it is so, the function returns the class of the hard register.
   Otherwise it returns NO_REGS.

             ??? what about memory

static enum reg_class single_reg_operand_class ( )

static

   The function checks that operand OP_NUM of the current insn can use
   only one hard register.  If it is so, the function returns the
   class of the hard register.  Otherwise it returns NO_REGS.

static void update_allocno_pressure_excess_length ( )

static

   Update ALLOCNO_EXCESS_PRESSURE_POINTS_NUM for the allocno
   associated with object OBJ.

Referenced by dec_register_pressure().

Variable Documentation

int* allocno_saved_at_call

static

   The number of last call at which given allocno was saved.

Referenced by mark_pseudo_reg_live(), and process_bb_node_lives().

sparseset allocnos_processed

static

   A temporary bitmap used in functions that wish to avoid visiting an allocno
   multiple times.

ira_loop_tree_node_t curr_bb_node

static

   The loop tree node corresponding to the current basic block.

int curr_point

static

   Number of the current program point.

Referenced by lra_debug_live_range_list(), and process_bb_node_lives().

int curr_reg_pressure[N_REG_CLASSES]

static

   The current register pressures for each pressure class for the current
   basic block.

HARD_REG_SET hard_regs_live

static

   Set of hard regs (except eliminable ones) currently live.

Referenced by find_call_crossed_cheap_reg(), make_hard_regno_born(), and mark_pseudo_regno_subword_dead().

int high_pressure_start_point[N_REG_CLASSES]

static

   Point where register pressure excess started or -1 if there is no
   register pressure excess.  Excess pressure for a register class at
   some point means that there are more allocnos of given register
   class living at the point than number of hard-registers of the
   class available for the allocation.  It is defined only for
   pressure classes.

Referenced by dec_register_pressure(), find_call_crossed_cheap_reg(), inc_register_pressure(), and make_object_born().

live_range_t * ira_finish_point_ranges

int ira_max_point

@verbatim

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see http://www.gnu.org/licenses/.

   The code in this file is similar to one in global but the code
   works on the allocno basis and creates live ranges instead of
   pseudo-register conflicts.

   Program points are enumerated by numbers from range
   0..IRA_MAX_POINT-1.  There are approximately two times more program
   points than insns.  Program points are places in the program where
   liveness info can be changed.  In most general case (there are more
   complicated cases too) some program points correspond to places
   where input operand dies and other ones correspond to places where
   output operands are born.

Referenced by split_live_ranges_for_shrink_wrap().

live_range_t* ira_start_point_ranges

   Arrays of size IRA_MAX_POINT mapping a program point to the allocno
   live ranges with given start/finish point.

int last_call_num

static

   The number of the last processed call.

Referenced by find_call_crossed_cheap_reg(), and process_bb_node_lives().

sparseset objects_live

static

   Objects live at current point in the scan.

Functions

Variables

Function Documentation

Variable Documentation