Functions
static int	count_insns (basic_block)
static bool	ignore_bb_p (const_basic_block)
static bool	better_p (const_edge, const_edge)
static edge	find_best_successor (basic_block)
static edge	find_best_predecessor (basic_block)
static int	find_trace (basic_block, basic_block *)
static void	mark_bb_seen ()
static bool	bb_seen_p ()
static bool	ignore_bb_p ()
static int	count_insns ()
static bool	better_p ()
static edge	find_best_successor ()
static edge	find_best_predecessor ()
static int	find_trace ()
static bool	tail_duplicate ()
static unsigned int	tracer ()
static bool	gate_tracer ()
gimple_opt_pass *	make_pass_tracer ()

Variables
static int	probability_cutoff
static int	branch_ratio_cutoff
sbitmap	bb_seen

Function Documentation

static bool bb_seen_p ( )

inlinestatic

References g, and basic_block_def::index.

static bool better_p	(	const_edge	,
		const_edge
	)

static

static bool better_p ( )

static

   Return true if E1 is more frequent than E2.

     This is needed to avoid changes in the decision after
     CFG is modified.

static int count_insns ( basic_block )

static

   The tracer pass for the GNU compiler.
   Contributed by Jan Hubicka, SuSE Labs.
   Adapted to work on GIMPLE instead of RTL by Robert Kidd, UIUC.
   Copyright (C) 2001-2013 Free Software Foundation, Inc.

   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/>.

   This pass performs the tail duplication needed for superblock formation.
   For more information see:

     Design and Analysis of Profile-Based Optimization in Compaq's
     Compilation Tools for Alpha; Journal of Instruction-Level
     Parallelism 3 (2000) 1-25

   Unlike Compaq's implementation we don't do the loop peeling as most
   probably a better job can be done by a special pass and we don't
   need to worry too much about the code size implications as the tail
   duplicates are crossjumped again if optimizations are not
   performed.

static int count_insns ( )

static

   Return number of instructions in the block.

References eni_size_weights, estimate_num_insns(), and gsi_stmt().

static edge find_best_predecessor ( basic_block )

static

static edge find_best_predecessor ( )

static

   Return most frequent predecessor of basic block BB.

static edge find_best_successor ( basic_block )

static

static edge find_best_successor ( )

static

   Return most frequent successor of basic block BB.

static int find_trace	(	basic_block	,
		basic_block *
	)

static

static int find_trace ( )

static

   Find the trace using bb and record it in the TRACE array.
   Return number of basic blocks recorded.

     Follow the trace in forward direction.

static bool gate_tracer ( )

static

References execute(), and tracer().

static bool ignore_bb_p ( const_basic_block )

static

static bool ignore_bb_p ( )

static

   Return true if we should ignore the basic block for purposes of tracing.

     A transaction is a single entry multiple exit region.  It must be
     duplicated in its entirety or not at all.

gimple_opt_pass* make_pass_tracer ( )

static void mark_bb_seen ( )

inlinestatic

static bool tail_duplicate ( )

static

   Look for basic blocks in frequency order, construct traces and tail duplicate
   if profitable.

     Create an oversized sbitmap to reduce the chance that we need to
     resize it.

                 We have the tendency to duplicate the loop header
                 of all do { } while loops.  Do not do that - it is
                 not profitable and it might create a loop with multiple
                 entries or at least rotate the loop.

                 Reconsider the original copy of block we've duplicated.
                 Removing the most common predecessor may make it to be
                 head.

             In case the trace became infrequent, stop duplicating.

static unsigned int tracer ( )

static

   Main entry point to this file.

     Trace formation is done on the fly inside tail_duplicate

         If we changed the CFG schedule loops for fixup by cleanup_cfg.

Referenced by gate_tracer().

Variable Documentation

sbitmap bb_seen

   A bit BB->index is set if BB has already been seen, i.e. it is
   connected to some trace already.

int branch_ratio_cutoff

static

int probability_cutoff

static

   Minimal outgoing edge probability considered for superblock formation.

Referenced by bb_in_region_p().

Functions

Variables

Function Documentation

Variable Documentation