Reorganize the gcc vendor import work area. This flattens out a bunch

of unnecessary path components that are relics of cvs2svn.

(These are directory moves)

1 files changed, 1924 insertions, 0 deletions

diff --git a/gcc/predict.c b/gcc/predict.c
new file mode 100644
index 0000000..9030763
--- /dev/null
+++ b/gcc/predict.c
@@ -0,0 +1,1924 @@
+/* Branch prediction routines for the GNU compiler.
+   Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
+   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 2, 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 COPYING.  If not, write to the Free
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA.  */
+
+/* References:
+
+   [1] "Branch Prediction for Free"
+       Ball and Larus; PLDI '93.
+   [2] "Static Branch Frequency and Program Profile Analysis"
+       Wu and Larus; MICRO-27.
+   [3] "Corpus-based Static Branch Prediction"
+       Calder, Grunwald, Lindsay, Martin, Mozer, and Zorn; PLDI '95.  */
+
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "rtl.h"
+#include "tm_p.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "insn-config.h"
+#include "regs.h"
+#include "flags.h"
+#include "output.h"
+#include "function.h"
+#include "except.h"
+#include "toplev.h"
+#include "recog.h"
+#include "expr.h"
+#include "predict.h"
+#include "coverage.h"
+#include "sreal.h"
+#include "params.h"
+#include "target.h"
+#include "cfgloop.h"
+#include "tree-flow.h"
+#include "ggc.h"
+#include "tree-dump.h"
+#include "tree-pass.h"
+#include "timevar.h"
+#include "tree-scalar-evolution.h"
+#include "cfgloop.h"
+
+/* real constants: 0, 1, 1-1/REG_BR_PROB_BASE, REG_BR_PROB_BASE,
+		   1/REG_BR_PROB_BASE, 0.5, BB_FREQ_MAX.  */
+static sreal real_zero, real_one, real_almost_one, real_br_prob_base,
+	     real_inv_br_prob_base, real_one_half, real_bb_freq_max;
+
+/* Random guesstimation given names.  */
+#define PROB_VERY_UNLIKELY	(REG_BR_PROB_BASE / 100 - 1)
+#define PROB_EVEN		(REG_BR_PROB_BASE / 2)
+#define PROB_VERY_LIKELY	(REG_BR_PROB_BASE - PROB_VERY_UNLIKELY)
+#define PROB_ALWAYS		(REG_BR_PROB_BASE)
+
+static void combine_predictions_for_insn (rtx, basic_block);
+static void dump_prediction (FILE *, enum br_predictor, int, basic_block, int);
+static void estimate_loops_at_level (struct loop *, bitmap);
+static void propagate_freq (struct loop *, bitmap);
+static void estimate_bb_frequencies (struct loops *);
+static void predict_paths_leading_to (basic_block, int *, enum br_predictor, enum prediction);
+static bool last_basic_block_p (basic_block);
+static void compute_function_frequency (void);
+static void choose_function_section (void);
+static bool can_predict_insn_p (rtx);
+
+/* Information we hold about each branch predictor.
+   Filled using information from predict.def.  */
+
+struct predictor_info
+{
+  const char *const name;	/* Name used in the debugging dumps.  */
+  const int hitrate;		/* Expected hitrate used by
+				   predict_insn_def call.  */
+  const int flags;
+};
+
+/* Use given predictor without Dempster-Shaffer theory if it matches
+   using first_match heuristics.  */
+#define PRED_FLAG_FIRST_MATCH 1
+
+/* Recompute hitrate in percent to our representation.  */
+
+#define HITRATE(VAL) ((int) ((VAL) * REG_BR_PROB_BASE + 50) / 100)
+
+#define DEF_PREDICTOR(ENUM, NAME, HITRATE, FLAGS) {NAME, HITRATE, FLAGS},
+static const struct predictor_info predictor_info[]= {
+#include "predict.def"
+
+  /* Upper bound on predictors.  */
+  {NULL, 0, 0}
+};
+#undef DEF_PREDICTOR
+
+/* Return true in case BB can be CPU intensive and should be optimized
+   for maximal performance.  */
+
+bool
+maybe_hot_bb_p (basic_block bb)
+{
+  if (profile_info && flag_branch_probabilities
+      && (bb->count
+	  < profile_info->sum_max / PARAM_VALUE (HOT_BB_COUNT_FRACTION)))
+    return false;
+  if (bb->frequency < BB_FREQ_MAX / PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION))
+    return false;
+  return true;
+}
+
+/* Return true in case BB is cold and should be optimized for size.  */
+
+bool
+probably_cold_bb_p (basic_block bb)
+{
+  if (profile_info && flag_branch_probabilities
+      && (bb->count
+	  < profile_info->sum_max / PARAM_VALUE (HOT_BB_COUNT_FRACTION)))
+    return true;
+  if (bb->frequency < BB_FREQ_MAX / PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION))
+    return true;
+  return false;
+}
+
+/* Return true in case BB is probably never executed.  */
+bool
+probably_never_executed_bb_p (basic_block bb)
+{
+  if (profile_info && flag_branch_probabilities)
+    return ((bb->count + profile_info->runs / 2) / profile_info->runs) == 0;
+  return false;
+}
+
+/* Return true if the one of outgoing edges is already predicted by
+   PREDICTOR.  */
+
+bool
+rtl_predicted_by_p (basic_block bb, enum br_predictor predictor)
+{
+  rtx note;
+  if (!INSN_P (BB_END (bb)))
+    return false;
+  for (note = REG_NOTES (BB_END (bb)); note; note = XEXP (note, 1))
+    if (REG_NOTE_KIND (note) == REG_BR_PRED
+	&& INTVAL (XEXP (XEXP (note, 0), 0)) == (int)predictor)
+      return true;
+  return false;
+}
+
+/* Return true if the one of outgoing edges is already predicted by
+   PREDICTOR.  */
+
+bool
+tree_predicted_by_p (basic_block bb, enum br_predictor predictor)
+{
+  struct edge_prediction *i;
+  for (i = bb->predictions; i; i = i->ep_next)
+    if (i->ep_predictor == predictor)
+      return true;
+  return false;
+}
+
+/* Return true when the probability of edge is reliable.
+  
+   The profile guessing code is good at predicting branch outcome (ie.
+   taken/not taken), that is predicted right slightly over 75% of time.
+   It is however notoriously poor on predicting the probability itself.
+   In general the profile appear a lot flatter (with probabilities closer
+   to 50%) than the reality so it is bad idea to use it to drive optimization
+   such as those disabling dynamic branch prediction for well predictable
+   branches.
+
+   There are two exceptions - edges leading to noreturn edges and edges
+   predicted by number of iterations heuristics are predicted well.  This macro
+   should be able to distinguish those, but at the moment it simply check for
+   noreturn heuristic that is only one giving probability over 99% or bellow
+   1%.  In future we might want to propagate reliability information across the
+   CFG if we find this information useful on multiple places.   */
+static bool
+probability_reliable_p (int prob)
+{
+  return (profile_status == PROFILE_READ
+	  || (profile_status == PROFILE_GUESSED
+	      && (prob <= HITRATE (1) || prob >= HITRATE (99))));
+}
+
+/* Same predicate as above, working on edges.  */
+bool
+edge_probability_reliable_p (edge e)
+{
+  return probability_reliable_p (e->probability);
+}
+
+/* Same predicate as edge_probability_reliable_p, working on notes.  */
+bool
+br_prob_note_reliable_p (rtx note)
+{
+  gcc_assert (REG_NOTE_KIND (note) == REG_BR_PROB);
+  return probability_reliable_p (INTVAL (XEXP (note, 0)));
+}
+
+static void
+predict_insn (rtx insn, enum br_predictor predictor, int probability)
+{
+  gcc_assert (any_condjump_p (insn));
+  if (!flag_guess_branch_prob)
+    return;
+
+  REG_NOTES (insn)
+    = gen_rtx_EXPR_LIST (REG_BR_PRED,
+			 gen_rtx_CONCAT (VOIDmode,
+					 GEN_INT ((int) predictor),
+					 GEN_INT ((int) probability)),
+			 REG_NOTES (insn));
+}
+
+/* Predict insn by given predictor.  */
+
+void
+predict_insn_def (rtx insn, enum br_predictor predictor,
+		  enum prediction taken)
+{
+   int probability = predictor_info[(int) predictor].hitrate;
+
+   if (taken != TAKEN)
+     probability = REG_BR_PROB_BASE - probability;
+
+   predict_insn (insn, predictor, probability);
+}
+
+/* Predict edge E with given probability if possible.  */
+
+void
+rtl_predict_edge (edge e, enum br_predictor predictor, int probability)
+{
+  rtx last_insn;
+  last_insn = BB_END (e->src);
+
+  /* We can store the branch prediction information only about
+     conditional jumps.  */
+  if (!any_condjump_p (last_insn))
+    return;
+
+  /* We always store probability of branching.  */
+  if (e->flags & EDGE_FALLTHRU)
+    probability = REG_BR_PROB_BASE - probability;
+
+  predict_insn (last_insn, predictor, probability);
+}
+
+/* Predict edge E with the given PROBABILITY.  */
+void
+tree_predict_edge (edge e, enum br_predictor predictor, int probability)
+{
+  gcc_assert (profile_status != PROFILE_GUESSED);
+  if ((e->src != ENTRY_BLOCK_PTR && EDGE_COUNT (e->src->succs) > 1)
+      && flag_guess_branch_prob && optimize)
+    {
+      struct edge_prediction *i = ggc_alloc (sizeof (struct edge_prediction));
+
+      i->ep_next = e->src->predictions;
+      e->src->predictions = i;
+      i->ep_probability = probability;
+      i->ep_predictor = predictor;
+      i->ep_edge = e;
+    }
+}
+
+/* Remove all predictions on given basic block that are attached
+   to edge E.  */
+void
+remove_predictions_associated_with_edge (edge e)
+{
+  if (e->src->predictions)
+    {
+      struct edge_prediction **prediction = &e->src->predictions;
+      while (*prediction)
+	{
+	  if ((*prediction)->ep_edge == e)
+	    *prediction = (*prediction)->ep_next;
+	  else
+	    prediction = &((*prediction)->ep_next);
+	}
+    }
+}
+
+/* Return true when we can store prediction on insn INSN.
+   At the moment we represent predictions only on conditional
+   jumps, not at computed jump or other complicated cases.  */
+static bool
+can_predict_insn_p (rtx insn)
+{
+  return (JUMP_P (insn)
+	  && any_condjump_p (insn)
+	  && EDGE_COUNT (BLOCK_FOR_INSN (insn)->succs) >= 2);
+}
+
+/* Predict edge E by given predictor if possible.  */
+
+void
+predict_edge_def (edge e, enum br_predictor predictor,
+		  enum prediction taken)
+{
+   int probability = predictor_info[(int) predictor].hitrate;
+
+   if (taken != TAKEN)
+     probability = REG_BR_PROB_BASE - probability;
+
+   predict_edge (e, predictor, probability);
+}
+
+/* Invert all branch predictions or probability notes in the INSN.  This needs
+   to be done each time we invert the condition used by the jump.  */
+
+void
+invert_br_probabilities (rtx insn)
+{
+  rtx note;
+
+  for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
+    if (REG_NOTE_KIND (note) == REG_BR_PROB)
+      XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
+    else if (REG_NOTE_KIND (note) == REG_BR_PRED)
+      XEXP (XEXP (note, 0), 1)
+	= GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (XEXP (note, 0), 1)));
+}
+
+/* Dump information about the branch prediction to the output file.  */
+
+static void
+dump_prediction (FILE *file, enum br_predictor predictor, int probability,
+		 basic_block bb, int used)
+{
+  edge e;
+  edge_iterator ei;
+
+  if (!file)
+    return;
+
+  FOR_EACH_EDGE (e, ei, bb->succs)
+    if (! (e->flags & EDGE_FALLTHRU))
+      break;
+
+  fprintf (file, "  %s heuristics%s: %.1f%%",
+	   predictor_info[predictor].name,
+	   used ? "" : " (ignored)", probability * 100.0 / REG_BR_PROB_BASE);
+
+  if (bb->count)
+    {
+      fprintf (file, "  exec ");
+      fprintf (file, HOST_WIDEST_INT_PRINT_DEC, bb->count);
+      if (e)
+	{
+	  fprintf (file, " hit ");
+	  fprintf (file, HOST_WIDEST_INT_PRINT_DEC, e->count);
+	  fprintf (file, " (%.1f%%)", e->count * 100.0 / bb->count);
+	}
+    }
+
+  fprintf (file, "\n");
+}
+
+/* We can not predict the probabilities of outgoing edges of bb.  Set them
+   evenly and hope for the best.  */
+static void
+set_even_probabilities (basic_block bb)
+{
+  int nedges = 0;
+  edge e;
+  edge_iterator ei;
+
+  FOR_EACH_EDGE (e, ei, bb->succs)
+    if (!(e->flags & (EDGE_EH | EDGE_FAKE)))
+      nedges ++;
+  FOR_EACH_EDGE (e, ei, bb->succs)
+    if (!(e->flags & (EDGE_EH | EDGE_FAKE)))
+      e->probability = (REG_BR_PROB_BASE + nedges / 2) / nedges;
+    else
+      e->probability = 0;
+}
+
+/* Combine all REG_BR_PRED notes into single probability and attach REG_BR_PROB
+   note if not already present.  Remove now useless REG_BR_PRED notes.  */
+
+static void
+combine_predictions_for_insn (rtx insn, basic_block bb)
+{
+  rtx prob_note;
+  rtx *pnote;
+  rtx note;
+  int best_probability = PROB_EVEN;
+  int best_predictor = END_PREDICTORS;
+  int combined_probability = REG_BR_PROB_BASE / 2;
+  int d;
+  bool first_match = false;
+  bool found = false;
+
+  if (!can_predict_insn_p (insn))
+    {
+      set_even_probabilities (bb);
+      return;
+    }
+
+  prob_note = find_reg_note (insn, REG_BR_PROB, 0);
+  pnote = &REG_NOTES (insn);
+  if (dump_file)
+    fprintf (dump_file, "Predictions for insn %i bb %i\n", INSN_UID (insn),
+	     bb->index);
+
+  /* We implement "first match" heuristics and use probability guessed
+     by predictor with smallest index.  */
+  for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
+    if (REG_NOTE_KIND (note) == REG_BR_PRED)
+      {
+	int predictor = INTVAL (XEXP (XEXP (note, 0), 0));
+	int probability = INTVAL (XEXP (XEXP (note, 0), 1));
+
+	found = true;
+	if (best_predictor > predictor)
+	  best_probability = probability, best_predictor = predictor;
+
+	d = (combined_probability * probability
+	     + (REG_BR_PROB_BASE - combined_probability)
+	     * (REG_BR_PROB_BASE - probability));
+
+	/* Use FP math to avoid overflows of 32bit integers.  */
+	if (d == 0)
+	  /* If one probability is 0% and one 100%, avoid division by zero.  */
+	  combined_probability = REG_BR_PROB_BASE / 2;
+	else
+	  combined_probability = (((double) combined_probability) * probability
+				  * REG_BR_PROB_BASE / d + 0.5);
+      }
+
+  /* Decide which heuristic to use.  In case we didn't match anything,
+     use no_prediction heuristic, in case we did match, use either
+     first match or Dempster-Shaffer theory depending on the flags.  */
+
+  if (predictor_info [best_predictor].flags & PRED_FLAG_FIRST_MATCH)
+    first_match = true;
+
+  if (!found)
+    dump_prediction (dump_file, PRED_NO_PREDICTION,
+		     combined_probability, bb, true);
+  else
+    {
+      dump_prediction (dump_file, PRED_DS_THEORY, combined_probability,
+		       bb, !first_match);
+      dump_prediction (dump_file, PRED_FIRST_MATCH, best_probability,
+		       bb, first_match);
+    }
+
+  if (first_match)
+    combined_probability = best_probability;
+  dump_prediction (dump_file, PRED_COMBINED, combined_probability, bb, true);
+
+  while (*pnote)
+    {
+      if (REG_NOTE_KIND (*pnote) == REG_BR_PRED)
+	{
+	  int predictor = INTVAL (XEXP (XEXP (*pnote, 0), 0));
+	  int probability = INTVAL (XEXP (XEXP (*pnote, 0), 1));
+
+	  dump_prediction (dump_file, predictor, probability, bb,
+			   !first_match || best_predictor == predictor);
+	  *pnote = XEXP (*pnote, 1);
+	}
+      else
+	pnote = &XEXP (*pnote, 1);
+    }
+
+  if (!prob_note)
+    {
+      REG_NOTES (insn)
+	= gen_rtx_EXPR_LIST (REG_BR_PROB,
+			     GEN_INT (combined_probability), REG_NOTES (insn));
+
+      /* Save the prediction into CFG in case we are seeing non-degenerated
+	 conditional jump.  */
+      if (!single_succ_p (bb))
+	{
+	  BRANCH_EDGE (bb)->probability = combined_probability;
+	  FALLTHRU_EDGE (bb)->probability
+	    = REG_BR_PROB_BASE - combined_probability;
+	}
+    }
+  else if (!single_succ_p (bb))
+    {
+      int prob = INTVAL (XEXP (prob_note, 0));
+
+      BRANCH_EDGE (bb)->probability = prob;
+      FALLTHRU_EDGE (bb)->probability = REG_BR_PROB_BASE - prob;
+    }
+  else
+    single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
+}
+
+/* Combine predictions into single probability and store them into CFG.
+   Remove now useless prediction entries.  */
+
+static void
+combine_predictions_for_bb (basic_block bb)
+{
+  int best_probability = PROB_EVEN;
+  int best_predictor = END_PREDICTORS;
+  int combined_probability = REG_BR_PROB_BASE / 2;
+  int d;
+  bool first_match = false;
+  bool found = false;
+  struct edge_prediction *pred;
+  int nedges = 0;
+  edge e, first = NULL, second = NULL;
+  edge_iterator ei;
+
+  FOR_EACH_EDGE (e, ei, bb->succs)
+    if (!(e->flags & (EDGE_EH | EDGE_FAKE)))
+      {
+	nedges ++;
+	if (first && !second)
+	  second = e;
+	if (!first)
+	  first = e;
+      }
+
+  /* When there is no successor or only one choice, prediction is easy. 
+
+     We are lazy for now and predict only basic blocks with two outgoing
+     edges.  It is possible to predict generic case too, but we have to
+     ignore first match heuristics and do more involved combining.  Implement
+     this later.  */
+  if (nedges != 2)
+    {
+      if (!bb->count)
+	set_even_probabilities (bb);
+      bb->predictions = NULL;
+      if (dump_file)
+	fprintf (dump_file, "%i edges in bb %i predicted to even probabilities\n",
+		 nedges, bb->index);
+      return;
+    }
+
+  if (dump_file)
+    fprintf (dump_file, "Predictions for bb %i\n", bb->index);
+
+  /* We implement "first match" heuristics and use probability guessed
+     by predictor with smallest index.  */
+  for (pred = bb->predictions; pred; pred = pred->ep_next)
+    {
+      int predictor = pred->ep_predictor;
+      int probability = pred->ep_probability;
+
+      if (pred->ep_edge != first)
+	probability = REG_BR_PROB_BASE - probability;
+
+      found = true;
+      if (best_predictor > predictor)
+	best_probability = probability, best_predictor = predictor;
+
+      d = (combined_probability * probability
+	   + (REG_BR_PROB_BASE - combined_probability)
+	   * (REG_BR_PROB_BASE - probability));
+
+      /* Use FP math to avoid overflows of 32bit integers.  */
+      if (d == 0)
+	/* If one probability is 0% and one 100%, avoid division by zero.  */
+	combined_probability = REG_BR_PROB_BASE / 2;
+      else
+	combined_probability = (((double) combined_probability) * probability
+				* REG_BR_PROB_BASE / d + 0.5);
+    }
+
+  /* Decide which heuristic to use.  In case we didn't match anything,
+     use no_prediction heuristic, in case we did match, use either
+     first match or Dempster-Shaffer theory depending on the flags.  */
+
+  if (predictor_info [best_predictor].flags & PRED_FLAG_FIRST_MATCH)
+    first_match = true;
+
+  if (!found)
+    dump_prediction (dump_file, PRED_NO_PREDICTION, combined_probability, bb, true);
+  else
+    {
+      dump_prediction (dump_file, PRED_DS_THEORY, combined_probability, bb,
+		       !first_match);
+      dump_prediction (dump_file, PRED_FIRST_MATCH, best_probability, bb,
+		       first_match);
+    }
+
+  if (first_match)
+    combined_probability = best_probability;
+  dump_prediction (dump_file, PRED_COMBINED, combined_probability, bb, true);
+
+  for (pred = bb->predictions; pred; pred = pred->ep_next)
+    {
+      int predictor = pred->ep_predictor;
+      int probability = pred->ep_probability;
+
+      if (pred->ep_edge != EDGE_SUCC (bb, 0))
+	probability = REG_BR_PROB_BASE - probability;
+      dump_prediction (dump_file, predictor, probability, bb,
+		       !first_match || best_predictor == predictor);
+    }
+  bb->predictions = NULL;
+
+  if (!bb->count)
+    {
+      first->probability = combined_probability;
+      second->probability = REG_BR_PROB_BASE - combined_probability;
+    }
+}
+
+/* Predict edge probabilities by exploiting loop structure.
+   When RTLSIMPLELOOPS is set, attempt to count number of iterations by analyzing
+   RTL otherwise use tree based approach.  */
+static void
+predict_loops (struct loops *loops_info, bool rtlsimpleloops)
+{
+  unsigned i;
+
+  if (!rtlsimpleloops)
+    scev_initialize (loops_info);
+
+  /* Try to predict out blocks in a loop that are not part of a
+     natural loop.  */
+  for (i = 1; i < loops_info->num; i++)
+    {
+      basic_block bb, *bbs;
+      unsigned j;
+      unsigned n_exits;
+      struct loop *loop = loops_info->parray[i];
+      struct niter_desc desc;
+      unsigned HOST_WIDE_INT niter;
+      edge *exits;
+
+      exits = get_loop_exit_edges (loop, &n_exits);
+
+      if (rtlsimpleloops)
+	{
+	  iv_analysis_loop_init (loop);
+	  find_simple_exit (loop, &desc);
+
+	  if (desc.simple_p && desc.const_iter)
+	    {
+	      int prob;
+	      niter = desc.niter + 1;
+	      if (niter == 0)        /* We might overflow here.  */
+		niter = desc.niter;
+	      if (niter
+		  > (unsigned int) PARAM_VALUE (PARAM_MAX_PREDICTED_ITERATIONS))
+		niter = PARAM_VALUE (PARAM_MAX_PREDICTED_ITERATIONS);
+
+	      prob = (REG_BR_PROB_BASE
+		      - (REG_BR_PROB_BASE + niter /2) / niter);
+	      /* Branch prediction algorithm gives 0 frequency for everything
+		 after the end of loop for loop having 0 probability to finish.  */
+	      if (prob == REG_BR_PROB_BASE)
+		prob = REG_BR_PROB_BASE - 1;
+	      predict_edge (desc.in_edge, PRED_LOOP_ITERATIONS,
+			    prob);
+	    }
+	}
+      else
+	{
+	  struct tree_niter_desc niter_desc;
+
+	  for (j = 0; j < n_exits; j++)
+	    {
+	      tree niter = NULL;
+
+	      if (number_of_iterations_exit (loop, exits[j], &niter_desc, false))
+		niter = niter_desc.niter;
+	      if (!niter || TREE_CODE (niter_desc.niter) != INTEGER_CST)
+	        niter = loop_niter_by_eval (loop, exits[j]);
+
+	      if (TREE_CODE (niter) == INTEGER_CST)
+		{
+		  int probability;
+		  int max = PARAM_VALUE (PARAM_MAX_PREDICTED_ITERATIONS);
+		  if (host_integerp (niter, 1)
+		      && tree_int_cst_lt (niter,
+				          build_int_cstu (NULL_TREE, max - 1)))
+		    {
+		      HOST_WIDE_INT nitercst = tree_low_cst (niter, 1) + 1;
+		      probability = ((REG_BR_PROB_BASE + nitercst / 2)
+				     / nitercst);
+		    }
+		  else
+		    probability = ((REG_BR_PROB_BASE + max / 2) / max);
+
+		  predict_edge (exits[j], PRED_LOOP_ITERATIONS, probability);
+		}
+	    }
+
+	}
+      free (exits);
+
+      bbs = get_loop_body (loop);
+
+      for (j = 0; j < loop->num_nodes; j++)
+	{
+	  int header_found = 0;
+	  edge e;
+	  edge_iterator ei;
+
+	  bb = bbs[j];
+
+	  /* Bypass loop heuristics on continue statement.  These
+	     statements construct loops via "non-loop" constructs
+	     in the source language and are better to be handled
+	     separately.  */
+	  if ((rtlsimpleloops && !can_predict_insn_p (BB_END (bb)))
+	      || predicted_by_p (bb, PRED_CONTINUE))
+	    continue;
+
+	  /* Loop branch heuristics - predict an edge back to a
+	     loop's head as taken.  */
+	  if (bb == loop->latch)
+	    {
+	      e = find_edge (loop->latch, loop->header);
+	      if (e)
+		{
+		  header_found = 1;
+		  predict_edge_def (e, PRED_LOOP_BRANCH, TAKEN);
+		}
+	    }
+
+	  /* Loop exit heuristics - predict an edge exiting the loop if the
+	     conditional has no loop header successors as not taken.  */
+	  if (!header_found)
+	    {
+	      /* For loop with many exits we don't want to predict all exits
+	         with the pretty large probability, because if all exits are
+		 considered in row, the loop would be predicted to iterate
+		 almost never.  The code to divide probability by number of
+		 exits is very rough.  It should compute the number of exits
+		 taken in each patch through function (not the overall number
+		 of exits that might be a lot higher for loops with wide switch
+		 statements in them) and compute n-th square root.
+
+		 We limit the minimal probability by 2% to avoid
+		 EDGE_PROBABILITY_RELIABLE from trusting the branch prediction
+		 as this was causing regression in perl benchmark containing such
+		 a wide loop.  */
+	        
+	      int probability = ((REG_BR_PROB_BASE
+		                  - predictor_info [(int) PRED_LOOP_EXIT].hitrate)
+				 / n_exits);
+	      if (probability < HITRATE (2))
+		probability = HITRATE (2);
+	      FOR_EACH_EDGE (e, ei, bb->succs)
+		if (e->dest->index < NUM_FIXED_BLOCKS
+		    || !flow_bb_inside_loop_p (loop, e->dest))
+		  predict_edge (e, PRED_LOOP_EXIT, probability);
+	    }
+	}
+      
+      /* Free basic blocks from get_loop_body.  */
+      free (bbs);
+    }
+
+  if (!rtlsimpleloops)
+    {
+      scev_finalize ();
+      current_loops = NULL;
+    }
+}
+
+/* Attempt to predict probabilities of BB outgoing edges using local
+   properties.  */
+static void
+bb_estimate_probability_locally (basic_block bb)
+{
+  rtx last_insn = BB_END (bb);
+  rtx cond;
+
+  if (! can_predict_insn_p (last_insn))
+    return;
+  cond = get_condition (last_insn, NULL, false, false);
+  if (! cond)
+    return;
+
+  /* Try "pointer heuristic."
+     A comparison ptr == 0 is predicted as false.
+     Similarly, a comparison ptr1 == ptr2 is predicted as false.  */
+  if (COMPARISON_P (cond)
+      && ((REG_P (XEXP (cond, 0)) && REG_POINTER (XEXP (cond, 0)))
+	  || (REG_P (XEXP (cond, 1)) && REG_POINTER (XEXP (cond, 1)))))
+    {
+      if (GET_CODE (cond) == EQ)
+	predict_insn_def (last_insn, PRED_POINTER, NOT_TAKEN);
+      else if (GET_CODE (cond) == NE)
+	predict_insn_def (last_insn, PRED_POINTER, TAKEN);
+    }
+  else
+
+  /* Try "opcode heuristic."
+     EQ tests are usually false and NE tests are usually true. Also,
+     most quantities are positive, so we can make the appropriate guesses
+     about signed comparisons against zero.  */
+    switch (GET_CODE (cond))
+      {
+      case CONST_INT:
+	/* Unconditional branch.  */
+	predict_insn_def (last_insn, PRED_UNCONDITIONAL,
+			  cond == const0_rtx ? NOT_TAKEN : TAKEN);
+	break;
+
+      case EQ:
+      case UNEQ:
+	/* Floating point comparisons appears to behave in a very
+	   unpredictable way because of special role of = tests in
+	   FP code.  */
+	if (FLOAT_MODE_P (GET_MODE (XEXP (cond, 0))))
+	  ;
+	/* Comparisons with 0 are often used for booleans and there is
+	   nothing useful to predict about them.  */
+	else if (XEXP (cond, 1) == const0_rtx
+		 || XEXP (cond, 0) == const0_rtx)
+	  ;
+	else
+	  predict_insn_def (last_insn, PRED_OPCODE_NONEQUAL, NOT_TAKEN);
+	break;
+
+      case NE:
+      case LTGT:
+	/* Floating point comparisons appears to behave in a very
+	   unpredictable way because of special role of = tests in
+	   FP code.  */
+	if (FLOAT_MODE_P (GET_MODE (XEXP (cond, 0))))
+	  ;
+	/* Comparisons with 0 are often used for booleans and there is
+	   nothing useful to predict about them.  */
+	else if (XEXP (cond, 1) == const0_rtx
+		 || XEXP (cond, 0) == const0_rtx)
+	  ;
+	else
+	  predict_insn_def (last_insn, PRED_OPCODE_NONEQUAL, TAKEN);
+	break;
+
+      case ORDERED:
+	predict_insn_def (last_insn, PRED_FPOPCODE, TAKEN);
+	break;
+
+      case UNORDERED:
+	predict_insn_def (last_insn, PRED_FPOPCODE, NOT_TAKEN);
+	break;
+
+      case LE:
+      case LT:
+	if (XEXP (cond, 1) == const0_rtx || XEXP (cond, 1) == const1_rtx
+	    || XEXP (cond, 1) == constm1_rtx)
+	  predict_insn_def (last_insn, PRED_OPCODE_POSITIVE, NOT_TAKEN);
+	break;
+
+      case GE:
+      case GT:
+	if (XEXP (cond, 1) == const0_rtx || XEXP (cond, 1) == const1_rtx
+	    || XEXP (cond, 1) == constm1_rtx)
+	  predict_insn_def (last_insn, PRED_OPCODE_POSITIVE, TAKEN);
+	break;
+
+      default:
+	break;
+      }
+}
+
+/* Set edge->probability for each successor edge of BB.  */
+void
+guess_outgoing_edge_probabilities (basic_block bb)
+{
+  bb_estimate_probability_locally (bb);
+  combine_predictions_for_insn (BB_END (bb), bb);
+}
+
+/* Return constant EXPR will likely have at execution time, NULL if unknown. 
+   The function is used by builtin_expect branch predictor so the evidence
+   must come from this construct and additional possible constant folding.
+  
+   We may want to implement more involved value guess (such as value range
+   propagation based prediction), but such tricks shall go to new
+   implementation.  */
+
+static tree
+expr_expected_value (tree expr, bitmap visited)
+{
+  if (TREE_CONSTANT (expr))
+    return expr;
+  else if (TREE_CODE (expr) == SSA_NAME)
+    {
+      tree def = SSA_NAME_DEF_STMT (expr);
+
+      /* If we were already here, break the infinite cycle.  */
+      if (bitmap_bit_p (visited, SSA_NAME_VERSION (expr)))
+	return NULL;
+      bitmap_set_bit (visited, SSA_NAME_VERSION (expr));
+
+      if (TREE_CODE (def) == PHI_NODE)
+	{
+	  /* All the arguments of the PHI node must have the same constant
+	     length.  */
+	  int i;
+	  tree val = NULL, new_val;
+
+	  for (i = 0; i < PHI_NUM_ARGS (def); i++)
+	    {
+	      tree arg = PHI_ARG_DEF (def, i);
+
+	      /* If this PHI has itself as an argument, we cannot
+		 determine the string length of this argument.  However,
+		 if we can find an expected constant value for the other
+		 PHI args then we can still be sure that this is
+		 likely a constant.  So be optimistic and just
+		 continue with the next argument.  */
+	      if (arg == PHI_RESULT (def))
+		continue;
+
+	      new_val = expr_expected_value (arg, visited);
+	      if (!new_val)
+		return NULL;
+	      if (!val)
+		val = new_val;
+	      else if (!operand_equal_p (val, new_val, false))
+		return NULL;
+	    }
+	  return val;
+	}
+      if (TREE_CODE (def) != MODIFY_EXPR || TREE_OPERAND (def, 0) != expr)
+	return NULL;
+      return expr_expected_value (TREE_OPERAND (def, 1), visited);
+    }
+  else if (TREE_CODE (expr) == CALL_EXPR)
+    {
+      tree decl = get_callee_fndecl (expr);
+      if (!decl)
+	return NULL;
+      if (DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
+	  && DECL_FUNCTION_CODE (decl) == BUILT_IN_EXPECT)
+	{
+	  tree arglist = TREE_OPERAND (expr, 1);
+	  tree val;
+
+	  if (arglist == NULL_TREE
+	      || TREE_CHAIN (arglist) == NULL_TREE)
+	    return NULL; 
+	  val = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (expr, 1)));
+	  if (TREE_CONSTANT (val))
+	    return val;
+	  return TREE_VALUE (TREE_CHAIN (TREE_OPERAND (expr, 1)));
+	}
+    }
+  if (BINARY_CLASS_P (expr) || COMPARISON_CLASS_P (expr))
+    {
+      tree op0, op1, res;
+      op0 = expr_expected_value (TREE_OPERAND (expr, 0), visited);
+      if (!op0)
+	return NULL;
+      op1 = expr_expected_value (TREE_OPERAND (expr, 1), visited);
+      if (!op1)
+	return NULL;
+      res = fold_build2 (TREE_CODE (expr), TREE_TYPE (expr), op0, op1);
+      if (TREE_CONSTANT (res))
+	return res;
+      return NULL;
+    }
+  if (UNARY_CLASS_P (expr))
+    {
+      tree op0, res;
+      op0 = expr_expected_value (TREE_OPERAND (expr, 0), visited);
+      if (!op0)
+	return NULL;
+      res = fold_build1 (TREE_CODE (expr), TREE_TYPE (expr), op0);
+      if (TREE_CONSTANT (res))
+	return res;
+      return NULL;
+    }
+  return NULL;
+}
+
+/* Get rid of all builtin_expect calls we no longer need.  */
+static void
+strip_builtin_expect (void)
+{
+  basic_block bb;
+  FOR_EACH_BB (bb)
+    {
+      block_stmt_iterator bi;
+      for (bi = bsi_start (bb); !bsi_end_p (bi); bsi_next (&bi))
+	{
+	  tree stmt = bsi_stmt (bi);
+	  tree fndecl;
+	  tree arglist;
+
+	  if (TREE_CODE (stmt) == MODIFY_EXPR
+	      && TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR
+	      && (fndecl = get_callee_fndecl (TREE_OPERAND (stmt, 1)))
+	      && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
+	      && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_EXPECT
+	      && (arglist = TREE_OPERAND (TREE_OPERAND (stmt, 1), 1))
+	      && TREE_CHAIN (arglist))
+	    {
+	      TREE_OPERAND (stmt, 1) = TREE_VALUE (arglist);
+	      update_stmt (stmt);
+	    }
+	}
+    }
+}
+
+/* Predict using opcode of the last statement in basic block.  */
+static void
+tree_predict_by_opcode (basic_block bb)
+{
+  tree stmt = last_stmt (bb);
+  edge then_edge;
+  tree cond;
+  tree op0;
+  tree type;
+  tree val;
+  bitmap visited;
+  edge_iterator ei;
+
+  if (!stmt || TREE_CODE (stmt) != COND_EXPR)
+    return;
+  FOR_EACH_EDGE (then_edge, ei, bb->succs)
+    if (then_edge->flags & EDGE_TRUE_VALUE)
+      break;
+  cond = TREE_OPERAND (stmt, 0);
+  if (!COMPARISON_CLASS_P (cond))
+    return;
+  op0 = TREE_OPERAND (cond, 0);
+  type = TREE_TYPE (op0);
+  visited = BITMAP_ALLOC (NULL);
+  val = expr_expected_value (cond, visited);
+  BITMAP_FREE (visited);
+  if (val)
+    {
+      if (integer_zerop (val))
+	predict_edge_def (then_edge, PRED_BUILTIN_EXPECT, NOT_TAKEN);
+      else
+	predict_edge_def (then_edge, PRED_BUILTIN_EXPECT, TAKEN);
+      return;
+    }
+  /* Try "pointer heuristic."
+     A comparison ptr == 0 is predicted as false.
+     Similarly, a comparison ptr1 == ptr2 is predicted as false.  */
+  if (POINTER_TYPE_P (type))
+    {
+      if (TREE_CODE (cond) == EQ_EXPR)
+	predict_edge_def (then_edge, PRED_TREE_POINTER, NOT_TAKEN);
+      else if (TREE_CODE (cond) == NE_EXPR)
+	predict_edge_def (then_edge, PRED_TREE_POINTER, TAKEN);
+    }
+  else
+
+  /* Try "opcode heuristic."
+     EQ tests are usually false and NE tests are usually true. Also,
+     most quantities are positive, so we can make the appropriate guesses
+     about signed comparisons against zero.  */
+    switch (TREE_CODE (cond))
+      {
+      case EQ_EXPR:
+      case UNEQ_EXPR:
+	/* Floating point comparisons appears to behave in a very
+	   unpredictable way because of special role of = tests in
+	   FP code.  */
+	if (FLOAT_TYPE_P (type))
+	  ;
+	/* Comparisons with 0 are often used for booleans and there is
+	   nothing useful to predict about them.  */
+	else if (integer_zerop (op0)
+		 || integer_zerop (TREE_OPERAND (cond, 1)))
+	  ;
+	else
+	  predict_edge_def (then_edge, PRED_TREE_OPCODE_NONEQUAL, NOT_TAKEN);
+	break;
+
+      case NE_EXPR:
+      case LTGT_EXPR:
+	/* Floating point comparisons appears to behave in a very
+	   unpredictable way because of special role of = tests in
+	   FP code.  */
+	if (FLOAT_TYPE_P (type))
+	  ;
+	/* Comparisons with 0 are often used for booleans and there is
+	   nothing useful to predict about them.  */
+	else if (integer_zerop (op0)
+		 || integer_zerop (TREE_OPERAND (cond, 1)))
+	  ;
+	else
+	  predict_edge_def (then_edge, PRED_TREE_OPCODE_NONEQUAL, TAKEN);
+	break;
+
+      case ORDERED_EXPR:
+	predict_edge_def (then_edge, PRED_TREE_FPOPCODE, TAKEN);
+	break;
+
+      case UNORDERED_EXPR:
+	predict_edge_def (then_edge, PRED_TREE_FPOPCODE, NOT_TAKEN);
+	break;
+
+      case LE_EXPR:
+      case LT_EXPR:
+	if (integer_zerop (TREE_OPERAND (cond, 1))
+	    || integer_onep (TREE_OPERAND (cond, 1))
+	    || integer_all_onesp (TREE_OPERAND (cond, 1))
+	    || real_zerop (TREE_OPERAND (cond, 1))
+	    || real_onep (TREE_OPERAND (cond, 1))
+	    || real_minus_onep (TREE_OPERAND (cond, 1)))
+	  predict_edge_def (then_edge, PRED_TREE_OPCODE_POSITIVE, NOT_TAKEN);
+	break;
+
+      case GE_EXPR:
+      case GT_EXPR:
+	if (integer_zerop (TREE_OPERAND (cond, 1))
+	    || integer_onep (TREE_OPERAND (cond, 1))
+	    || integer_all_onesp (TREE_OPERAND (cond, 1))
+	    || real_zerop (TREE_OPERAND (cond, 1))
+	    || real_onep (TREE_OPERAND (cond, 1))
+	    || real_minus_onep (TREE_OPERAND (cond, 1)))
+	  predict_edge_def (then_edge, PRED_TREE_OPCODE_POSITIVE, TAKEN);
+	break;
+
+      default:
+	break;
+      }
+}
+
+/* Try to guess whether the value of return means error code.  */
+static enum br_predictor
+return_prediction (tree val, enum prediction *prediction)
+{
+  /* VOID.  */
+  if (!val)
+    return PRED_NO_PREDICTION;
+  /* Different heuristics for pointers and scalars.  */
+  if (POINTER_TYPE_P (TREE_TYPE (val)))
+    {
+      /* NULL is usually not returned.  */
+      if (integer_zerop (val))
+	{
+	  *prediction = NOT_TAKEN;
+	  return PRED_NULL_RETURN;
+	}
+    }
+  else if (INTEGRAL_TYPE_P (TREE_TYPE (val)))
+    {
+      /* Negative return values are often used to indicate
+         errors.  */
+      if (TREE_CODE (val) == INTEGER_CST
+	  && tree_int_cst_sgn (val) < 0)
+	{
+	  *prediction = NOT_TAKEN;
+	  return PRED_NEGATIVE_RETURN;
+	}
+      /* Constant return values seems to be commonly taken.
+         Zero/one often represent booleans so exclude them from the
+	 heuristics.  */
+      if (TREE_CONSTANT (val)
+	  && (!integer_zerop (val) && !integer_onep (val)))
+	{
+	  *prediction = TAKEN;
+	  return PRED_NEGATIVE_RETURN;
+	}
+    }
+  return PRED_NO_PREDICTION;
+}
+
+/* Find the basic block with return expression and look up for possible
+   return value trying to apply RETURN_PREDICTION heuristics.  */
+static void
+apply_return_prediction (int *heads)
+{
+  tree return_stmt = NULL;
+  tree return_val;
+  edge e;
+  tree phi;
+  int phi_num_args, i;
+  enum br_predictor pred;
+  enum prediction direction;
+  edge_iterator ei;
+
+  FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
+    {
+      return_stmt = last_stmt (e->src);
+      if (TREE_CODE (return_stmt) == RETURN_EXPR)
+	break;
+    }
+  if (!e)
+    return;
+  return_val = TREE_OPERAND (return_stmt, 0);
+  if (!return_val)
+    return;
+  if (TREE_CODE (return_val) == MODIFY_EXPR)
+    return_val = TREE_OPERAND (return_val, 1);
+  if (TREE_CODE (return_val) != SSA_NAME
+      || !SSA_NAME_DEF_STMT (return_val)
+      || TREE_CODE (SSA_NAME_DEF_STMT (return_val)) != PHI_NODE)
+    return;
+  for (phi = SSA_NAME_DEF_STMT (return_val); phi; phi = PHI_CHAIN (phi))
+    if (PHI_RESULT (phi) == return_val)
+      break;
+  if (!phi)
+    return;
+  phi_num_args = PHI_NUM_ARGS (phi);
+  pred = return_prediction (PHI_ARG_DEF (phi, 0), &direction);
+
+  /* Avoid the degenerate case where all return values form the function
+     belongs to same category (ie they are all positive constants)
+     so we can hardly say something about them.  */
+  for (i = 1; i < phi_num_args; i++)
+    if (pred != return_prediction (PHI_ARG_DEF (phi, i), &direction))
+      break;
+  if (i != phi_num_args)
+    for (i = 0; i < phi_num_args; i++)
+      {
+	pred = return_prediction (PHI_ARG_DEF (phi, i), &direction);
+	if (pred != PRED_NO_PREDICTION)
+	  predict_paths_leading_to (PHI_ARG_EDGE (phi, i)->src, heads, pred,
+				    direction);
+      }
+}
+
+/* Look for basic block that contains unlikely to happen events
+   (such as noreturn calls) and mark all paths leading to execution
+   of this basic blocks as unlikely.  */
+
+static void
+tree_bb_level_predictions (void)
+{
+  basic_block bb;
+  int *heads;
+
+  heads = XNEWVEC (int, last_basic_block);
+  memset (heads, ENTRY_BLOCK, sizeof (int) * last_basic_block);
+  heads[ENTRY_BLOCK_PTR->next_bb->index] = last_basic_block;
+
+  apply_return_prediction (heads);
+
+  FOR_EACH_BB (bb)
+    {
+      block_stmt_iterator bsi = bsi_last (bb);
+
+      for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+	{
+	  tree stmt = bsi_stmt (bsi);
+	  switch (TREE_CODE (stmt))
+	    {
+	      case MODIFY_EXPR:
+		if (TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR)
+		  {
+		    stmt = TREE_OPERAND (stmt, 1);
+		    goto call_expr;
+		  }
+		break;
+	      case CALL_EXPR:
+call_expr:;
+		if (call_expr_flags (stmt) & ECF_NORETURN)
+		  predict_paths_leading_to (bb, heads, PRED_NORETURN,
+		      			    NOT_TAKEN);
+		break;
+	      default:
+		break;
+	    }
+	}
+    }
+
+  free (heads);
+}
+
+/* Predict branch probabilities and estimate profile of the tree CFG.  */
+static unsigned int
+tree_estimate_probability (void)
+{
+  basic_block bb;
+  struct loops loops_info;
+
+  flow_loops_find (&loops_info);
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    flow_loops_dump (&loops_info, dump_file, NULL, 0);
+
+  add_noreturn_fake_exit_edges ();
+  connect_infinite_loops_to_exit ();
+  calculate_dominance_info (CDI_DOMINATORS);
+  calculate_dominance_info (CDI_POST_DOMINATORS);
+
+  tree_bb_level_predictions ();
+
+  mark_irreducible_loops (&loops_info);
+  predict_loops (&loops_info, false);
+
+  FOR_EACH_BB (bb)
+    {
+      edge e;
+      edge_iterator ei;
+
+      FOR_EACH_EDGE (e, ei, bb->succs)
+	{
+	  /* Predict early returns to be probable, as we've already taken
+	     care for error returns and other cases are often used for
+	     fast paths through function.  */
+	  if (e->dest == EXIT_BLOCK_PTR
+	      && TREE_CODE (last_stmt (bb)) == RETURN_EXPR
+	      && !single_pred_p (bb))
+	    {
+	      edge e1;
+	      edge_iterator ei1;
+
+	      FOR_EACH_EDGE (e1, ei1, bb->preds)
+	      	if (!predicted_by_p (e1->src, PRED_NULL_RETURN)
+		    && !predicted_by_p (e1->src, PRED_CONST_RETURN)
+		    && !predicted_by_p (e1->src, PRED_NEGATIVE_RETURN)
+		    && !last_basic_block_p (e1->src))
+		  predict_edge_def (e1, PRED_TREE_EARLY_RETURN, NOT_TAKEN);
+	    }
+
+	  /* Look for block we are guarding (ie we dominate it,
+	     but it doesn't postdominate us).  */
+	  if (e->dest != EXIT_BLOCK_PTR && e->dest != bb
+	      && dominated_by_p (CDI_DOMINATORS, e->dest, e->src)
+	      && !dominated_by_p (CDI_POST_DOMINATORS, e->src, e->dest))
+	    {
+	      block_stmt_iterator bi;
+
+	      /* The call heuristic claims that a guarded function call
+		 is improbable.  This is because such calls are often used
+		 to signal exceptional situations such as printing error
+		 messages.  */
+	      for (bi = bsi_start (e->dest); !bsi_end_p (bi);
+		   bsi_next (&bi))
+		{
+		  tree stmt = bsi_stmt (bi);
+		  if ((TREE_CODE (stmt) == CALL_EXPR
+		       || (TREE_CODE (stmt) == MODIFY_EXPR
+			   && TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR))
+		      /* Constant and pure calls are hardly used to signalize
+			 something exceptional.  */
+		      && TREE_SIDE_EFFECTS (stmt))
+		    {
+		      predict_edge_def (e, PRED_CALL, NOT_TAKEN);
+		      break;
+		    }
+		}
+	    }
+	}
+      tree_predict_by_opcode (bb);
+    }
+  FOR_EACH_BB (bb)
+    combine_predictions_for_bb (bb);
+
+  strip_builtin_expect ();
+  estimate_bb_frequencies (&loops_info);
+  free_dominance_info (CDI_POST_DOMINATORS);
+  remove_fake_exit_edges ();
+  flow_loops_free (&loops_info);
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    dump_tree_cfg (dump_file, dump_flags);
+  if (profile_status == PROFILE_ABSENT)
+    profile_status = PROFILE_GUESSED;
+  return 0;
+}
+
+/* __builtin_expect dropped tokens into the insn stream describing expected
+   values of registers.  Generate branch probabilities based off these
+   values.  */
+
+void
+expected_value_to_br_prob (void)
+{
+  rtx insn, cond, ev = NULL_RTX, ev_reg = NULL_RTX;
+
+  for (insn = get_insns (); insn ; insn = NEXT_INSN (insn))
+    {
+      switch (GET_CODE (insn))
+	{
+	case NOTE:
+	  /* Look for expected value notes.  */
+	  if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EXPECTED_VALUE)
+	    {
+	      ev = NOTE_EXPECTED_VALUE (insn);
+	      ev_reg = XEXP (ev, 0);
+	      delete_insn (insn);
+	    }
+	  continue;
+
+	case CODE_LABEL:
+	  /* Never propagate across labels.  */
+	  ev = NULL_RTX;
+	  continue;
+
+	case JUMP_INSN:
+	  /* Look for simple conditional branches.  If we haven't got an
+	     expected value yet, no point going further.  */
+	  if (!JUMP_P (insn) || ev == NULL_RTX
+	      || ! any_condjump_p (insn))
+	    continue;
+	  break;
+
+	default:
+	  /* Look for insns that clobber the EV register.  */
+	  if (ev && reg_set_p (ev_reg, insn))
+	    ev = NULL_RTX;
+	  continue;
+	}
+
+      /* Collect the branch condition, hopefully relative to EV_REG.  */
+      /* ???  At present we'll miss things like
+		(expected_value (eq r70 0))
+		(set r71 -1)
+		(set r80 (lt r70 r71))
+		(set pc (if_then_else (ne r80 0) ...))
+	 as canonicalize_condition will render this to us as
+		(lt r70, r71)
+	 Could use cselib to try and reduce this further.  */
+      cond = XEXP (SET_SRC (pc_set (insn)), 0);
+      cond = canonicalize_condition (insn, cond, 0, NULL, ev_reg,
+				     false, false);
+      if (! cond || XEXP (cond, 0) != ev_reg
+	  || GET_CODE (XEXP (cond, 1)) != CONST_INT)
+	continue;
+
+      /* Substitute and simplify.  Given that the expression we're
+	 building involves two constants, we should wind up with either
+	 true or false.  */
+      cond = gen_rtx_fmt_ee (GET_CODE (cond), VOIDmode,
+			     XEXP (ev, 1), XEXP (cond, 1));
+      cond = simplify_rtx (cond);
+
+      /* Turn the condition into a scaled branch probability.  */
+      gcc_assert (cond == const_true_rtx || cond == const0_rtx);
+      predict_insn_def (insn, PRED_BUILTIN_EXPECT,
+		        cond == const_true_rtx ? TAKEN : NOT_TAKEN);
+    }
+}
+
+/* Check whether this is the last basic block of function.  Commonly
+   there is one extra common cleanup block.  */
+static bool
+last_basic_block_p (basic_block bb)
+{
+  if (bb == EXIT_BLOCK_PTR)
+    return false;
+
+  return (bb->next_bb == EXIT_BLOCK_PTR
+	  || (bb->next_bb->next_bb == EXIT_BLOCK_PTR
+	      && single_succ_p (bb)
+	      && single_succ (bb)->next_bb == EXIT_BLOCK_PTR));
+}
+
+/* Sets branch probabilities according to PREDiction and
+   FLAGS. HEADS[bb->index] should be index of basic block in that we
+   need to alter branch predictions (i.e. the first of our dominators
+   such that we do not post-dominate it) (but we fill this information
+   on demand, so -1 may be there in case this was not needed yet).  */
+
+static void
+predict_paths_leading_to (basic_block bb, int *heads, enum br_predictor pred,
+			  enum prediction taken)
+{
+  edge e;
+  edge_iterator ei;
+  int y;
+
+  if (heads[bb->index] == ENTRY_BLOCK)
+    {
+      /* This is first time we need this field in heads array; so
+         find first dominator that we do not post-dominate (we are
+         using already known members of heads array).  */
+      basic_block ai = bb;
+      basic_block next_ai = get_immediate_dominator (CDI_DOMINATORS, bb);
+      int head;
+
+      while (heads[next_ai->index] == ENTRY_BLOCK)
+	{
+	  if (!dominated_by_p (CDI_POST_DOMINATORS, next_ai, bb))
+	    break;
+	  heads[next_ai->index] = ai->index;
+	  ai = next_ai;
+	  next_ai = get_immediate_dominator (CDI_DOMINATORS, next_ai);
+	}
+      if (!dominated_by_p (CDI_POST_DOMINATORS, next_ai, bb))
+	head = next_ai->index;
+      else
+	head = heads[next_ai->index];
+      while (next_ai != bb)
+	{
+	  next_ai = ai;
+	  ai = BASIC_BLOCK (heads[ai->index]);
+	  heads[next_ai->index] = head;
+	}
+    }
+  y = heads[bb->index];
+
+  /* Now find the edge that leads to our branch and aply the prediction.  */
+
+  if (y == last_basic_block)
+    return;
+  FOR_EACH_EDGE (e, ei, BASIC_BLOCK (y)->succs)
+    if (e->dest->index >= NUM_FIXED_BLOCKS
+	&& dominated_by_p (CDI_POST_DOMINATORS, e->dest, bb))
+      predict_edge_def (e, pred, taken);
+}
+
+/* This is used to carry information about basic blocks.  It is
+   attached to the AUX field of the standard CFG block.  */
+
+typedef struct block_info_def
+{
+  /* Estimated frequency of execution of basic_block.  */
+  sreal frequency;
+
+  /* To keep queue of basic blocks to process.  */
+  basic_block next;
+
+  /* Number of predecessors we need to visit first.  */
+  int npredecessors;
+} *block_info;
+
+/* Similar information for edges.  */
+typedef struct edge_info_def
+{
+  /* In case edge is a loopback edge, the probability edge will be reached
+     in case header is.  Estimated number of iterations of the loop can be
+     then computed as 1 / (1 - back_edge_prob).  */
+  sreal back_edge_prob;
+  /* True if the edge is a loopback edge in the natural loop.  */
+  unsigned int back_edge:1;
+} *edge_info;
+
+#define BLOCK_INFO(B)	((block_info) (B)->aux)
+#define EDGE_INFO(E)	((edge_info) (E)->aux)
+
+/* Helper function for estimate_bb_frequencies.
+   Propagate the frequencies for LOOP.  */
+
+static void
+propagate_freq (struct loop *loop, bitmap tovisit)
+{
+  basic_block head = loop->header;
+  basic_block bb;
+  basic_block last;
+  unsigned i;
+  edge e;
+  basic_block nextbb;
+  bitmap_iterator bi;
+
+  /* For each basic block we need to visit count number of his predecessors
+     we need to visit first.  */
+  EXECUTE_IF_SET_IN_BITMAP (tovisit, 0, i, bi)
+    {
+      edge_iterator ei;
+      int count = 0;
+
+       /* The outermost "loop" includes the exit block, which we can not
+	  look up via BASIC_BLOCK.  Detect this and use EXIT_BLOCK_PTR
+	  directly.  Do the same for the entry block.  */
+      bb = BASIC_BLOCK (i);
+
+      FOR_EACH_EDGE (e, ei, bb->preds)
+	{
+	  bool visit = bitmap_bit_p (tovisit, e->src->index);
+
+	  if (visit && !(e->flags & EDGE_DFS_BACK))
+	    count++;
+	  else if (visit && dump_file && !EDGE_INFO (e)->back_edge)
+	    fprintf (dump_file,
+		     "Irreducible region hit, ignoring edge to %i->%i\n",
+		     e->src->index, bb->index);
+	}
+      BLOCK_INFO (bb)->npredecessors = count;
+    }
+
+  memcpy (&BLOCK_INFO (head)->frequency, &real_one, sizeof (real_one));
+  last = head;
+  for (bb = head; bb; bb = nextbb)
+    {
+      edge_iterator ei;
+      sreal cyclic_probability, frequency;
+
+      memcpy (&cyclic_probability, &real_zero, sizeof (real_zero));
+      memcpy (&frequency, &real_zero, sizeof (real_zero));
+
+      nextbb = BLOCK_INFO (bb)->next;
+      BLOCK_INFO (bb)->next = NULL;
+
+      /* Compute frequency of basic block.  */
+      if (bb != head)
+	{
+#ifdef ENABLE_CHECKING
+	  FOR_EACH_EDGE (e, ei, bb->preds)
+	    gcc_assert (!bitmap_bit_p (tovisit, e->src->index)
+			|| (e->flags & EDGE_DFS_BACK));
+#endif
+
+	  FOR_EACH_EDGE (e, ei, bb->preds)
+	    if (EDGE_INFO (e)->back_edge)
+	      {
+		sreal_add (&cyclic_probability, &cyclic_probability,
+			   &EDGE_INFO (e)->back_edge_prob);
+	      }
+	    else if (!(e->flags & EDGE_DFS_BACK))
+	      {
+		sreal tmp;
+
+		/*  frequency += (e->probability
+				  * BLOCK_INFO (e->src)->frequency /
+				  REG_BR_PROB_BASE);  */
+
+		sreal_init (&tmp, e->probability, 0);
+		sreal_mul (&tmp, &tmp, &BLOCK_INFO (e->src)->frequency);
+		sreal_mul (&tmp, &tmp, &real_inv_br_prob_base);
+		sreal_add (&frequency, &frequency, &tmp);
+	      }
+
+	  if (sreal_compare (&cyclic_probability, &real_zero) == 0)
+	    {
+	      memcpy (&BLOCK_INFO (bb)->frequency, &frequency,
+		      sizeof (frequency));
+	    }
+	  else
+	    {
+	      if (sreal_compare (&cyclic_probability, &real_almost_one) > 0)
+		{
+		  memcpy (&cyclic_probability, &real_almost_one,
+			  sizeof (real_almost_one));
+		}
+
+	      /* BLOCK_INFO (bb)->frequency = frequency
+					      / (1 - cyclic_probability) */
+
+	      sreal_sub (&cyclic_probability, &real_one, &cyclic_probability);
+	      sreal_div (&BLOCK_INFO (bb)->frequency,
+			 &frequency, &cyclic_probability);
+	    }
+	}
+
+      bitmap_clear_bit (tovisit, bb->index);
+
+      e = find_edge (bb, head);
+      if (e)
+	{
+	  sreal tmp;
+	    
+	  /* EDGE_INFO (e)->back_edge_prob
+	     = ((e->probability * BLOCK_INFO (bb)->frequency)
+	     / REG_BR_PROB_BASE); */
+	    
+	  sreal_init (&tmp, e->probability, 0);
+	  sreal_mul (&tmp, &tmp, &BLOCK_INFO (bb)->frequency);
+	  sreal_mul (&EDGE_INFO (e)->back_edge_prob,
+		     &tmp, &real_inv_br_prob_base);
+	}
+
+      /* Propagate to successor blocks.  */
+      FOR_EACH_EDGE (e, ei, bb->succs)
+	if (!(e->flags & EDGE_DFS_BACK)
+	    && BLOCK_INFO (e->dest)->npredecessors)
+	  {
+	    BLOCK_INFO (e->dest)->npredecessors--;
+	    if (!BLOCK_INFO (e->dest)->npredecessors)
+	      {
+		if (!nextbb)
+		  nextbb = e->dest;
+		else
+		  BLOCK_INFO (last)->next = e->dest;
+		
+		last = e->dest;
+	      }
+	  }
+    }
+}
+
+/* Estimate probabilities of loopback edges in loops at same nest level.  */
+
+static void
+estimate_loops_at_level (struct loop *first_loop, bitmap tovisit)
+{
+  struct loop *loop;
+
+  for (loop = first_loop; loop; loop = loop->next)
+    {
+      edge e;
+      basic_block *bbs;
+      unsigned i;
+
+      estimate_loops_at_level (loop->inner, tovisit);
+
+      /* Do not do this for dummy function loop.  */
+      if (EDGE_COUNT (loop->latch->succs) > 0)
+	{
+	  /* Find current loop back edge and mark it.  */
+	  e = loop_latch_edge (loop);
+	  EDGE_INFO (e)->back_edge = 1;
+       }
+
+      bbs = get_loop_body (loop);
+      for (i = 0; i < loop->num_nodes; i++)
+	bitmap_set_bit (tovisit, bbs[i]->index);
+      free (bbs);
+      propagate_freq (loop, tovisit);
+    }
+}
+
+/* Convert counts measured by profile driven feedback to frequencies.
+   Return nonzero iff there was any nonzero execution count.  */
+
+int
+counts_to_freqs (void)
+{
+  gcov_type count_max, true_count_max = 0;
+  basic_block bb;
+
+  FOR_EACH_BB (bb)
+    true_count_max = MAX (bb->count, true_count_max);
+
+  count_max = MAX (true_count_max, 1);
+  FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
+    bb->frequency = (bb->count * BB_FREQ_MAX + count_max / 2) / count_max;
+  return true_count_max;
+}
+
+/* Return true if function is likely to be expensive, so there is no point to
+   optimize performance of prologue, epilogue or do inlining at the expense
+   of code size growth.  THRESHOLD is the limit of number of instructions
+   function can execute at average to be still considered not expensive.  */
+
+bool
+expensive_function_p (int threshold)
+{
+  unsigned int sum = 0;
+  basic_block bb;
+  unsigned int limit;
+
+  /* We can not compute accurately for large thresholds due to scaled
+     frequencies.  */
+  gcc_assert (threshold <= BB_FREQ_MAX);
+
+  /* Frequencies are out of range.  This either means that function contains
+     internal loop executing more than BB_FREQ_MAX times or profile feedback
+     is available and function has not been executed at all.  */
+  if (ENTRY_BLOCK_PTR->frequency == 0)
+    return true;
+
+  /* Maximally BB_FREQ_MAX^2 so overflow won't happen.  */
+  limit = ENTRY_BLOCK_PTR->frequency * threshold;
+  FOR_EACH_BB (bb)
+    {
+      rtx insn;
+
+      for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
+	   insn = NEXT_INSN (insn))
+	if (active_insn_p (insn))
+	  {
+	    sum += bb->frequency;
+	    if (sum > limit)
+	      return true;
+	}
+    }
+
+  return false;
+}
+
+/* Estimate basic blocks frequency by given branch probabilities.  */
+
+static void
+estimate_bb_frequencies (struct loops *loops)
+{
+  basic_block bb;
+  sreal freq_max;
+
+  if (!flag_branch_probabilities || !counts_to_freqs ())
+    {
+      static int real_values_initialized = 0;
+      bitmap tovisit;
+
+      if (!real_values_initialized)
+        {
+	  real_values_initialized = 1;
+	  sreal_init (&real_zero, 0, 0);
+	  sreal_init (&real_one, 1, 0);
+	  sreal_init (&real_br_prob_base, REG_BR_PROB_BASE, 0);
+	  sreal_init (&real_bb_freq_max, BB_FREQ_MAX, 0);
+	  sreal_init (&real_one_half, 1, -1);
+	  sreal_div (&real_inv_br_prob_base, &real_one, &real_br_prob_base);
+	  sreal_sub (&real_almost_one, &real_one, &real_inv_br_prob_base);
+	}
+
+      mark_dfs_back_edges ();
+
+      single_succ_edge (ENTRY_BLOCK_PTR)->probability = REG_BR_PROB_BASE;
+
+      /* Set up block info for each basic block.  */
+      tovisit = BITMAP_ALLOC (NULL);
+      alloc_aux_for_blocks (sizeof (struct block_info_def));
+      alloc_aux_for_edges (sizeof (struct edge_info_def));
+      FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
+	{
+	  edge e;
+	  edge_iterator ei;
+
+	  FOR_EACH_EDGE (e, ei, bb->succs)
+	    {
+	      sreal_init (&EDGE_INFO (e)->back_edge_prob, e->probability, 0);
+	      sreal_mul (&EDGE_INFO (e)->back_edge_prob,
+			 &EDGE_INFO (e)->back_edge_prob,
+			 &real_inv_br_prob_base);
+	    }
+	}
+
+      /* First compute probabilities locally for each loop from innermost
+         to outermost to examine probabilities for back edges.  */
+      estimate_loops_at_level (loops->tree_root, tovisit);
+
+      memcpy (&freq_max, &real_zero, sizeof (real_zero));
+      FOR_EACH_BB (bb)
+	if (sreal_compare (&freq_max, &BLOCK_INFO (bb)->frequency) < 0)
+	  memcpy (&freq_max, &BLOCK_INFO (bb)->frequency, sizeof (freq_max));
+
+      sreal_div (&freq_max, &real_bb_freq_max, &freq_max);
+      FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
+	{
+	  sreal tmp;
+
+	  sreal_mul (&tmp, &BLOCK_INFO (bb)->frequency, &freq_max);
+	  sreal_add (&tmp, &tmp, &real_one_half);
+	  bb->frequency = sreal_to_int (&tmp);
+	}
+
+      free_aux_for_blocks ();
+      free_aux_for_edges ();
+      BITMAP_FREE (tovisit);
+    }
+  compute_function_frequency ();
+  if (flag_reorder_functions)
+    choose_function_section ();
+}
+
+/* Decide whether function is hot, cold or unlikely executed.  */
+static void
+compute_function_frequency (void)
+{
+  basic_block bb;
+
+  if (!profile_info || !flag_branch_probabilities)
+    return;
+  cfun->function_frequency = FUNCTION_FREQUENCY_UNLIKELY_EXECUTED;
+  FOR_EACH_BB (bb)
+    {
+      if (maybe_hot_bb_p (bb))
+	{
+	  cfun->function_frequency = FUNCTION_FREQUENCY_HOT;
+	  return;
+	}
+      if (!probably_never_executed_bb_p (bb))
+	cfun->function_frequency = FUNCTION_FREQUENCY_NORMAL;
+    }
+}
+
+/* Choose appropriate section for the function.  */
+static void
+choose_function_section (void)
+{
+  if (DECL_SECTION_NAME (current_function_decl)
+      || !targetm.have_named_sections
+      /* Theoretically we can split the gnu.linkonce text section too,
+	 but this requires more work as the frequency needs to match
+	 for all generated objects so we need to merge the frequency
+	 of all instances.  For now just never set frequency for these.  */
+      || DECL_ONE_ONLY (current_function_decl))
+    return;
+
+  /* If we are doing the partitioning optimization, let the optimization
+     choose the correct section into which to put things.  */
+
+  if (flag_reorder_blocks_and_partition)
+    return;
+
+  if (cfun->function_frequency == FUNCTION_FREQUENCY_HOT)
+    DECL_SECTION_NAME (current_function_decl) =
+      build_string (strlen (HOT_TEXT_SECTION_NAME), HOT_TEXT_SECTION_NAME);
+  if (cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED)
+    DECL_SECTION_NAME (current_function_decl) =
+      build_string (strlen (UNLIKELY_EXECUTED_TEXT_SECTION_NAME),
+		    UNLIKELY_EXECUTED_TEXT_SECTION_NAME);
+}
+
+static bool
+gate_estimate_probability (void)
+{
+  return flag_guess_branch_prob;
+}
+
+struct tree_opt_pass pass_profile = 
+{
+  "profile",				/* name */
+  gate_estimate_probability,		/* gate */
+  tree_estimate_probability,		/* execute */
+  NULL,					/* sub */
+  NULL,					/* next */
+  0,					/* static_pass_number */
+  TV_BRANCH_PROB,			/* tv_id */
+  PROP_cfg,				/* properties_required */
+  0,					/* properties_provided */
+  0,					/* properties_destroyed */
+  0,					/* todo_flags_start */
+  TODO_ggc_collect | TODO_verify_ssa,			/* todo_flags_finish */
+  0					/* letter */
+};