/* Branch prediction routines for the GNU compiler.
- Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
+ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009
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
+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
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. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
/* References:
#include "timevar.h"
#include "tree-scalar-evolution.h"
#include "cfgloop.h"
+#include "pointer-set.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)
+/* Random guesstimation given names.
+ PROV_VERY_UNLIKELY should be small enough so basic block predicted
+ by it gets bellow HOT_BB_FREQUENCY_FRANCTION. */
+#define PROB_VERY_UNLIKELY (REG_BR_PROB_BASE / 2000 - 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_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 predict_paths_leading_to (basic_block, enum br_predictor, enum prediction);
static void compute_function_frequency (void);
static void choose_function_section (void);
-static bool can_predict_insn_p (rtx);
+static bool can_predict_insn_p (const_rtx);
/* Information we hold about each branch predictor.
Filled using information from predict.def. */
};
#undef DEF_PREDICTOR
+/* Return TRUE if frequency FREQ is considered to be hot. */
+
+static inline bool
+maybe_hot_frequency_p (int freq)
+{
+ if (!profile_info || !flag_branch_probabilities)
+ {
+ if (cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED)
+ return false;
+ if (cfun->function_frequency == FUNCTION_FREQUENCY_HOT)
+ return true;
+ }
+ if (profile_status == PROFILE_ABSENT)
+ return true;
+ if (freq < BB_FREQ_MAX / PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION))
+ return false;
+ return true;
+}
+
+/* Return TRUE if frequency FREQ is considered to be hot. */
+
+static inline bool
+maybe_hot_count_p (gcov_type count)
+{
+ if (profile_status != PROFILE_READ)
+ return true;
+ /* Code executed at most once is not hot. */
+ if (profile_info->runs >= count)
+ return false;
+ return (count
+ > profile_info->sum_max / PARAM_VALUE (HOT_BB_COUNT_FRACTION));
+}
+
/* Return true in case BB can be CPU intensive and should be optimized
for maximal performance. */
bool
-maybe_hot_bb_p (basic_block bb)
+maybe_hot_bb_p (const_basic_block bb)
+{
+ if (profile_status == PROFILE_READ)
+ return maybe_hot_count_p (bb->count);
+ return maybe_hot_frequency_p (bb->frequency);
+}
+
+/* Return true if the call can be hot. */
+
+bool
+cgraph_maybe_hot_edge_p (struct cgraph_edge *edge)
{
if (profile_info && flag_branch_probabilities
- && (bb->count
- < profile_info->sum_max / PARAM_VALUE (HOT_BB_COUNT_FRACTION)))
+ && (edge->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))
+ if (lookup_attribute ("cold", DECL_ATTRIBUTES (edge->callee->decl))
+ || lookup_attribute ("cold", DECL_ATTRIBUTES (edge->caller->decl)))
+ return false;
+ if (lookup_attribute ("hot", DECL_ATTRIBUTES (edge->caller->decl)))
+ return true;
+ if (flag_guess_branch_prob
+ && edge->frequency <= (CGRAPH_FREQ_BASE
+ / PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION)))
return false;
return true;
}
-/* Return true in case BB is cold and should be optimized for size. */
+/* Return true in case BB can be CPU intensive and should be optimized
+ for maximal performance. */
bool
-probably_cold_bb_p (basic_block bb)
+maybe_hot_edge_p (edge e)
{
- 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;
+ if (profile_status == PROFILE_READ)
+ return maybe_hot_count_p (e->count);
+ return maybe_hot_frequency_p (EDGE_FREQUENCY (e));
}
/* Return true in case BB is probably never executed. */
bool
-probably_never_executed_bb_p (basic_block bb)
+probably_never_executed_bb_p (const_basic_block bb)
{
if (profile_info && flag_branch_probabilities)
return ((bb->count + profile_info->runs / 2) / profile_info->runs) == 0;
+ if ((!profile_info || !flag_branch_probabilities)
+ && cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED)
+ return true;
+ return false;
+}
+
+/* Return true when current function should always be optimized for size. */
+
+bool
+optimize_function_for_size_p (struct function *fun)
+{
+ return (optimize_size
+ || (fun && (fun->function_frequency
+ == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED)));
+}
+
+/* Return true when current function should always be optimized for speed. */
+
+bool
+optimize_function_for_speed_p (struct function *fun)
+{
+ return !optimize_function_for_size_p (fun);
+}
+
+/* Return TRUE when BB should be optimized for size. */
+
+bool
+optimize_bb_for_size_p (const_basic_block bb)
+{
+ return optimize_function_for_size_p (cfun) || !maybe_hot_bb_p (bb);
+}
+
+/* Return TRUE when BB should be optimized for speed. */
+
+bool
+optimize_bb_for_speed_p (const_basic_block bb)
+{
+ return !optimize_bb_for_size_p (bb);
+}
+
+/* Return TRUE when BB should be optimized for size. */
+
+bool
+optimize_edge_for_size_p (edge e)
+{
+ return optimize_function_for_size_p (cfun) || !maybe_hot_edge_p (e);
+}
+
+/* Return TRUE when BB should be optimized for speed. */
+
+bool
+optimize_edge_for_speed_p (edge e)
+{
+ return !optimize_edge_for_size_p (e);
+}
+
+/* Return TRUE when BB should be optimized for size. */
+
+bool
+optimize_insn_for_size_p (void)
+{
+ return optimize_function_for_size_p (cfun) || !crtl->maybe_hot_insn_p;
+}
+
+/* Return TRUE when BB should be optimized for speed. */
+
+bool
+optimize_insn_for_speed_p (void)
+{
+ return !optimize_insn_for_size_p ();
+}
+
+/* Return TRUE when LOOP should be optimized for size. */
+
+bool
+optimize_loop_for_size_p (struct loop *loop)
+{
+ return optimize_bb_for_size_p (loop->header);
+}
+
+/* Return TRUE when LOOP should be optimized for speed. */
+
+bool
+optimize_loop_for_speed_p (struct loop *loop)
+{
+ return optimize_bb_for_speed_p (loop->header);
+}
+
+/* Return TRUE when LOOP nest should be optimized for speed. */
+
+bool
+optimize_loop_nest_for_speed_p (struct loop *loop)
+{
+ struct loop *l = loop;
+ if (optimize_loop_for_speed_p (loop))
+ return true;
+ l = loop->inner;
+ while (l && l != loop)
+ {
+ if (optimize_loop_for_speed_p (l))
+ return true;
+ if (l->inner)
+ l = l->inner;
+ else if (l->next)
+ l = l->next;
+ else
+ {
+ while (l != loop && !l->next)
+ l = loop_outer (l);
+ if (l != loop)
+ l = l->next;
+ }
+ }
+ return false;
+}
+
+/* Return TRUE when LOOP nest should be optimized for size. */
+
+bool
+optimize_loop_nest_for_size_p (struct loop *loop)
+{
+ return !optimize_loop_nest_for_speed_p (loop);
+}
+
+/* Return true when edge E is likely to be well predictable by branch
+ predictor. */
+
+bool
+predictable_edge_p (edge e)
+{
+ if (profile_status == PROFILE_ABSENT)
+ return false;
+ if ((e->probability
+ <= PARAM_VALUE (PARAM_PREDICTABLE_BRANCH_OUTCOME) * REG_BR_PROB_BASE / 100)
+ || (REG_BR_PROB_BASE - e->probability
+ <= PARAM_VALUE (PARAM_PREDICTABLE_BRANCH_OUTCOME) * REG_BR_PROB_BASE / 100))
+ return true;
return false;
}
+
+/* Set RTL expansion for BB profile. */
+
+void
+rtl_profile_for_bb (basic_block bb)
+{
+ crtl->maybe_hot_insn_p = maybe_hot_bb_p (bb);
+}
+
+/* Set RTL expansion for edge profile. */
+
+void
+rtl_profile_for_edge (edge e)
+{
+ crtl->maybe_hot_insn_p = maybe_hot_edge_p (e);
+}
+
+/* Set RTL expansion to default mode (i.e. when profile info is not known). */
+void
+default_rtl_profile (void)
+{
+ crtl->maybe_hot_insn_p = true;
+}
+
/* 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)
+rtl_predicted_by_p (const_basic_block bb, enum br_predictor predictor)
{
rtx note;
if (!INSN_P (BB_END (bb)))
return false;
}
+/* This map contains for a basic block the list of predictions for the
+ outgoing edges. */
+
+static struct pointer_map_t *bb_predictions;
+
/* 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)
+gimple_predicted_by_p (const_basic_block bb, enum br_predictor predictor)
{
struct edge_prediction *i;
- for (i = bb->predictions; i; i = i->ep_next)
+ void **preds = pointer_map_contains (bb_predictions, bb);
+
+ if (!preds)
+ return false;
+
+ for (i = (struct edge_prediction *) *preds; i; i = i->ep_next)
if (i->ep_predictor == predictor)
return true;
return false;
/* Same predicate as above, working on edges. */
bool
-edge_probability_reliable_p (edge e)
+edge_probability_reliable_p (const_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)
+br_prob_note_reliable_p (const_rtx note)
{
gcc_assert (REG_NOTE_KIND (note) == REG_BR_PROB);
return probability_reliable_p (INTVAL (XEXP (note, 0)));
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));
+ add_reg_note (insn, REG_BR_PRED,
+ gen_rtx_CONCAT (VOIDmode,
+ GEN_INT ((int) predictor),
+ GEN_INT ((int) probability)));
}
/* Predict insn by given predictor. */
/* Predict edge E with the given PROBABILITY. */
void
-tree_predict_edge (edge e, enum br_predictor predictor, int probability)
+gimple_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));
+ struct edge_prediction *i = XNEW (struct edge_prediction);
+ void **preds = pointer_map_insert (bb_predictions, e->src);
- i->ep_next = e->src->predictions;
- e->src->predictions = i;
+ i->ep_next = (struct edge_prediction *) *preds;
+ *preds = i;
i->ep_probability = probability;
i->ep_predictor = predictor;
i->ep_edge = e;
void
remove_predictions_associated_with_edge (edge e)
{
- if (e->src->predictions)
+ void **preds;
+
+ if (!bb_predictions)
+ return;
+
+ preds = pointer_map_contains (bb_predictions, e->src);
+
+ if (preds)
{
- struct edge_prediction **prediction = &e->src->predictions;
+ struct edge_prediction **prediction = (struct edge_prediction **) preds;
+ struct edge_prediction *next;
+
while (*prediction)
{
if ((*prediction)->ep_edge == e)
- *prediction = (*prediction)->ep_next;
+ {
+ next = (*prediction)->ep_next;
+ free (*prediction);
+ *prediction = next;
+ }
else
prediction = &((*prediction)->ep_next);
}
}
}
+/* Clears the list of predictions stored for BB. */
+
+static void
+clear_bb_predictions (basic_block bb)
+{
+ void **preds = pointer_map_contains (bb_predictions, bb);
+ struct edge_prediction *pred, *next;
+
+ if (!preds)
+ return;
+
+ for (pred = (struct edge_prediction *) *preds; pred; pred = next)
+ {
+ next = pred->ep_next;
+ free (pred);
+ }
+ *preds = NULL;
+}
+
/* 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)
+can_predict_insn_p (const_rtx insn)
{
return (JUMP_P (insn)
&& any_condjump_p (insn)
rtx *pnote;
rtx note;
int best_probability = PROB_EVEN;
- int best_predictor = END_PREDICTORS;
+ enum br_predictor best_predictor = END_PREDICTORS;
int combined_probability = REG_BR_PROB_BASE / 2;
int d;
bool first_match = false;
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));
+ enum br_predictor predictor = ((enum br_predictor)
+ INTVAL (XEXP (XEXP (note, 0), 0)));
int probability = INTVAL (XEXP (XEXP (note, 0), 1));
found = true;
{
if (REG_NOTE_KIND (*pnote) == REG_BR_PRED)
{
- int predictor = INTVAL (XEXP (XEXP (*pnote, 0), 0));
+ enum br_predictor predictor = ((enum br_predictor)
+ INTVAL (XEXP (XEXP (*pnote, 0), 0)));
int probability = INTVAL (XEXP (XEXP (*pnote, 0), 1));
dump_prediction (dump_file, predictor, probability, bb,
if (!prob_note)
{
- REG_NOTES (insn)
- = gen_rtx_EXPR_LIST (REG_BR_PROB,
- GEN_INT (combined_probability), REG_NOTES (insn));
+ add_reg_note (insn, REG_BR_PROB, GEN_INT (combined_probability));
/* Save the prediction into CFG in case we are seeing non-degenerated
conditional jump. */
combine_predictions_for_bb (basic_block bb)
{
int best_probability = PROB_EVEN;
- int best_predictor = END_PREDICTORS;
+ enum br_predictor best_predictor = END_PREDICTORS;
int combined_probability = REG_BR_PROB_BASE / 2;
int d;
bool first_match = false;
int nedges = 0;
edge e, first = NULL, second = NULL;
edge_iterator ei;
+ void **preds;
FOR_EACH_EDGE (e, ei, bb->succs)
if (!(e->flags & (EDGE_EH | EDGE_FAKE)))
{
if (!bb->count)
set_even_probabilities (bb);
- bb->predictions = NULL;
+ clear_bb_predictions (bb);
if (dump_file)
fprintf (dump_file, "%i edges in bb %i predicted to even probabilities\n",
nedges, bb->index);
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)
+ preds = pointer_map_contains (bb_predictions, bb);
+ if (preds)
{
- int predictor = pred->ep_predictor;
- int probability = pred->ep_probability;
+ /* We implement "first match" heuristics and use probability guessed
+ by predictor with smallest index. */
+ for (pred = (struct edge_prediction *) *preds; pred; pred = pred->ep_next)
+ {
+ enum br_predictor predictor = pred->ep_predictor;
+ int probability = pred->ep_probability;
- if (pred->ep_edge != first)
- probability = REG_BR_PROB_BASE - probability;
+ if (pred->ep_edge != first)
+ probability = REG_BR_PROB_BASE - probability;
- found = true;
- if (best_predictor > predictor)
- best_probability = probability, best_predictor = predictor;
+ found = true;
+ /* First match heuristics would be widly confused if we predicted
+ both directions. */
+ if (best_predictor > predictor)
+ {
+ struct edge_prediction *pred2;
+ int prob = probability;
+
+ for (pred2 = (struct edge_prediction *) *preds; pred2; pred2 = pred2->ep_next)
+ if (pred2 != pred && pred2->ep_predictor == pred->ep_predictor)
+ {
+ int probability2 = pred->ep_probability;
+
+ if (pred2->ep_edge != first)
+ probability2 = REG_BR_PROB_BASE - probability2;
+
+ if ((probability < REG_BR_PROB_BASE / 2) !=
+ (probability2 < REG_BR_PROB_BASE / 2))
+ break;
+
+ /* If the same predictor later gave better result, go for it! */
+ if ((probability >= REG_BR_PROB_BASE / 2 && (probability2 > probability))
+ || (probability <= REG_BR_PROB_BASE / 2 && (probability2 < probability)))
+ prob = probability2;
+ }
+ if (!pred2)
+ best_probability = prob, best_predictor = predictor;
+ }
- d = (combined_probability * probability
- + (REG_BR_PROB_BASE - combined_probability)
- * (REG_BR_PROB_BASE - probability));
+ 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);
+ /* 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,
combined_probability = best_probability;
dump_prediction (dump_file, PRED_COMBINED, combined_probability, bb, true);
- for (pred = bb->predictions; pred; pred = pred->ep_next)
+ if (preds)
{
- int predictor = pred->ep_predictor;
- int probability = pred->ep_probability;
+ for (pred = (struct edge_prediction *) *preds; pred; pred = pred->ep_next)
+ {
+ enum br_predictor 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);
+ 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;
+ clear_bb_predictions (bb);
if (!bb->count)
{
}
}
-/* 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. */
+/* Predict edge probabilities by exploiting loop structure. */
+
static void
-predict_loops (struct loops *loops_info)
+predict_loops (void)
{
- unsigned i;
-
- scev_initialize (loops_info);
+ loop_iterator li;
+ struct loop *loop;
/* Try to predict out blocks in a loop that are not part of a
natural loop. */
- for (i = 1; i < loops_info->num; i++)
+ FOR_EACH_LOOP (li, loop, 0)
{
basic_block bb, *bbs;
unsigned j, n_exits;
- struct loop *loop = loops_info->parray[i];
VEC (edge, heap) *exits;
struct tree_niter_desc niter_desc;
edge ex;
for (j = 0; VEC_iterate (edge, exits, j, ex); j++)
{
tree niter = NULL;
+ HOST_WIDE_INT nitercst;
+ int max = PARAM_VALUE (PARAM_MAX_PREDICTED_ITERATIONS);
+ int probability;
+ enum br_predictor predictor;
if (number_of_iterations_exit (loop, ex, &niter_desc, false))
niter = niter_desc.niter;
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);
- }
+ && compare_tree_int (niter, max-1) == -1)
+ nitercst = tree_low_cst (niter, 1) + 1;
else
- probability = ((REG_BR_PROB_BASE + max / 2) / max);
+ nitercst = max;
+ predictor = PRED_LOOP_ITERATIONS;
+ }
+ /* If we have just one exit and we can derive some information about
+ the number of iterations of the loop from the statements inside
+ the loop, use it to predict this exit. */
+ else if (n_exits == 1)
+ {
+ nitercst = estimated_loop_iterations_int (loop, false);
+ if (nitercst < 0)
+ continue;
+ if (nitercst > max)
+ nitercst = max;
- predict_edge (ex, PRED_LOOP_ITERATIONS, probability);
+ predictor = PRED_LOOP_ITERATIONS_GUESSED;
}
+ else
+ continue;
+
+ probability = ((REG_BR_PROB_BASE + nitercst / 2) / nitercst);
+ predict_edge (ex, predictor, probability);
}
VEC_free (edge, heap, exits);
/* Loop exit heuristics - predict an edge exiting the loop if the
conditional has no loop header successors as not taken. */
- if (!header_found)
+ if (!header_found
+ /* If we already used more reliable loop exit predictors, do not
+ bother with PRED_LOOP_EXIT. */
+ && !predicted_by_p (bb, PRED_LOOP_ITERATIONS_GUESSED)
+ && !predicted_by_p (bb, PRED_LOOP_ITERATIONS))
{
/* For loop with many exits we don't want to predict all exits
with the pretty large probability, because if all exits are
/* Free basic blocks from get_loop_body. */
free (bbs);
}
-
- scev_finalize ();
}
/* Attempt to predict probabilities of BB outgoing edges using local
combine_predictions_for_insn (BB_END (bb), bb);
}
\f
-/* 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, bitmap);
+
+/* Helper function for expr_expected_value. */
static tree
-expr_expected_value (tree expr, bitmap visited)
+expr_expected_value_1 (tree type, tree op0, enum tree_code code, tree op1, bitmap visited)
{
- if (TREE_CONSTANT (expr))
- return expr;
- else if (TREE_CODE (expr) == SSA_NAME)
+ gimple def;
+
+ if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS)
{
- tree def = SSA_NAME_DEF_STMT (expr);
+ if (TREE_CONSTANT (op0))
+ return op0;
+
+ if (code != SSA_NAME)
+ return NULL_TREE;
+
+ def = SSA_NAME_DEF_STMT (op0);
/* If we were already here, break the infinite cycle. */
- if (bitmap_bit_p (visited, SSA_NAME_VERSION (expr)))
+ if (bitmap_bit_p (visited, SSA_NAME_VERSION (op0)))
return NULL;
- bitmap_set_bit (visited, SSA_NAME_VERSION (expr));
+ bitmap_set_bit (visited, SSA_NAME_VERSION (op0));
- if (TREE_CODE (def) == PHI_NODE)
+ if (gimple_code (def) == GIMPLE_PHI)
{
/* All the arguments of the PHI node must have the same constant
length. */
- int i;
+ int i, n = gimple_phi_num_args (def);
tree val = NULL, new_val;
- for (i = 0; i < PHI_NUM_ARGS (def); i++)
+ for (i = 0; i < n; i++)
{
tree arg = PHI_ARG_DEF (def, i);
}
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)
+ if (is_gimple_assign (def))
{
- 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 (gimple_assign_lhs (def) != op0)
+ return NULL;
+
+ return expr_expected_value_1 (TREE_TYPE (gimple_assign_lhs (def)),
+ gimple_assign_rhs1 (def),
+ gimple_assign_rhs_code (def),
+ gimple_assign_rhs2 (def),
+ visited);
}
+
+ if (is_gimple_call (def))
+ {
+ tree decl = gimple_call_fndecl (def);
+ if (!decl)
+ return NULL;
+ if (DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
+ && DECL_FUNCTION_CODE (decl) == BUILT_IN_EXPECT)
+ {
+ tree val;
+
+ if (gimple_call_num_args (def) != 2)
+ return NULL;
+ val = gimple_call_arg (def, 0);
+ if (TREE_CONSTANT (val))
+ return val;
+ return gimple_call_arg (def, 1);
+ }
+ }
+
+ return NULL;
}
- if (BINARY_CLASS_P (expr) || COMPARISON_CLASS_P (expr))
+
+ if (get_gimple_rhs_class (code) == GIMPLE_BINARY_RHS)
{
- tree op0, op1, res;
- op0 = expr_expected_value (TREE_OPERAND (expr, 0), visited);
+ tree res;
+ op0 = expr_expected_value (op0, visited);
if (!op0)
return NULL;
- op1 = expr_expected_value (TREE_OPERAND (expr, 1), visited);
+ op1 = expr_expected_value (op1, visited);
if (!op1)
return NULL;
- res = fold_build2 (TREE_CODE (expr), TREE_TYPE (expr), op0, op1);
+ res = fold_build2 (code, type, op0, op1);
if (TREE_CONSTANT (res))
return res;
return NULL;
}
- if (UNARY_CLASS_P (expr))
+ if (get_gimple_rhs_class (code) == GIMPLE_UNARY_RHS)
{
- tree op0, res;
- op0 = expr_expected_value (TREE_OPERAND (expr, 0), visited);
+ tree res;
+ op0 = expr_expected_value (op0, visited);
if (!op0)
return NULL;
- res = fold_build1 (TREE_CODE (expr), TREE_TYPE (expr), op0);
+ res = fold_build1 (code, type, op0);
if (TREE_CONSTANT (res))
return res;
return NULL;
}
return NULL;
}
+
+/* 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)
+{
+ enum tree_code code;
+ tree op0, op1;
+
+ if (TREE_CONSTANT (expr))
+ return expr;
+
+ extract_ops_from_tree (expr, &code, &op0, &op1);
+ return expr_expected_value_1 (TREE_TYPE (expr),
+ op0, code, op1, visited);
+}
+
\f
-/* Get rid of all builtin_expect calls we no longer need. */
-static void
-strip_builtin_expect (void)
+/* Get rid of all builtin_expect calls and GIMPLE_PREDICT statements
+ we no longer need. */
+static unsigned int
+strip_predict_hints (void)
{
basic_block bb;
+ gimple ass_stmt;
+ tree var;
+
FOR_EACH_BB (bb)
{
- block_stmt_iterator bi;
- for (bi = bsi_start (bb); !bsi_end_p (bi); bsi_next (&bi))
+ gimple_stmt_iterator bi;
+ for (bi = gsi_start_bb (bb); !gsi_end_p (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))
+ gimple stmt = gsi_stmt (bi);
+
+ if (gimple_code (stmt) == GIMPLE_PREDICT)
+ {
+ gsi_remove (&bi, true);
+ continue;
+ }
+ else if (gimple_code (stmt) == GIMPLE_CALL)
{
- TREE_OPERAND (stmt, 1) = TREE_VALUE (arglist);
- update_stmt (stmt);
+ tree fndecl = gimple_call_fndecl (stmt);
+
+ if (fndecl
+ && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
+ && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_EXPECT
+ && gimple_call_num_args (stmt) == 2)
+ {
+ var = gimple_call_lhs (stmt);
+ ass_stmt = gimple_build_assign (var, gimple_call_arg (stmt, 0));
+
+ gsi_replace (&bi, ass_stmt, true);
+ }
}
+ gsi_next (&bi);
}
}
+ return 0;
}
\f
/* Predict using opcode of the last statement in basic block. */
static void
tree_predict_by_opcode (basic_block bb)
{
- tree stmt = last_stmt (bb);
+ gimple stmt = last_stmt (bb);
edge then_edge;
- tree cond;
- tree op0;
+ tree op0, op1;
tree type;
tree val;
+ enum tree_code cmp;
bitmap visited;
edge_iterator ei;
- if (!stmt || TREE_CODE (stmt) != COND_EXPR)
+ if (!stmt || gimple_code (stmt) != GIMPLE_COND)
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);
+ op0 = gimple_cond_lhs (stmt);
+ op1 = gimple_cond_rhs (stmt);
+ cmp = gimple_cond_code (stmt);
type = TREE_TYPE (op0);
visited = BITMAP_ALLOC (NULL);
- val = expr_expected_value (cond, visited);
+ val = expr_expected_value_1 (boolean_type_node, op0, cmp, op1, visited);
BITMAP_FREE (visited);
if (val)
{
Similarly, a comparison ptr1 == ptr2 is predicted as false. */
if (POINTER_TYPE_P (type))
{
- if (TREE_CODE (cond) == EQ_EXPR)
+ if (cmp == EQ_EXPR)
predict_edge_def (then_edge, PRED_TREE_POINTER, NOT_TAKEN);
- else if (TREE_CODE (cond) == NE_EXPR)
+ else if (cmp == NE_EXPR)
predict_edge_def (then_edge, PRED_TREE_POINTER, TAKEN);
}
else
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))
+ switch (cmp)
{
case EQ_EXPR:
case UNEQ_EXPR:
;
/* 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 if (integer_zerop (op0) || integer_zerop (op1))
;
else
predict_edge_def (then_edge, PRED_TREE_OPCODE_NONEQUAL, NOT_TAKEN);
/* 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)))
+ || integer_zerop (op1))
;
else
predict_edge_def (then_edge, PRED_TREE_OPCODE_NONEQUAL, TAKEN);
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)))
+ if (integer_zerop (op1)
+ || integer_onep (op1)
+ || integer_all_onesp (op1)
+ || real_zerop (op1)
+ || real_onep (op1)
+ || real_minus_onep (op1))
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)))
+ if (integer_zerop (op1)
+ || integer_onep (op1)
+ || integer_all_onesp (op1)
+ || real_zerop (op1)
+ || real_onep (op1)
+ || real_minus_onep (op1))
predict_edge_def (then_edge, PRED_TREE_OPCODE_POSITIVE, TAKEN);
break;
}
/* Try to guess whether the value of return means error code. */
+
static enum br_predictor
return_prediction (tree val, enum prediction *prediction)
{
&& (!integer_zerop (val) && !integer_onep (val)))
{
*prediction = TAKEN;
- return PRED_NEGATIVE_RETURN;
+ return PRED_CONST_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)
+apply_return_prediction (void)
{
- tree return_stmt = NULL;
+ gimple return_stmt = NULL;
tree return_val;
edge e;
- tree phi;
+ gimple phi;
int phi_num_args, i;
enum br_predictor pred;
enum prediction direction;
FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
{
return_stmt = last_stmt (e->src);
- if (TREE_CODE (return_stmt) == RETURN_EXPR)
+ if (return_stmt
+ && gimple_code (return_stmt) == GIMPLE_RETURN)
break;
}
if (!e)
return;
- return_val = TREE_OPERAND (return_stmt, 0);
+ return_val = gimple_return_retval (return_stmt);
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)
+ || gimple_code (SSA_NAME_DEF_STMT (return_val)) != GIMPLE_PHI)
return;
- phi_num_args = PHI_NUM_ARGS (phi);
+ phi = SSA_NAME_DEF_STMT (return_val);
+ phi_num_args = gimple_phi_num_args (phi);
pred = return_prediction (PHI_ARG_DEF (phi, 0), &direction);
/* Avoid the degenerate case where all return values form the function
{
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,
+ predict_paths_leading_to (gimple_phi_arg_edge (phi, i)->src, pred,
direction);
}
}
tree_bb_level_predictions (void)
{
basic_block bb;
- int *heads;
+ bool has_return_edges = false;
+ edge e;
+ edge_iterator ei;
- heads = XCNEWVEC (int, last_basic_block);
- heads[ENTRY_BLOCK_PTR->next_bb->index] = last_basic_block;
+ FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
+ if (!(e->flags & (EDGE_ABNORMAL | EDGE_FAKE | EDGE_EH)))
+ {
+ has_return_edges = true;
+ break;
+ }
- apply_return_prediction (heads);
+ apply_return_prediction ();
FOR_EACH_BB (bb)
{
- block_stmt_iterator bsi = bsi_last (bb);
+ gimple_stmt_iterator gsi;
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- tree stmt = bsi_stmt (bsi);
- switch (TREE_CODE (stmt))
+ gimple stmt = gsi_stmt (gsi);
+ tree decl;
+
+ if (is_gimple_call (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;
+ if ((gimple_call_flags (stmt) & ECF_NORETURN)
+ && has_return_edges)
+ predict_paths_leading_to (bb, PRED_NORETURN,
+ NOT_TAKEN);
+ decl = gimple_call_fndecl (stmt);
+ if (decl
+ && lookup_attribute ("cold",
+ DECL_ATTRIBUTES (decl)))
+ predict_paths_leading_to (bb, PRED_COLD_FUNCTION,
+ NOT_TAKEN);
+ }
+ else if (gimple_code (stmt) == GIMPLE_PREDICT)
+ {
+ predict_paths_leading_to (bb, gimple_predict_predictor (stmt),
+ gimple_predict_outcome (stmt));
+ /* Keep GIMPLE_PREDICT around so early inlining will propagate
+ hints to callers. */
}
}
}
-
- free (heads);
}
-/* Predict branch probabilities and estimate profile of the tree CFG. */
-static unsigned int
-tree_estimate_probability (void)
-{
- basic_block bb;
+#ifdef ENABLE_CHECKING
- loop_optimizer_init (0);
- if (dump_file && (dump_flags & TDF_DETAILS))
- flow_loops_dump (current_loops, dump_file, NULL, 0);
+/* Callback for pointer_map_traverse, asserts that the pointer map is
+ empty. */
- add_noreturn_fake_exit_edges ();
- connect_infinite_loops_to_exit ();
- calculate_dominance_info (CDI_DOMINATORS);
- calculate_dominance_info (CDI_POST_DOMINATORS);
+static bool
+assert_is_empty (const void *key ATTRIBUTE_UNUSED, void **value,
+ void *data ATTRIBUTE_UNUSED)
+{
+ gcc_assert (!*value);
+ return false;
+}
+#endif
- tree_bb_level_predictions ();
+/* Predict branch probabilities and estimate profile for basic block BB. */
- mark_irreducible_loops (current_loops);
- if (current_loops)
- predict_loops (current_loops);
+static void
+tree_estimate_probability_bb (basic_block bb)
+{
+ edge e;
+ edge_iterator ei;
+ gimple last;
- FOR_EACH_BB (bb)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
- 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.
+
+ Since we've already removed the return statements, we are
+ looking for CFG like:
+
+ if (conditional)
+ {
+ ..
+ goto return_block
+ }
+ some other blocks
+ return_block:
+ return_stmt. */
+ if (e->dest != bb->next_bb
+ && e->dest != EXIT_BLOCK_PTR
+ && single_succ_p (e->dest)
+ && single_succ_edge (e->dest)->dest == EXIT_BLOCK_PTR
+ && (last = last_stmt (e->dest)) != NULL
+ && gimple_code (last) == GIMPLE_RETURN)
{
- /* 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;
+ edge e1;
+ edge_iterator ei1;
+ if (single_succ_p (bb))
+ {
FOR_EACH_EDGE (e1, ei1, bb->preds)
- if (!predicted_by_p (e1->src, PRED_NULL_RETURN)
+ 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))
+ && !predicted_by_p (e1->src, PRED_NEGATIVE_RETURN))
predict_edge_def (e1, PRED_TREE_EARLY_RETURN, NOT_TAKEN);
}
+ else
+ if (!predicted_by_p (e->src, PRED_NULL_RETURN)
+ && !predicted_by_p (e->src, PRED_CONST_RETURN)
+ && !predicted_by_p (e->src, PRED_NEGATIVE_RETURN))
+ predict_edge_def (e, 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))
+ /* 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))
+ {
+ gimple_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 = gsi_start_bb (e->dest); !gsi_end_p (bi);
+ gsi_next (&bi))
{
- 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))
+ gimple stmt = gsi_stmt (bi);
+ if (is_gimple_call (stmt)
+ /* Constant and pure calls are hardly used to signalize
+ something exceptional. */
+ && gimple_has_side_effects (stmt))
{
- 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;
- }
+ predict_edge_def (e, PRED_CALL, NOT_TAKEN);
+ break;
}
}
}
- tree_predict_by_opcode (bb);
}
+ tree_predict_by_opcode (bb);
+}
+
+/* Predict branch probabilities and estimate profile of the tree CFG.
+ This function can be called from the loop optimizers to recompute
+ the profile information. */
+
+void
+tree_estimate_probability (void)
+{
+ basic_block bb;
+
+ add_noreturn_fake_exit_edges ();
+ connect_infinite_loops_to_exit ();
+ /* We use loop_niter_by_eval, which requires that the loops have
+ preheaders. */
+ create_preheaders (CP_SIMPLE_PREHEADERS);
+ calculate_dominance_info (CDI_POST_DOMINATORS);
+
+ bb_predictions = pointer_map_create ();
+ tree_bb_level_predictions ();
+ record_loop_exits ();
+
+ if (number_of_loops () > 1)
+ predict_loops ();
+
+ FOR_EACH_BB (bb)
+ tree_estimate_probability_bb (bb);
+
FOR_EACH_BB (bb)
combine_predictions_for_bb (bb);
- strip_builtin_expect ();
- estimate_bb_frequencies (current_loops);
+#ifdef ENABLE_CHECKING
+ pointer_map_traverse (bb_predictions, assert_is_empty, NULL);
+#endif
+ pointer_map_destroy (bb_predictions);
+ bb_predictions = NULL;
+
+ estimate_bb_frequencies ();
free_dominance_info (CDI_POST_DOMINATORS);
remove_fake_exit_edges ();
+}
+
+/* Predict branch probabilities and estimate profile of the tree CFG.
+ This is the driver function for PASS_PROFILE. */
+
+static unsigned int
+tree_estimate_probability_driver (void)
+{
+ unsigned nb_loops;
+
+ loop_optimizer_init (0);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ flow_loops_dump (dump_file, NULL, 0);
+
+ mark_irreducible_loops ();
+
+ nb_loops = number_of_loops ();
+ if (nb_loops > 1)
+ scev_initialize ();
+
+ tree_estimate_probability ();
+
+ if (nb_loops > 1)
+ scev_finalize ();
+
loop_optimizer_finalize ();
if (dump_file && (dump_flags & TDF_DETAILS))
- dump_tree_cfg (dump_file, dump_flags);
+ gimple_dump_cfg (dump_file, dump_flags);
if (profile_status == PROFILE_ABSENT)
profile_status = PROFILE_GUESSED;
return 0;
}
\f
-/* 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). */
+/* Predict edges to successors of CUR whose sources are not postdominated by
+ BB by PRED and recurse to all postdominators. */
static void
-predict_paths_leading_to (basic_block bb, int *heads, enum br_predictor pred,
- enum prediction taken)
+predict_paths_for_bb (basic_block cur, basic_block bb,
+ enum br_predictor pred,
+ enum prediction taken)
{
edge e;
edge_iterator ei;
- int y;
+ basic_block son;
- if (heads[bb->index] == ENTRY_BLOCK)
+ /* We are looking for all edges forming edge cut induced by
+ set of all blocks postdominated by BB. */
+ FOR_EACH_EDGE (e, ei, cur->preds)
+ if (e->src->index >= NUM_FIXED_BLOCKS
+ && !dominated_by_p (CDI_POST_DOMINATORS, e->src, bb))
{
- /* 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;
- }
+ gcc_assert (bb == cur || dominated_by_p (CDI_POST_DOMINATORS, cur, bb));
+ predict_edge_def (e, pred, taken);
}
- y = heads[bb->index];
+ for (son = first_dom_son (CDI_POST_DOMINATORS, cur);
+ son;
+ son = next_dom_son (CDI_POST_DOMINATORS, son))
+ predict_paths_for_bb (son, bb, pred, taken);
+}
- /* Now find the edge that leads to our branch and aply the prediction. */
+/* Sets branch probabilities according to PREDiction and
+ FLAGS. */
- 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);
+static void
+predict_paths_leading_to (basic_block bb, enum br_predictor pred,
+ enum prediction taken)
+{
+ predict_paths_for_bb (bb, bb, pred, taken);
}
\f
/* This is used to carry information about basic blocks. It is
}
}
-/* Propates frequencies through structure of LOOPS. */
+/* Propagates frequencies through structure of loops. */
static void
-estimate_loops (struct loops *loops)
+estimate_loops (void)
{
bitmap tovisit = BITMAP_ALLOC (NULL);
basic_block bb;
/* Start by estimating the frequencies in the loops. */
- if (loops)
- estimate_loops_at_level (loops->tree_root->inner);
+ if (number_of_loops () > 1)
+ estimate_loops_at_level (current_loops->tree_root->inner);
/* Now propagate the frequencies through all the blocks. */
FOR_ALL_BB (bb)
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;
}
/* Estimate basic blocks frequency by given branch probabilities. */
-static void
-estimate_bb_frequencies (struct loops *loops)
+void
+estimate_bb_frequencies (void)
{
basic_block bb;
sreal freq_max;
- if (!flag_branch_probabilities || !counts_to_freqs ())
+ if (profile_status != PROFILE_READ || !counts_to_freqs ())
{
static int real_values_initialized = 0;
/* First compute probabilities locally for each loop from innermost
to outermost to examine probabilities for back edges. */
- estimate_loops (loops);
+ estimate_loops ();
memcpy (&freq_max, &real_zero, sizeof (real_zero));
FOR_EACH_BB (bb)
basic_block bb;
if (!profile_info || !flag_branch_probabilities)
- return;
+ {
+ if (lookup_attribute ("cold", DECL_ATTRIBUTES (current_function_decl))
+ != NULL)
+ cfun->function_frequency = FUNCTION_FREQUENCY_UNLIKELY_EXECUTED;
+ else if (lookup_attribute ("hot", DECL_ATTRIBUTES (current_function_decl))
+ != NULL)
+ cfun->function_frequency = FUNCTION_FREQUENCY_HOT;
+ return;
+ }
cfun->function_frequency = FUNCTION_FREQUENCY_UNLIKELY_EXECUTED;
FOR_EACH_BB (bb)
{
return flag_guess_branch_prob;
}
-struct tree_opt_pass pass_profile =
+/* Build PREDICT_EXPR. */
+tree
+build_predict_expr (enum br_predictor predictor, enum prediction taken)
{
+ tree t = build1 (PREDICT_EXPR, void_type_node,
+ build_int_cst (NULL, predictor));
+ SET_PREDICT_EXPR_OUTCOME (t, taken);
+ return t;
+}
+
+const char *
+predictor_name (enum br_predictor predictor)
+{
+ return predictor_info[predictor].name;
+}
+
+struct gimple_opt_pass pass_profile =
+{
+ {
+ GIMPLE_PASS,
"profile", /* name */
gate_estimate_probability, /* gate */
- tree_estimate_probability, /* execute */
+ tree_estimate_probability_driver, /* 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 */
+ }
+};
+
+struct gimple_opt_pass pass_strip_predict_hints =
+{
+ {
+ GIMPLE_PASS,
+ NULL, /* name */
+ NULL, /* gate */
+ strip_predict_hints, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_ggc_collect | TODO_verify_ssa, /* todo_flags_finish */
- 0 /* letter */
+ TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */
+ }
};