/* Branch prediction routines for the GNU compiler.
- Copyright (C) 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
+ Free Software Foundation, Inc.
This file is part of GCC.
real_inv_br_prob_base, real_one_half, real_bb_freq_max;
/* Random guesstimation given names. */
-#define PROB_VERY_UNLIKELY (REG_BR_PROB_BASE / 10 - 1)
+#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 *loop);
-static void propagate_freq (struct loop *);
+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);
bool
tree_predicted_by_p (basic_block bb, enum br_predictor predictor)
{
- struct edge_prediction *i = bb_ann (bb)->predictions;
- for (i = bb_ann (bb)->predictions; i; i = i->next)
+ struct edge_prediction *i;
+ for (i = bb->predictions; i; i = i->next)
if (i->predictor == predictor)
return true;
return false;
}
-void
+static void
predict_insn (rtx insn, enum br_predictor predictor, int probability)
{
- if (!any_condjump_p (insn))
- abort ();
+ gcc_assert (any_condjump_p (insn));
if (!flag_guess_branch_prob)
return;
void
tree_predict_edge (edge e, enum br_predictor predictor, int probability)
{
- struct edge_prediction *i = ggc_alloc (sizeof (struct edge_prediction));
+ 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->next = e->src->predictions;
+ e->src->predictions = i;
+ i->probability = probability;
+ i->predictor = predictor;
+ i->edge = e;
+ }
+}
- i->next = bb_ann (e->src)->predictions;
- bb_ann (e->src)->predictions = i;
- i->probability = probability;
- i->predictor = predictor;
- i->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)->edge == e)
+ *prediction = (*prediction)->next;
+ else
+ prediction = &((*prediction)->next);
+ }
+ }
}
/* Return true when we can store prediction on insn INSN.
/* Save the prediction into CFG in case we are seeing non-degenerated
conditional jump. */
- if (EDGE_COUNT (bb->succs) > 1)
+ if (!single_succ_p (bb))
{
BRANCH_EDGE (bb)->probability = combined_probability;
FALLTHRU_EDGE (bb)->probability
= REG_BR_PROB_BASE - combined_probability;
}
}
- else if (EDGE_COUNT (bb->succs) > 1)
+ else if (!single_succ_p (bb))
{
int prob = INTVAL (XEXP (prob_note, 0));
FALLTHRU_EDGE (bb)->probability = REG_BR_PROB_BASE - prob;
}
else
- EDGE_SUCC (bb, 0)->probability = REG_BR_PROB_BASE;
+ single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
}
/* Combine predictions into single probability and store them into CFG.
{
if (!bb->count)
set_even_probabilities (bb);
- bb_ann (bb)->predictions = NULL;
+ bb->predictions = NULL;
if (file)
fprintf (file, "%i edges in bb %i predicted to even probabilities\n",
nedges, bb->index);
/* We implement "first match" heuristics and use probability guessed
by predictor with smallest index. */
- for (pred = bb_ann (bb)->predictions; pred; pred = pred->next)
+ for (pred = bb->predictions; pred; pred = pred->next)
{
int predictor = pred->predictor;
int probability = pred->probability;
combined_probability = best_probability;
dump_prediction (file, PRED_COMBINED, combined_probability, bb, true);
- for (pred = bb_ann (bb)->predictions; pred; pred = pred->next)
+ for (pred = bb->predictions; pred; pred = pred->next)
{
int predictor = pred->predictor;
int probability = pred->probability;
dump_prediction (file, predictor, probability, bb,
!first_match || best_predictor == predictor);
}
- bb_ann (bb)->predictions = NULL;
+ bb->predictions = NULL;
if (!bb->count)
{
{
basic_block bb, *bbs;
unsigned j;
- int exits;
+ unsigned n_exits;
struct loop *loop = loops_info->parray[i];
struct niter_desc desc;
unsigned HOST_WIDE_INT niter;
+ edge *exits;
- flow_loop_scan (loop, LOOP_EXIT_EDGES);
- exits = loop->num_exits;
+ exits = get_loop_exit_edges (loop, &n_exits);
if (rtlsimpleloops)
{
}
else
{
- edge *exits;
- unsigned j, n_exits;
struct tree_niter_desc niter_desc;
- exits = get_loop_exit_edges (loop, &n_exits);
for (j = 0; j < n_exits; j++)
{
tree niter = NULL;
}
}
- free (exits);
}
+ free (exits);
bbs = get_loop_body (loop);
/* Loop branch heuristics - predict an edge back to a
loop's head as taken. */
- FOR_EACH_EDGE (e, ei, bb->succs)
- if (e->dest == loop->header
- && e->src == loop->latch)
- {
- header_found = 1;
- predict_edge_def (e, PRED_LOOP_BRANCH, 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. */
(e, PRED_LOOP_EXIT,
(REG_BR_PROB_BASE
- predictor_info [(int) PRED_LOOP_EXIT].hitrate)
- / exits);
+ / n_exits);
}
/* Free basic blocks from get_loop_body. */
}
if (!rtlsimpleloops)
- scev_reset ();
+ {
+ scev_finalize ();
+ current_loops = NULL;
+ }
}
/* Attempt to predict probabilities of BB outgoing edges using local
care for error returns and other are often used for fast paths
trought function. */
if ((e->dest == EXIT_BLOCK_PTR
- || (EDGE_COUNT (e->dest->succs) == 1
- && EDGE_SUCC (e->dest, 0)->dest == EXIT_BLOCK_PTR))
+ || (single_succ_p (e->dest)
+ && single_succ (e->dest) == EXIT_BLOCK_PTR))
&& !predicted_by_p (bb, PRED_NULL_RETURN)
&& !predicted_by_p (bb, PRED_CONST_RETURN)
&& !predicted_by_p (bb, PRED_NEGATIVE_RETURN)
/* If this PHI has itself as an argument, we cannot
determine the string length of this argument. However,
- if we can find a expected constant value for the other
+ 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. */
tree decl = get_callee_fndecl (expr);
if (!decl)
return NULL;
- if (DECL_BUILT_IN (decl) && DECL_FUNCTION_CODE (decl) == BUILT_IN_EXPECT)
+ 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 (TREE_CODE (stmt) == MODIFY_EXPR
&& TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR
&& (fndecl = get_callee_fndecl (TREE_OPERAND (stmt, 1)))
- && DECL_BUILT_IN (fndecl)
+ && 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);
- modify_stmt (stmt);
+ update_stmt (stmt);
}
}
}
return;
op0 = TREE_OPERAND (cond, 0);
type = TREE_TYPE (op0);
- visited = BITMAP_XMALLOC ();
+ visited = BITMAP_ALLOC (NULL);
val = expr_expected_value (cond, visited);
- BITMAP_XFREE (visited);
+ BITMAP_FREE (visited);
if (val)
{
if (integer_zerop (val))
|| !SSA_NAME_DEF_STMT (return_val)
|| TREE_CODE (SSA_NAME_DEF_STMT (return_val)) != PHI_NODE)
return;
- phi = SSA_NAME_DEF_STMT (return_val);
- while (phi)
- {
- tree next = PHI_CHAIN (phi);
- if (PHI_RESULT (phi) == return_val)
- break;
- phi = next;
- }
+ 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);
basic_block bb;
struct loops loops_info;
- flow_loops_find (&loops_info, LOOP_TREE);
+ flow_loops_find (&loops_info);
if (dump_file && (dump_flags & TDF_DETAILS))
flow_loops_dump (&loops_info, dump_file, NULL, 0);
tree_bb_level_predictions ();
+ mark_irreducible_loops (&loops_info);
predict_loops (&loops_info, false);
FOR_EACH_BB (bb)
fast paths trought function. */
if (e->dest == EXIT_BLOCK_PTR
&& TREE_CODE (last_stmt (bb)) == RETURN_EXPR
- && EDGE_COUNT (bb->preds) > 1)
+ && !single_pred_p (bb))
{
edge e1;
edge_iterator ei1;
cond = simplify_rtx (cond);
/* Turn the condition into a scaled branch probability. */
- if (cond != const_true_rtx && cond != const0_rtx)
- abort ();
+ gcc_assert (cond == const_true_rtx || cond == const0_rtx);
predict_insn_def (insn, PRED_BUILTIN_EXPECT,
cond == const_true_rtx ? TAKEN : NOT_TAKEN);
}
return (bb->next_bb == EXIT_BLOCK_PTR
|| (bb->next_bb->next_bb == EXIT_BLOCK_PTR
- && EDGE_COUNT (bb->succs) == 1
- && EDGE_SUCC (bb, 0)->dest->next_bb == EXIT_BLOCK_PTR));
+ && single_succ_p (bb)
+ && single_succ (bb)->next_bb == EXIT_BLOCK_PTR));
}
/* Sets branch probabilities according to PREDiction and
/* To keep queue of basic blocks to process. */
basic_block next;
- /* True if block needs to be visited in propagate_freq. */
- unsigned int tovisit:1;
-
/* Number of predecessors we need to visit first. */
int npredecessors;
} *block_info;
Propagate the frequencies for LOOP. */
static void
-propagate_freq (struct loop *loop)
+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. */
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
+ EXECUTE_IF_SET_IN_BITMAP (tovisit, 0, i, bi)
{
- if (BLOCK_INFO (bb)->tovisit)
+ 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. */
+ if (i == (unsigned)ENTRY_BLOCK)
+ bb = ENTRY_BLOCK_PTR;
+ else if (i == (unsigned)EXIT_BLOCK)
+ bb = EXIT_BLOCK_PTR;
+ else
+ bb = BASIC_BLOCK (i);
+
+ FOR_EACH_EDGE (e, ei, bb->preds)
{
- edge_iterator ei;
- int count = 0;
-
- FOR_EACH_EDGE (e, ei, bb->preds)
- if (BLOCK_INFO (e->src)->tovisit && !(e->flags & EDGE_DFS_BACK))
- count++;
- else if (BLOCK_INFO (e->src)->tovisit
- && 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;
+ 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));
{
#ifdef ENABLE_CHECKING
FOR_EACH_EDGE (e, ei, bb->preds)
- if (BLOCK_INFO (e->src)->tovisit && !(e->flags & EDGE_DFS_BACK))
- abort ();
+ gcc_assert (!bitmap_bit_p (tovisit, e->src->index)
+ || (e->flags & EDGE_DFS_BACK));
#endif
FOR_EACH_EDGE (e, ei, bb->preds)
}
}
- BLOCK_INFO (bb)->tovisit = 0;
+ bitmap_clear_bit (tovisit, bb->index);
- /* Compute back edge frequencies. */
- FOR_EACH_EDGE (e, ei, bb->succs)
- if (e->dest == head)
- {
- sreal tmp;
+ 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); */
+ /* 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);
- }
+ 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)
/* Estimate probabilities of loopback edges in loops at same nest level. */
static void
-estimate_loops_at_level (struct loop *first_loop)
+estimate_loops_at_level (struct loop *first_loop, bitmap tovisit)
{
struct loop *loop;
basic_block *bbs;
unsigned i;
- estimate_loops_at_level (loop->inner);
+ estimate_loops_at_level (loop->inner, tovisit);
/* Do not do this for dummy function loop. */
if (EDGE_COUNT (loop->latch->succs) > 0)
bbs = get_loop_body (loop);
for (i = 0; i < loop->num_nodes; i++)
- BLOCK_INFO (bbs[i])->tovisit = 1;
+ bitmap_set_bit (tovisit, bbs[i]->index);
free (bbs);
- propagate_freq (loop);
+ propagate_freq (loop, tovisit);
}
}
/* We can not compute accurately for large thresholds due to scaled
frequencies. */
- if (threshold > BB_FREQ_MAX)
- abort ();
+ 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
if (!flag_branch_probabilities || !counts_to_freqs ())
{
static int real_values_initialized = 0;
+ bitmap tovisit;
if (!real_values_initialized)
{
mark_dfs_back_edges ();
- EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->probability = REG_BR_PROB_BASE;
+ 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;
- BLOCK_INFO (bb)->tovisit = 0;
FOR_EACH_EDGE (e, ei, bb->succs)
{
sreal_init (&EDGE_INFO (e)->back_edge_prob, e->probability, 0);
/* First compute probabilities locally for each loop from innermost
to outermost to examine probabilities for back edges. */
- estimate_loops_at_level (loops->tree_root);
+ estimate_loops_at_level (loops->tree_root, tovisit);
memcpy (&freq_max, &real_zero, sizeof (real_zero));
FOR_EACH_BB (bb)
free_aux_for_blocks ();
free_aux_for_edges ();
+ BITMAP_FREE (tovisit);
}
compute_function_frequency ();
if (flag_reorder_functions)
UNLIKELY_EXECUTED_TEXT_SECTION_NAME);
}
+static bool
+gate_estimate_probability (void)
+{
+ return flag_guess_branch_prob;
+}
struct tree_opt_pass pass_profile =
{
"profile", /* name */
- NULL, /* gate */
+ gate_estimate_probability, /* gate */
tree_estimate_probability, /* execute */
NULL, /* sub */
NULL, /* next */
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