/* 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.
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, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA. */
/* References:
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)
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)
- if (i->predictor == predictor)
+ struct edge_prediction *i;
+ for (i = bb->predictions; i; i = i->ep_next)
+ if (i->ep_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->ep_next = e->src->predictions;
+ e->src->predictions = i;
+ i->ep_probability = probability;
+ i->ep_predictor = predictor;
+ i->ep_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)->ep_edge == e)
+ *prediction = (*prediction)->ep_next;
+ else
+ prediction = &((*prediction)->ep_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.
Remove now useless prediction entries. */
static void
-combine_predictions_for_bb (FILE *file, basic_block bb)
+combine_predictions_for_bb (basic_block bb)
{
int best_probability = PROB_EVEN;
int best_predictor = END_PREDICTORS;
{
if (!bb->count)
set_even_probabilities (bb);
- bb_ann (bb)->predictions = NULL;
- if (file)
- fprintf (file, "%i edges in bb %i predicted to even probabilities\n",
+ bb->predictions = NULL;
+ if (dump_file)
+ fprintf (dump_file, "%i edges in bb %i predicted to even probabilities\n",
nedges, bb->index);
return;
}
- if (file)
- fprintf (file, "Predictions for bb %i\n", 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_ann (bb)->predictions; pred; pred = pred->next)
+ for (pred = bb->predictions; pred; pred = pred->ep_next)
{
- int predictor = pred->predictor;
- int probability = pred->probability;
+ int predictor = pred->ep_predictor;
+ int probability = pred->ep_probability;
- if (pred->edge != first)
+ if (pred->ep_edge != first)
probability = REG_BR_PROB_BASE - probability;
found = true;
first_match = true;
if (!found)
- dump_prediction (file, PRED_NO_PREDICTION, combined_probability, bb, true);
+ dump_prediction (dump_file, PRED_NO_PREDICTION, combined_probability, bb, true);
else
{
- dump_prediction (file, PRED_DS_THEORY, combined_probability, bb,
+ dump_prediction (dump_file, PRED_DS_THEORY, combined_probability, bb,
!first_match);
- dump_prediction (file, PRED_FIRST_MATCH, best_probability, bb,
+ dump_prediction (dump_file, PRED_FIRST_MATCH, best_probability, bb,
first_match);
}
if (first_match)
combined_probability = best_probability;
- dump_prediction (file, PRED_COMBINED, combined_probability, bb, true);
+ dump_prediction (dump_file, PRED_COMBINED, combined_probability, bb, true);
- for (pred = bb_ann (bb)->predictions; pred; pred = pred->next)
+ for (pred = bb->predictions; pred; pred = pred->ep_next)
{
- int predictor = pred->predictor;
- int probability = pred->probability;
+ int predictor = pred->ep_predictor;
+ int probability = pred->ep_probability;
- if (pred->edge != EDGE_SUCC (bb, 0))
+ if (pred->ep_edge != EDGE_SUCC (bb, 0))
probability = REG_BR_PROB_BASE - probability;
- dump_prediction (file, predictor, probability, bb,
+ dump_prediction (dump_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)
{
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);
}
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;
- if (number_of_iterations_exit (loop, exits[j], &niter_desc))
+ 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,
- REG_BR_PROB_BASE - 1)))
+ 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;
+ probability = ((REG_BR_PROB_BASE + nitercst / 2)
+ / nitercst);
}
else
- probability = 1;
+ probability = ((REG_BR_PROB_BASE + max / 2) / max);
predict_edge (exits[j], PRED_LOOP_ITERATIONS, probability);
}
}
- 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. */
if (!header_found)
FOR_EACH_EDGE (e, ei, bb->succs)
- if (e->dest->index < 0
+ if (e->dest->index < NUM_FIXED_BLOCKS
|| !flow_bb_inside_loop_p (loop, e->dest))
predict_edge
(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_finalize ();
+ {
+ 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;
op1 = expr_expected_value (TREE_OPERAND (expr, 1), visited);
if (!op1)
return NULL;
- res = fold (build (TREE_CODE (expr), TREE_TYPE (expr), op0, op1));
+ res = fold_build2 (TREE_CODE (expr), TREE_TYPE (expr), op0, op1);
if (TREE_CONSTANT (res))
return res;
return NULL;
op0 = expr_expected_value (TREE_OPERAND (expr, 0), visited);
if (!op0)
return NULL;
- res = fold (build1 (TREE_CODE (expr), TREE_TYPE (expr), op0));
+ res = fold_build1 (TREE_CODE (expr), TREE_TYPE (expr), op0);
if (TREE_CONSTANT (res))
return res;
return NULL;
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))
static void
apply_return_prediction (int *heads)
{
- tree return_stmt;
+ tree return_stmt = NULL;
tree return_val;
edge e;
tree phi;
|| !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;
int *heads;
- heads = xmalloc (sizeof (int) * last_basic_block);
- memset (heads, -1, sizeof (int) * last_basic_block);
+ 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);
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);
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;
tree_predict_by_opcode (bb);
}
FOR_EACH_BB (bb)
- combine_predictions_for_bb (dump_file, bb);
+ combine_predictions_for_bb (bb);
- if (0) /* FIXME: Enable once we are pass down the profile to RTL level. */
- strip_builtin_expect ();
+ strip_builtin_expect ();
estimate_bb_frequencies (&loops_info);
free_dominance_info (CDI_POST_DOMINATORS);
remove_fake_exit_edges ();
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
edge_iterator ei;
int y;
- if (heads[bb->index] < 0)
+ 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
basic_block next_ai = get_immediate_dominator (CDI_DOMINATORS, bb);
int head;
- while (heads[next_ai->index] < 0)
+ while (heads[next_ai->index] == ENTRY_BLOCK)
{
if (!dominated_by_p (CDI_POST_DOMINATORS, next_ai, bb))
break;
while (next_ai != bb)
{
next_ai = ai;
- if (heads[ai->index] == ENTRY_BLOCK)
- ai = ENTRY_BLOCK_PTR;
- else
- ai = BASIC_BLOCK (heads[ai->index]);
+ ai = BASIC_BLOCK (heads[ai->index]);
heads[next_ai->index] = head;
}
}
if (y == last_basic_block)
return;
FOR_EACH_EDGE (e, ei, BASIC_BLOCK (y)->succs)
- if (e->dest->index >= 0
+ if (e->dest->index >= NUM_FIXED_BLOCKS
&& dominated_by_p (CDI_POST_DOMINATORS, e->dest, bb))
predict_edge_def (e, pred, taken);
}
/* Similar information for edges. */
typedef struct edge_info_def
{
- /* In case edge is an loopback edge, the probability edge will be reached
+ /* 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 an loopback edge in the natural loop. */
+ /* True if the edge is a loopback edge in the natural loop. */
unsigned int back_edge:1;
} *edge_info;
/* 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);
+ bb = BASIC_BLOCK (i);
FOR_EACH_EDGE (e, ei, bb->preds)
{
{
#ifdef ENABLE_CHECKING
FOR_EACH_EDGE (e, ei, bb->preds)
- if (bitmap_bit_p (tovisit, e->src->index)
- && !(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)
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)
/* 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
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_XMALLOC ();
+ 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)
free_aux_for_blocks ();
free_aux_for_edges ();
- BITMAP_XFREE (tovisit);
+ 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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