/* Branch prediction routines for the GNU compiler.
- Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008
+ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009
Free Software Foundation, Inc.
This file is part of GCC.
#undef DEF_PREDICTOR
/* Return TRUE if frequency FREQ is considered to be hot. */
-static bool
+
+static inline bool
maybe_hot_frequency_p (int freq)
{
if (!profile_info || !flag_branch_probabilities)
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 (const_basic_block bb)
{
- if (profile_info && flag_branch_probabilities
- && (bb->count
- < profile_info->sum_max / PARAM_VALUE (HOT_BB_COUNT_FRACTION)))
- return false;
+ if (profile_status == PROFILE_READ)
+ return maybe_hot_count_p (bb->count);
return maybe_hot_frequency_p (bb->frequency);
}
bool
maybe_hot_edge_p (edge e)
{
- if (profile_info && flag_branch_probabilities
- && (e->count
- < profile_info->sum_max / PARAM_VALUE (HOT_BB_COUNT_FRACTION)))
- 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 cold and should be optimized for size. */
-
-bool
-probably_cold_bb_p (const_basic_block bb)
-{
- if (profile_info && flag_branch_probabilities
- && (bb->count
- < profile_info->sum_max / PARAM_VALUE (HOT_BB_COUNT_FRACTION)))
- return true;
- if ((!profile_info || !flag_branch_probabilities)
- && cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED)
- 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 (const_basic_block bb)
optimize_function_for_size_p (struct function *fun)
{
return (optimize_size
- || fun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED);
+ || (fun && (fun->function_frequency
+ == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED)));
}
/* Return true when current function should always be optimized for speed. */
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,
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;
by predictor with smallest index. */
for (pred = (struct edge_prediction *) *preds; pred; pred = pred->ep_next)
{
- int predictor = pred->ep_predictor;
+ enum br_predictor predictor = pred->ep_predictor;
int probability = pred->ep_probability;
if (pred->ep_edge != first)
probability = REG_BR_PROB_BASE - probability;
found = true;
+ /* First match heuristics would be widly confused if we predicted
+ both directions. */
if (best_predictor > predictor)
- best_probability = probability, 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)
{
for (pred = (struct edge_prediction *) *preds; pred; pred = pred->ep_next)
{
- int predictor = pred->ep_predictor;
+ enum br_predictor predictor = pred->ep_predictor;
int probability = pred->ep_probability;
if (pred->ep_edge != EDGE_SUCC (bb, 0))
tree_bb_level_predictions (void)
{
basic_block bb;
+ bool has_return_edges = false;
+ edge e;
+ edge_iterator ei;
+
+ 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 ();
if (is_gimple_call (stmt))
{
- if (gimple_call_flags (stmt) & ECF_NORETURN)
+ if ((gimple_call_flags (stmt) & ECF_NORETURN)
+ && has_return_edges)
predict_paths_leading_to (bb, PRED_NORETURN,
NOT_TAKEN);
decl = gimple_call_fndecl (stmt);
{
edge e;
edge_iterator ei;
+ gimple last;
FOR_EACH_EDGE (e, ei, bb->succs)
{
&& e->dest != EXIT_BLOCK_PTR
&& single_succ_p (e->dest)
&& single_succ_edge (e->dest)->dest == EXIT_BLOCK_PTR
- && gimple_code (last_stmt (e->dest)) == GIMPLE_RETURN)
+ && (last = last_stmt (e->dest)) != NULL
+ && gimple_code (last) == GIMPLE_RETURN)
{
edge e1;
edge_iterator ei1;
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;
{
tree t = build1 (PREDICT_EXPR, void_type_node,
build_int_cst (NULL, predictor));
- PREDICT_EXPR_OUTCOME (t) = taken;
+ SET_PREDICT_EXPR_OUTCOME (t, taken);
return t;
}
{
{
GIMPLE_PASS,
- "", /* name */
+ NULL, /* name */
NULL, /* gate */
strip_predict_hints, /* execute */
NULL, /* sub */
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