/* Branch prediction routines for the GNU compiler.
- Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009
+ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
This file is part of GCC.
#include "function.h"
#include "except.h"
#include "diagnostic-core.h"
-#include "toplev.h"
#include "recog.h"
#include "expr.h"
#include "predict.h"
static void combine_predictions_for_insn (rtx, basic_block);
static void dump_prediction (FILE *, enum br_predictor, int, basic_block, int);
static void predict_paths_leading_to (basic_block, enum br_predictor, enum prediction);
-static void choose_function_section (void);
+static void predict_paths_leading_to_edge (edge, enum br_predictor, enum prediction);
static bool can_predict_insn_p (const_rtx);
/* Information we hold about each branch predictor.
static inline bool
maybe_hot_frequency_p (int freq)
{
- struct cgraph_node *node = cgraph_node (current_function_decl);
+ struct cgraph_node *node = cgraph_get_node (current_function_decl);
if (!profile_info || !flag_branch_probabilities)
{
if (node->frequency == NODE_FREQUENCY_UNLIKELY_EXECUTED)
if (profile_status == PROFILE_ABSENT)
return true;
if (node->frequency == NODE_FREQUENCY_EXECUTED_ONCE
- && freq <= (ENTRY_BLOCK_PTR->frequency * 2 / 3))
+ && freq < (ENTRY_BLOCK_PTR->frequency * 2 / 3))
return false;
- if (freq < BB_FREQ_MAX / PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION))
+ if (freq < ENTRY_BLOCK_PTR->frequency / PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION))
return false;
return true;
}
return maybe_hot_frequency_p (EDGE_FREQUENCY (e));
}
+
/* Return true in case BB is probably never executed. */
+
bool
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)
- && cgraph_node (current_function_decl)->frequency == NODE_FREQUENCY_UNLIKELY_EXECUTED)
+ && (cgraph_get_node (current_function_decl)->frequency
+ == NODE_FREQUENCY_UNLIKELY_EXECUTED))
return true;
return false;
}
+/* Return true if NODE should be optimized for size. */
+
+bool
+cgraph_optimize_for_size_p (struct cgraph_node *node)
+{
+ if (optimize_size)
+ return true;
+ if (node && (node->frequency == NODE_FREQUENCY_UNLIKELY_EXECUTED))
+ return true;
+ else
+ 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->decl
- && (cgraph_node (fun->decl)->frequency
- == NODE_FREQUENCY_UNLIKELY_EXECUTED)));
+ if (optimize_size)
+ return true;
+ if (!fun || !fun->decl)
+ return false;
+ return cgraph_optimize_for_size_p (cgraph_get_node (fun->decl));
}
/* Return true when current function should always be optimized for speed. */
static struct pointer_map_t *bb_predictions;
+/* Structure representing predictions in tree level. */
+
+struct edge_prediction {
+ struct edge_prediction *ep_next;
+ edge ep_edge;
+ enum br_predictor ep_predictor;
+ int ep_probability;
+};
+
/* Return true if the one of outgoing edges is already predicted by
PREDICTOR. */
the loop, use it to predict this exit. */
else if (n_exits == 1)
{
- nitercst = estimated_loop_iterations_int (loop, false);
+ nitercst = max_stmt_executions_int (loop, false);
if (nitercst < 0)
continue;
if (nitercst > max)
/* Helper function for expr_expected_value. */
static tree
-expr_expected_value_1 (tree type, tree op0, enum tree_code code, tree op1, bitmap visited)
+expr_expected_value_1 (tree type, tree op0, enum tree_code code,
+ tree op1, bitmap visited)
{
gimple 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 (DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
+ switch (DECL_FUNCTION_CODE (decl))
+ {
+ case 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);
+ }
- 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);
+ case BUILT_IN_SYNC_BOOL_COMPARE_AND_SWAP_N:
+ case BUILT_IN_SYNC_BOOL_COMPARE_AND_SWAP_1:
+ case BUILT_IN_SYNC_BOOL_COMPARE_AND_SWAP_2:
+ case BUILT_IN_SYNC_BOOL_COMPARE_AND_SWAP_4:
+ case BUILT_IN_SYNC_BOOL_COMPARE_AND_SWAP_8:
+ case BUILT_IN_SYNC_BOOL_COMPARE_AND_SWAP_16:
+ case BUILT_IN_ATOMIC_COMPARE_EXCHANGE:
+ case BUILT_IN_ATOMIC_COMPARE_EXCHANGE_N:
+ case BUILT_IN_ATOMIC_COMPARE_EXCHANGE_1:
+ case BUILT_IN_ATOMIC_COMPARE_EXCHANGE_2:
+ case BUILT_IN_ATOMIC_COMPARE_EXCHANGE_4:
+ case BUILT_IN_ATOMIC_COMPARE_EXCHANGE_8:
+ case BUILT_IN_ATOMIC_COMPARE_EXCHANGE_16:
+ /* Assume that any given atomic operation has low contention,
+ and thus the compare-and-swap operation succeeds. */
+ return boolean_true_node;
}
}
{
pred = return_prediction (PHI_ARG_DEF (phi, i), &direction);
if (pred != PRED_NO_PREDICTION)
- predict_paths_leading_to (gimple_phi_arg_edge (phi, i)->src, pred,
- direction);
+ predict_paths_leading_to_edge (gimple_phi_arg_edge (phi, i), pred,
+ direction);
}
}
static void
predict_paths_for_bb (basic_block cur, basic_block bb,
enum br_predictor pred,
- enum prediction taken)
+ enum prediction taken,
+ bitmap visited)
{
edge e;
edge_iterator ei;
edge_iterator ei2;
bool found = false;
- /* Ignore abnormals, we predict them as not taken anyway. */
- if (e->flags & (EDGE_EH | EDGE_FAKE | EDGE_ABNORMAL))
+ /* Ignore fake edges and eh, we predict them as not taken anyway. */
+ if (e->flags & (EDGE_EH | EDGE_FAKE))
continue;
gcc_assert (bb == cur || dominated_by_p (CDI_POST_DOMINATORS, cur, bb));
- /* See if there is how many edge from e->src that is not abnormal
+ /* See if there is an edge from e->src that is not abnormal
and does not lead to BB. */
FOR_EACH_EDGE (e2, ei2, e->src->succs)
if (e2 != e
- && !(e2->flags & (EDGE_EH | EDGE_FAKE | EDGE_ABNORMAL))
+ && !(e2->flags & (EDGE_EH | EDGE_FAKE))
&& !dominated_by_p (CDI_POST_DOMINATORS, e2->dest, bb))
{
found = true;
/* If there is non-abnormal path leaving e->src, predict edge
using predictor. Otherwise we need to look for paths
- leading to e->src. */
+ leading to e->src.
+
+ The second may lead to infinite loop in the case we are predicitng
+ regions that are only reachable by abnormal edges. We simply
+ prevent visiting given BB twice. */
if (found)
predict_edge_def (e, pred, taken);
- else
- predict_paths_for_bb (e->src, e->src, pred, taken);
+ else if (bitmap_set_bit (visited, e->src->index))
+ predict_paths_for_bb (e->src, e->src, pred, taken, visited);
}
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);
+ predict_paths_for_bb (son, bb, pred, taken, visited);
}
/* Sets branch probabilities according to PREDiction and
predict_paths_leading_to (basic_block bb, enum br_predictor pred,
enum prediction taken)
{
- predict_paths_for_bb (bb, bb, pred, taken);
+ bitmap visited = BITMAP_ALLOC (NULL);
+ predict_paths_for_bb (bb, bb, pred, taken, visited);
+ BITMAP_FREE (visited);
+}
+
+/* Like predict_paths_leading_to but take edge instead of basic block. */
+
+static void
+predict_paths_leading_to_edge (edge e, enum br_predictor pred,
+ enum prediction taken)
+{
+ bool has_nonloop_edge = false;
+ edge_iterator ei;
+ edge e2;
+
+ basic_block bb = e->src;
+ FOR_EACH_EDGE (e2, ei, bb->succs)
+ if (e2->dest != e->src && e2->dest != e->dest
+ && !(e->flags & (EDGE_EH | EDGE_FAKE))
+ && !dominated_by_p (CDI_POST_DOMINATORS, e->src, e2->dest))
+ {
+ has_nonloop_edge = true;
+ break;
+ }
+ if (!has_nonloop_edge)
+ {
+ bitmap visited = BITMAP_ALLOC (NULL);
+ predict_paths_for_bb (bb, bb, pred, taken, visited);
+ BITMAP_FREE (visited);
+ }
+ else
+ predict_edge_def (e, pred, taken);
}
\f
/* This is used to carry information about basic blocks. It is
free_aux_for_edges ();
}
compute_function_frequency ();
- if (flag_reorder_functions)
- choose_function_section ();
}
/* Decide whether function is hot, cold or unlikely executed. */
compute_function_frequency (void)
{
basic_block bb;
- struct cgraph_node *node = cgraph_node (current_function_decl);
+ struct cgraph_node *node = cgraph_get_node (current_function_decl);
if (DECL_STATIC_CONSTRUCTOR (current_function_decl)
|| MAIN_NAME_P (DECL_NAME (current_function_decl)))
node->only_called_at_startup = true;
}
}
-/* Choose appropriate section for the function. */
-static void
-choose_function_section (void)
-{
- struct cgraph_node *node = cgraph_node (current_function_decl);
- 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 (node->frequency == NODE_FREQUENCY_HOT)
- DECL_SECTION_NAME (current_function_decl) =
- build_string (strlen (HOT_TEXT_SECTION_NAME), HOT_TEXT_SECTION_NAME);
- if (node->frequency == NODE_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)
{
build_predict_expr (enum br_predictor predictor, enum prediction taken)
{
tree t = build1 (PREDICT_EXPR, void_type_node,
- build_int_cst (NULL, predictor));
+ build_int_cst (integer_type_node, predictor));
SET_PREDICT_EXPR_OUTCOME (t, taken);
return t;
}
{
{
GIMPLE_PASS,
- "profile", /* name */
+ "profile_estimate", /* name */
gate_estimate_probability, /* gate */
tree_estimate_probability_driver, /* execute */
NULL, /* sub */
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