#include "config.h"
#include "system.h"
#include "tree.h"
#include "rtl.h"
#include "tm_p.h"
#include "hard-reg-set.h"
#include "basic-block.h"
#include "insn-config.h"
#include "regs.h"
#include "flags.h"
#include "output.h"
#include "function.h"
#include "except.h"
#include "toplev.h"
#include "recog.h"
#include "expr.h"
#include "predict.h"
#define PROB_NEVER (0)
#define PROB_VERY_UNLIKELY (REG_BR_PROB_BASE / 10 - 1)
#define PROB_UNLIKELY (REG_BR_PROB_BASE * 4 / 10 - 1)
#define PROB_EVEN (REG_BR_PROB_BASE / 2)
#define PROB_LIKELY (REG_BR_PROB_BASE - PROB_UNLIKELY)
#define PROB_VERY_LIKELY (REG_BR_PROB_BASE - PROB_VERY_UNLIKELY)
#define PROB_ALWAYS (REG_BR_PROB_BASE)
static void combine_predictions_for_insn PARAMS ((rtx, basic_block));
static void dump_prediction PARAMS ((enum br_predictor, int,
basic_block, int));
static void estimate_loops_at_level PARAMS ((struct loop *loop));
static void propagate_freq PARAMS ((basic_block));
static void estimate_bb_frequencies PARAMS ((struct loops *));
static void counts_to_freqs PARAMS ((void));
struct predictor_info
{
const char *const name;
const int hitrate;
const int flags;
};
#define PRED_FLAG_FIRST_MATCH 1
#define HITRATE(VAL) ((int) ((VAL) * REG_BR_PROB_BASE + 50) / 100)
#define DEF_PREDICTOR(ENUM, NAME, HITRATE, FLAGS) {NAME, HITRATE, FLAGS},
static const struct predictor_info predictor_info[]= {
#include "predict.def"
{NULL, 0, 0}
};
#undef DEF_PREDICTOR
void
predict_insn (insn, predictor, probability)
rtx insn;
int probability;
enum br_predictor predictor;
{
if (!any_condjump_p (insn))
abort ();
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));
}
void
predict_insn_def (insn, predictor, taken)
rtx insn;
enum br_predictor predictor;
enum prediction taken;
{
int probability = predictor_info[(int) predictor].hitrate;
if (taken != TAKEN)
probability = REG_BR_PROB_BASE - probability;
predict_insn (insn, predictor, probability);
}
void
predict_edge (e, predictor, probability)
edge e;
int probability;
enum br_predictor predictor;
{
rtx last_insn;
last_insn = e->src->end;
if (!any_condjump_p (last_insn))
return;
if (e->flags & EDGE_FALLTHRU)
probability = REG_BR_PROB_BASE - probability;
predict_insn (last_insn, predictor, probability);
}
void
predict_edge_def (e, predictor, taken)
edge e;
enum br_predictor predictor;
enum prediction taken;
{
int probability = predictor_info[(int) predictor].hitrate;
if (taken != TAKEN)
probability = REG_BR_PROB_BASE - probability;
predict_edge (e, predictor, probability);
}
void
invert_br_probabilities (insn)
rtx insn;
{
rtx note;
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
if (REG_NOTE_KIND (note) == REG_BR_PROB)
XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
else if (REG_NOTE_KIND (note) == REG_BR_PRED)
XEXP (XEXP (note, 0), 1)
= GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (XEXP (note, 0), 1)));
}
static void
dump_prediction (predictor, probability, bb, used)
enum br_predictor predictor;
int probability;
basic_block bb;
int used;
{
edge e = bb->succ;
if (!rtl_dump_file)
return;
while (e->flags & EDGE_FALLTHRU)
e = e->succ_next;
fprintf (rtl_dump_file, " %s heuristics%s: %.1f%%",
predictor_info[predictor].name,
used ? "" : " (ignored)", probability * 100.0 / REG_BR_PROB_BASE);
if (bb->count)
{
fprintf (rtl_dump_file, " exec ");
fprintf (rtl_dump_file, HOST_WIDEST_INT_PRINT_DEC, bb->count);
fprintf (rtl_dump_file, " hit ");
fprintf (rtl_dump_file, HOST_WIDEST_INT_PRINT_DEC, e->count);
fprintf (rtl_dump_file, " (%.1f%%)", e->count * 100.0 / bb->count);
}
fprintf (rtl_dump_file, "\n");
}
static void
combine_predictions_for_insn (insn, bb)
rtx insn;
basic_block bb;
{
rtx prob_note = find_reg_note (insn, REG_BR_PROB, 0);
rtx *pnote = ®_NOTES (insn);
rtx note;
int best_probability = PROB_EVEN;
int best_predictor = END_PREDICTORS;
int combined_probability = REG_BR_PROB_BASE / 2;
int d;
bool first_match = false;
bool found = false;
if (rtl_dump_file)
fprintf (rtl_dump_file, "Predictions for insn %i bb %i\n", INSN_UID (insn),
bb->index);
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));
int probability = INTVAL (XEXP (XEXP (note, 0), 1));
found = true;
if (best_predictor > predictor)
best_probability = probability, best_predictor = predictor;
d = (combined_probability * probability
+ (REG_BR_PROB_BASE - combined_probability)
* (REG_BR_PROB_BASE - probability));
if (d == 0)
combined_probability = REG_BR_PROB_BASE / 2;
else
combined_probability = (((double) combined_probability) * probability
* REG_BR_PROB_BASE / d + 0.5);
}
if (predictor_info [best_predictor].flags & PRED_FLAG_FIRST_MATCH)
first_match = true;
if (!found)
dump_prediction (PRED_NO_PREDICTION, combined_probability, bb, true);
else
{
dump_prediction (PRED_DS_THEORY, combined_probability, bb, !first_match);
dump_prediction (PRED_FIRST_MATCH, best_probability, bb, first_match);
}
if (first_match)
combined_probability = best_probability;
dump_prediction (PRED_COMBINED, combined_probability, bb, true);
while (*pnote)
{
if (REG_NOTE_KIND (*pnote) == REG_BR_PRED)
{
int predictor = INTVAL (XEXP (XEXP (*pnote, 0), 0));
int probability = INTVAL (XEXP (XEXP (*pnote, 0), 1));
dump_prediction (predictor, probability, bb,
!first_match || best_predictor == predictor);
*pnote = XEXP (*pnote, 1);
}
else
pnote = &XEXP (*pnote, 1);
}
if (!prob_note)
{
REG_NOTES (insn)
= gen_rtx_EXPR_LIST (REG_BR_PROB,
GEN_INT (combined_probability), REG_NOTES (insn));
if (bb->succ->succ_next)
{
BRANCH_EDGE (bb)->probability = combined_probability;
FALLTHRU_EDGE (bb)->probability
= REG_BR_PROB_BASE - combined_probability;
}
}
}
void
estimate_probability (loops_info)
struct loops *loops_info;
{
sbitmap *dominators, *post_dominators;
int i;
int found_noreturn = 0;
dominators = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
post_dominators = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
calculate_dominance_info (NULL, dominators, CDI_DOMINATORS);
calculate_dominance_info (NULL, post_dominators, CDI_POST_DOMINATORS);
for (i = 0; i < loops_info->num; i++)
{
int j;
int exits;
struct loop *loop = &loops_info->array[i];
flow_loop_scan (loops_info, loop, LOOP_EXIT_EDGES);
exits = loop->num_exits;
for (j = loop->first->index; j <= loop->last->index; ++j)
if (TEST_BIT (loop->nodes, j))
{
int header_found = 0;
edge e;
for (e = BASIC_BLOCK(j)->succ; e; e = e->succ_next)
if (e->dest == loop->header
&& e->src == loop->latch)
{
header_found = 1;
predict_edge_def (e, PRED_LOOP_BRANCH, TAKEN);
}
if (!header_found)
for (e = BASIC_BLOCK(j)->succ; e; e = e->succ_next)
if (e->dest->index < 0
|| !TEST_BIT (loop->nodes, e->dest->index))
predict_edge
(e, PRED_LOOP_EXIT,
(REG_BR_PROB_BASE
- predictor_info [(int) PRED_LOOP_EXIT].hitrate)
/ exits);
}
}
for (i = 0; i < n_basic_blocks; i++)
{
basic_block bb = BASIC_BLOCK (i);
rtx last_insn = bb->end;
rtx cond, earliest;
edge e;
if (bb->succ == NULL && !found_noreturn)
{
int y;
found_noreturn = 1;
for (y = 0; y < n_basic_blocks; y++)
if (!TEST_BIT (post_dominators[y], i))
for (e = BASIC_BLOCK (y)->succ; e; e = e->succ_next)
if (e->dest->index >= 0
&& TEST_BIT (post_dominators[e->dest->index], i))
predict_edge_def (e, PRED_NORETURN, NOT_TAKEN);
}
if (GET_CODE (last_insn) != JUMP_INSN || ! any_condjump_p (last_insn))
continue;
for (e = bb->succ; e; e = e->succ_next)
{
if (e->dest == EXIT_BLOCK_PTR
|| (e->dest->succ && !e->dest->succ->succ_next
&& e->dest->succ->dest == EXIT_BLOCK_PTR))
predict_edge_def (e, PRED_ERROR_RETURN, NOT_TAKEN);
if (e->dest != EXIT_BLOCK_PTR && e->dest != bb
&& TEST_BIT (dominators[e->dest->index], e->src->index)
&& !TEST_BIT (post_dominators[e->src->index], e->dest->index))
{
rtx insn;
for (insn = e->dest->head; insn != NEXT_INSN (e->dest->end);
insn = NEXT_INSN (insn))
if (GET_CODE (insn) == CALL_INSN
&& ! CONST_OR_PURE_CALL_P (insn))
{
predict_edge_def (e, PRED_CALL, NOT_TAKEN);
break;
}
}
}
cond = get_condition (last_insn, &earliest);
if (! cond)
continue;
if (GET_RTX_CLASS (GET_CODE (cond)) == '<'
&& ((REG_P (XEXP (cond, 0)) && REG_POINTER (XEXP (cond, 0)))
|| (REG_P (XEXP (cond, 1)) && REG_POINTER (XEXP (cond, 1)))))
{
if (GET_CODE (cond) == EQ)
predict_insn_def (last_insn, PRED_POINTER, NOT_TAKEN);
else if (GET_CODE (cond) == NE)
predict_insn_def (last_insn, PRED_POINTER, TAKEN);
}
else
switch (GET_CODE (cond))
{
case CONST_INT:
predict_insn_def (last_insn, PRED_UNCONDITIONAL,
cond == const0_rtx ? NOT_TAKEN : TAKEN);
break;
case EQ:
case UNEQ:
if (FLOAT_MODE_P (GET_MODE (XEXP (cond, 0))))
;
else if (XEXP (cond, 1) == const0_rtx
|| XEXP (cond, 0) == const0_rtx)
;
else
predict_insn_def (last_insn, PRED_OPCODE_NONEQUAL, NOT_TAKEN);
break;
case NE:
case LTGT:
if (FLOAT_MODE_P (GET_MODE (XEXP (cond, 0))))
;
else if (XEXP (cond, 1) == const0_rtx
|| XEXP (cond, 0) == const0_rtx)
;
else
predict_insn_def (last_insn, PRED_OPCODE_NONEQUAL, TAKEN);
break;
case ORDERED:
predict_insn_def (last_insn, PRED_FPOPCODE, TAKEN);
break;
case UNORDERED:
predict_insn_def (last_insn, PRED_FPOPCODE, NOT_TAKEN);
break;
case LE:
case LT:
if (XEXP (cond, 1) == const0_rtx || XEXP (cond, 1) == const1_rtx
|| XEXP (cond, 1) == constm1_rtx)
predict_insn_def (last_insn, PRED_OPCODE_POSITIVE, NOT_TAKEN);
break;
case GE:
case GT:
if (XEXP (cond, 1) == const0_rtx || XEXP (cond, 1) == const1_rtx
|| XEXP (cond, 1) == constm1_rtx)
predict_insn_def (last_insn, PRED_OPCODE_POSITIVE, TAKEN);
break;
default:
break;
}
}
for (i = 0; i < n_basic_blocks; i++)
if (GET_CODE (BLOCK_END (i)) == JUMP_INSN
&& any_condjump_p (BLOCK_END (i)))
combine_predictions_for_insn (BLOCK_END (i), BASIC_BLOCK (i));
sbitmap_vector_free (post_dominators);
sbitmap_vector_free (dominators);
estimate_bb_frequencies (loops_info);
}
void
expected_value_to_br_prob ()
{
rtx insn, cond, ev = NULL_RTX, ev_reg = NULL_RTX;
for (insn = get_insns (); insn ; insn = NEXT_INSN (insn))
{
switch (GET_CODE (insn))
{
case NOTE:
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EXPECTED_VALUE)
{
ev = NOTE_EXPECTED_VALUE (insn);
ev_reg = XEXP (ev, 0);
delete_insn (insn);
}
continue;
case CODE_LABEL:
ev = NULL_RTX;
continue;
case JUMP_INSN:
if (GET_CODE (insn) != JUMP_INSN || ev == NULL_RTX
|| ! any_condjump_p (insn))
continue;
break;
default:
if (ev && reg_set_p (ev_reg, insn))
ev = NULL_RTX;
continue;
}
cond = XEXP (SET_SRC (pc_set (insn)), 0);
cond = canonicalize_condition (insn, cond, 0, NULL, ev_reg);
if (! cond || XEXP (cond, 0) != ev_reg
|| GET_CODE (XEXP (cond, 1)) != CONST_INT)
continue;
cond = gen_rtx_fmt_ee (GET_CODE (cond), VOIDmode,
XEXP (ev, 1), XEXP (cond, 1));
cond = simplify_rtx (cond);
if (cond != const_true_rtx && cond != const0_rtx)
abort ();
predict_insn_def (insn, PRED_BUILTIN_EXPECT,
cond == const_true_rtx ? TAKEN : NOT_TAKEN);
}
}
typedef struct block_info_def
{
volatile double frequency;
basic_block next;
int tovisit:1;
int npredecessors;
} *block_info;
typedef struct edge_info_def
{
volatile double back_edge_prob;
int back_edge:1;
} *edge_info;
#define BLOCK_INFO(B) ((block_info) (B)->aux)
#define EDGE_INFO(E) ((edge_info) (E)->aux)
static void
propagate_freq (head)
basic_block head;
{
basic_block bb = head;
basic_block last = bb;
edge e;
basic_block nextbb;
int n;
for (n = 0; n < n_basic_blocks; n++)
{
basic_block bb = BASIC_BLOCK (n);
if (BLOCK_INFO (bb)->tovisit)
{
int count = 0;
for (e = bb->pred; e; e = e->pred_next)
if (BLOCK_INFO (e->src)->tovisit && !(e->flags & EDGE_DFS_BACK))
count++;
else if (BLOCK_INFO (e->src)->tovisit
&& rtl_dump_file && !EDGE_INFO (e)->back_edge)
fprintf (rtl_dump_file,
"Irreducible region hit, ignoring edge to %i->%i\n",
e->src->index, bb->index);
BLOCK_INFO (bb)->npredecessors = count;
}
}
BLOCK_INFO (head)->frequency = 1;
for (; bb; bb = nextbb)
{
double cyclic_probability = 0, frequency = 0;
nextbb = BLOCK_INFO (bb)->next;
BLOCK_INFO (bb)->next = NULL;
if (bb != head)
{
#ifdef ENABLE_CHECKING
for (e = bb->pred; e; e = e->pred_next)
if (BLOCK_INFO (e->src)->tovisit && !(e->flags & EDGE_DFS_BACK))
abort ();
#endif
for (e = bb->pred; e; e = e->pred_next)
if (EDGE_INFO (e)->back_edge)
cyclic_probability += EDGE_INFO (e)->back_edge_prob;
else if (!(e->flags & EDGE_DFS_BACK))
frequency += (e->probability
* BLOCK_INFO (e->src)->frequency /
REG_BR_PROB_BASE);
if (cyclic_probability > 1.0 - 1.0 / REG_BR_PROB_BASE)
cyclic_probability = 1.0 - 1.0 / REG_BR_PROB_BASE;
BLOCK_INFO (bb)->frequency = frequency / (1 - cyclic_probability);
}
BLOCK_INFO (bb)->tovisit = 0;
for (e = bb->succ; e; e = e->succ_next)
if (e->dest == head)
EDGE_INFO (e)->back_edge_prob
= ((e->probability * BLOCK_INFO (bb)->frequency)
/ REG_BR_PROB_BASE);
for (e = bb->succ; e; e = e->succ_next)
if (!(e->flags & EDGE_DFS_BACK)
&& BLOCK_INFO (e->dest)->npredecessors)
{
BLOCK_INFO (e->dest)->npredecessors--;
if (!BLOCK_INFO (e->dest)->npredecessors)
{
if (!nextbb)
nextbb = e->dest;
else
BLOCK_INFO (last)->next = e->dest;
last = e->dest;
}
}
}
}
static void
estimate_loops_at_level (first_loop)
struct loop *first_loop;
{
struct loop *l, *loop = first_loop;
for (loop = first_loop; loop; loop = loop->next)
{
int n;
edge e;
estimate_loops_at_level (loop->inner);
for (e = loop->latch->succ; e->dest != loop->header; e = e->succ_next)
;
EDGE_INFO (e)->back_edge = 1;
if (loop->shared)
{
for (l = loop->next; l; l = l->next)
if (l->header == loop->header)
break;
if (l)
continue;
}
for (l = loop->shared ? first_loop : loop; l != loop->next; l = l->next)
if (loop->header == l->header)
EXECUTE_IF_SET_IN_SBITMAP (l->nodes, 0, n,
BLOCK_INFO (BASIC_BLOCK (n))->tovisit = 1
);
propagate_freq (loop->header);
}
}
static void
counts_to_freqs ()
{
HOST_WIDEST_INT count_max = 1;
int i;
for (i = 0; i < n_basic_blocks; i++)
count_max = MAX (BASIC_BLOCK (i)->count, count_max);
for (i = -2; i < n_basic_blocks; i++)
{
basic_block bb;
if (i == -2)
bb = ENTRY_BLOCK_PTR;
else if (i == -1)
bb = EXIT_BLOCK_PTR;
else
bb = BASIC_BLOCK (i);
bb->frequency = (bb->count * BB_FREQ_MAX + count_max / 2) / count_max;
}
}
bool
expensive_function_p (threshold)
int threshold;
{
unsigned int sum = 0;
int i;
unsigned int limit;
if (threshold > BB_FREQ_MAX)
abort ();
if (ENTRY_BLOCK_PTR->frequency == 0)
return true;
limit = ENTRY_BLOCK_PTR->frequency * threshold;
for (i = 0; i < n_basic_blocks; i++)
{
basic_block bb = BASIC_BLOCK (i);
rtx insn;
for (insn = bb->head; insn != NEXT_INSN (bb->end);
insn = NEXT_INSN (insn))
if (active_insn_p (insn))
{
sum += bb->frequency;
if (sum > limit)
return true;
}
}
return false;
}
static void
estimate_bb_frequencies (loops)
struct loops *loops;
{
int i;
double freq_max = 0;
mark_dfs_back_edges ();
if (flag_branch_probabilities)
{
counts_to_freqs ();
return;
}
for (i = 0; i < n_basic_blocks; i++)
{
rtx last_insn = BLOCK_END (i);
int probability;
edge fallthru, branch;
if (GET_CODE (last_insn) != JUMP_INSN || !any_condjump_p (last_insn)
|| BASIC_BLOCK (i)->succ->succ_next == NULL)
{
int nedges = 0;
edge e;
for (e = BASIC_BLOCK (i)->succ; e; e = e->succ_next)
{
nedges++;
if (e->probability != 0)
break;
}
if (!e)
for (e = BASIC_BLOCK (i)->succ; e; e = e->succ_next)
e->probability = (REG_BR_PROB_BASE + nedges / 2) / nedges;
}
else
{
probability = INTVAL (XEXP (find_reg_note (last_insn,
REG_BR_PROB, 0), 0));
fallthru = BASIC_BLOCK (i)->succ;
if (!fallthru->flags & EDGE_FALLTHRU)
fallthru = fallthru->succ_next;
branch = BASIC_BLOCK (i)->succ;
if (branch->flags & EDGE_FALLTHRU)
branch = branch->succ_next;
branch->probability = probability;
fallthru->probability = REG_BR_PROB_BASE - probability;
}
}
ENTRY_BLOCK_PTR->succ->probability = REG_BR_PROB_BASE;
alloc_aux_for_blocks (sizeof (struct block_info_def));
alloc_aux_for_edges (sizeof (struct edge_info_def));
for (i = -2; i < n_basic_blocks; i++)
{
edge e;
basic_block bb;
if (i == -2)
bb = ENTRY_BLOCK_PTR;
else if (i == -1)
bb = EXIT_BLOCK_PTR;
else
bb = BASIC_BLOCK (i);
BLOCK_INFO (bb)->tovisit = 0;
for (e = bb->succ; e; e = e->succ_next)
EDGE_INFO (e)->back_edge_prob = ((double) e->probability
/ REG_BR_PROB_BASE);
}
estimate_loops_at_level (loops->tree_root);
for (i = 0; i < n_basic_blocks; i++)
BLOCK_INFO (BASIC_BLOCK (i))->tovisit = 1;
BLOCK_INFO (ENTRY_BLOCK_PTR)->tovisit = 1;
BLOCK_INFO (EXIT_BLOCK_PTR)->tovisit = 1;
propagate_freq (ENTRY_BLOCK_PTR);
for (i = 0; i < n_basic_blocks; i++)
if (BLOCK_INFO (BASIC_BLOCK (i))->frequency > freq_max)
freq_max = BLOCK_INFO (BASIC_BLOCK (i))->frequency;
for (i = -2; i < n_basic_blocks; i++)
{
basic_block bb;
volatile double tmp;
if (i == -2)
bb = ENTRY_BLOCK_PTR;
else if (i == -1)
bb = EXIT_BLOCK_PTR;
else
bb = BASIC_BLOCK (i);
tmp = BLOCK_INFO (bb)->frequency * BB_FREQ_MAX;
tmp /= freq_max;
tmp += 0.5;
bb->frequency = tmp;
}
free_aux_for_blocks ();
free_aux_for_edges ();
}