X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Fpredict.c;h=0cf6b9606bc3b5355f10218db4495f6f328f36ee;hb=82b5b12f979a9a3a3b90aea311fc6941a6c19fa8;hp=c59e57b0c5ea5eab03d08cca43b57d8aa99de740;hpb=2a1990e9c656063ab626fab258ae2d418378c76d;p=pf3gnuchains%2Fgcc-fork.git diff --git a/gcc/predict.c b/gcc/predict.c index c59e57b0c5e..0cf6b9606bc 100644 --- a/gcc/predict.c +++ b/gcc/predict.c @@ -1,12 +1,12 @@ /* Branch prediction routines for the GNU compiler. - Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005 + Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free -Software Foundation; either version 2, or (at your option) any later +Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY @@ -15,9 +15,8 @@ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. 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, 51 Franklin Street, Fifth Floor, Boston, MA -02110-1301, USA. */ +along with GCC; see the file COPYING3. If not see +. */ /* References: @@ -60,6 +59,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA #include "timevar.h" #include "tree-scalar-evolution.h" #include "cfgloop.h" +#include "pointer-set.h" /* real constants: 0, 1, 1-1/REG_BR_PROB_BASE, REG_BR_PROB_BASE, 1/REG_BR_PROB_BASE, 0.5, BB_FREQ_MAX. */ @@ -74,14 +74,10 @@ static sreal real_zero, real_one, real_almost_one, real_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 *, 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); static void compute_function_frequency (void); static void choose_function_section (void); -static bool can_predict_insn_p (rtx); +static bool can_predict_insn_p (const_rtx); /* Information we hold about each branch predictor. Filled using information from predict.def. */ @@ -115,12 +111,19 @@ static const struct predictor_info predictor_info[]= { for maximal performance. */ bool -maybe_hot_bb_p (basic_block bb) +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_info || !flag_branch_probabilities) + { + if (cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED) + return false; + if (cfun->function_frequency == FUNCTION_FREQUENCY_HOT) + return true; + } if (bb->frequency < BB_FREQ_MAX / PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION)) return false; return true; @@ -129,12 +132,15 @@ maybe_hot_bb_p (basic_block bb) /* Return true in case BB is cold and should be optimized for size. */ bool -probably_cold_bb_p (basic_block bb) +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; @@ -142,10 +148,13 @@ probably_cold_bb_p (basic_block bb) /* Return true in case BB is probably never executed. */ bool -probably_never_executed_bb_p (basic_block bb) +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) + && cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED) + return true; return false; } @@ -153,7 +162,7 @@ probably_never_executed_bb_p (basic_block bb) PREDICTOR. */ bool -rtl_predicted_by_p (basic_block bb, enum br_predictor predictor) +rtl_predicted_by_p (const_basic_block bb, enum br_predictor predictor) { rtx note; if (!INSN_P (BB_END (bb))) @@ -165,19 +174,68 @@ rtl_predicted_by_p (basic_block bb, enum br_predictor predictor) return false; } +/* This map contains for a basic block the list of predictions for the + outgoing edges. */ + +static struct pointer_map_t *bb_predictions; + /* Return true if the one of outgoing edges is already predicted by PREDICTOR. */ bool -tree_predicted_by_p (basic_block bb, enum br_predictor predictor) +tree_predicted_by_p (const_basic_block bb, enum br_predictor predictor) { struct edge_prediction *i; - for (i = bb->predictions; i; i = i->ep_next) + void **preds = pointer_map_contains (bb_predictions, bb); + + if (!preds) + return false; + + for (i = *preds; i; i = i->ep_next) if (i->ep_predictor == predictor) return true; return false; } +/* Return true when the probability of edge is reliable. + + The profile guessing code is good at predicting branch outcome (ie. + taken/not taken), that is predicted right slightly over 75% of time. + It is however notoriously poor on predicting the probability itself. + In general the profile appear a lot flatter (with probabilities closer + to 50%) than the reality so it is bad idea to use it to drive optimization + such as those disabling dynamic branch prediction for well predictable + branches. + + There are two exceptions - edges leading to noreturn edges and edges + predicted by number of iterations heuristics are predicted well. This macro + should be able to distinguish those, but at the moment it simply check for + noreturn heuristic that is only one giving probability over 99% or bellow + 1%. In future we might want to propagate reliability information across the + CFG if we find this information useful on multiple places. */ +static bool +probability_reliable_p (int prob) +{ + return (profile_status == PROFILE_READ + || (profile_status == PROFILE_GUESSED + && (prob <= HITRATE (1) || prob >= HITRATE (99)))); +} + +/* Same predicate as above, working on edges. */ +bool +edge_probability_reliable_p (const_edge e) +{ + return probability_reliable_p (e->probability); +} + +/* Same predicate as edge_probability_reliable_p, working on notes. */ +bool +br_prob_note_reliable_p (const_rtx note) +{ + gcc_assert (REG_NOTE_KIND (note) == REG_BR_PROB); + return probability_reliable_p (INTVAL (XEXP (note, 0))); +} + static void predict_insn (rtx insn, enum br_predictor predictor, int probability) { @@ -235,10 +293,11 @@ tree_predict_edge (edge e, enum br_predictor predictor, int probability) 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)); + struct edge_prediction *i = XNEW (struct edge_prediction); + void **preds = pointer_map_insert (bb_predictions, e->src); - i->ep_next = e->src->predictions; - e->src->predictions = i; + i->ep_next = *preds; + *preds = i; i->ep_probability = probability; i->ep_predictor = predictor; i->ep_edge = e; @@ -250,24 +309,56 @@ tree_predict_edge (edge e, enum br_predictor predictor, int probability) void remove_predictions_associated_with_edge (edge e) { - if (e->src->predictions) + void **preds; + + if (!bb_predictions) + return; + + preds = pointer_map_contains (bb_predictions, e->src); + + if (preds) { - struct edge_prediction **prediction = &e->src->predictions; + struct edge_prediction **prediction = (struct edge_prediction **) preds; + struct edge_prediction *next; + while (*prediction) { if ((*prediction)->ep_edge == e) - *prediction = (*prediction)->ep_next; + { + next = (*prediction)->ep_next; + free (*prediction); + *prediction = next; + } else prediction = &((*prediction)->ep_next); } } } +/* Clears the list of predictions stored for BB. */ + +static void +clear_bb_predictions (basic_block bb) +{ + void **preds = pointer_map_contains (bb_predictions, bb); + struct edge_prediction *pred, *next; + + if (!preds) + return; + + for (pred = *preds; pred; pred = next) + { + next = pred->ep_next; + free (pred); + } + *preds = NULL; +} + /* Return true when we can store prediction on insn INSN. At the moment we represent predictions only on conditional jumps, not at computed jump or other complicated cases. */ static bool -can_predict_insn_p (rtx insn) +can_predict_insn_p (const_rtx insn) { return (JUMP_P (insn) && any_condjump_p (insn) @@ -490,6 +581,7 @@ combine_predictions_for_bb (basic_block bb) int nedges = 0; edge e, first = NULL, second = NULL; edge_iterator ei; + void **preds; FOR_EACH_EDGE (e, ei, bb->succs) if (!(e->flags & (EDGE_EH | EDGE_FAKE))) @@ -511,7 +603,7 @@ combine_predictions_for_bb (basic_block bb) { if (!bb->count) set_even_probabilities (bb); - bb->predictions = NULL; + clear_bb_predictions (bb); if (dump_file) fprintf (dump_file, "%i edges in bb %i predicted to even probabilities\n", nedges, bb->index); @@ -521,31 +613,36 @@ combine_predictions_for_bb (basic_block bb) 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->predictions; pred; pred = pred->ep_next) + preds = pointer_map_contains (bb_predictions, bb); + if (preds) { - int predictor = pred->ep_predictor; - int probability = pred->ep_probability; + /* We implement "first match" heuristics and use probability guessed + by predictor with smallest index. */ + for (pred = *preds; pred; pred = pred->ep_next) + { + int predictor = pred->ep_predictor; + int probability = pred->ep_probability; - if (pred->ep_edge != first) - probability = REG_BR_PROB_BASE - probability; + if (pred->ep_edge != first) + probability = REG_BR_PROB_BASE - probability; - found = true; - if (best_predictor > predictor) - best_probability = probability, best_predictor = predictor; + 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)); + d = (combined_probability * probability + + (REG_BR_PROB_BASE - combined_probability) + * (REG_BR_PROB_BASE - probability)); - /* Use FP math to avoid overflows of 32bit integers. */ - if (d == 0) - /* If one probability is 0% and one 100%, avoid division by zero. */ - combined_probability = REG_BR_PROB_BASE / 2; - else - combined_probability = (((double) combined_probability) * probability - * REG_BR_PROB_BASE / d + 0.5); + /* Use FP math to avoid overflows of 32bit integers. */ + if (d == 0) + /* If one probability is 0% and one 100%, avoid division by zero. */ + combined_probability = REG_BR_PROB_BASE / 2; + else + combined_probability = (((double) combined_probability) + * probability + * REG_BR_PROB_BASE / d + 0.5); + } } /* Decide which heuristic to use. In case we didn't match anything, @@ -569,17 +666,20 @@ combine_predictions_for_bb (basic_block bb) combined_probability = best_probability; dump_prediction (dump_file, PRED_COMBINED, combined_probability, bb, true); - for (pred = bb->predictions; pred; pred = pred->ep_next) + if (preds) { - int predictor = pred->ep_predictor; - int probability = pred->ep_probability; + for (pred = *preds; pred; pred = pred->ep_next) + { + int predictor = pred->ep_predictor; + int probability = pred->ep_probability; - if (pred->ep_edge != EDGE_SUCC (bb, 0)) - probability = REG_BR_PROB_BASE - probability; - dump_prediction (dump_file, predictor, probability, bb, - !first_match || best_predictor == predictor); + if (pred->ep_edge != EDGE_SUCC (bb, 0)) + probability = REG_BR_PROB_BASE - probability; + dump_prediction (dump_file, predictor, probability, bb, + !first_match || best_predictor == predictor); + } } - bb->predictions = NULL; + clear_bb_predictions (bb); if (!bb->count) { @@ -588,90 +688,71 @@ combine_predictions_for_bb (basic_block bb) } } -/* Predict edge probabilities by exploiting loop structure. - When RTLSIMPLELOOPS is set, attempt to count number of iterations by analyzing - RTL otherwise use tree based approach. */ +/* Predict edge probabilities by exploiting loop structure. */ + static void -predict_loops (struct loops *loops_info, bool rtlsimpleloops) +predict_loops (void) { - unsigned i; + loop_iterator li; + struct loop *loop; - if (!rtlsimpleloops) - scev_initialize (loops_info); + scev_initialize (); /* Try to predict out blocks in a loop that are not part of a natural loop. */ - for (i = 1; i < loops_info->num; i++) + FOR_EACH_LOOP (li, loop, 0) { basic_block bb, *bbs; - unsigned j; - unsigned n_exits; - struct loop *loop = loops_info->parray[i]; - struct niter_desc desc; - unsigned HOST_WIDE_INT niter; - edge *exits; + unsigned j, n_exits; + VEC (edge, heap) *exits; + struct tree_niter_desc niter_desc; + edge ex; - exits = get_loop_exit_edges (loop, &n_exits); + exits = get_loop_exit_edges (loop); + n_exits = VEC_length (edge, exits); - if (rtlsimpleloops) + for (j = 0; VEC_iterate (edge, exits, j, ex); j++) { - iv_analysis_loop_init (loop); - find_simple_exit (loop, &desc); - - if (desc.simple_p && desc.const_iter) + tree niter = NULL; + HOST_WIDE_INT nitercst; + int max = PARAM_VALUE (PARAM_MAX_PREDICTED_ITERATIONS); + int probability; + enum br_predictor predictor; + + if (number_of_iterations_exit (loop, ex, &niter_desc, false)) + niter = niter_desc.niter; + if (!niter || TREE_CODE (niter_desc.niter) != INTEGER_CST) + niter = loop_niter_by_eval (loop, ex); + + if (TREE_CODE (niter) == INTEGER_CST) { - int prob; - 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); - /* Branch prediction algorithm gives 0 frequency for everything - after the end of loop for loop having 0 probability to finish. */ - if (prob == REG_BR_PROB_BASE) - prob = REG_BR_PROB_BASE - 1; - predict_edge (desc.in_edge, PRED_LOOP_ITERATIONS, - prob); + if (host_integerp (niter, 1) + && compare_tree_int (niter, max-1) == -1) + nitercst = tree_low_cst (niter, 1) + 1; + else + nitercst = max; + predictor = PRED_LOOP_ITERATIONS; } - } - else - { - struct tree_niter_desc niter_desc; - - for (j = 0; j < n_exits; j++) + /* If we have just one exit and we can derive some information about + the number of iterations of the loop from the statements inside + the loop, use it to predict this exit. */ + else if (n_exits == 1) { - tree niter = NULL; - - 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, max - 1))) - { - HOST_WIDE_INT nitercst = tree_low_cst (niter, 1) + 1; - probability = ((REG_BR_PROB_BASE + nitercst / 2) - / nitercst); - } - else - probability = ((REG_BR_PROB_BASE + max / 2) / max); + nitercst = estimated_loop_iterations_int (loop, false); + if (nitercst < 0) + continue; + if (nitercst > max) + nitercst = max; - predict_edge (exits[j], PRED_LOOP_ITERATIONS, probability); - } + predictor = PRED_LOOP_ITERATIONS_GUESSED; } + else + continue; + probability = ((REG_BR_PROB_BASE + nitercst / 2) / nitercst); + predict_edge (ex, predictor, probability); } - free (exits); + VEC_free (edge, heap, exits); bbs = get_loop_body (loop); @@ -687,8 +768,7 @@ predict_loops (struct loops *loops_info, bool rtlsimpleloops) statements construct loops via "non-loop" constructs in the source language and are better to be handled separately. */ - if ((rtlsimpleloops && !can_predict_insn_p (BB_END (bb))) - || predicted_by_p (bb, PRED_CONTINUE)) + if (predicted_by_p (bb, PRED_CONTINUE)) continue; /* Loop branch heuristics - predict an edge back to a @@ -705,26 +785,43 @@ predict_loops (struct loops *loops_info, bool rtlsimpleloops) /* 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 < 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) - / n_exits); + if (!header_found + /* If we already used more reliable loop exit predictors, do not + bother with PRED_LOOP_EXIT. */ + && !predicted_by_p (bb, PRED_LOOP_ITERATIONS_GUESSED) + && !predicted_by_p (bb, PRED_LOOP_ITERATIONS)) + { + /* For loop with many exits we don't want to predict all exits + with the pretty large probability, because if all exits are + considered in row, the loop would be predicted to iterate + almost never. The code to divide probability by number of + exits is very rough. It should compute the number of exits + taken in each patch through function (not the overall number + of exits that might be a lot higher for loops with wide switch + statements in them) and compute n-th square root. + + We limit the minimal probability by 2% to avoid + EDGE_PROBABILITY_RELIABLE from trusting the branch prediction + as this was causing regression in perl benchmark containing such + a wide loop. */ + + int probability = ((REG_BR_PROB_BASE + - predictor_info [(int) PRED_LOOP_EXIT].hitrate) + / n_exits); + if (probability < HITRATE (2)) + probability = HITRATE (2); + FOR_EACH_EDGE (e, ei, bb->succs) + if (e->dest->index < NUM_FIXED_BLOCKS + || !flow_bb_inside_loop_p (loop, e->dest)) + predict_edge (e, PRED_LOOP_EXIT, probability); + } } /* Free basic blocks from get_loop_body. */ free (bbs); } - if (!rtlsimpleloops) - { - scev_finalize (); - current_loops = NULL; - } + scev_finalize (); } /* Attempt to predict probabilities of BB outgoing edges using local @@ -826,85 +923,6 @@ bb_estimate_probability_locally (basic_block bb) } } -/* Statically estimate the probability that a branch will be taken and produce - estimated profile. When profile feedback is present never executed portions - of function gets estimated. */ - -void -estimate_probability (struct loops *loops_info) -{ - basic_block bb; - - connect_infinite_loops_to_exit (); - calculate_dominance_info (CDI_DOMINATORS); - calculate_dominance_info (CDI_POST_DOMINATORS); - - predict_loops (loops_info, true); - - iv_analysis_done (); - - /* Attempt to predict conditional jumps using a number of heuristics. */ - FOR_EACH_BB (bb) - { - rtx last_insn = BB_END (bb); - edge e; - edge_iterator ei; - - if (! can_predict_insn_p (last_insn)) - continue; - - FOR_EACH_EDGE (e, ei, bb->succs) - { - /* Predict early returns to be probable, as we've already taken - care for error returns and other are often used for fast paths - trought function. */ - if ((e->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) - && !last_basic_block_p (e->dest)) - predict_edge_def (e, PRED_EARLY_RETURN, TAKEN); - - /* Look for block we are guarding (i.e. we dominate it, - but it doesn't postdominate us). */ - if (e->dest != EXIT_BLOCK_PTR && e->dest != bb - && dominated_by_p (CDI_DOMINATORS, e->dest, e->src) - && !dominated_by_p (CDI_POST_DOMINATORS, e->src, e->dest)) - { - rtx insn; - - /* The call heuristic claims that a guarded function call - is improbable. This is because such calls are often used - to signal exceptional situations such as printing error - messages. */ - for (insn = BB_HEAD (e->dest); insn != NEXT_INSN (BB_END (e->dest)); - insn = NEXT_INSN (insn)) - if (CALL_P (insn) - /* Constant and pure calls are hardly used to signalize - something exceptional. */ - && ! CONST_OR_PURE_CALL_P (insn)) - { - predict_edge_def (e, PRED_CALL, NOT_TAKEN); - break; - } - } - } - bb_estimate_probability_locally (bb); - } - - /* Attach the combined probability to each conditional jump. */ - FOR_EACH_BB (bb) - combine_predictions_for_insn (BB_END (bb), bb); - - remove_fake_edges (); - estimate_bb_frequencies (loops_info); - free_dominance_info (CDI_POST_DOMINATORS); - if (profile_status == PROFILE_ABSENT) - profile_status = PROFILE_GUESSED; -} - /* Set edge->probability for each successor edge of BB. */ void guess_outgoing_edge_probabilities (basic_block bb) @@ -965,9 +983,10 @@ expr_expected_value (tree expr, bitmap visited) } return val; } - if (TREE_CODE (def) != MODIFY_EXPR || TREE_OPERAND (def, 0) != expr) + if (TREE_CODE (def) != GIMPLE_MODIFY_STMT + || GIMPLE_STMT_OPERAND (def, 0) != expr) return NULL; - return expr_expected_value (TREE_OPERAND (def, 1), visited); + return expr_expected_value (GIMPLE_STMT_OPERAND (def, 1), visited); } else if (TREE_CODE (expr) == CALL_EXPR) { @@ -977,16 +996,14 @@ expr_expected_value (tree expr, bitmap visited) 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 (arglist == NULL_TREE - || TREE_CHAIN (arglist) == NULL_TREE) - return NULL; - val = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (expr, 1))); + if (call_expr_nargs (expr) != 2) + return NULL; + val = CALL_EXPR_ARG (expr, 0); if (TREE_CONSTANT (val)) return val; - return TREE_VALUE (TREE_CHAIN (TREE_OPERAND (expr, 1))); + return CALL_EXPR_ARG (expr, 1); } } if (BINARY_CLASS_P (expr) || COMPARISON_CLASS_P (expr)) @@ -1029,17 +1046,17 @@ strip_builtin_expect (void) { tree stmt = bsi_stmt (bi); tree fndecl; - tree arglist; + tree call; - if (TREE_CODE (stmt) == MODIFY_EXPR - && TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR - && (fndecl = get_callee_fndecl (TREE_OPERAND (stmt, 1))) + if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT + && (call = GIMPLE_STMT_OPERAND (stmt, 1)) + && TREE_CODE (call) == CALL_EXPR + && (fndecl = get_callee_fndecl (call)) && 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)) + && call_expr_nargs (call) == 2) { - TREE_OPERAND (stmt, 1) = TREE_VALUE (arglist); + GIMPLE_STMT_OPERAND (stmt, 1) = CALL_EXPR_ARG (call, 0); update_stmt (stmt); } } @@ -1199,7 +1216,7 @@ return_prediction (tree val, enum prediction *prediction) && (!integer_zerop (val) && !integer_onep (val))) { *prediction = TAKEN; - return PRED_NEGATIVE_RETURN; + return PRED_CONST_RETURN; } } return PRED_NO_PREDICTION; @@ -1222,7 +1239,8 @@ apply_return_prediction (int *heads) FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds) { return_stmt = last_stmt (e->src); - if (TREE_CODE (return_stmt) == RETURN_EXPR) + if (return_stmt + && TREE_CODE (return_stmt) == RETURN_EXPR) break; } if (!e) @@ -1230,8 +1248,8 @@ apply_return_prediction (int *heads) return_val = TREE_OPERAND (return_stmt, 0); if (!return_val) return; - if (TREE_CODE (return_val) == MODIFY_EXPR) - return_val = TREE_OPERAND (return_val, 1); + if (TREE_CODE (return_val) == GIMPLE_MODIFY_STMT) + return_val = GIMPLE_STMT_OPERAND (return_val, 1); if (TREE_CODE (return_val) != SSA_NAME || !SSA_NAME_DEF_STMT (return_val) || TREE_CODE (SSA_NAME_DEF_STMT (return_val)) != PHI_NODE) @@ -1270,8 +1288,7 @@ tree_bb_level_predictions (void) basic_block bb; int *heads; - heads = XNEWVEC (int, last_basic_block); - memset (heads, ENTRY_BLOCK, sizeof (int) * last_basic_block); + heads = XCNEWVEC (int, last_basic_block); heads[ENTRY_BLOCK_PTR->next_bb->index] = last_basic_block; apply_return_prediction (heads); @@ -1283,12 +1300,13 @@ tree_bb_level_predictions (void) for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) { tree stmt = bsi_stmt (bsi); + tree decl; switch (TREE_CODE (stmt)) { - case MODIFY_EXPR: - if (TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR) + case GIMPLE_MODIFY_STMT: + if (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == CALL_EXPR) { - stmt = TREE_OPERAND (stmt, 1); + stmt = GIMPLE_STMT_OPERAND (stmt, 1); goto call_expr; } break; @@ -1297,6 +1315,12 @@ call_expr:; if (call_expr_flags (stmt) & ECF_NORETURN) predict_paths_leading_to (bb, heads, PRED_NORETURN, NOT_TAKEN); + decl = get_callee_fndecl (stmt); + if (decl + && lookup_attribute ("cold", + DECL_ATTRIBUTES (decl))) + predict_paths_leading_to (bb, heads, PRED_COLD_FUNCTION, + NOT_TAKEN); break; default: break; @@ -1307,26 +1331,44 @@ call_expr:; free (heads); } +#ifdef ENABLE_CHECKING + +/* Callback for pointer_map_traverse, asserts that the pointer map is + empty. */ + +static bool +assert_is_empty (const void *key ATTRIBUTE_UNUSED, void **value, + void *data ATTRIBUTE_UNUSED) +{ + gcc_assert (!*value); + return false; +} +#endif + /* Predict branch probabilities and estimate profile of the tree CFG. */ static unsigned int tree_estimate_probability (void) { basic_block bb; - struct loops loops_info; - flow_loops_find (&loops_info); + loop_optimizer_init (0); if (dump_file && (dump_flags & TDF_DETAILS)) - flow_loops_dump (&loops_info, dump_file, NULL, 0); + flow_loops_dump (dump_file, NULL, 0); add_noreturn_fake_exit_edges (); connect_infinite_loops_to_exit (); - calculate_dominance_info (CDI_DOMINATORS); + /* We use loop_niter_by_eval, which requires that the loops have + preheaders. */ + create_preheaders (CP_SIMPLE_PREHEADERS); calculate_dominance_info (CDI_POST_DOMINATORS); + bb_predictions = pointer_map_create (); tree_bb_level_predictions (); - mark_irreducible_loops (&loops_info); - predict_loops (&loops_info, false); + mark_irreducible_loops (); + record_loop_exits (); + if (number_of_loops () > 1) + predict_loops (); FOR_EACH_BB (bb) { @@ -1337,20 +1379,41 @@ tree_estimate_probability (void) { /* Predict early returns to be probable, as we've already taken care for error returns and other cases are often used for - fast paths trought function. */ - if (e->dest == EXIT_BLOCK_PTR - && TREE_CODE (last_stmt (bb)) == RETURN_EXPR - && !single_pred_p (bb)) + fast paths through function. + + Since we've already removed the return statements, we are + looking for CFG like: + + if (conditional) + { + .. + goto return_block + } + some other blocks + return_block: + return_stmt. */ + if (e->dest != bb->next_bb + && e->dest != EXIT_BLOCK_PTR + && single_succ_p (e->dest) + && single_succ_edge (e->dest)->dest == EXIT_BLOCK_PTR + && TREE_CODE (last_stmt (e->dest)) == RETURN_EXPR) { edge e1; edge_iterator ei1; - FOR_EACH_EDGE (e1, ei1, bb->preds) - if (!predicted_by_p (e1->src, PRED_NULL_RETURN) - && !predicted_by_p (e1->src, PRED_CONST_RETURN) - && !predicted_by_p (e1->src, PRED_NEGATIVE_RETURN) - && !last_basic_block_p (e1->src)) - predict_edge_def (e1, PRED_TREE_EARLY_RETURN, NOT_TAKEN); + if (single_succ_p (bb)) + { + FOR_EACH_EDGE (e1, ei1, bb->preds) + if (!predicted_by_p (e1->src, PRED_NULL_RETURN) + && !predicted_by_p (e1->src, PRED_CONST_RETURN) + && !predicted_by_p (e1->src, PRED_NEGATIVE_RETURN)) + predict_edge_def (e1, PRED_TREE_EARLY_RETURN, NOT_TAKEN); + } + else + if (!predicted_by_p (e->src, PRED_NULL_RETURN) + && !predicted_by_p (e->src, PRED_CONST_RETURN) + && !predicted_by_p (e->src, PRED_NEGATIVE_RETURN)) + predict_edge_def (e, PRED_TREE_EARLY_RETURN, NOT_TAKEN); } /* Look for block we are guarding (ie we dominate it, @@ -1370,8 +1433,9 @@ tree_estimate_probability (void) { tree stmt = bsi_stmt (bi); if ((TREE_CODE (stmt) == CALL_EXPR - || (TREE_CODE (stmt) == MODIFY_EXPR - && TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR)) + || (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT + && TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) + == CALL_EXPR)) /* Constant and pure calls are hardly used to signalize something exceptional. */ && TREE_SIDE_EFFECTS (stmt)) @@ -1387,11 +1451,17 @@ tree_estimate_probability (void) FOR_EACH_BB (bb) combine_predictions_for_bb (bb); +#ifdef ENABLE_CHECKING + pointer_map_traverse (bb_predictions, assert_is_empty, NULL); +#endif + pointer_map_destroy (bb_predictions); + bb_predictions = NULL; + strip_builtin_expect (); - estimate_bb_frequencies (&loops_info); + estimate_bb_frequencies (); free_dominance_info (CDI_POST_DOMINATORS); remove_fake_exit_edges (); - flow_loops_free (&loops_info); + loop_optimizer_finalize (); if (dump_file && (dump_flags & TDF_DETAILS)) dump_tree_cfg (dump_file, dump_flags); if (profile_status == PROFILE_ABSENT) @@ -1399,93 +1469,6 @@ tree_estimate_probability (void) return 0; } -/* __builtin_expect dropped tokens into the insn stream describing expected - values of registers. Generate branch probabilities based off these - values. */ - -void -expected_value_to_br_prob (void) -{ - 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: - /* Look for expected value notes. */ - 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: - /* Never propagate across labels. */ - ev = NULL_RTX; - continue; - - case JUMP_INSN: - /* Look for simple conditional branches. If we haven't got an - expected value yet, no point going further. */ - if (!JUMP_P (insn) || ev == NULL_RTX - || ! any_condjump_p (insn)) - continue; - break; - - default: - /* Look for insns that clobber the EV register. */ - if (ev && reg_set_p (ev_reg, insn)) - ev = NULL_RTX; - continue; - } - - /* Collect the branch condition, hopefully relative to EV_REG. */ - /* ??? At present we'll miss things like - (expected_value (eq r70 0)) - (set r71 -1) - (set r80 (lt r70 r71)) - (set pc (if_then_else (ne r80 0) ...)) - as canonicalize_condition will render this to us as - (lt r70, r71) - Could use cselib to try and reduce this further. */ - cond = XEXP (SET_SRC (pc_set (insn)), 0); - cond = canonicalize_condition (insn, cond, 0, NULL, ev_reg, - false, false); - if (! cond || XEXP (cond, 0) != ev_reg - || GET_CODE (XEXP (cond, 1)) != CONST_INT) - continue; - - /* Substitute and simplify. Given that the expression we're - building involves two constants, we should wind up with either - true or false. */ - cond = gen_rtx_fmt_ee (GET_CODE (cond), VOIDmode, - XEXP (ev, 1), XEXP (cond, 1)); - cond = simplify_rtx (cond); - - /* Turn the condition into a scaled branch probability. */ - gcc_assert (cond == const_true_rtx || cond == const0_rtx); - predict_insn_def (insn, PRED_BUILTIN_EXPECT, - cond == const_true_rtx ? TAKEN : NOT_TAKEN); - } -} - -/* Check whether this is the last basic block of function. Commonly - there is one extra common cleanup block. */ -static bool -last_basic_block_p (basic_block bb) -{ - if (bb == EXIT_BLOCK_PTR) - return false; - - return (bb->next_bb == EXIT_BLOCK_PTR - || (bb->next_bb->next_bb == EXIT_BLOCK_PTR - && single_succ_p (bb) - && single_succ (bb)->next_bb == EXIT_BLOCK_PTR)); -} - /* Sets branch probabilities according to PREDiction and FLAGS. HEADS[bb->index] should be index of basic block in that we need to alter branch predictions (i.e. the first of our dominators @@ -1570,12 +1553,12 @@ typedef struct edge_info_def #define EDGE_INFO(E) ((edge_info) (E)->aux) /* Helper function for estimate_bb_frequencies. - Propagate the frequencies for LOOP. */ + Propagate the frequencies in blocks marked in + TOVISIT, starting in HEAD. */ static void -propagate_freq (struct loop *loop, bitmap tovisit) +propagate_freq (basic_block head, bitmap tovisit) { - basic_block head = loop->header; basic_block bb; basic_block last; unsigned i; @@ -1712,7 +1695,7 @@ propagate_freq (struct loop *loop, bitmap tovisit) /* Estimate probabilities of loopback edges in loops at same nest level. */ static void -estimate_loops_at_level (struct loop *first_loop, bitmap tovisit) +estimate_loops_at_level (struct loop *first_loop) { struct loop *loop; @@ -1721,25 +1704,44 @@ estimate_loops_at_level (struct loop *first_loop, bitmap tovisit) edge e; basic_block *bbs; unsigned i; + bitmap tovisit = BITMAP_ALLOC (NULL); - estimate_loops_at_level (loop->inner, tovisit); + estimate_loops_at_level (loop->inner); - /* Do not do this for dummy function loop. */ - if (EDGE_COUNT (loop->latch->succs) > 0) - { - /* Find current loop back edge and mark it. */ - e = loop_latch_edge (loop); - EDGE_INFO (e)->back_edge = 1; - } + /* Find current loop back edge and mark it. */ + e = loop_latch_edge (loop); + EDGE_INFO (e)->back_edge = 1; bbs = get_loop_body (loop); for (i = 0; i < loop->num_nodes; i++) bitmap_set_bit (tovisit, bbs[i]->index); free (bbs); - propagate_freq (loop, tovisit); + propagate_freq (loop->header, tovisit); + BITMAP_FREE (tovisit); } } +/* Propagates frequencies through structure of loops. */ + +static void +estimate_loops (void) +{ + bitmap tovisit = BITMAP_ALLOC (NULL); + basic_block bb; + + /* Start by estimating the frequencies in the loops. */ + if (number_of_loops () > 1) + estimate_loops_at_level (current_loops->tree_root->inner); + + /* Now propagate the frequencies through all the blocks. */ + FOR_ALL_BB (bb) + { + bitmap_set_bit (tovisit, bb->index); + } + propagate_freq (ENTRY_BLOCK_PTR, tovisit); + BITMAP_FREE (tovisit); +} + /* Convert counts measured by profile driven feedback to frequencies. Return nonzero iff there was any nonzero execution count. */ @@ -1755,6 +1757,7 @@ counts_to_freqs (void) count_max = MAX (true_count_max, 1); FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb) bb->frequency = (bb->count * BB_FREQ_MAX + count_max / 2) / count_max; + return true_count_max; } @@ -1801,8 +1804,8 @@ expensive_function_p (int threshold) /* Estimate basic blocks frequency by given branch probabilities. */ -static void -estimate_bb_frequencies (struct loops *loops) +void +estimate_bb_frequencies (void) { basic_block bb; sreal freq_max; @@ -1810,7 +1813,6 @@ estimate_bb_frequencies (struct loops *loops) if (!flag_branch_probabilities || !counts_to_freqs ()) { static int real_values_initialized = 0; - bitmap tovisit; if (!real_values_initialized) { @@ -1829,7 +1831,6 @@ estimate_bb_frequencies (struct loops *loops) 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) @@ -1848,7 +1849,7 @@ estimate_bb_frequencies (struct loops *loops) /* First compute probabilities locally for each loop from innermost to outermost to examine probabilities for back edges. */ - estimate_loops_at_level (loops->tree_root, tovisit); + estimate_loops (); memcpy (&freq_max, &real_zero, sizeof (real_zero)); FOR_EACH_BB (bb) @@ -1867,7 +1868,6 @@ estimate_bb_frequencies (struct loops *loops) free_aux_for_blocks (); free_aux_for_edges (); - BITMAP_FREE (tovisit); } compute_function_frequency (); if (flag_reorder_functions) @@ -1881,7 +1881,15 @@ compute_function_frequency (void) basic_block bb; if (!profile_info || !flag_branch_probabilities) - return; + { + if (lookup_attribute ("cold", DECL_ATTRIBUTES (current_function_decl)) + != NULL) + cfun->function_frequency = FUNCTION_FREQUENCY_UNLIKELY_EXECUTED; + else if (lookup_attribute ("hot", DECL_ATTRIBUTES (current_function_decl)) + != NULL) + cfun->function_frequency = FUNCTION_FREQUENCY_HOT; + return; + } cfun->function_frequency = FUNCTION_FREQUENCY_UNLIKELY_EXECUTED; FOR_EACH_BB (bb) {