3 * File name: ir/ana/execution_frequency.c
4 * Purpose: Compute an estimate of basic block executions.
5 * Author: Goetz Lindenmaier
9 * Copyright: (c) 2004 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
16 #include "execution_frequency.h"
18 #include "firm_common_t.h"
25 #include "interval_analysis.h"
27 /*------------------------------------------------------------------*/
28 /* A hashmap mapping the frequency to block and loop nodes. Block
29 * and loop nodes are regions. */
30 /*------------------------------------------------------------------*/
37 /* We use this set for all nodes in all irgraphs. */
38 static set *exec_freq_set = NULL;
40 static int exec_freq_cmp(const void *e1, const void *e2, size_t size) {
41 reg_exec_freq *ef1 = (reg_exec_freq *)e1;
42 reg_exec_freq *ef2 = (reg_exec_freq *)e2;
43 return (ef1->reg != ef2->reg);
46 static INLINE unsigned int exec_freq_hash(void *e) {
47 unsigned int v = (unsigned int) ((reg_exec_freq *)e)->reg;
51 static INLINE void set_region_exec_freq(void *reg, double freq) {
55 set_insert(exec_freq_set, &ef, sizeof(ef), exec_freq_hash(&ef));
58 INLINE double get_region_exec_freq(void *reg) {
59 reg_exec_freq ef, *found;
62 found = set_find(exec_freq_set, &ef, sizeof(ef), exec_freq_hash(&ef));
67 /* Returns the number of times the block is executed. */
68 double get_Block_exec_freq(ir_node *b) {
69 return get_region_exec_freq((void *)b);
72 double get_irn_exec_freq(ir_node *n) {
73 if (!is_Block(n)) n = get_nodes_block(n);
74 return get_Block_exec_freq(n);
78 /*------------------------------------------------------------------*/
79 /* The algorithm to compute the execution freqencies.
81 * Walk the control flow loop tree which we consider the interval
82 * tree. Compute the execution for the lowest loop, add inner loops
83 * to worklist. Consider the inner loops as simple nodes. Check that
84 * there is only one loop header in each loop. */
85 /*------------------------------------------------------------------*/
87 static double exception_prob = 0.001;
89 static INLINE int is_loop_head(ir_node *cond) {
93 static INLINE double get_weighted_region_exec_freq(void *reg, int pos) {
94 void *pred_reg = get_region_in(reg, pos);
95 double res, full_freq = get_region_exec_freq(pred_reg);
96 int n_outs = get_region_n_outs (pred_reg);
97 int n_exc_outs = get_region_n_exc_outs(pred_reg);
100 if (is_ir_node(reg)) {
101 cfop = skip_Proj(get_Block_cfgpred((ir_node *)reg, pos));
103 assert(is_ir_loop(reg));
104 cfop = get_loop_cfop(reg, pos);
107 if (is_fragile_op(cfop)) {
108 res = full_freq * exception_prob;
111 /* Equally distribute the weight after exceptions to the left over outs. */
112 res = (full_freq *(1 - exception_prob * n_exc_outs)) / (n_outs - n_exc_outs);
118 static INLINE void compute_region_freqency(void *reg, double head_weight) {
119 int i, n_ins = get_region_n_ins(reg);
122 //printf("head weight %lf: ", head_weight); DDMR(reg);
124 for (i = 0; i < n_ins; ++i) {
125 void *pred_reg = get_region_in(reg, i);
127 my_freq += get_weighted_region_exec_freq(reg, i);
131 if (my_freq == 0.0) {
132 /* All preds are from outer loop. We are a head or so. */
133 my_freq = head_weight;
135 set_region_exec_freq(reg, my_freq);
138 static void check_proper_head(ir_loop *l, void *reg) {
139 int i, n_ins = get_region_n_ins(reg);
140 for (i = 0; i < n_ins; ++i) {
141 assert(!get_region_in(reg, i));
145 /* Compute the ex freq for current_ir_graph */
146 static void compute_frequency(int default_loop_weight) {
147 ir_loop *outermost_l = get_irg_loop(current_ir_graph);
148 pdeq *block_worklist = new_pdeq1(outermost_l);
150 /* Outermost start is considered a loop head. We will soon multiply
151 by default_loop_weight. */
152 set_region_exec_freq(outermost_l, 1.0/default_loop_weight);
154 while (!pdeq_empty(block_worklist)) {
155 ir_loop *l = (ir_loop *)pdeq_getl(block_worklist);
156 int i, n_elems = get_loop_n_elements(l);
158 /* The header is initialized with the freqency of the full loop times the iteration weight. */
159 check_proper_head(l, get_loop_element(l, 0).son);
161 for (i = 0; i < n_elems; ++i) {
162 loop_element e = get_loop_element(l, i);
163 if (is_ir_loop(e.son)) pdeq_putr(block_worklist, e.son);
164 compute_region_freqency(e.son, default_loop_weight * get_region_exec_freq(l));
167 del_pdeq(block_worklist);
170 /* Compute the execution frequency for all blocks in the given
173 * irg: The graph to be analyzed.
174 * default_loop_weight: The number of executions of a loop.
176 void compute_execution_frequency(ir_graph *irg, int default_loop_weight, double exception_probability) {
177 ir_graph *rem = current_ir_graph;
178 current_ir_graph = irg;
179 exception_prob = exception_probability;
180 if (!exec_freq_set) exec_freq_set = new_set(exec_freq_cmp, 256);
182 construct_intervals(current_ir_graph);
183 compute_frequency(default_loop_weight);
186 dump_loop_tree (current_ir_graph, "-execfreq");
187 dump_ir_block_graph(current_ir_graph, "-execfreq");
188 dump_interval_graph(current_ir_graph, "-execfreq");
191 current_ir_graph = rem;
195 void compute_execution_frequencies(int default_loop_weight, double exception_probability) {
196 int i, n_irgs = get_irp_n_irgs();
198 for (i = 0; i < n_irgs; ++i) {
199 compute_execution_frequency(get_irp_irg(i), default_loop_weight, exception_probability);
203 /** free occupied memory, reset */
204 void free_execution_frequency(void) {
206 del_set(exec_freq_set);