13 #include "bechordal.h"
16 #include "bephicongr_t.h"
17 #include "bephicoal_t.h"
19 #define DEBUG_LVL SET_LEVEL_2
21 #define MAX_PHI_CLS_SIZE (1<<(sizeof(unsigned char)*8)) /* possible colors added should fit into unsigned char */
23 #define CHANGE_IMPOSSIBLE -1
29 typedef struct _phi_unit_t {
31 unsigned char phi_count;
34 ir_node **members; /**< [0] is the phi node. [1..count-1] the arguments of the phi not interfering with it */
35 char *is_live_in; /**< [i]==1 means members[i] is live-in in (all of) its cf-pred-blocks of the phi node */
36 int *colors; /**< [i] is the color to set for members[i]. [i] == NO_COLOR means dont change anything for members[i]*/
37 int size; /**< size of the max independent set of members. The set is markes by colors[i] != NO_COLOR */
38 int changes; /**< number of re-assigned nodes belonging to phi-classes */
42 static firm_dbg_module_t *dbgphi = NULL;
45 * Contains ir_nodes of phi-classes whose colors were reassigned during coalescing.
46 * So one can perform a check not to switch them twice or more.
48 static pset *pinned_nodes = NULL;
51 * Contains ir_nodes of phi-classes whose colors may change unlimited times.
52 * These nodes are not optimizable, so there is no need to pin their color.
54 static pset *free_nodes = NULL;
57 /* TODO: ask/check if additional ir_node-space is initialized with 0000 */
58 #define belongs_to_a_phi_class(n) (get_irn_phi_info(n)->phi)
60 #define is_color_free(bl,col) (!bitset_is_set(get_ra_block_info(bl)->used_colors, col))
63 * Sets the color of node @p n to @p col, but acts
66 static INLINE void set_color(ir_node *n, int col) {
67 assert(!pset_find_ptr(pinned_nodes, n));
68 set_irn_color(n, col);
69 if (belongs_to_a_phi_class(n) && !pset_find_ptr(free_nodes, n))
70 pset_insert_ptr(pinned_nodes, n);
74 * Tries to set the color of @p n to @p col. Performs recoloring of other nodes
75 * as required to preserve correctness.
76 * @param n The node to set the color for
77 * @param col The color to set.
78 * @param dryrun If true no colors are actually set, only testing is performed.
79 * If false colors get set and it must be sure that no conflicts will occur.
80 * @return If setting the color is impossible CHANGE_IMPOSSIBLE is returned
81 * else the number of nodes that need a (cascading) change is returned.
83 static int color_irn(ir_node *n, int col, int dryrun) {
86 DBG((dbgphi, LEVEL_2, "\t\t\t%n --> %d\n", n, col));
87 assert(is_color(col));
89 if (get_irn_color(n) == col) {
90 DBG((dbgphi, LEVEL_2, "\t\t\t Same\n"));
91 /* to insert it into pinned_nodes color it with its color :) */
96 if (pset_find_ptr(pinned_nodes, n)) {
97 DBG((dbgphi, LEVEL_2, "\t\t\t Pinned\n"));
99 assert(0 && "No prior check with dryrun or buggy");
100 return CHANGE_IMPOSSIBLE;
103 bl = get_nodes_block(n);
104 if (is_color_free(bl, col) && !is_live_out(bl, n)) {
105 DBG((dbgphi, LEVEL_2, "\t\t\t Free\n"));
111 /* for now, in the aldi-version return impossible */
112 DBG((dbgphi, LEVEL_2, "\t\t\t Impossible\n"));
113 return CHANGE_IMPOSSIBLE;
120 * Tries to set as much members of a phi unit as possible to color @p col.
121 * - Each change taken alone is guaranteed to be conflict free.
122 * - _If_ all members are neither live-in nor live-out in their cf-pred-blocks
123 * _then_ all changes together can be applied conflivt free.
124 * - _If_ there is a member, which is live-in or live-out in its cf-pred-block
125 * of the phi node, it is possible that all changes together will conflict.
126 * - TODO: Write sth. about dom-tree influence on this.
128 static void try_colors(phi_unit_t *pu, int col, int b_size, int b_changes) {
130 struct obstack ob_changes;
131 int i, o, cand_size, total_changes, *changes;
132 ir_node **cand, **mis;
136 obstack_init(&ob_changes);
138 /* first init pessimistically, so we can just return
139 * if we see there wont be a better result */
140 for (i = 0; i < pu->count; ++i)
141 pu->colors[i] = NO_COLOR;
145 /* For all members check if color would be possible.
146 * Does not check if color is possible in combination with
147 * other members colors being set */
149 for (i = 0; i < pu->count; ++i) {
150 DBG((dbgphi, 1, "\t\t Testing %n\n", pu->members[i]));
151 int curr_changes = color_irn(pu->members[i], col, DRYRUN);
152 if (curr_changes != CHANGE_IMPOSSIBLE) {
153 DBG((dbgphi, 1, "\t\t\tAdding to cand\n"));
154 obstack_ptr_grow(&ob, pu->members[i]);
155 obstack_grow(&ob_changes, &curr_changes, sizeof(curr_changes));
157 total_changes += curr_changes;
159 DBG((dbgphi, 1, "\t\t\tImpossible\n"));
161 /* if color is not possible for the phi node then exit (phi comes first)*/
165 cand = obstack_finish(&ob);
166 changes = obstack_finish(&ob_changes);
168 /* shortcut: if cand is worse than best then mis wont be better. */
169 if (cand_size < b_size || (cand_size == b_size && total_changes >= b_changes))
172 /* now take the candidates cand and determine a max independent set
173 * with respect to edges representing live range interference */
174 /* TODO: make this 'un-greedy' */
175 DBG((dbgphi, 1, "\t\t Max indep set\n"));
176 for (i = 0; i < cand_size; ++i) {
178 for (o = 0; o < pu->size; ++o) {
179 mis = (ir_node**) obstack_base(&ob);
180 if (values_interfere(cand[i], mis[o])) {
187 DBG((dbgphi, 1, "\t\t\tAdding to mis %n\n", cand[i]));
188 obstack_ptr_grow(&ob, cand[i]);
190 pu->changes += changes[i];
193 mis = obstack_finish(&ob);
195 /* Now set the colors of all nodes in the mis to col. */
196 for (i = 0; i < pu->count; ++i)
197 for (o = 0; o < pu->size; ++o)
198 if (pu->members[i] == mis[o] && get_irn_color(pu->members[i]) != col)
202 obstack_free(&ob_changes, NULL);
203 obstack_free(&ob, NULL);
208 * Sets the colors of members[i] to colors[i] as far as possible.
209 * Each single change must be conflict free (checked by try_colors).
210 * In some cases not all colors can be set.
212 /*TODO : BUGGY due to false reasoning with live-outs
213 * thus fallback to save variant with testing all before setting. */
214 static void set_colors(phi_unit_t *pu) {
216 int change_is_save, live_in_occured = 0;
218 for (i = 0; i < pu->count; ++i)
219 if (pu->colors[i] != NO_COLOR) {
220 if (pu->is_live_in[i])
223 // change_is_save = CHANGE_SAVE;
224 // if (live_in_occured)
225 change_is_save = color_irn(pu->members[i], pu->colors[i], DRYRUN);
227 /* HINT: Dont change to == CHANGE_SAVE */
228 if (change_is_save != CHANGE_IMPOSSIBLE) {
229 DBG((dbgphi, 1, "\t\tSetting %n to %d\n", pu->members[i], pu->colors[i]));
230 color_irn(pu->members[i], pu->colors[i], PERFORM);
232 DBG((dbgphi, 1, "\t\tConflict due to a live-in: %n\n", pu->members[i]));
239 * Tries to re-allocate colors of this phi-class, to achieve a lower number of
240 * copies placed during phi destruction. Optimized version. Works only for
241 * phi-classes/phi-units with exactly 1 phi node, which is the case for approx.
242 * 80% of all phi classes.
244 static void coalesce_1_phi(phi_unit_t *pu) {
245 int *b_colors, b_size, b_changes, b_color;
248 /* init best search result */
249 b_colors = malloc(pu->count * sizeof(*b_colors));
250 for (i = 0; i < pu->count; ++i)
251 b_colors[i] = NO_COLOR;
256 /* find optimum of all colors */
257 for (col = MAX_COLORS-1; col >= 0; --col) {
258 DBG((dbgphi, 1, "\tTrying color %d\n", col));
259 try_colors(pu, col, b_size, b_changes);
261 /* did we find a better max ind. set? */
262 if (pu->size > b_size || (pu->size == b_size && pu->changes < b_changes)) {
264 b_changes = pu->changes;
266 memcpy(b_colors, pu->colors, pu->count * sizeof(*b_colors));
267 DBG((dbgphi, 1, "\t!! Better size: %d Changes: %d\n", b_size, b_changes));
270 /* shortcut: if all members can be colored we are content and doubt that
271 * reducing b_changes justifies all the further trying. */
272 if (b_size == pu->count)
276 /* now apply the found optimum */
277 DBG((dbgphi, 1, "\tBest color: %d Copies: %d/%d Changes: %d\n", b_color, pu->count-b_size, pu->count, b_changes));
279 pu->changes = b_changes;
280 memcpy(pu->colors, b_colors, pu->count * sizeof(*b_colors));
287 * Tries to re-allocate colors of this phi-class, to achieve a lower number of
288 * copies placed during phi destruction. General purpose version.
290 static void coalesce_n_phi(phi_unit_t *pu) {
291 DBG((dbgphi, 1, "\n"));
296 * Prepares a phi class for further processing as a phi unit.
297 * @param pc The phi class to prepare.
298 * @return A so called phi unit containing some prepared informations
299 * needed by the following coalescing phase.
301 static phi_unit_t *new_phi_unit(pset *pc) {
303 ir_node *n, *phi = NULL;
305 assert(pset_count(pc) <= MAX_PHI_CLS_SIZE && "Phi class too large!");
307 /* get the phi count of this class */
308 pu = malloc(sizeof(*pu));
310 for (n = pset_first(pc); n; n = pset_next(pc))
316 if (pu->phi_count == 1) {
317 ir_node **tmp, *phi_block;
323 /* build member set not containing phi interferers */
324 DBG((dbgphi, 1, "Phi-1 class:\n"));
325 pu->count = 1; /*for the phi*/
326 for (n = pset_first(pc); n; n = pset_next(pc)) {
329 if (!values_interfere(phi, n)) {
330 DBG((dbgphi, 1, "\tAdding to members: %n\n", n));
331 obstack_ptr_grow(&ob, n);
334 DBG((dbgphi, 1, "\tPhi interferer: %n\n", n));
335 pset_insert_ptr(free_nodes, n);
338 tmp = obstack_finish(&ob);
339 pu->members = malloc(pu->count * sizeof(*pu->members));
340 pu->members[0] = phi;
341 memcpy(&pu->members[1], tmp, (pu->count-1) * sizeof(*tmp));
343 /* init of colors array */
344 pu->colors = malloc(pu->count * sizeof(*pu->colors));
346 /* live-in analysis */
347 /* HINT: It is possible that a node occurs twice as arg of a phi,
348 * one time being live-in, and another time not being live-in.
350 pu->is_live_in = calloc(pu->count, sizeof(*pu->is_live_in));
351 phi_block = get_nodes_block(phi);
352 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
354 ir_node *arg, *block_ith_pred;
356 arg = get_irn_n(phi, i);
357 block_ith_pred = get_nodes_block(get_irn_n(phi_block, i));
359 /* find the arg in the members array */
361 for (o = 0; o < pu->count; ++o)
362 if (pu->members[o] == arg) {
369 if (is_live_in(block_ith_pred, arg)) {
370 pu->is_live_in[midx] |= 1;
371 DBG((dbgphi, 1, "\t%n is live-in in %n\n", arg, block_ith_pred));
375 obstack_free(&ob, NULL);
377 DBG((dbgphi, 1, "Phi-n class:\n"));
381 DBG((dbgphi, 1, "\n"));
389 static void free_phi_unit(phi_unit_t *pu) {
390 DBG((dbgphi, 1, "\n"));
391 if (pu->phi_count == 1) {
394 free(pu->is_live_in);
402 void be_phi_coalesce(pset *all_phi_classes) {
405 pinned_nodes = pset_new_ptr(256);
406 free_nodes = pset_new_ptr(64);
408 for (pc = pset_first(all_phi_classes); pc; pc = pset_next(all_phi_classes)) {
409 phi_unit_t *pu = new_phi_unit(pc);
410 if (pu->phi_count == 1)
417 del_pset(free_nodes);
418 del_pset(pinned_nodes);
422 void be_phi_coal_init(void) {
423 dbgphi = firm_dbg_register("Phi coalescing");
424 firm_dbg_set_mask(dbgphi, DEBUG_LVL);