19 DEBUG_ONLY(static firm_dbg_module_t *dbg);
23 * Add the new predecessor x to node node, which is either a Block or a Phi
25 static void add_pred(ir_node* node, ir_node* x)
31 assert(is_Block(node) || is_Phi(node));
33 n = get_irn_arity(node);
34 NEW_ARR_A(ir_node*, ins, n + 1);
35 for (i = 0; i < n; i++) ins[i] = get_irn_n(node, i);
37 set_irn_in(node, n + 1, ins);
42 * Remove predecessor j from node, which is either a Block or a Phi
43 * returns true if only one predecessor is left
45 static int remove_pred(ir_node* node, int j)
49 assert(is_Block(node) || is_Phi(node));
51 n = get_irn_arity(node);
53 ir_node* pred = get_irn_n(node, 1 - j);
56 pred = get_nodes_block(pred);
57 set_irn_in(node, get_irn_arity(pred), get_irn_in(pred) + 1);
67 NEW_ARR_A(ir_node*, ins, n - 1);
68 for (i = 0; i < j; i++) ins[i] = get_irn_n(node, i);
69 for (i++; i < n; i++) ins[i - 1] = get_irn_n(node, i);
70 set_irn_in(node, n - 1, ins);
76 static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
84 assert(!is_Bad(block));
86 // already processed this block?
87 if(irn_visited(block)) {
88 ir_node *value = (ir_node*) get_irn_link(block);
92 // blocks with only 1 pred need no phi
93 n_cfgpreds = get_Block_n_cfgpreds(block);
95 ir_node *pred_block = get_Block_cfgpred_block(block, 0);
96 ir_node *value = search_def_and_create_phis(pred_block, mode);
98 set_irn_link(block, value);
99 mark_irn_visited(block);
104 in = alloca(sizeof(in[0]) * n_cfgpreds);
105 for(i = 0; i < n_cfgpreds; ++i)
106 in[i] = new_Unknown(mode);
108 irg = get_irn_irg(block);
109 phi = new_r_Phi(irg, block, n_cfgpreds, in, mode);
110 set_irn_link(block, phi);
111 mark_irn_visited(block);
114 for(i = 0; i < n_cfgpreds; ++i) {
115 ir_node *pred_block = get_Block_cfgpred_block(block, i);
118 pred_val = search_def_and_create_phis(pred_block, mode);
119 set_irn_n(phi, i, pred_val);
127 * Given a set of values this function constructs SSA-form for all users of the
128 * values (the user are determined through the out-edges of the values).
130 static void construct_ssa(ir_node * const *blocks, ir_node * const *vals, int n_vals)
138 irg = get_irn_irg(vals[0]);
139 inc_irg_visited(irg);
141 mode = get_irn_mode(vals[0]);
142 for(i = 0; i < n_vals; ++i) {
143 ir_node *value = vals[i];
144 ir_node *value_block = blocks[i];
146 assert(get_irn_mode(value) == mode);
148 set_irn_link(value_block, value);
149 mark_irn_visited(value_block);
152 for(i = 0; i < n_vals; ++i) {
153 const ir_edge_t *edge, *next;
154 ir_node *value = vals[i];
156 // this can happen when fixing phi preds, we mustn't fix the users
157 if(get_nodes_block(value) != blocks[i]) {
161 foreach_out_edge_safe(value, edge, next) {
162 ir_node *user = get_edge_src_irn(edge);
163 int j = get_edge_src_pos(edge);
164 ir_node *user_block = get_nodes_block(user);
168 if(get_irn_op(user) == op_End)
172 ir_node *pred_block = get_Block_cfgpred_block(user_block, j);
173 newval = search_def_and_create_phis(pred_block, mode);
175 newval = search_def_and_create_phis(user_block, mode);
178 // don't fix newly created phis from the SSA construction
180 set_irn_n(user, j, newval);
188 * Compare node compares two Const nodes
189 * Returns true if this direction is taken
191 static int handle_const_const(ir_node* cnst_left, cnst_right, pn_Cmp pnc)
201 static int handle_phi_const(ir_node* block, ir_node* cond_block, ir_node* phi, ir_node* cnst, pn_Cmp pnc)
209 tv_cnst = get_Const_tarval(cnst);
210 n_phi = get_Phi_n_preds(phi);
211 for (j = 0; j < n_phi; j++) {
212 const ir_edge_t *edge, *next;
218 pred = get_Phi_pred(phi, j);
219 // TODO handle Phi cascades
223 tv_phi = get_Const_tarval(pred);
225 cmp_val = tarval_cmp(tv_phi, tv_cnst);
226 if (cmp_val == pn_Cmp_False) continue;
227 if ((cmp_val & pnc) != cmp_val) continue;
231 "> Found condition evaluation candidate %+F->%+F predecessor %d\n",
235 add_pred(block, get_Block_cfgpred(cond_block, j));
236 // split critical edges
237 /*if(get_irn_arity(block) == 2)*/ {
242 in[0] = get_Block_cfgpred(block, 0);
243 new_block = new_r_Block(current_ir_graph, 1, in);
244 new_jmp = new_r_Jmp(current_ir_graph, new_block);
245 set_Block_cfgpred(block, 0, new_jmp);
248 pred_block = get_Block_cfgpred_block(cond_block, j);
250 /* Look at all nodes in the cond_block and copy them into pred */
251 foreach_out_edge(cond_block, edge) {
252 ir_node *node = get_edge_src_irn(edge);
255 // ignore these as SSA construction would fail on ProjX
256 if (is_Proj(node) && get_irn_mode(node) == mode_X)
259 // we can evaluate Phis right now, all other nodes get copied
261 copy = get_Phi_pred(node, j);
263 copy = exact_copy(node);
264 set_nodes_block(copy, pred_block);
267 set_irn_link(node, copy);
270 /* fix data-flow (and reconstruct SSA if needed) */
271 foreach_out_edge(cond_block, edge) {
275 ir_node *node = get_edge_src_irn(edge);
276 assert(get_nodes_block(node) == cond_block);
277 if (is_Proj(node) && get_irn_mode(node) == mode_X)
280 blocks[0] = cond_block;
282 blocks[1] = pred_block;
283 vals[1] = get_irn_link(node);
284 construct_ssa(blocks, vals, 2);
288 foreach_out_edge_safe(cond_block, edge, next) {
289 ir_node *node = get_edge_src_irn(edge);
292 remove_pred(node, j);
296 remove_pred(cond_block, j);
298 if (remove_pred(cond_block, j))
300 // the phi got shortened
308 irg = get_irn_irg(block);
309 set_irg_doms_inconsistent(irg);
310 set_irg_extblk_inconsistent(irg);
311 set_irg_loopinfo_inconsistent(irg);
320 static void cond_eval(ir_node* block, void* env)
325 n_block = get_Block_n_cfgpreds(block);
326 for (i = 0; i < n_block; i++) {
336 pred = get_Block_cfgpred(block, i);
337 if (!is_Proj(pred)) continue;
340 pred = get_Proj_pred(projx);
341 if (!is_Cond(pred)) continue;
344 pred = get_Cond_selector(cond);
345 assert(is_Proj(pred));
346 // TODO handle switches
347 if (get_irn_mode(pred) != mode_b) continue;
348 pnc = get_Proj_proj(pred);
350 cmp = get_Proj_pred(pred);
353 left = get_Cmp_left(cmp);
354 right = get_Cmp_right(cmp);
355 assert(get_irn_mode(left) == get_irn_mode(right));
357 if (get_Proj_proj(projx) == 0) {
358 pnc = get_negated_pnc(pnc, get_irn_mode(left));
361 #if 0 // TODO implement
362 if (is_Const(left) && is_Const(right)) {
363 if (!handle_const_const()) {
370 cond_block = get_nodes_block(cond);
371 if (is_Phi(left) && is_Const(right)) {
372 if (get_nodes_block(left) != cond_block) continue;
373 handle_phi_const(block, cond_block, left, right, pnc);
376 if (is_Const(left) && is_Phi(right)) {
377 if (get_nodes_block(right) != cond_block) continue;
378 handle_phi_const(block, cond_block, right, left, get_inversed_pnc(pnc));
382 if (is_Phi(left) && is_Phi(right)) {
390 void opt_cond_eval(ir_graph* irg)
392 FIRM_DBG_REGISTER(dbg, "firm.opt.condeval");
393 firm_dbg_set_mask(dbg, SET_LEVEL_5);
395 DB((dbg, LEVEL_1, "===> Performing condition evaluation on %+F\n", irg));
397 if(edges_activated(irg))
398 edges_deactivate(irg);
400 remove_critical_cf_edges(irg);
402 normalize_proj_nodes(irg);
404 irg_block_walk_graph(irg, cond_eval, NULL, NULL);
406 irg_block_walk_graph(irg, NULL, cond_eval, NULL);
407 irg_block_walk_graph(irg, NULL, cond_eval, NULL);
408 irg_block_walk_graph(irg, NULL, cond_eval, NULL);