2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Peephole optimisation framework keeps track of which registers contain which values
23 * @author Matthias Braun
30 #include "bepeephole.h"
32 #include "iredges_t.h"
42 #include "besched_t.h"
45 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
47 static const arch_env_t *arch_env;
49 static ir_node *current_node;
50 static ir_node *prev_node;
51 ir_node ***register_values;
53 static void clear_reg_value(ir_node *node)
55 const arch_register_t *reg;
56 const arch_register_class_t *cls;
60 if(!mode_is_data(get_irn_mode(node)))
63 reg = arch_get_irn_register(arch_env, node);
65 panic("No register assigned at %+F\n", node);
67 if(arch_register_type_is(reg, virtual))
69 cls = arch_register_get_class(reg);
70 reg_idx = arch_register_get_index(reg);
71 cls_idx = arch_register_class_index(cls);
73 //assert(register_values[cls_idx][reg_idx] != NULL);
74 DBG((dbg, LEVEL_1, "Clear Register %s\n", reg->name));
75 register_values[cls_idx][reg_idx] = NULL;
78 static void set_reg_value(ir_node *node)
80 const arch_register_t *reg;
81 const arch_register_class_t *cls;
85 if(!mode_is_data(get_irn_mode(node)))
88 reg = arch_get_irn_register(arch_env, node);
90 panic("No register assigned at %+F\n", node);
92 if(arch_register_type_is(reg, virtual))
94 cls = arch_register_get_class(reg);
95 reg_idx = arch_register_get_index(reg);
96 cls_idx = arch_register_class_index(cls);
98 DBG((dbg, LEVEL_1, "Set Register %s: %+F\n", reg->name, node));
99 register_values[cls_idx][reg_idx] = node;
102 static void clear_defs(ir_node *node)
104 /* clear values defined */
105 if(get_irn_mode(node) == mode_T) {
106 const ir_edge_t *edge;
107 foreach_out_edge(node, edge) {
108 ir_node *proj = get_edge_src_irn(edge);
109 clear_reg_value(proj);
112 clear_reg_value(node);
116 static void set_uses(ir_node *node)
120 /* set values used */
121 arity = get_irn_arity(node);
122 for(i = 0; i < arity; ++i) {
123 ir_node *in = get_irn_n(node, i);
128 void be_peephole_before_exchange(const ir_node *old_node, ir_node *new_node)
130 const arch_register_t *reg;
131 const arch_register_class_t *cls;
135 DBG((dbg, LEVEL_1, "About to exchange %+F with %+F\n", old_node, new_node));
137 if (old_node == current_node) {
138 if (is_Proj(new_node)) {
139 current_node = get_Proj_pred(new_node);
141 current_node = new_node;
145 if (!mode_is_data(get_irn_mode(old_node)))
148 reg = arch_get_irn_register(arch_env, old_node);
150 panic("No register assigned at %+F\n", old_node);
152 cls = arch_register_get_class(reg);
153 reg_idx = arch_register_get_index(reg);
154 cls_idx = arch_register_class_index(cls);
156 if (register_values[cls_idx][reg_idx] == old_node) {
157 register_values[cls_idx][reg_idx] = new_node;
160 be_liveness_remove(lv, old_node);
163 void be_peephole_after_exchange(ir_node *new_node)
165 be_liveness_introduce(lv, new_node);
168 void be_peephole_before_exchange_and_kill(const ir_node *old_node, ir_node *new_node)
170 const arch_register_t *reg;
171 const arch_register_class_t *cls;
175 DBG((dbg, LEVEL_1, "About to exchange and kill %+F with %+F\n", old_node, new_node));
177 if (old_node == current_node) {
178 /* current_node will be killed. Its scheduling predecessor
179 must be processed next. */
180 prev_node = sched_prev(current_node);
183 if (!mode_is_data(get_irn_mode(old_node)))
186 reg = arch_get_irn_register(arch_env, old_node);
188 panic("No register assigned at %+F\n", old_node);
190 assert(reg == arch_get_irn_register(arch_env, new_node) &&
191 "KILLING a node and replacing by different register is not allowed");
193 cls = arch_register_get_class(reg);
194 reg_idx = arch_register_get_index(reg);
195 cls_idx = arch_register_class_index(cls);
197 if (register_values[cls_idx][reg_idx] == old_node) {
198 register_values[cls_idx][reg_idx] = new_node;
201 be_liveness_remove(lv, old_node);
205 * block-walker: run peephole optimization on the given block.
207 static void process_block(ir_node *block, void *data)
214 /* construct initial register assignment */
215 n_classes = arch_env_get_n_reg_class(arch_env);
216 for(i = 0; i < n_classes; ++i) {
217 const arch_register_class_t *cls = arch_env_get_reg_class(arch_env, i);
218 unsigned n_regs = arch_register_class_n_regs(cls);
219 memset(register_values[i], 0, sizeof(ir_node*) * n_regs);
222 assert(lv->nodes && "live sets must be computed");
223 DBG((dbg, LEVEL_1, "\nProcessing block %+F (from end)\n", block));
224 be_lv_foreach(lv, block, be_lv_state_end, l) {
225 ir_node *node = be_lv_get_irn(lv, block, l);
228 DBG((dbg, LEVEL_1, "\nstart processing\n"));
230 /* walk the block from last insn to the first */
231 current_node = sched_last(block);
232 for( ; !sched_is_begin(current_node);
233 current_node = prev_node != NULL ? prev_node : sched_prev(current_node)) {
236 peephole_opt_func peephole_node;
239 if (is_Phi(current_node))
242 clear_defs(current_node);
243 set_uses(current_node);
245 op = get_irn_op(current_node);
246 peephole_node = (peephole_opt_func)op->ops.generic;
247 if (peephole_node == NULL)
251 peephole_node(current_node);
252 /* was the current node replaced? */
253 if (current_node != last)
254 set_uses(current_node);
259 * Walk through the block schedule and skip all barrier nodes.
261 static void skip_barrier(ir_node *ret_blk, ir_graph *irg) {
264 sched_foreach_reverse(ret_blk, irn) {
265 if (be_is_Barrier(irn)) {
266 const ir_edge_t *edge, *next;
268 foreach_out_edge_safe(irn, edge, next) {
269 ir_node *proj = get_edge_src_irn(edge);
270 int pn = (int)get_Proj_proj(proj);
271 ir_node *pred = get_irn_n(irn, pn);
273 edges_reroute_kind(proj, pred, EDGE_KIND_NORMAL, irg);
274 edges_reroute_kind(proj, pred, EDGE_KIND_DEP, irg);
284 * Kill the Barrier nodes for better peephole optimization.
286 static void kill_barriers(ir_graph *irg) {
287 ir_node *end_blk = get_irg_end_block(irg);
291 /* skip the barrier on all return blocks */
292 for (i = get_Block_n_cfgpreds(end_blk) - 1; i >= 0; --i) {
293 ir_node *be_ret = get_Block_cfgpred(end_blk, i);
294 ir_node *ret_blk = get_nodes_block(be_ret);
296 skip_barrier(ret_blk, irg);
299 /* skip the barrier on the start block */
300 start_blk = get_irg_start_block(irg);
301 skip_barrier(start_blk, irg);
305 * Tries to optimize a beIncSp node with it's previous IncSP node.
306 * Must be run from a be_peephole_opt() context.
308 ir_node *be_peephole_IncSP_IncSP(ir_node *node)
313 ir_node *pred = be_get_IncSP_pred(node);
315 if (!be_is_IncSP(pred))
318 if (get_irn_n_edges(pred) > 1)
321 pred_offs = be_get_IncSP_offset(pred);
322 curr_offs = be_get_IncSP_offset(node);
324 if (pred_offs == BE_STACK_FRAME_SIZE_EXPAND) {
325 if (curr_offs != BE_STACK_FRAME_SIZE_SHRINK) {
329 } else if (pred_offs == BE_STACK_FRAME_SIZE_SHRINK) {
330 if (curr_offs != BE_STACK_FRAME_SIZE_EXPAND) {
334 } else if (curr_offs == BE_STACK_FRAME_SIZE_EXPAND ||
335 curr_offs == BE_STACK_FRAME_SIZE_SHRINK) {
338 offs = curr_offs + pred_offs;
341 /* add node offset to pred and remove our IncSP */
342 be_set_IncSP_offset(pred, offs);
344 be_peephole_before_exchange_and_kill(node, pred);
346 /* rewire dependency/data edges */
347 edges_reroute_kind(node, pred, EDGE_KIND_DEP, current_ir_graph);
348 edges_reroute(node, pred, current_ir_graph);
355 void be_peephole_opt(be_irg_t *birg)
357 ir_graph *irg = be_get_birg_irg(birg);
361 /* barrier nodes are used for register allocations. They hinders
362 * peephole optimizations, so remove them here. */
365 /* we sometimes find BadE nodes in float apps like optest_float.c or
366 * kahansum.c for example... */
367 be_liveness_invalidate(birg->lv);
368 be_liveness_assure_sets(be_assure_liveness(birg));
370 arch_env = be_get_birg_arch_env(birg);
371 lv = be_get_birg_liveness(birg);
373 n_classes = arch_env_get_n_reg_class(arch_env);
374 register_values = alloca(sizeof(register_values[0]) * n_classes);
375 for(i = 0; i < n_classes; ++i) {
376 const arch_register_class_t *cls = arch_env_get_reg_class(arch_env, i);
377 unsigned n_regs = arch_register_class_n_regs(cls);
378 register_values[i] = alloca(sizeof(ir_node*) * n_regs);
381 irg_block_walk_graph(irg, process_block, NULL, NULL);
384 void be_peephole_init(void)
386 clear_irp_opcodes_generic_func();
389 void be_init_peephole(void)
391 FIRM_DBG_REGISTER(dbg, "firm.be.peephole");
394 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spillbelady);