4 * Copyright: (c) Universitaet Karlsruhe
5 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
30 #include "irprintf_t.h"
32 #include "irgraph_t.h"
34 #include "iredges_t.h"
38 #include "beraextern.h"
43 #include "besched_t.h"
48 #include "bessadestrsimple.h"
52 typedef struct _ssa_destr_env_t {
54 const arch_register_class_t *cls;
55 const arch_env_t *aenv;
59 #define pset_foreach(pset, irn) for(irn=pset_first(pset); irn; irn=pset_next(pset))
60 #define set_foreach(set, e) for(e=set_first(set); e; e=set_next(set))
62 static phi_classes_t *pc = NULL;
64 /******************************************************************************
66 \ \ / / | | |__ \ \ \ / /
67 \ \ / /_ _| |___ ) | \ \ / /_ _ _ __ ___
68 \ \/ / _` | / __| / / \ \/ / _` | '__/ __|
69 \ / (_| | \__ \ / /_ \ / (_| | | \__ \
70 \/ \__,_|_|___/ |____| \/ \__,_|_| |___/
71 *****************************************************************************/
74 * The link field of an irn points to the var_info struct
75 * representing the corresponding variable.
77 #define set_var_info(irn, vi) set_irn_link(irn, vi)
79 #define HASH_VAR_NR(var_nr) var_nr
81 static int compare_var_infos(const void *e1, const void *e2, size_t size) {
82 const be_var_info_t *v1 = e1;
83 const be_var_info_t *v2 = e2;
85 if (v1->var_nr == SET_REMOVED || v2->var_nr == SET_REMOVED)
88 return v1->var_nr != v2->var_nr;
91 be_var_info_t *be_var_find(set *vars, int var_nr) {
95 return set_find(vars, &vi, sizeof(vi), HASH_VAR_NR(var_nr));
98 be_var_info_t *be_var_find_or_insert(set *vars, int var_nr) {
99 be_var_info_t vi, *found;
100 memset(&vi, 0, sizeof(vi));
103 found = set_insert(vars, &vi, sizeof(vi), HASH_VAR_NR(var_nr));
106 found->values = pset_new_ptr(1);
112 * Adds a value to a variable. Sets all pointers accordingly.
114 be_var_info_t *be_var_add_value(set *vars, int var_nr, ir_node *irn) {
115 be_var_info_t *vi = be_var_find_or_insert(vars, var_nr);
117 /* var 2 value mapping */
118 pset_insert_ptr(vi->values, irn);
120 /* value 2 var mapping */
121 set_var_info(irn, vi);
126 pset *be_get_var_values(set *vars, int var_nr) {
127 be_var_info_t *vi = be_var_find(vars, var_nr);
128 assert(vi && "Variable does not exist");
132 static INLINE ir_node *get_first_phi(ir_node **s) {
135 for (i = ARR_LEN(s) - 1; i >= 0; --i) {
140 assert(0 && "There must be a phi in this");
146 * Define variables (numbers) for all SSA-values.
147 * All values in a phi class get assigned the same variable name.
148 * The link field maps values to the var-name
150 static void values_to_vars(ir_node *irn, void *env) {
151 ssa_destr_env_t *sde = env;
152 int nr, i, build_vals = 0;
155 if (arch_get_irn_reg_class(sde->aenv, irn, -1) == NULL)
158 vals = get_phi_class(pc, irn);
161 nr = get_irn_node_nr(get_first_phi(vals));
163 /* not a phi class member, value == var */
164 nr = get_irn_node_nr(irn);
165 vals = NEW_ARR_F(ir_node *, 1);
170 /* values <--> var mapping */
171 for (i = ARR_LEN(vals) - 1; i >= 0; --i) {
172 be_var_add_value(sde->vars, nr, vals[i]);
179 /******************************************************************************
181 / ____/ ____| /\ | __ \ | |
182 | (___| (___ / \ ______| | | | ___ ___| |_ _ __
183 \___ \\___ \ / /\ \______| | | |/ _ \/ __| __| '__|
184 ____) |___) / ____ \ | |__| | __/\__ \ |_| |
185 |_____/_____/_/ \_\ |_____/ \___||___/\__|_|
187 *****************************************************************************/
189 #define mark_as_done(irn, pos) set_irn_link(irn, INT_TO_PTR(pos+1))
190 #define has_been_done(irn, pos) (PTR_TO_INT(get_irn_link(irn)) > pos)
193 * Insert a copy for the argument of @p start_phi found at position @p pos.
194 * Also searches a phi-loop of arbitrary length to detect and resolve
195 * the class of phi-swap-problems. To search for a loop recursion is used.
197 * 1) Simplest case (phi with a non-phi arg):
198 * A single copy is inserted.
200 * 2) Phi chain (phi (with phi-arg)* with non-phi arg):
201 * Several copies are placed, each after returning from recursion.
204 * On detection a loop breaker is inserted, which is a copy of the start_phi.
205 * This copy then pretends beeing the argumnent of the last phi.
206 * Now case 2) can be used.
208 * The values of @p start_phi and @p pos never change during recursion.
210 * @p start_phi Phi node to process
211 * @p pos Argument position to insert copy/copies for
212 * @p curr_phi Phi node currently processed during recursion. Equals start_phi on initial call
214 * @return NULL If no copy is necessary
215 * NULL If the phi has already been processed at this pos
216 * Link field is used to keep track of processed positions
217 * In all other cases the ir_node *copy which was placed is returned.
219 static ir_node *insert_copies(ssa_destr_env_t *sde, const arch_register_class_t *cls, ir_node *start_phi, int pos, ir_node *curr_phi) {
220 ir_node *arg = get_irn_n(curr_phi, pos);
221 ir_node *arg_blk = get_nodes_block(arg);
222 ir_node *pred_blk = get_Block_cfgpred_block(get_nodes_block(curr_phi), pos);
223 ir_node *curr_cpy, *last_cpy;
225 assert(is_Phi(start_phi) && is_Phi(curr_phi));
227 if (has_been_done(start_phi, pos))
230 /* In case this is a 'normal' phi we insert at the
231 * end of the pred block before cf nodes */
232 last_cpy = sched_skip(pred_blk, 0, sched_skip_cf_predicator, (void *)sde->aenv);
233 last_cpy = sched_next(last_cpy);
235 /* If we detect a loop stop recursion. */
236 if (arg == start_phi) {
237 ir_node *loop_breaker;
238 if (start_phi == curr_phi) {
239 /* Phi directly uses itself. No copy necessary */
243 /* At least 2 phis are involved */
244 /* Insert a loop breaking copy (an additional variable T) */
245 loop_breaker = be_new_Copy(cls, sde->irg, pred_blk, start_phi);
246 sched_add_before(last_cpy, loop_breaker);
251 /* If arg is a phi in the same block we have to continue search */
252 if (is_Phi(arg) && arg_blk == get_nodes_block(start_phi))
253 last_cpy = insert_copies(sde, cls, start_phi, pos, arg);
255 /* Insert copy of argument (may be the loop-breaker) */
256 curr_cpy = be_new_Copy(cls, sde->irg, pred_blk, arg);
257 set_irn_n(curr_phi, pos, curr_cpy);
258 mark_as_done(curr_phi, pos);
259 sched_add_before(last_cpy, curr_cpy);
265 * Perform simple SSA-destruction with copies.
266 * The order of processing _must_ be
267 * for all positions {
272 * else the magic to keep track of processed phi-positions will fail in
273 * function 'insert_copies'
275 static void ssa_destr_simple_walker(ir_node *blk, void *env) {
276 ssa_destr_env_t *sde = env;
279 const arch_register_class_t *cls;
281 /* for all argument positions of the phis */
282 for (pos=0, max=get_irn_arity(blk); pos<max; ++pos) {
284 /* for all phi nodes (which are scheduled first) */
285 sched_foreach(blk, phi) {
289 if (arch_irn_is(sde->aenv, phi, ignore))
292 cls = arch_get_irn_reg_class(sde->aenv, phi, -1);
293 insert_copies(sde, cls, phi, pos, phi);
299 set *be_ssa_destr_simple(ir_graph *irg, const arch_env_t *aenv) {
304 sde.vars = new_set(compare_var_infos, 16);
307 irg_block_walk_graph(irg, ssa_destr_simple_walker, NULL, &sde);
309 /* Mapping of SSA-Values <--> Variables */
310 pc = phi_class_new_from_irg(irg, 0);
312 irg_walk_graph(irg, values_to_vars, NULL, &sde);
317 void free_ssa_destr_simple(set *vars)
321 set_foreach(vars, vi)
322 del_pset(vi->values);