for now forbid rematerialisation of flag changing nodes
[libfirm] / ir / lower / lower_mode_b.c
1 /*
2  * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
3  *
4  * This file is part of libFirm.
5  *
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.
10  *
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.
14  *
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
17  * PURPOSE.
18  */
19
20 /**
21  * @file
22  * @author      Matthias Braun, Christoph Mallon
23  * @version     $Id$
24  */
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28
29 #include <stdlib.h>
30
31 #include "irnode_t.h"
32 #include "ircons_t.h"
33 #include "irgwalk.h"
34 #include "irtools.h"
35 #include "tv.h"
36 #include "error.h"
37 #include "lowering.h"
38
39 static ir_mode *lowered_mode     = NULL;
40 static int      lower_direct_cmp = 0;
41 static ir_type *lowered_type     = NULL;
42
43 static ir_node *create_not(dbg_info *dbgi, ir_node *node)
44 {
45         ir_graph *irg    = current_ir_graph;
46         ir_node  *block  = get_nodes_block(node);
47         tarval   *tv_one = get_tarval_one(lowered_mode);
48         ir_node  *one    = new_d_Const(dbgi, lowered_mode, tv_one);
49
50         return new_rd_Eor(dbgi, irg, block, node, one, lowered_mode);
51 }
52
53 static ir_node *create_convb(ir_node *node)
54 {
55         ir_graph *irg   = current_ir_graph;
56         ir_node  *block = get_nodes_block(node);
57         ir_node  *conv  = new_rd_Conv(NULL, irg, block, node, mode_b);
58
59         return conv;
60 }
61
62 static ir_node *create_conv_lowered_mode(ir_node *node)
63 {
64         ir_graph *irg   = current_ir_graph;
65         ir_node  *block = get_nodes_block(node);
66         ir_node  *conv  = new_rd_Conv(NULL, irg, block, node, lowered_mode);
67
68         return conv;
69 }
70
71 static ir_type *create_lowered_type(void)
72 {
73         if(lowered_type == NULL) {
74                 lowered_type = new_type_primitive(new_id_from_str("__lowered_mode_b"),
75                                                   lowered_mode);
76         }
77         return lowered_type;
78 }
79
80 static void adjust_method_type(ir_type *method_type)
81 {
82         int i;
83         int n_params;
84         int n_res;
85
86         n_params = get_method_n_params(method_type);
87         for(i = 0; i < n_params; ++i) {
88                 ir_type *param = get_method_param_type(method_type, i);
89                 if(get_type_mode(param) == mode_b) {
90                         set_method_param_type(method_type, i, create_lowered_type());
91                 }
92         }
93
94         n_res = get_method_n_ress(method_type);
95         for(i = 0; i < n_res; ++i) {
96                 ir_type *res_type = get_method_res_type(method_type, i);
97                 if(get_type_mode(res_type) == mode_b) {
98                         set_method_res_type(method_type, i, create_lowered_type());
99                 }
100         }
101 }
102
103 static ir_node *lower_node(ir_node *node)
104 {
105         ir_graph *irg   = current_ir_graph;
106         dbg_info *dbgi  = get_irn_dbg_info(node);
107         ir_op    *op    = get_irn_op(node);
108         ir_node  *block = get_nodes_block(node);
109         ir_node  *res;
110
111         assert(get_irn_mode(node) == mode_b);
112
113         res = get_irn_link(node);
114         if(res != NULL)
115                 return res;
116
117         /* TODO: be robust against phi-loops... */
118         if(op == op_Phi) {
119                 int       i, arity;
120                 ir_node **in;
121                 ir_node  *unknown, *new_phi;
122
123                 arity = get_irn_arity(node);
124                 in    = alloca(arity * sizeof(in[0]));
125                 unknown = new_Unknown(lowered_mode);
126                 for(i = 0; i < arity; ++i) {
127                         in[i] = unknown;
128                 }
129                 new_phi = new_rd_Phi(dbgi, irg, block, arity, in,
130                                               lowered_mode);
131                 set_irn_link(node, new_phi);
132
133                 for(i = 0; i < arity; ++i) {
134                         ir_node *in     = get_irn_n(node, i);
135                         ir_node *low_in = lower_node(in);
136
137                         set_irn_n(new_phi, i, low_in);
138                 }
139
140                 return new_phi;
141         }
142
143         if(op == op_And || op == op_Or || op == op_Eor) {
144                 int i, arity;
145                 ir_node *copy = exact_copy(node);
146
147                 arity = get_irn_arity(node);
148                 for(i = 0; i < arity; ++i) {
149                         ir_node *in     = get_irn_n(node, i);
150                         ir_node *low_in = lower_node(in);
151
152                         set_irn_n(copy, i, low_in);
153                 }
154                 set_irn_mode(copy, lowered_mode);
155
156                 set_irn_link(node, copy);
157                 return copy;
158         }
159         if(op == op_Not) {
160                 ir_node *op     = get_Not_op(node);
161                 ir_node *low_op = lower_node(op);
162
163                 res = create_not(dbgi, low_op);
164                 set_irn_link(node, res);
165                 return res;
166         }
167         if(op == op_Psi) {
168                 ir_node *cond        = get_Psi_cond(node, 0);
169                 ir_node *low_cond    = lower_node(cond);
170                 ir_node *v_true      = get_Psi_val(node, 0);
171                 ir_node *low_v_true  = lower_node(v_true);
172                 ir_node *v_false     = get_Psi_default(node);
173                 ir_node *low_v_false = lower_node(v_false);
174
175                 ir_node *and0     = new_rd_And(dbgi, irg, block, low_cond, low_v_true,
176                                                lowered_mode);
177
178                 ir_node *not_cond = create_not(dbgi, low_cond);
179
180                 ir_node *and1     = new_rd_And(dbgi, irg, block, not_cond, low_v_false,
181                                                lowered_mode);
182
183                 ir_node *or       = new_rd_Or(dbgi, irg, block, and0, and1,
184                                               lowered_mode);
185
186                 set_irn_link(node, or);
187                 return or;
188         }
189         if(op == op_Conv) {
190                 tarval  *tv_one   = get_tarval_one(lowered_mode);
191                 ir_node *one      = new_d_Const(dbgi, lowered_mode, tv_one);
192                 tarval  *tv_zero  = get_tarval_null(lowered_mode);
193                 ir_node *zero     = new_d_Const(dbgi, lowered_mode, tv_zero);
194                 ir_node *pred     = get_Conv_op(node);
195                 ir_mode *mode     = get_irn_mode(pred);
196                 tarval  *tv_zeroc = get_tarval_null(mode);
197                 ir_node *zero_cmp = new_d_Const(dbgi, mode, tv_zeroc);
198
199                 ir_node *cmp      = new_rd_Cmp(dbgi, irg, block, pred, zero_cmp);
200                 ir_node *proj     = new_rd_Proj(dbgi, irg, block, cmp, mode_b,
201                                                 pn_Cmp_Lg);
202                 ir_node *vals[2]  = { one, zero };
203                 ir_node *psi      = new_rd_Psi(dbgi, irg, block, 1, &proj, vals,
204                                                lowered_mode);
205
206                 set_irn_link(node, psi);
207                 return psi;
208         }
209         if(op == op_Proj) {
210                 ir_node *pred = get_Proj_pred(node);
211
212                 if(is_Cmp(pred)) {
213                         ir_node *left  = get_Cmp_left(pred);
214                         ir_node *right = get_Cmp_right(pred);
215                         ir_mode *mode  = get_irn_mode(left);
216
217                         if ((mode_is_int(mode) || mode_is_reference(mode)) && (
218                                                 get_mode_size_bits(mode) < get_mode_size_bits(lowered_mode) ||
219                                                 (is_Const(right) && is_Const_null(right))
220                                         )) {
221                                 int      pnc      = get_Proj_proj(node);
222                                 int      need_not = 0;
223                                 ir_node *a        = NULL;
224                                 ir_node *b        = NULL;
225
226                                 if(pnc == pn_Cmp_Lt) {
227                                         /* a < b  ->  (a - b) >> 31 */
228                                         a = left;
229                                         b = right;
230                                 } else if(pnc == pn_Cmp_Le) {
231                                         /* a <= b  -> ((a - b) >> 31) ^ 1 */
232                                         a        = right;
233                                         b        = left;
234                                         need_not = 1;
235                                 } else if(pnc == pn_Cmp_Gt) {
236                                         /* a > b   -> (b - a) >> 31 */
237                                         a = right;
238                                         b = left;
239                                 } else if(pnc == pn_Cmp_Ge) {
240                                         /* a >= b   -> ((a - b) >> 31) ^ 1 */
241                                         a        = left;
242                                         b        = right;
243                                         need_not = 1;
244                                 }
245
246                                 if(a != NULL) {
247                                         tarval  *tv        = new_tarval_from_long(31, mode_Iu);
248                                         ir_node *shift_cnt = new_d_Const(dbgi, mode_Iu, tv);
249
250                                         if(mode != lowered_mode) {
251                                                 a = new_rd_Conv(dbgi, irg, block, a, lowered_mode);
252                                                 b = new_rd_Conv(dbgi, irg, block, b, lowered_mode);
253                                         }
254
255                                         res = new_rd_Sub(dbgi, irg, block, a, b, lowered_mode);
256                                         res = new_rd_Shr(dbgi, irg, block, res, shift_cnt,
257                                                          lowered_mode);
258
259                                         if(need_not) {
260                                                 res = create_not(dbgi, res);
261                                         }
262                                         set_irn_link(node, res);
263                                         return res;
264                                 }
265                         }
266
267                         {
268                         /* synthesize the 0/1 value */
269                         tarval  *tv_one  = get_tarval_one(lowered_mode);
270                         ir_node *one     = new_d_Const(dbgi, lowered_mode, tv_one);
271                         tarval  *tv_zero = get_tarval_null(lowered_mode);
272                         ir_node *zero    = new_d_Const(dbgi, lowered_mode, tv_zero);
273
274                         ir_node *vals[2] = { one, zero };
275                         ir_node *psi     = new_rd_Psi(dbgi, irg, block, 1, &node, vals,
276                                                       lowered_mode);
277
278                         set_irn_link(node, psi);
279                         return psi;
280                         }
281                 } else if(is_Proj(pred) && is_Call(get_Proj_pred(pred))) {
282                         ir_type   *type   = get_Call_type(get_Proj_pred(pred));
283                         adjust_method_type(type);
284                         set_irn_mode(node, lowered_mode);
285                         return node;
286                 } else if(is_Proj(pred) && is_Start(get_Proj_pred(pred))) {
287                         ir_entity *entity = get_irg_entity(irg);
288                         ir_type   *type   = get_entity_type(entity);
289                         adjust_method_type(type);
290                         set_irn_mode(node, lowered_mode);
291                         return node;
292                 }
293
294                 panic("unexpected projb: %+F (pred: %+F)", node, pred);
295         }
296         if(op == op_Const) {
297                 tarval *tv = get_Const_tarval(node);
298                 if(tv == get_tarval_b_true()) {
299                         tarval  *tv_one  = get_tarval_one(lowered_mode);
300                         res              = new_d_Const(dbgi, lowered_mode, tv_one);
301                 } else if(tv == get_tarval_b_false()) {
302                         tarval  *tv_zero = get_tarval_null(lowered_mode);
303                         res              = new_d_Const(dbgi, lowered_mode, tv_zero);
304                 } else {
305                         panic("invalid boolean const %+F", node);
306                 }
307                 set_irn_link(node, res);
308                 return res;
309         }
310
311         panic("didn't expect %+F to have mode_b", node);
312 }
313
314 static void lower_mode_b_walker(ir_node *node, void *env)
315 {
316         int i, arity;
317         (void) env;
318
319         arity = get_irn_arity(node);
320         for(i = 0; i < arity; ++i) {
321                 ir_node *lowered_in;
322                 ir_node *in = get_irn_n(node, i);
323                 if(get_irn_mode(in) != mode_b)
324                         continue;
325
326                 if(! lower_direct_cmp) {
327                         if(is_Cond(node)
328                                         || (is_Psi(node) && get_irn_mode(node) != mode_b)) {
329                                 if(is_Proj(in)) {
330                                         ir_node *pred = get_Proj_pred(in);
331                                         if(is_Cmp(pred))
332                                                 continue;
333                                 }
334                         }
335                 }
336
337                 lowered_in = lower_node(in);
338
339                 if(is_Return(node)) {
340                         ir_entity *entity = get_irg_entity(current_ir_graph);
341                         ir_type   *type   = get_entity_type(entity);
342                         adjust_method_type(type);
343                 } else if(is_Call(node)) {
344                         ir_type *type = get_Call_type(node);
345                         adjust_method_type(type);
346                 } else {
347                         lowered_in = create_convb(lowered_in);
348                 }
349                 set_irn_n(node, i, lowered_in);
350         }
351 }
352
353 static void clear_links(ir_node *node, void *env)
354 {
355         (void) env;
356         set_irn_link(node, NULL);
357 }
358
359 void ir_lower_mode_b(ir_graph *irg, ir_mode *mode, int do_lower_direct_cmp)
360 {
361         lowered_mode     = mode;
362         lower_direct_cmp = do_lower_direct_cmp;
363         set_using_irn_link(irg);
364         irg_walk_graph(irg, clear_links, NULL, NULL);
365         irg_walk_graph(irg, lower_mode_b_walker, NULL, NULL);
366         clear_using_irn_link(irg);
367 }