ir_constant_expression.cpp revision f14e596f11b4e44c75a880536efb1e8c5a72da7d 
1/*
2 * Copyright © 2010 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24/**
25 * \file ir_constant_expression.cpp
26 * Evaluate and process constant valued expressions
27 *
28 * In GLSL, constant valued expressions are used in several places.  These
29 * must be processed and evaluated very early in the compilation process.
30 *
31 *    * Sizes of arrays
32 *    * Initializers for uniforms
33 *    * Initializers for \c const variables
34 */
35
36#include <math.h>
37#include "ir.h"
38#include "ir_visitor.h"
39#include "glsl_types.h"
40
41/**
42 * Visitor class for evaluating constant expressions
43 */
44class ir_constant_visitor : public ir_visitor {
45public:
46   ir_constant_visitor()
47      : value(NULL)
48   {
49      /* empty */
50   }
51
52   virtual ~ir_constant_visitor()
53   {
54      /* empty */
55   }
56
57   /**
58    * \name Visit methods
59    *
60    * As typical for the visitor pattern, there must be one \c visit method for
61    * each concrete subclass of \c ir_instruction.  Virtual base classes within
62    * the hierarchy should not have \c visit methods.
63    */
64   /*@{*/
65   virtual void visit(ir_variable *);
66   virtual void visit(ir_function_signature *);
67   virtual void visit(ir_function *);
68   virtual void visit(ir_expression *);
69   virtual void visit(ir_texture *);
70   virtual void visit(ir_swizzle *);
71   virtual void visit(ir_dereference_variable *);
72   virtual void visit(ir_dereference_array *);
73   virtual void visit(ir_dereference_record *);
74   virtual void visit(ir_assignment *);
75   virtual void visit(ir_constant *);
76   virtual void visit(ir_call *);
77   virtual void visit(ir_return *);
78   virtual void visit(ir_discard *);
79   virtual void visit(ir_if *);
80   virtual void visit(ir_loop *);
81   virtual void visit(ir_loop_jump *);
82   /*@}*/
83
84   /**
85    * Value of the constant expression.
86    *
87    * \note
88    * This field will be \c NULL if the expression is not constant valued.
89    */
90   /* FINIHSME: This cannot hold values for constant arrays or structures. */
91   ir_constant *value;
92};
93
94
95ir_constant *
96ir_instruction::constant_expression_value()
97{
98   ir_constant_visitor visitor;
99
100   this->accept(& visitor);
101   return visitor.value;
102}
103
104
105void
106ir_constant_visitor::visit(ir_variable *ir)
107{
108   (void) ir;
109   value = NULL;
110}
111
112
113void
114ir_constant_visitor::visit(ir_function_signature *ir)
115{
116   (void) ir;
117   value = NULL;
118}
119
120
121void
122ir_constant_visitor::visit(ir_function *ir)
123{
124   (void) ir;
125   value = NULL;
126}
127
128void
129ir_constant_visitor::visit(ir_expression *ir)
130{
131   value = NULL;
132   ir_constant *op[2] = { NULL, NULL };
133   ir_constant_data data;
134
135   memset(&data, 0, sizeof(data));
136
137   for (unsigned operand = 0; operand < ir->get_num_operands(); operand++) {
138      op[operand] = ir->operands[operand]->constant_expression_value();
139      if (!op[operand])
140	 return;
141   }
142
143   if (op[1] != NULL)
144      assert(op[0]->type->base_type == op[1]->type->base_type);
145
146   bool op0_scalar = op[0]->type->is_scalar();
147   bool op1_scalar = op[1] != NULL && op[1]->type->is_scalar();
148
149   /* When iterating over a vector or matrix's components, we want to increase
150    * the loop counter.  However, for scalars, we want to stay at 0.
151    */
152   unsigned c0_inc = op0_scalar ? 1 : 0;
153   unsigned c1_inc = op1_scalar ? 1 : 0;
154   unsigned components = op[op1_scalar ? 0 : 1]->type->components();
155
156   switch (ir->operation) {
157   case ir_unop_logic_not:
158      assert(op[0]->type->base_type == GLSL_TYPE_BOOL);
159      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++)
160	 data.b[c] = !op[0]->value.b[c];
161      break;
162
163   case ir_unop_f2i:
164      assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
165      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
166	 data.i[c] = op[0]->value.f[c];
167      }
168      break;
169   case ir_unop_i2f:
170      assert(op[0]->type->base_type == GLSL_TYPE_UINT ||
171	     op[0]->type->base_type == GLSL_TYPE_INT);
172      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
173	 if (op[0]->type->base_type == GLSL_TYPE_INT)
174	    data.f[c] = op[0]->value.i[c];
175	 else
176	    data.f[c] = op[0]->value.u[c];
177      }
178      break;
179   case ir_unop_b2f:
180      assert(op[0]->type->base_type == GLSL_TYPE_BOOL);
181      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
182	 data.f[c] = op[0]->value.b[c] ? 1.0 : 0.0;
183      }
184      break;
185   case ir_unop_f2b:
186      assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
187      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
188	 data.b[c] = bool(op[0]->value.f[c]);
189      }
190      break;
191   case ir_unop_b2i:
192      assert(op[0]->type->base_type == GLSL_TYPE_BOOL);
193      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
194	 data.u[c] = op[0]->value.b[c] ? 1 : 0;
195      }
196      break;
197   case ir_unop_i2b:
198      assert(op[0]->type->is_integer());
199      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
200	 data.b[c] = bool(op[0]->value.u[c]);
201      }
202      break;
203
204   case ir_unop_fract:
205      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
206	 switch (ir->type->base_type) {
207	 case GLSL_TYPE_UINT:
208	    data.u[c] = 0;
209	    break;
210	 case GLSL_TYPE_INT:
211	    data.i[c] = 0;
212	    break;
213	 case GLSL_TYPE_FLOAT:
214	    data.f[c] = op[0]->value.f[c] - floor(op[0]->value.f[c]);
215	    break;
216	 default:
217	    assert(0);
218	 }
219      }
220      break;
221
222   case ir_unop_neg:
223      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
224	 switch (ir->type->base_type) {
225	 case GLSL_TYPE_UINT:
226	    data.u[c] = -op[0]->value.u[c];
227	    break;
228	 case GLSL_TYPE_INT:
229	    data.i[c] = -op[0]->value.i[c];
230	    break;
231	 case GLSL_TYPE_FLOAT:
232	    data.f[c] = -op[0]->value.f[c];
233	    break;
234	 default:
235	    assert(0);
236	 }
237      }
238      break;
239
240   case ir_unop_abs:
241      assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
242      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
243	 switch (ir->type->base_type) {
244	 case GLSL_TYPE_UINT:
245	    data.u[c] = op[0]->value.u[c];
246	    break;
247	 case GLSL_TYPE_INT:
248	    data.i[c] = op[0]->value.i[c];
249	    if (data.i[c] < 0)
250	       data.i[c] = -data.i[c];
251	    break;
252	 case GLSL_TYPE_FLOAT:
253	    data.f[c] = fabs(op[0]->value.f[c]);
254	    break;
255	 default:
256	    assert(0);
257	 }
258      }
259      break;
260
261   case ir_unop_rcp:
262      assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
263      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
264	 switch (ir->type->base_type) {
265	 case GLSL_TYPE_UINT:
266	    if (op[0]->value.u[c] != 0.0)
267	       data.u[c] = 1 / op[0]->value.u[c];
268	    break;
269	 case GLSL_TYPE_INT:
270	    if (op[0]->value.i[c] != 0.0)
271	       data.i[c] = 1 / op[0]->value.i[c];
272	    break;
273	 case GLSL_TYPE_FLOAT:
274	    if (op[0]->value.f[c] != 0.0)
275	       data.f[c] = 1.0 / op[0]->value.f[c];
276	    break;
277	 default:
278	    assert(0);
279	 }
280      }
281      break;
282
283   case ir_unop_rsq:
284      assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
285      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
286	 data.f[c] = 1.0 / sqrtf(op[0]->value.f[c]);
287      }
288      break;
289
290   case ir_unop_sqrt:
291      assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
292      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
293	 data.f[c] = sqrtf(op[0]->value.f[c]);
294      }
295      break;
296
297   case ir_unop_exp:
298      assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
299      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
300	 data.f[c] = expf(op[0]->value.f[c]);
301      }
302      break;
303
304   case ir_unop_log:
305      assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
306      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
307	 data.f[c] = logf(op[0]->value.f[c]);
308      }
309      break;
310
311   case ir_unop_dFdx:
312   case ir_unop_dFdy:
313      assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
314      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
315	 data.f[c] = 0.0;
316      }
317      break;
318
319   case ir_binop_dot:
320      assert(op[0]->type->is_vector() && op[1]->type->is_vector());
321      data.f[0] = 0;
322      for (unsigned c = 0; c < op[0]->type->components(); c++) {
323	 switch (ir->operands[0]->type->base_type) {
324	 case GLSL_TYPE_UINT:
325	    data.u[0] += op[0]->value.u[c] * op[1]->value.u[c];
326	    break;
327	 case GLSL_TYPE_INT:
328	    data.i[0] += op[0]->value.i[c] * op[1]->value.i[c];
329	    break;
330	 case GLSL_TYPE_FLOAT:
331	    data.f[0] += op[0]->value.f[c] * op[1]->value.f[c];
332	    break;
333	 default:
334	    assert(0);
335	 }
336      }
337
338      break;
339   case ir_binop_add:
340      assert(op[0]->type == op[1]->type || op0_scalar || op1_scalar);
341      for (unsigned c = 0, c0 = 0, c1 = 0;
342	   c < components;
343	   c0 += c0_inc, c1 += c1_inc, c++) {
344
345	 switch (ir->operands[0]->type->base_type) {
346	 case GLSL_TYPE_UINT:
347	    data.u[c] = op[0]->value.u[c0] + op[1]->value.u[c1];
348	    break;
349	 case GLSL_TYPE_INT:
350	    data.i[c] = op[0]->value.i[c0] + op[1]->value.i[c1];
351	    break;
352	 case GLSL_TYPE_FLOAT:
353	    data.f[c] = op[0]->value.f[c0] + op[1]->value.f[c1];
354	    break;
355	 default:
356	    assert(0);
357	 }
358      }
359
360      break;
361   case ir_binop_sub:
362      assert(op[0]->type == op[1]->type || op0_scalar || op1_scalar);
363      for (unsigned c = 0, c0 = 0, c1 = 0;
364	   c < components;
365	   c0 += c0_inc, c1 += c1_inc, c++) {
366
367	 switch (ir->operands[0]->type->base_type) {
368	 case GLSL_TYPE_UINT:
369	    data.u[c] = op[0]->value.u[c0] - op[1]->value.u[c1];
370	    break;
371	 case GLSL_TYPE_INT:
372	    data.i[c] = op[0]->value.i[c0] - op[1]->value.i[c1];
373	    break;
374	 case GLSL_TYPE_FLOAT:
375	    data.f[c] = op[0]->value.f[c0] - op[1]->value.f[c1];
376	    break;
377	 default:
378	    assert(0);
379	 }
380      }
381
382      break;
383   case ir_binop_mul:
384      /* Check for equal types, or unequal types involving scalars */
385      if ((op[0]->type == op[1]->type && !op[0]->type->is_matrix())
386	  || op0_scalar || op1_scalar) {
387	 for (unsigned c = 0, c0 = 0, c1 = 0;
388	      c < components;
389	      c0 += c0_inc, c1 += c1_inc, c++) {
390
391	    switch (ir->operands[0]->type->base_type) {
392	    case GLSL_TYPE_UINT:
393	       data.u[c] = op[0]->value.u[c0] * op[1]->value.u[c1];
394	       break;
395	    case GLSL_TYPE_INT:
396	       data.i[c] = op[0]->value.i[c0] * op[1]->value.i[c1];
397	       break;
398	    case GLSL_TYPE_FLOAT:
399	       data.f[c] = op[0]->value.f[c0] * op[1]->value.f[c1];
400	       break;
401	    default:
402	       assert(0);
403	    }
404	 }
405      } else {
406	 assert(op[0]->type->is_matrix() || op[1]->type->is_matrix());
407
408	 /* Multiply an N-by-M matrix with an M-by-P matrix.  Since either
409	  * matrix can be a GLSL vector, either N or P can be 1.
410	  *
411	  * For vec*mat, the vector is treated as a row vector.  This
412	  * means the vector is a 1-row x M-column matrix.
413	  *
414	  * For mat*vec, the vector is treated as a column vector.  Since
415	  * matrix_columns is 1 for vectors, this just works.
416	  */
417	 const unsigned n = op[0]->type->is_vector()
418	    ? 1 : op[0]->type->vector_elements;
419	 const unsigned m = op[1]->type->vector_elements;
420	 const unsigned p = op[1]->type->matrix_columns;
421	 for (unsigned j = 0; j < p; j++) {
422	    for (unsigned i = 0; i < n; i++) {
423	       for (unsigned k = 0; k < m; k++) {
424		  data.f[i+n*j] += op[0]->value.f[i+n*k]*op[1]->value.f[k+m*j];
425	       }
426	    }
427	 }
428      }
429
430      break;
431   case ir_binop_div:
432      assert(op[0]->type == op[1]->type || op0_scalar || op1_scalar);
433      for (unsigned c = 0, c0 = 0, c1 = 0;
434	   c < components;
435	   c0 += c0_inc, c1 += c1_inc, c++) {
436
437	 switch (ir->operands[0]->type->base_type) {
438	 case GLSL_TYPE_UINT:
439	    data.u[c] = op[0]->value.u[c0] / op[1]->value.u[c1];
440	    break;
441	 case GLSL_TYPE_INT:
442	    data.i[c] = op[0]->value.i[c0] / op[1]->value.i[c1];
443	    break;
444	 case GLSL_TYPE_FLOAT:
445	    data.f[c] = op[0]->value.f[c0] / op[1]->value.f[c1];
446	    break;
447	 default:
448	    assert(0);
449	 }
450      }
451
452      break;
453   case ir_binop_logic_and:
454      assert(op[0]->type->base_type == GLSL_TYPE_BOOL);
455      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++)
456	 data.b[c] = op[0]->value.b[c] && op[1]->value.b[c];
457      break;
458   case ir_binop_logic_xor:
459      assert(op[0]->type->base_type == GLSL_TYPE_BOOL);
460      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++)
461	 data.b[c] = op[0]->value.b[c] ^ op[1]->value.b[c];
462      break;
463   case ir_binop_logic_or:
464      assert(op[0]->type->base_type == GLSL_TYPE_BOOL);
465      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++)
466	 data.b[c] = op[0]->value.b[c] || op[1]->value.b[c];
467      break;
468
469   case ir_binop_less:
470      switch (ir->operands[0]->type->base_type) {
471      case GLSL_TYPE_UINT:
472	 data.b[0] = op[0]->value.u[0] < op[1]->value.u[0];
473	 break;
474      case GLSL_TYPE_INT:
475	 data.b[0] = op[0]->value.i[0] < op[1]->value.i[0];
476	 break;
477      case GLSL_TYPE_FLOAT:
478	 data.b[0] = op[0]->value.f[0] < op[1]->value.f[0];
479	 break;
480      default:
481	 assert(0);
482      }
483      break;
484   case ir_binop_greater:
485      switch (ir->operands[0]->type->base_type) {
486      case GLSL_TYPE_UINT:
487	 data.b[0] = op[0]->value.u[0] > op[1]->value.u[0];
488	 break;
489      case GLSL_TYPE_INT:
490	 data.b[0] = op[0]->value.i[0] > op[1]->value.i[0];
491	 break;
492      case GLSL_TYPE_FLOAT:
493	 data.b[0] = op[0]->value.f[0] > op[1]->value.f[0];
494	 break;
495      default:
496	 assert(0);
497      }
498      break;
499   case ir_binop_lequal:
500      switch (ir->operands[0]->type->base_type) {
501      case GLSL_TYPE_UINT:
502	 data.b[0] = op[0]->value.u[0] <= op[1]->value.u[0];
503	 break;
504      case GLSL_TYPE_INT:
505	 data.b[0] = op[0]->value.i[0] <= op[1]->value.i[0];
506	 break;
507      case GLSL_TYPE_FLOAT:
508	 data.b[0] = op[0]->value.f[0] <= op[1]->value.f[0];
509	 break;
510      default:
511	 assert(0);
512      }
513      break;
514   case ir_binop_gequal:
515      switch (ir->operands[0]->type->base_type) {
516      case GLSL_TYPE_UINT:
517	 data.b[0] = op[0]->value.u[0] >= op[1]->value.u[0];
518	 break;
519      case GLSL_TYPE_INT:
520	 data.b[0] = op[0]->value.i[0] >= op[1]->value.i[0];
521	 break;
522      case GLSL_TYPE_FLOAT:
523	 data.b[0] = op[0]->value.f[0] >= op[1]->value.f[0];
524	 break;
525      default:
526	 assert(0);
527      }
528      break;
529
530   case ir_binop_equal:
531      data.b[0] = true;
532      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
533	 switch (ir->operands[0]->type->base_type) {
534	 case GLSL_TYPE_UINT:
535	    data.b[0] = data.b[0] && op[0]->value.u[c] == op[1]->value.u[c];
536	    break;
537	 case GLSL_TYPE_INT:
538	    data.b[0] = data.b[0] && op[0]->value.i[c] == op[1]->value.i[c];
539	    break;
540	 case GLSL_TYPE_FLOAT:
541	    data.b[0] = data.b[0] && op[0]->value.f[c] == op[1]->value.f[c];
542	    break;
543	 case GLSL_TYPE_BOOL:
544	    data.b[0] = data.b[0] && op[0]->value.b[c] == op[1]->value.b[c];
545	    break;
546	 default:
547	    assert(0);
548	 }
549      }
550      break;
551   case ir_binop_nequal:
552      data.b[0] = false;
553      for (unsigned c = 0; c < ir->operands[0]->type->components(); c++) {
554	 switch (ir->operands[0]->type->base_type) {
555	 case GLSL_TYPE_UINT:
556	    data.b[0] = data.b[0] || op[0]->value.u[c] != op[1]->value.u[c];
557	    break;
558	 case GLSL_TYPE_INT:
559	    data.b[0] = data.b[0] || op[0]->value.i[c] != op[1]->value.i[c];
560	    break;
561	 case GLSL_TYPE_FLOAT:
562	    data.b[0] = data.b[0] || op[0]->value.f[c] != op[1]->value.f[c];
563	    break;
564	 case GLSL_TYPE_BOOL:
565	    data.b[0] = data.b[0] || op[0]->value.b[c] != op[1]->value.b[c];
566	    break;
567	 default:
568	    assert(0);
569	 }
570      }
571      break;
572
573   default:
574      /* FINISHME: Should handle all expression types. */
575      return;
576   }
577
578   void *ctx = talloc_parent(ir);
579   this->value = new(ctx) ir_constant(ir->type, &data);
580}
581
582
583void
584ir_constant_visitor::visit(ir_texture *ir)
585{
586   // FINISHME: Do stuff with texture lookups
587   (void) ir;
588   value = NULL;
589}
590
591
592void
593ir_constant_visitor::visit(ir_swizzle *ir)
594{
595   ir_constant *v = ir->val->constant_expression_value();
596
597   this->value = NULL;
598
599   if (v != NULL) {
600      ir_constant_data data;
601
602      const unsigned swiz_idx[4] = {
603	 ir->mask.x, ir->mask.y, ir->mask.z, ir->mask.w
604      };
605
606      for (unsigned i = 0; i < ir->mask.num_components; i++) {
607	 switch (v->type->base_type) {
608	 case GLSL_TYPE_UINT:
609	 case GLSL_TYPE_INT:   data.u[i] = v->value.u[swiz_idx[i]]; break;
610	 case GLSL_TYPE_FLOAT: data.f[i] = v->value.f[swiz_idx[i]]; break;
611	 case GLSL_TYPE_BOOL:  data.b[i] = v->value.b[swiz_idx[i]]; break;
612	 default:              assert(!"Should not get here."); break;
613	 }
614      }
615
616      void *ctx = talloc_parent(ir);
617      this->value = new(ctx) ir_constant(ir->type, &data);
618   }
619}
620
621
622void
623ir_constant_visitor::visit(ir_dereference_variable *ir)
624{
625   value = NULL;
626
627   ir_variable *var = ir->variable_referenced();
628   if (var && var->constant_value)
629      value = (ir_constant *)var->constant_value->clone(NULL);
630}
631
632
633void
634ir_constant_visitor::visit(ir_dereference_array *ir)
635{
636   void *ctx = talloc_parent(ir);
637   ir_constant *array = ir->array->constant_expression_value();
638   ir_constant *idx = ir->array_index->constant_expression_value();
639
640   this->value = NULL;
641
642   if ((array != NULL) && (idx != NULL)) {
643      if (array->type->is_matrix()) {
644	 /* Array access of a matrix results in a vector.
645	  */
646	 const unsigned column = idx->value.u[0];
647
648	 const glsl_type *const column_type = array->type->column_type();
649
650	 /* Offset in the constant matrix to the first element of the column
651	  * to be extracted.
652	  */
653	 const unsigned mat_idx = column * column_type->vector_elements;
654
655	 ir_constant_data data;
656
657	 switch (column_type->base_type) {
658	 case GLSL_TYPE_UINT:
659	 case GLSL_TYPE_INT:
660	    for (unsigned i = 0; i < column_type->vector_elements; i++)
661	       data.u[i] = array->value.u[mat_idx + i];
662
663	    break;
664
665	 case GLSL_TYPE_FLOAT:
666	    for (unsigned i = 0; i < column_type->vector_elements; i++)
667	       data.f[i] = array->value.f[mat_idx + i];
668
669	    break;
670
671	 default:
672	    assert(!"Should not get here.");
673	    break;
674	 }
675
676	 this->value = new(ctx) ir_constant(column_type, &data);
677      } else if (array->type->is_vector()) {
678	 const unsigned component = idx->value.u[0];
679
680	 this->value = new(ctx) ir_constant(array, component);
681      } else {
682	 /* FINISHME: Handle access of constant arrays. */
683      }
684   }
685}
686
687
688void
689ir_constant_visitor::visit(ir_dereference_record *ir)
690{
691   ir_constant *v = ir->record->constant_expression_value();
692
693   this->value = (v != NULL) ? v->get_record_field(ir->field) : NULL;
694}
695
696
697void
698ir_constant_visitor::visit(ir_assignment *ir)
699{
700   (void) ir;
701   value = NULL;
702}
703
704
705void
706ir_constant_visitor::visit(ir_constant *ir)
707{
708   value = ir;
709}
710
711
712void
713ir_constant_visitor::visit(ir_call *ir)
714{
715   (void) ir;
716   value = NULL;
717}
718
719
720void
721ir_constant_visitor::visit(ir_return *ir)
722{
723   (void) ir;
724   value = NULL;
725}
726
727
728void
729ir_constant_visitor::visit(ir_discard *ir)
730{
731   (void) ir;
732   value = NULL;
733}
734
735
736void
737ir_constant_visitor::visit(ir_if *ir)
738{
739   (void) ir;
740   value = NULL;
741}
742
743
744void
745ir_constant_visitor::visit(ir_loop *ir)
746{
747   (void) ir;
748   value = NULL;
749}
750
751
752void
753ir_constant_visitor::visit(ir_loop_jump *ir)
754{
755   (void) ir;
756   value = NULL;
757}
758