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simplify_expr.cpp
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1/*******************************************************************\
2
3Module:
4
5Author: Daniel Kroening, kroening@kroening.com
6
7\*******************************************************************/
8
9#include "simplify_expr.h"
10
11#include <algorithm>
12
13#include "bitvector_expr.h"
14#include "byte_operators.h"
15#include "c_types.h"
16#include "config.h"
17#include "expr_util.h"
18#include "fixedbv.h"
19#include "floatbv_expr.h"
20#include "invariant.h"
21#include "mathematical_expr.h"
22#include "namespace.h"
23#include "pointer_expr.h"
24#include "pointer_offset_size.h"
25#include "pointer_offset_sum.h"
26#include "rational.h"
27#include "rational_tools.h"
28#include "simplify_utils.h"
29#include "std_expr.h"
30#include "string_expr.h"
31
32// #define DEBUGX
33
34#ifdef DEBUGX
35#include "format_expr.h"
36#include <iostream>
37#endif
38
39#include "simplify_expr_class.h"
40
41// #define USE_CACHE
42
43#ifdef USE_CACHE
44struct simplify_expr_cachet
45{
46public:
47 #if 1
48 typedef std::unordered_map<
49 exprt, exprt, irep_full_hash, irep_full_eq> containert;
50 #else
51 typedef std::unordered_map<exprt, exprt, irep_hash> containert;
52 #endif
53
54 containert container_normal;
55
56 containert &container()
57 {
58 return container_normal;
59 }
60};
61
62simplify_expr_cachet simplify_expr_cache;
63#endif
64
66{
67 if(expr.op().is_constant())
68 {
69 const typet &type = to_unary_expr(expr).op().type();
70
71 if(type.id()==ID_floatbv)
72 {
74 value.set_sign(false);
75 return value.to_expr();
76 }
77 else if(type.id()==ID_signedbv ||
78 type.id()==ID_unsignedbv)
79 {
80 auto value = numeric_cast<mp_integer>(to_unary_expr(expr).op());
81 if(value.has_value())
82 {
83 if(*value >= 0)
84 {
85 return to_unary_expr(expr).op();
86 }
87 else
88 {
89 value->negate();
90 return from_integer(*value, type);
91 }
92 }
93 }
94 }
95
96 return unchanged(expr);
97}
98
100{
101 if(expr.op().is_constant())
102 {
103 const typet &type = expr.op().type();
104
105 if(type.id()==ID_floatbv)
106 {
108 return make_boolean_expr(value.get_sign());
109 }
110 else if(type.id()==ID_signedbv ||
111 type.id()==ID_unsignedbv)
112 {
113 const auto value = numeric_cast<mp_integer>(expr.op());
114 if(value.has_value())
115 {
116 return make_boolean_expr(*value >= 0);
117 }
118 }
119 }
120
121 return unchanged(expr);
122}
123
126{
127 const exprt &op = expr.op();
128
129 if(op.is_constant())
130 {
131 const typet &op_type = op.type();
132
133 if(op_type.id() == ID_signedbv || op_type.id() == ID_unsignedbv)
134 {
135 const auto width = to_bitvector_type(op_type).get_width();
136 const auto &value = to_constant_expr(op).get_value();
137 std::size_t result = 0;
138
139 for(std::size_t i = 0; i < width; i++)
140 if(get_bvrep_bit(value, width, i))
141 result++;
142
143 return from_integer(result, expr.type());
144 }
145 }
146
147 return unchanged(expr);
148}
149
152{
153 const bool is_little_endian =
155
156 const auto const_bits_opt = expr2bits(expr.op(), is_little_endian, ns);
157
158 if(!const_bits_opt.has_value())
159 return unchanged(expr);
160
161 std::size_t n_leading_zeros =
162 is_little_endian ? const_bits_opt->rfind('1') : const_bits_opt->find('1');
163 if(n_leading_zeros == std::string::npos)
164 {
165 if(!expr.zero_permitted())
166 return unchanged(expr);
167
168 n_leading_zeros = const_bits_opt->size();
169 }
170 else if(is_little_endian)
171 n_leading_zeros = const_bits_opt->size() - n_leading_zeros - 1;
172
173 return from_integer(n_leading_zeros, expr.type());
174}
175
178{
179 const bool is_little_endian =
181
182 const auto const_bits_opt = expr2bits(expr.op(), is_little_endian, ns);
183
184 if(!const_bits_opt.has_value())
185 return unchanged(expr);
186
187 std::size_t n_trailing_zeros =
188 is_little_endian ? const_bits_opt->find('1') : const_bits_opt->rfind('1');
189 if(n_trailing_zeros == std::string::npos)
190 {
191 if(!expr.zero_permitted())
192 return unchanged(expr);
193
194 n_trailing_zeros = const_bits_opt->size();
195 }
196 else if(!is_little_endian)
197 n_trailing_zeros = const_bits_opt->size() - n_trailing_zeros - 1;
198
199 return from_integer(n_trailing_zeros, expr.type());
200}
201
204{
205 const bool is_little_endian =
207
208 const auto const_bits_opt = expr2bits(expr.op(), is_little_endian, ns);
209
210 if(!const_bits_opt.has_value())
211 return unchanged(expr);
212
213 std::size_t first_one_bit =
214 is_little_endian ? const_bits_opt->find('1') : const_bits_opt->rfind('1');
215 if(first_one_bit == std::string::npos)
216 first_one_bit = 0;
217 else if(is_little_endian)
218 ++first_one_bit;
219 else
220 first_one_bit = const_bits_opt->size() - first_one_bit;
221
222 return from_integer(first_one_bit, expr.type());
223}
224
230 const function_application_exprt &expr,
231 const namespacet &ns)
232{
233 const refined_string_exprt &s1 = to_string_expr(expr.arguments().at(0));
234 const auto s1_data_opt = try_get_string_data_array(s1.content(), ns);
235
236 if(!s1_data_opt)
237 return simplify_exprt::unchanged(expr);
238
239 const array_exprt &s1_data = s1_data_opt->get();
240 const refined_string_exprt &s2 = to_string_expr(expr.arguments().at(1));
241 const auto s2_data_opt = try_get_string_data_array(s2.content(), ns);
242
243 if(!s2_data_opt)
244 return simplify_exprt::unchanged(expr);
245
246 const array_exprt &s2_data = s2_data_opt->get();
247 const bool res = s2_data.operands().size() <= s1_data.operands().size() &&
248 std::equal(
249 s2_data.operands().rbegin(),
250 s2_data.operands().rend(),
251 s1_data.operands().rbegin());
252
253 return from_integer(res ? 1 : 0, expr.type());
254}
255
258 const function_application_exprt &expr,
259 const namespacet &ns)
260{
261 // We want to get both arguments of any starts-with comparison, and
262 // trace them back to the actual string instance. All variables on the
263 // way must be constant for us to be sure this will work.
264 auto &first_argument = to_string_expr(expr.arguments().at(0));
265 auto &second_argument = to_string_expr(expr.arguments().at(1));
266
267 const auto first_value_opt =
268 try_get_string_data_array(first_argument.content(), ns);
269
270 if(!first_value_opt)
271 {
272 return simplify_exprt::unchanged(expr);
273 }
274
275 const array_exprt &first_value = first_value_opt->get();
276
277 const auto second_value_opt =
278 try_get_string_data_array(second_argument.content(), ns);
279
280 if(!second_value_opt)
281 {
282 return simplify_exprt::unchanged(expr);
283 }
284
285 const array_exprt &second_value = second_value_opt->get();
286
287 // Is our 'contains' array directly contained in our target.
288 const bool includes =
289 std::search(
290 first_value.operands().begin(),
291 first_value.operands().end(),
292 second_value.operands().begin(),
293 second_value.operands().end()) != first_value.operands().end();
294
295 return from_integer(includes ? 1 : 0, expr.type());
296}
297
303 const function_application_exprt &expr,
304 const namespacet &ns)
305{
306 const function_application_exprt &function_app =
308 const refined_string_exprt &s =
309 to_string_expr(function_app.arguments().at(0));
310
311 if(!s.length().is_constant())
312 return simplify_exprt::unchanged(expr);
313
314 const auto numeric_length =
316
317 return from_integer(numeric_length == 0 ? 1 : 0, expr.type());
318}
319
328 const function_application_exprt &expr,
329 const namespacet &ns)
330{
331 const refined_string_exprt &s1 = to_string_expr(expr.arguments().at(0));
332 const auto s1_data_opt = try_get_string_data_array(s1.content(), ns);
333
334 if(!s1_data_opt)
335 return simplify_exprt::unchanged(expr);
336
337 const refined_string_exprt &s2 = to_string_expr(expr.arguments().at(1));
338 const auto s2_data_opt = try_get_string_data_array(s2.content(), ns);
339
340 if(!s2_data_opt)
341 return simplify_exprt::unchanged(expr);
342
343 const array_exprt &s1_data = s1_data_opt->get();
344 const array_exprt &s2_data = s2_data_opt->get();
345
346 if(s1_data.operands() == s2_data.operands())
347 return from_integer(0, expr.type());
348
349 const mp_integer s1_size = s1_data.operands().size();
350 const mp_integer s2_size = s2_data.operands().size();
351 const bool first_shorter = s1_size < s2_size;
352 const exprt::operandst &ops1 =
353 first_shorter ? s1_data.operands() : s2_data.operands();
354 const exprt::operandst &ops2 =
355 first_shorter ? s2_data.operands() : s1_data.operands();
356 auto it_pair = std::mismatch(ops1.begin(), ops1.end(), ops2.begin());
357
358 if(it_pair.first == ops1.end())
359 return from_integer(s1_size - s2_size, expr.type());
360
361 const mp_integer char1 =
363 const mp_integer char2 =
365
366 return from_integer(
367 first_shorter ? char1 - char2 : char2 - char1, expr.type());
368}
369
377 const function_application_exprt &expr,
378 const namespacet &ns,
379 const bool search_from_end)
380{
381 std::size_t starting_index = 0;
382
383 // Determine starting index for the comparison (if given)
384 if(expr.arguments().size() == 3)
385 {
386 auto &starting_index_expr = expr.arguments().at(2);
387
388 if(!starting_index_expr.is_constant())
389 {
390 return simplify_exprt::unchanged(expr);
391 }
392
393 const mp_integer idx =
394 numeric_cast_v<mp_integer>(to_constant_expr(starting_index_expr));
395
396 // Negative indices are treated like 0
397 if(idx > 0)
398 {
399 starting_index = numeric_cast_v<std::size_t>(idx);
400 }
401 }
402
403 const refined_string_exprt &s1 = to_string_expr(expr.arguments().at(0));
404
405 const auto s1_data_opt = try_get_string_data_array(s1.content(), ns);
406
407 if(!s1_data_opt)
408 {
409 return simplify_exprt::unchanged(expr);
410 }
411
412 const array_exprt &s1_data = s1_data_opt->get();
413
414 const auto search_string_size = s1_data.operands().size();
415 if(starting_index >= search_string_size)
416 {
417 return from_integer(-1, expr.type());
418 }
419
420 unsigned long starting_offset =
421 starting_index > 0 ? (search_string_size - 1) - starting_index : 0;
423 {
424 // Second argument is a string
425
426 const refined_string_exprt &s2 = to_string_expr(expr.arguments().at(1));
427
428 const auto s2_data_opt = try_get_string_data_array(s2.content(), ns);
429
430 if(!s2_data_opt)
431 {
432 return simplify_exprt::unchanged(expr);
433 }
434
435 const array_exprt &s2_data = s2_data_opt->get();
436
437 // Searching for empty string is a special case and is simply the
438 // "always found at the first searched position. This needs to take into
439 // account starting position and if you're starting from the beginning or
440 // end.
441 if(s2_data.operands().empty())
442 return from_integer(
443 search_from_end
444 ? starting_index > 0 ? starting_index : search_string_size
445 : 0,
446 expr.type());
447
448 if(search_from_end)
449 {
450 auto end = std::prev(s1_data.operands().end(), starting_offset);
451 auto it = std::find_end(
452 s1_data.operands().begin(),
453 end,
454 s2_data.operands().begin(),
455 s2_data.operands().end());
456 if(it != end)
457 return from_integer(
458 std::distance(s1_data.operands().begin(), it), expr.type());
459 }
460 else
461 {
462 auto it = std::search(
463 std::next(s1_data.operands().begin(), starting_index),
464 s1_data.operands().end(),
465 s2_data.operands().begin(),
466 s2_data.operands().end());
467
468 if(it != s1_data.operands().end())
469 return from_integer(
470 std::distance(s1_data.operands().begin(), it), expr.type());
471 }
472 }
473 else if(expr.arguments().at(1).is_constant())
474 {
475 // Second argument is a constant character
476
477 const constant_exprt &c1 = to_constant_expr(expr.arguments().at(1));
478 const auto c1_val = numeric_cast_v<mp_integer>(c1);
479
480 auto pred = [&](const exprt &c2) {
481 const auto c2_val = numeric_cast_v<mp_integer>(to_constant_expr(c2));
482
483 return c1_val == c2_val;
484 };
485
486 if(search_from_end)
487 {
488 auto it = std::find_if(
489 std::next(s1_data.operands().rbegin(), starting_offset),
490 s1_data.operands().rend(),
491 pred);
492 if(it != s1_data.operands().rend())
493 return from_integer(
494 std::distance(s1_data.operands().begin(), it.base() - 1),
495 expr.type());
496 }
497 else
498 {
499 auto it = std::find_if(
500 std::next(s1_data.operands().begin(), starting_index),
501 s1_data.operands().end(),
502 pred);
503 if(it != s1_data.operands().end())
504 return from_integer(
505 std::distance(s1_data.operands().begin(), it), expr.type());
506 }
507 }
508 else
509 {
510 return simplify_exprt::unchanged(expr);
511 }
512
513 return from_integer(-1, expr.type());
514}
515
522 const function_application_exprt &expr,
523 const namespacet &ns)
524{
525 if(!expr.arguments().at(1).is_constant())
526 {
527 return simplify_exprt::unchanged(expr);
528 }
529
530 const auto &index = to_constant_expr(expr.arguments().at(1));
531
532 const refined_string_exprt &s = to_string_expr(expr.arguments().at(0));
533
534 const auto char_seq_opt = try_get_string_data_array(s.content(), ns);
535
536 if(!char_seq_opt)
537 {
538 return simplify_exprt::unchanged(expr);
539 }
540
541 const array_exprt &char_seq = char_seq_opt->get();
542
543 const auto i_opt = numeric_cast<std::size_t>(index);
544
545 if(!i_opt || *i_opt >= char_seq.operands().size())
546 {
547 return simplify_exprt::unchanged(expr);
548 }
549
550 const auto &c = to_constant_expr(char_seq.operands().at(*i_opt));
551
552 if(c.type() != expr.type())
553 {
554 return simplify_exprt::unchanged(expr);
555 }
556
557 return c;
558}
559
562{
563 auto &operands = string_data.operands();
564 for(auto &operand : operands)
565 {
566 auto &constant_value = to_constant_expr(operand);
567 auto character = numeric_cast_v<unsigned int>(constant_value);
568
569 // Can't guarantee matches against non-ASCII characters.
570 if(character >= 128)
571 return false;
572
573 if(isalpha(character))
574 {
575 if(isupper(character))
576 constant_value =
577 from_integer(tolower(character), constant_value.type());
578 }
579 }
580
581 return true;
582}
583
590 const function_application_exprt &expr,
591 const namespacet &ns)
592{
593 // We want to get both arguments of any starts-with comparison, and
594 // trace them back to the actual string instance. All variables on the
595 // way must be constant for us to be sure this will work.
596 auto &first_argument = to_string_expr(expr.arguments().at(0));
597 auto &second_argument = to_string_expr(expr.arguments().at(1));
598
599 const auto first_value_opt =
600 try_get_string_data_array(first_argument.content(), ns);
601
602 if(!first_value_opt)
603 {
604 return simplify_exprt::unchanged(expr);
605 }
606
607 array_exprt first_value = first_value_opt->get();
608
609 const auto second_value_opt =
610 try_get_string_data_array(second_argument.content(), ns);
611
612 if(!second_value_opt)
613 {
614 return simplify_exprt::unchanged(expr);
615 }
616
617 array_exprt second_value = second_value_opt->get();
618
619 // Just lower-case both expressions.
620 if(
621 !lower_case_string_expression(first_value) ||
622 !lower_case_string_expression(second_value))
623 return simplify_exprt::unchanged(expr);
624
625 bool is_equal = first_value == second_value;
626 return from_integer(is_equal ? 1 : 0, expr.type());
627}
628
635 const function_application_exprt &expr,
636 const namespacet &ns)
637{
638 // We want to get both arguments of any starts-with comparison, and
639 // trace them back to the actual string instance. All variables on the
640 // way must be constant for us to be sure this will work.
641 auto &first_argument = to_string_expr(expr.arguments().at(0));
642 auto &second_argument = to_string_expr(expr.arguments().at(1));
643
644 const auto first_value_opt =
645 try_get_string_data_array(first_argument.content(), ns);
646
647 if(!first_value_opt)
648 {
649 return simplify_exprt::unchanged(expr);
650 }
651
652 const array_exprt &first_value = first_value_opt->get();
653
654 const auto second_value_opt =
655 try_get_string_data_array(second_argument.content(), ns);
656
657 if(!second_value_opt)
658 {
659 return simplify_exprt::unchanged(expr);
660 }
661
662 const array_exprt &second_value = second_value_opt->get();
663
664 mp_integer offset_int = 0;
665 if(expr.arguments().size() == 3)
666 {
667 auto &offset = expr.arguments()[2];
668 if(!offset.is_constant())
669 return simplify_exprt::unchanged(expr);
670 offset_int = numeric_cast_v<mp_integer>(to_constant_expr(offset));
671 }
672
673 // test whether second_value is a prefix of first_value
674 bool is_prefix =
675 offset_int >= 0 && mp_integer(first_value.operands().size()) >=
676 offset_int + second_value.operands().size();
677 if(is_prefix)
678 {
679 exprt::operandst::const_iterator second_it =
680 second_value.operands().begin();
681 for(const auto &first_op : first_value.operands())
682 {
683 if(offset_int > 0)
684 --offset_int;
685 else if(second_it == second_value.operands().end())
686 break;
687 else if(first_op != *second_it)
688 {
689 is_prefix = false;
690 break;
691 }
692 else
693 ++second_it;
694 }
695 }
696
697 return from_integer(is_prefix ? 1 : 0, expr.type());
698}
699
701 const function_application_exprt &expr)
702{
703 if(expr.function().id() == ID_lambda)
704 {
705 // expand the function application
706 return to_lambda_expr(expr.function()).application(expr.arguments());
707 }
708
709 if(expr.function().id() != ID_symbol)
710 return unchanged(expr);
711
712 const irep_idt &func_id = to_symbol_expr(expr.function()).get_identifier();
713
714 // String.startsWith() is used to implement String.equals() in the models
715 // library
716 if(func_id == ID_cprover_string_startswith_func)
717 {
718 return simplify_string_startswith(expr, ns);
719 }
720 else if(func_id == ID_cprover_string_endswith_func)
721 {
722 return simplify_string_endswith(expr, ns);
723 }
724 else if(func_id == ID_cprover_string_is_empty_func)
725 {
726 return simplify_string_is_empty(expr, ns);
727 }
728 else if(func_id == ID_cprover_string_compare_to_func)
729 {
730 return simplify_string_compare_to(expr, ns);
731 }
732 else if(func_id == ID_cprover_string_index_of_func)
733 {
734 return simplify_string_index_of(expr, ns, false);
735 }
736 else if(func_id == ID_cprover_string_char_at_func)
737 {
738 return simplify_string_char_at(expr, ns);
739 }
740 else if(func_id == ID_cprover_string_contains_func)
741 {
742 return simplify_string_contains(expr, ns);
743 }
744 else if(func_id == ID_cprover_string_last_index_of_func)
745 {
746 return simplify_string_index_of(expr, ns, true);
747 }
748 else if(func_id == ID_cprover_string_equals_ignore_case_func)
749 {
751 }
752
753 return unchanged(expr);
754}
755
758{
759 const typet &expr_type = expr.type();
760 const typet &op_type = expr.op().type();
761
762 // eliminate casts of infinity
763 if(expr.op().id() == ID_infinity)
764 {
765 typet new_type=expr.type();
766 exprt tmp = expr.op();
767 tmp.type()=new_type;
768 return std::move(tmp);
769 }
770
771 // casts from NULL to any integer
772 if(
773 op_type.id() == ID_pointer && expr.op().is_constant() &&
774 to_constant_expr(expr.op()).get_value() == ID_NULL &&
775 (expr_type.id() == ID_unsignedbv || expr_type.id() == ID_signedbv) &&
776 config.ansi_c.NULL_is_zero)
777 {
778 return from_integer(0, expr_type);
779 }
780
781 // casts from pointer to integer
782 // where width of integer >= width of pointer
783 // (void*)(intX)expr -> (void*)expr
784 if(
785 expr_type.id() == ID_pointer && expr.op().id() == ID_typecast &&
786 (op_type.id() == ID_signedbv || op_type.id() == ID_unsignedbv ||
787 op_type.id() == ID_bv) &&
788 to_bitvector_type(op_type).get_width() >=
789 to_bitvector_type(expr_type).get_width())
790 {
791 auto new_expr = expr;
792 new_expr.op() = to_typecast_expr(expr.op()).op();
793 return changed(simplify_typecast(new_expr)); // rec. call
794 }
795
796 // eliminate redundant typecasts
797 if(expr.type() == expr.op().type())
798 {
799 return expr.op();
800 }
801
802 // eliminate casts to proper bool
803 if(expr_type.id()==ID_bool)
804 {
805 // rewrite (bool)x to x!=0
806 binary_relation_exprt inequality(
807 expr.op(),
808 op_type.id() == ID_floatbv ? ID_ieee_float_notequal : ID_notequal,
809 from_integer(0, op_type));
810 inequality.add_source_location()=expr.source_location();
811 return changed(simplify_node(inequality));
812 }
813
814 // eliminate casts from proper bool
815 if(
816 op_type.id() == ID_bool &&
817 (expr_type.id() == ID_signedbv || expr_type.id() == ID_unsignedbv ||
818 expr_type.id() == ID_c_bool || expr_type.id() == ID_c_bit_field))
819 {
820 // rewrite (T)(bool) to bool?1:0
821 auto one = from_integer(1, expr_type);
822 auto zero = from_integer(0, expr_type);
824 if_exprt{expr.op(), std::move(one), std::move(zero)}));
825 }
826
827 // circular casts through types shorter than `int`
828 // we use fixed bit widths as this is specifically for the Java bytecode
829 // front-end
830 if(op_type == signedbv_typet(32) && expr.op().id() == ID_typecast)
831 {
832 if(expr_type==c_bool_typet(8) ||
833 expr_type==signedbv_typet(8) ||
834 expr_type==signedbv_typet(16) ||
835 expr_type==unsignedbv_typet(16))
836 {
837 // We checked that the id was ID_typecast in the enclosing `if`
838 const auto &typecast = expr_checked_cast<typecast_exprt>(expr.op());
839 if(typecast.op().type()==expr_type)
840 {
841 return typecast.op();
842 }
843 }
844 }
845
846 // eliminate casts to _Bool
847 if(expr_type.id()==ID_c_bool &&
848 op_type.id()!=ID_bool)
849 {
850 // rewrite (_Bool)x to (_Bool)(x!=0)
851 exprt inequality = is_not_zero(expr.op(), ns);
852 auto new_expr = expr;
853 new_expr.op() = simplify_node(std::move(inequality));
854 return changed(simplify_typecast(new_expr)); // recursive call
855 }
856
857 // eliminate typecasts from NULL
858 if(
859 expr_type.id() == ID_pointer && expr.op().is_constant() &&
860 (to_constant_expr(expr.op()).get_value() == ID_NULL ||
861 (expr.op().is_zero() && config.ansi_c.NULL_is_zero)))
862 {
863 exprt tmp = expr.op();
864 tmp.type()=expr.type();
865 to_constant_expr(tmp).set_value(ID_NULL);
866 return std::move(tmp);
867 }
868
869 // eliminate duplicate pointer typecasts
870 // (T1 *)(T2 *)x -> (T1 *)x
871 if(
872 expr_type.id() == ID_pointer && expr.op().id() == ID_typecast &&
873 op_type.id() == ID_pointer)
874 {
875 auto new_expr = expr;
876 new_expr.op() = to_typecast_expr(expr.op()).op();
877 return changed(simplify_typecast(new_expr)); // recursive call
878 }
879
880 // casts from integer to pointer and back:
881 // (int)(void *)int -> (int)(size_t)int
882 if(
883 (expr_type.id() == ID_signedbv || expr_type.id() == ID_unsignedbv) &&
884 expr.op().id() == ID_typecast && expr.op().operands().size() == 1 &&
885 op_type.id() == ID_pointer)
886 {
887 auto inner_cast = to_typecast_expr(expr.op());
888 inner_cast.type() = size_type();
889
890 auto outer_cast = expr;
891 outer_cast.op() = simplify_typecast(inner_cast); // rec. call
892 return changed(simplify_typecast(outer_cast)); // rec. call
893 }
894
895 // mildly more elaborate version of the above:
896 // (int)((T*)0 + int) -> (int)(sizeof(T)*(size_t)int) if NULL is zero
897 if(
898 config.ansi_c.NULL_is_zero &&
899 (expr_type.id() == ID_signedbv || expr_type.id() == ID_unsignedbv) &&
900 op_type.id() == ID_pointer && expr.op().id() == ID_plus &&
901 expr.op().operands().size() == 2)
902 {
903 const auto &op_plus_expr = to_plus_expr(expr.op());
904
905 if(
906 (op_plus_expr.op0().id() == ID_typecast &&
907 to_typecast_expr(op_plus_expr.op0()).op().is_zero()) ||
908 (op_plus_expr.op0().is_constant() &&
909 to_constant_expr(op_plus_expr.op0()).is_null_pointer()))
910 {
911 auto sub_size =
912 pointer_offset_size(to_pointer_type(op_type).base_type(), ns);
913 if(sub_size.has_value())
914 {
915 auto new_expr = expr;
916 exprt offset_expr =
917 simplify_typecast(typecast_exprt(op_plus_expr.op1(), size_type()));
918
919 // void*
920 if(*sub_size == 0 || *sub_size == 1)
921 new_expr.op() = offset_expr;
922 else
923 {
924 new_expr.op() = simplify_mult(
925 mult_exprt(from_integer(*sub_size, size_type()), offset_expr));
926 }
927
928 return changed(simplify_typecast(new_expr)); // rec. call
929 }
930 }
931 }
932
933 // Push a numerical typecast into various integer operations, i.e.,
934 // (T)(x OP y) ---> (T)x OP (T)y
935 //
936 // Doesn't work for many, e.g., pointer difference, floating-point,
937 // division, modulo.
938 // Many operations fail if the width of T
939 // is bigger than that of (x OP y). This includes ID_bitnot and
940 // anything that might overflow, e.g., ID_plus.
941 //
942 if((expr_type.id()==ID_signedbv || expr_type.id()==ID_unsignedbv) &&
943 (op_type.id()==ID_signedbv || op_type.id()==ID_unsignedbv))
944 {
945 bool enlarge=
946 to_bitvector_type(expr_type).get_width()>
947 to_bitvector_type(op_type).get_width();
948
949 if(!enlarge)
950 {
951 irep_idt op_id = expr.op().id();
952
953 if(
954 op_id == ID_plus || op_id == ID_minus || op_id == ID_mult ||
955 op_id == ID_unary_minus || op_id == ID_bitxor || op_id == ID_bitxnor ||
956 op_id == ID_bitor || op_id == ID_bitand)
957 {
958 exprt result = expr.op();
959
960 if(
961 result.operands().size() >= 1 &&
962 to_multi_ary_expr(result).op0().type() == result.type())
963 {
964 result.type()=expr.type();
965
966 Forall_operands(it, result)
967 {
968 auto new_operand = typecast_exprt(*it, expr.type());
969 *it = simplify_typecast(new_operand); // recursive call
970 }
971
972 return changed(simplify_node(result)); // possibly recursive call
973 }
974 }
975 else if(op_id==ID_ashr || op_id==ID_lshr || op_id==ID_shl)
976 {
977 }
978 }
979 }
980
981 // Push a numerical typecast into pointer arithmetic
982 // (T)(ptr + int) ---> (T)((size_t)ptr + sizeof(subtype)*(size_t)int)
983 //
984 if(
985 (expr_type.id() == ID_signedbv || expr_type.id() == ID_unsignedbv) &&
986 op_type.id() == ID_pointer && expr.op().id() == ID_plus)
987 {
988 const auto step =
989 pointer_offset_size(to_pointer_type(op_type).base_type(), ns);
990
991 if(step.has_value() && *step != 0)
992 {
993 const typet size_t_type(size_type());
994 auto new_expr = expr;
995
996 new_expr.op().type() = size_t_type;
997
998 for(auto &op : new_expr.op().operands())
999 {
1000 exprt new_op = simplify_typecast(typecast_exprt(op, size_t_type));
1001 if(op.type().id() != ID_pointer && *step > 1)
1002 {
1003 new_op =
1004 simplify_mult(mult_exprt(from_integer(*step, size_t_type), new_op));
1005 }
1006 op = std::move(new_op);
1007 }
1008
1009 new_expr.op() = simplify_plus(to_plus_expr(new_expr.op()));
1010
1011 return changed(simplify_typecast(new_expr)); // recursive call
1012 }
1013 }
1014
1015 const irep_idt &expr_type_id=expr_type.id();
1016 const exprt &operand = expr.op();
1017 const irep_idt &op_type_id=op_type.id();
1018
1019 if(operand.is_constant())
1020 {
1021 const irep_idt &value=to_constant_expr(operand).get_value();
1022
1023 // preserve the sizeof type annotation
1024 typet c_sizeof_type=
1025 static_cast<const typet &>(operand.find(ID_C_c_sizeof_type));
1026
1027 if(op_type_id==ID_integer ||
1028 op_type_id==ID_natural)
1029 {
1030 // from integer to ...
1031
1032 mp_integer int_value=string2integer(id2string(value));
1033
1034 if(expr_type_id==ID_bool)
1035 {
1036 return make_boolean_expr(int_value != 0);
1037 }
1038
1039 if(expr_type_id==ID_unsignedbv ||
1040 expr_type_id==ID_signedbv ||
1041 expr_type_id==ID_c_enum ||
1042 expr_type_id==ID_c_bit_field ||
1043 expr_type_id==ID_integer)
1044 {
1045 return from_integer(int_value, expr_type);
1046 }
1047 else if(expr_type_id == ID_c_enum_tag)
1048 {
1049 const auto &c_enum_type = ns.follow_tag(to_c_enum_tag_type(expr_type));
1050 if(!c_enum_type.is_incomplete()) // possibly incomplete
1051 {
1052 exprt tmp = from_integer(int_value, c_enum_type);
1053 tmp.type() = expr_type; // we maintain the tag type
1054 return std::move(tmp);
1055 }
1056 }
1057 }
1058 else if(op_type_id==ID_rational)
1059 {
1060 }
1061 else if(op_type_id==ID_real)
1062 {
1063 }
1064 else if(op_type_id==ID_bool)
1065 {
1066 if(expr_type_id==ID_unsignedbv ||
1067 expr_type_id==ID_signedbv ||
1068 expr_type_id==ID_integer ||
1069 expr_type_id==ID_natural ||
1070 expr_type_id==ID_rational ||
1071 expr_type_id==ID_c_bool ||
1072 expr_type_id==ID_c_enum ||
1073 expr_type_id==ID_c_bit_field)
1074 {
1075 if(operand.is_true())
1076 {
1077 return from_integer(1, expr_type);
1078 }
1079 else if(operand.is_false())
1080 {
1081 return from_integer(0, expr_type);
1082 }
1083 }
1084 else if(expr_type_id==ID_c_enum_tag)
1085 {
1086 const auto &c_enum_type = ns.follow_tag(to_c_enum_tag_type(expr_type));
1087 if(!c_enum_type.is_incomplete()) // possibly incomplete
1088 {
1089 unsigned int_value = operand.is_true() ? 1u : 0u;
1090 exprt tmp=from_integer(int_value, c_enum_type);
1091 tmp.type()=expr_type; // we maintain the tag type
1092 return std::move(tmp);
1093 }
1094 }
1095 else if(expr_type_id==ID_pointer &&
1096 operand.is_false() &&
1097 config.ansi_c.NULL_is_zero)
1098 {
1099 return null_pointer_exprt(to_pointer_type(expr_type));
1100 }
1101 }
1102 else if(op_type_id==ID_unsignedbv ||
1103 op_type_id==ID_signedbv ||
1104 op_type_id==ID_c_bit_field ||
1105 op_type_id==ID_c_bool)
1106 {
1107 mp_integer int_value;
1108
1109 if(to_integer(to_constant_expr(operand), int_value))
1110 return unchanged(expr);
1111
1112 if(expr_type_id==ID_bool)
1113 {
1114 return make_boolean_expr(int_value != 0);
1115 }
1116
1117 if(expr_type_id==ID_c_bool)
1118 {
1119 return from_integer(int_value != 0, expr_type);
1120 }
1121
1122 if(expr_type_id==ID_integer)
1123 {
1124 return from_integer(int_value, expr_type);
1125 }
1126
1127 if(expr_type_id==ID_natural)
1128 {
1129 if(int_value>=0)
1130 {
1131 return from_integer(int_value, expr_type);
1132 }
1133 }
1134
1135 if(expr_type_id==ID_unsignedbv ||
1136 expr_type_id==ID_signedbv ||
1137 expr_type_id==ID_bv ||
1138 expr_type_id==ID_c_bit_field)
1139 {
1140 auto result = from_integer(int_value, expr_type);
1141
1142 if(c_sizeof_type.is_not_nil())
1143 result.set(ID_C_c_sizeof_type, c_sizeof_type);
1144
1145 return std::move(result);
1146 }
1147
1148 if(expr_type_id==ID_c_enum_tag)
1149 {
1150 const auto &c_enum_type = ns.follow_tag(to_c_enum_tag_type(expr_type));
1151 if(!c_enum_type.is_incomplete()) // possibly incomplete
1152 {
1153 exprt tmp=from_integer(int_value, c_enum_type);
1154 tmp.type()=expr_type; // we maintain the tag type
1155 return std::move(tmp);
1156 }
1157 }
1158
1159 if(expr_type_id==ID_c_enum)
1160 {
1161 return from_integer(int_value, expr_type);
1162 }
1163
1164 if(expr_type_id==ID_fixedbv)
1165 {
1166 // int to float
1167 const fixedbv_typet &f_expr_type=
1168 to_fixedbv_type(expr_type);
1169
1170 fixedbvt f;
1171 f.spec=fixedbv_spect(f_expr_type);
1172 f.from_integer(int_value);
1173 return f.to_expr();
1174 }
1175
1176 if(expr_type_id==ID_floatbv)
1177 {
1178 // int to float
1179 const floatbv_typet &f_expr_type=
1180 to_floatbv_type(expr_type);
1181
1183 ieee_floatt f(f_expr_type, rm);
1184 f.from_integer(int_value);
1185
1186 return f.to_expr();
1187 }
1188
1189 if(expr_type_id==ID_rational)
1190 {
1191 rationalt r(int_value);
1192 return from_rational(r);
1193 }
1194 }
1195 else if(op_type_id==ID_fixedbv)
1196 {
1197 if(expr_type_id==ID_unsignedbv ||
1198 expr_type_id==ID_signedbv)
1199 {
1200 // cast from fixedbv to int
1201 fixedbvt f(to_constant_expr(expr.op()));
1202 return from_integer(f.to_integer(), expr_type);
1203 }
1204 else if(expr_type_id==ID_fixedbv)
1205 {
1206 // fixedbv to fixedbv
1207 fixedbvt f(to_constant_expr(expr.op()));
1208 f.round(fixedbv_spect(to_fixedbv_type(expr_type)));
1209 return f.to_expr();
1210 }
1211 else if(expr_type_id == ID_bv)
1212 {
1213 fixedbvt f{to_constant_expr(expr.op())};
1214 return from_integer(f.get_value(), expr_type);
1215 }
1216 }
1217 else if(op_type_id==ID_floatbv)
1218 {
1219 ieee_floatt f(
1220 to_constant_expr(expr.op()),
1222
1223 if(expr_type_id==ID_unsignedbv ||
1224 expr_type_id==ID_signedbv)
1225 {
1226 // cast from float to int
1227 return from_integer(f.to_integer(), expr_type);
1228 }
1229 else if(expr_type_id==ID_floatbv)
1230 {
1231 // float to double or double to float
1233 return f.to_expr();
1234 }
1235 else if(expr_type_id==ID_fixedbv)
1236 {
1237 fixedbvt fixedbv;
1238 fixedbv.spec=fixedbv_spect(to_fixedbv_type(expr_type));
1240 factor.from_integer(power(2, fixedbv.spec.get_fraction_bits()));
1241 f*=factor;
1242 fixedbv.set_value(f.to_integer());
1243 return fixedbv.to_expr();
1244 }
1245 else if(expr_type_id == ID_bv)
1246 {
1247 return from_integer(f.pack(), expr_type);
1248 }
1249 }
1250 else if(op_type_id==ID_bv)
1251 {
1252 if(
1253 expr_type_id == ID_unsignedbv || expr_type_id == ID_signedbv ||
1254 expr_type_id == ID_c_enum || expr_type_id == ID_c_enum_tag ||
1255 expr_type_id == ID_c_bit_field)
1256 {
1257 const auto width = to_bv_type(op_type).get_width();
1258 const auto int_value = bvrep2integer(value, width, false);
1259 if(expr_type_id != ID_c_enum_tag)
1260 return from_integer(int_value, expr_type);
1261 else
1262 {
1263 c_enum_tag_typet tag_type = to_c_enum_tag_type(expr_type);
1264 auto result = from_integer(int_value, ns.follow_tag(tag_type));
1265 result.type() = tag_type;
1266 return std::move(result);
1267 }
1268 }
1269 else if(expr_type_id == ID_floatbv)
1270 {
1271 const auto width = to_bv_type(op_type).get_width();
1272 const auto int_value = bvrep2integer(value, width, false);
1273 ieee_float_valuet ieee_float{to_floatbv_type(expr_type)};
1274 ieee_float.unpack(int_value);
1275 return ieee_float.to_expr();
1276 }
1277 else if(expr_type_id == ID_fixedbv)
1278 {
1279 const auto width = to_bv_type(op_type).get_width();
1280 const auto int_value = bvrep2integer(value, width, false);
1281 fixedbvt fixedbv{fixedbv_spect{to_fixedbv_type(expr_type)}};
1282 fixedbv.set_value(int_value);
1283 return fixedbv.to_expr();
1284 }
1285 }
1286 else if(op_type_id==ID_c_enum_tag) // enum to int
1287 {
1288 const typet &base_type =
1289 ns.follow_tag(to_c_enum_tag_type(op_type)).underlying_type();
1290 if(base_type.id()==ID_signedbv || base_type.id()==ID_unsignedbv)
1291 {
1292 // enum constants use the representation of their base type
1293 auto new_expr = expr;
1294 new_expr.op().type() = base_type;
1295 return changed(simplify_typecast(new_expr)); // recursive call
1296 }
1297 }
1298 else if(op_type_id==ID_c_enum) // enum to int
1299 {
1300 const typet &base_type = to_c_enum_type(op_type).underlying_type();
1301 if(base_type.id()==ID_signedbv || base_type.id()==ID_unsignedbv)
1302 {
1303 // enum constants use the representation of their base type
1304 auto new_expr = expr;
1305 new_expr.op().type() = base_type;
1306 return changed(simplify_typecast(new_expr)); // recursive call
1307 }
1308 }
1309 }
1310 else if(operand.id()==ID_typecast) // typecast of typecast
1311 {
1312 // (T1)(T2)x ---> (T1)
1313 // where T1 has fewer bits than T2
1314 if(
1315 op_type_id == expr_type_id &&
1316 (expr_type_id == ID_unsignedbv || expr_type_id == ID_signedbv ||
1317 expr_type_id == ID_bv) &&
1318 to_bitvector_type(expr_type).get_width() <=
1319 to_bitvector_type(operand.type()).get_width())
1320 {
1321 auto new_expr = expr;
1322 new_expr.op() = to_typecast_expr(operand).op();
1323 // might enable further simplification
1324 return changed(simplify_typecast(new_expr)); // recursive call
1325 }
1326 }
1327 else if(operand.id()==ID_address_of)
1328 {
1329 const exprt &o=to_address_of_expr(operand).object();
1330
1331 // turn &array into &array[0] when casting to pointer-to-element-type
1332 if(
1333 o.type().id() == ID_array &&
1334 expr_type == pointer_type(to_array_type(o.type()).element_type()))
1335 {
1336 auto result =
1338
1339 return changed(simplify_address_of(result)); // recursive call
1340 }
1341 }
1342 else if(auto extractbits = expr_try_dynamic_cast<extractbits_exprt>(operand))
1343 {
1344 if(
1345 can_cast_type<bitvector_typet>(expr_type) &&
1347 to_bitvector_type(expr_type).get_width() ==
1348 to_bitvector_type(operand.type()).get_width())
1349 {
1350 extractbits_exprt result = *extractbits;
1351 result.type() = expr_type;
1352 return changed(simplify_extractbits(result));
1353 }
1354 }
1355
1356 return unchanged(expr);
1357}
1358
1361{
1362 const typet &expr_type = expr.type();
1363 const typet &op_type = expr.op().type();
1364
1365 // (T)(a?b:c) --> a?(T)b:(T)c; don't do this for floating-point type casts as
1366 // the type cast itself may be costly
1367 if(
1368 expr.op().id() == ID_if && expr_type.id() != ID_floatbv &&
1369 op_type.id() != ID_floatbv)
1370 {
1371 if_exprt if_expr = lift_if(expr, 0);
1372 return changed(simplify_if_preorder(if_expr));
1373 }
1374 else
1375 {
1376 auto r_it = simplify_rec(expr.op()); // recursive call
1377 if(r_it.has_changed())
1378 {
1379 auto tmp = expr;
1380 tmp.op() = r_it.expr;
1381 return tmp;
1382 }
1383 }
1384
1385 return unchanged(expr);
1386}
1387
1390{
1391 const exprt &pointer = expr.pointer();
1392
1393 if(pointer.type().id()!=ID_pointer)
1394 return unchanged(expr);
1395
1396 if(pointer.id()==ID_address_of)
1397 {
1398 exprt tmp=to_address_of_expr(pointer).object();
1399 // one address_of is gone, try again
1400 return changed(simplify_rec(tmp));
1401 }
1402 // rewrite *(&a[0] + x) to a[x]
1403 else if(
1404 pointer.id() == ID_plus && pointer.operands().size() == 2 &&
1405 to_plus_expr(pointer).op0().id() == ID_address_of)
1406 {
1407 const auto &pointer_plus_expr = to_plus_expr(pointer);
1408
1409 const address_of_exprt &address_of =
1410 to_address_of_expr(pointer_plus_expr.op0());
1411
1412 if(address_of.object().id()==ID_index)
1413 {
1414 const index_exprt &old=to_index_expr(address_of.object());
1415 if(old.array().type().id() == ID_array)
1416 {
1417 index_exprt idx(
1418 old.array(),
1419 pointer_offset_sum(old.index(), pointer_plus_expr.op1()),
1420 to_array_type(old.array().type()).element_type());
1421 return changed(simplify_rec(idx));
1422 }
1423 }
1424 }
1425
1426 return unchanged(expr);
1427}
1428
1431{
1432 const exprt &pointer = expr.pointer();
1433
1434 if(pointer.id() == ID_if)
1435 {
1436 if_exprt if_expr = lift_if(expr, 0);
1437 return changed(simplify_if_preorder(if_expr));
1438 }
1439 else
1440 {
1441 auto r_it = simplify_rec(pointer); // recursive call
1442 if(r_it.has_changed())
1443 {
1444 auto tmp = expr;
1445 tmp.pointer() = r_it.expr;
1446 return tmp;
1447 }
1448 }
1449
1450 return unchanged(expr);
1451}
1452
1455{
1456 return unchanged(expr);
1457}
1458
1460{
1461 // now look at first operand
1462
1463 if(
1464 expr.old().type().id() == ID_struct ||
1465 expr.old().type().id() == ID_struct_tag)
1466 {
1467 if(expr.old().id() == ID_struct || expr.old().is_constant())
1468 {
1469 const irep_idt &component_name = expr.where().get(ID_component_name);
1470
1471 const struct_typet &old_type_followed =
1472 expr.old().type().id() == ID_struct_tag
1473 ? ns.follow_tag(to_struct_tag_type(expr.old().type()))
1474 : to_struct_type(expr.old().type());
1475 if(!old_type_followed.has_component(component_name))
1476 return unchanged(expr);
1477
1478 std::size_t number = old_type_followed.component_number(component_name);
1479
1480 if(number >= expr.old().operands().size())
1481 return unchanged(expr);
1482
1483 exprt result = expr.old();
1484 result.operands()[number] = expr.new_value();
1485 return result;
1486 }
1487 }
1488 else if(
1489 expr.old().type().id() == ID_array || expr.old().type().id() == ID_vector)
1490 {
1491 if(
1492 expr.old().id() == ID_array || expr.old().is_constant() ||
1493 expr.old().id() == ID_vector)
1494 {
1495 const auto i = numeric_cast<mp_integer>(expr.where());
1496
1497 if(i.has_value() && *i >= 0 && *i < expr.old().operands().size())
1498 {
1499 exprt result = expr.old();
1500 result.operands()[numeric_cast_v<std::size_t>(*i)] = expr.new_value();
1501 return result;
1502 }
1503 }
1504 }
1505
1506 return unchanged(expr);
1507}
1508
1511{
1512 // this is to push updates into (possibly nested) constants
1513
1514 const exprt::operandst &designator = expr.designator();
1515
1516 exprt updated_value = expr.old();
1517 exprt *value_ptr=&updated_value;
1518
1519 for(const auto &e : designator)
1520 {
1521 if(e.id()==ID_index_designator &&
1522 value_ptr->id()==ID_array)
1523 {
1524 const auto i = numeric_cast<mp_integer>(to_index_designator(e).index());
1525
1526 if(!i.has_value())
1527 return unchanged(expr);
1528
1529 if(*i < 0 || *i >= value_ptr->operands().size())
1530 return unchanged(expr);
1531
1532 value_ptr = &value_ptr->operands()[numeric_cast_v<std::size_t>(*i)];
1533 }
1534 else if(e.id()==ID_member_designator &&
1535 value_ptr->id()==ID_struct)
1536 {
1537 const irep_idt &component_name=
1538 e.get(ID_component_name);
1539 const struct_typet &value_ptr_struct_type =
1540 value_ptr->type().id() == ID_struct_tag
1541 ? ns.follow_tag(to_struct_tag_type(value_ptr->type()))
1542 : to_struct_type(value_ptr->type());
1543 if(!value_ptr_struct_type.has_component(component_name))
1544 return unchanged(expr);
1545 auto &designator_as_struct_expr = to_struct_expr(*value_ptr);
1546 value_ptr = &designator_as_struct_expr.component(component_name, ns);
1547 CHECK_RETURN(value_ptr->is_not_nil());
1548 }
1549 else
1550 return unchanged(expr); // give up, unknown designator
1551 }
1552
1553 // found, done
1554 *value_ptr = expr.new_value();
1555 return updated_value;
1556}
1557
1559{
1560 if(expr.id()==ID_plus)
1561 {
1562 if(expr.type().id()==ID_pointer)
1563 {
1564 // kill integers from sum
1565 for(auto &op : expr.operands())
1566 if(op.type().id() == ID_pointer)
1567 return changed(simplify_object(op)); // recursive call
1568 }
1569 }
1570 else if(expr.id()==ID_typecast)
1571 {
1572 auto const &typecast_expr = to_typecast_expr(expr);
1573 const typet &op_type = typecast_expr.op().type();
1574
1575 if(op_type.id()==ID_pointer)
1576 {
1577 // cast from pointer to pointer
1578 return changed(simplify_object(typecast_expr.op())); // recursive call
1579 }
1580 else if(op_type.id()==ID_signedbv || op_type.id()==ID_unsignedbv)
1581 {
1582 // cast from integer to pointer
1583
1584 // We do a bit of special treatment for (TYPE *)(a+(int)&o) and
1585 // (TYPE *)(a+(int)((T*)&o+x)), which are re-written to '&o'.
1586
1587 const exprt &casted_expr = typecast_expr.op();
1588 if(casted_expr.id() == ID_plus && casted_expr.operands().size() == 2)
1589 {
1590 const auto &plus_expr = to_plus_expr(casted_expr);
1591
1592 const exprt &cand = plus_expr.op0().id() == ID_typecast
1593 ? plus_expr.op0()
1594 : plus_expr.op1();
1595
1596 if(cand.id() == ID_typecast)
1597 {
1598 const auto &typecast_op = to_typecast_expr(cand).op();
1599
1600 if(typecast_op.id() == ID_address_of)
1601 {
1602 return typecast_op;
1603 }
1604 else if(
1605 typecast_op.id() == ID_plus && typecast_op.operands().size() == 2 &&
1606 to_plus_expr(typecast_op).op0().id() == ID_typecast &&
1607 to_typecast_expr(to_plus_expr(typecast_op).op0()).op().id() ==
1608 ID_address_of)
1609 {
1610 return to_typecast_expr(to_plus_expr(typecast_op).op0()).op();
1611 }
1612 }
1613 }
1614 }
1615 }
1616 else if(expr.id()==ID_address_of)
1617 {
1618 const auto &object = to_address_of_expr(expr).object();
1619
1620 if(object.id() == ID_index)
1621 {
1622 // &some[i] -> &some
1623 address_of_exprt new_expr(to_index_expr(object).array());
1624 return changed(simplify_object(new_expr)); // recursion
1625 }
1626 else if(object.id() == ID_member)
1627 {
1628 // &some.f -> &some
1629 address_of_exprt new_expr(to_member_expr(object).compound());
1630 return changed(simplify_object(new_expr)); // recursion
1631 }
1632 }
1633
1634 return unchanged(expr);
1635}
1636
1639{
1640 // lift up any ID_if on the object
1641 if(expr.op().id() == ID_if)
1642 {
1643 if_exprt if_expr = lift_if(expr, 0);
1644 if_expr.true_case() =
1646 if_expr.false_case() =
1648 return changed(simplify_if(if_expr));
1649 }
1650
1651 const auto el_size = pointer_offset_bits(expr.type(), ns);
1652 if(el_size.has_value() && *el_size < 0)
1653 return unchanged(expr);
1654
1655 // byte_extract(byte_extract(root, offset1), offset2) =>
1656 // byte_extract(root, offset1+offset2)
1657 if(expr.op().id()==expr.id())
1658 {
1659 auto tmp = expr;
1660
1663 to_byte_extract_expr(expr.op()).offset(), expr.offset().type()),
1664 expr.offset()));
1665 tmp.op() = to_byte_extract_expr(expr.op()).op();
1666
1667 return changed(simplify_byte_extract(tmp)); // recursive call
1668 }
1669
1670 // byte_extract(byte_update(root, offset, value), offset) =>
1671 // value
1672 if(
1673 ((expr.id() == ID_byte_extract_big_endian &&
1674 expr.op().id() == ID_byte_update_big_endian) ||
1675 (expr.id() == ID_byte_extract_little_endian &&
1676 expr.op().id() == ID_byte_update_little_endian)) &&
1677 expr.offset() == to_byte_update_expr(as_const(expr).op()).offset())
1678 {
1679 const auto &op_byte_update = to_byte_update_expr(expr.op());
1680
1681 if(expr.type() == op_byte_update.value().type())
1682 {
1683 return op_byte_update.value();
1684 }
1685 else if(el_size.has_value())
1686 {
1687 const auto update_bits_opt =
1688 pointer_offset_bits(op_byte_update.value().type(), ns);
1689
1690 if(update_bits_opt.has_value() && *el_size <= *update_bits_opt)
1691 {
1692 auto tmp = expr;
1693 tmp.op() = op_byte_update.value();
1694 tmp.offset() = from_integer(0, expr.offset().type());
1695
1696 return changed(simplify_byte_extract(tmp)); // recursive call
1697 }
1698 }
1699 }
1700
1701 auto offset = numeric_cast<mp_integer>(expr.offset());
1702 if(offset.has_value() && *offset < 0)
1703 return unchanged(expr);
1704
1705 // try to simplify byte_extract(byte_update(...))
1706 auto const bu = expr_try_dynamic_cast<byte_update_exprt>(expr.op());
1707 std::optional<mp_integer> update_offset;
1708 if(bu)
1709 update_offset = numeric_cast<mp_integer>(bu->offset());
1710 if(
1711 offset.has_value() && bu && el_size.has_value() &&
1712 update_offset.has_value())
1713 {
1714 // byte_extract(byte_update(root, offset_u, value), offset_e) so that the
1715 // update does not affect what is being extracted simplifies to
1716 // byte_extract(root, offset_e)
1717 //
1718 // byte_extract(byte_update(root, offset_u, value), offset_e) so that the
1719 // extracted range fully lies within the update value simplifies to
1720 // byte_extract(value, offset_e - offset_u)
1721 if(
1722 *offset * expr.get_bits_per_byte() + *el_size <=
1723 *update_offset * bu->get_bits_per_byte())
1724 {
1725 // extracting before the update
1726 auto tmp = expr;
1727 tmp.op() = bu->op();
1728 return changed(simplify_byte_extract(tmp)); // recursive call
1729 }
1730 else if(
1731 const auto update_size = pointer_offset_bits(bu->value().type(), ns))
1732 {
1733 if(
1734 *offset * expr.get_bits_per_byte() >=
1735 *update_offset * bu->get_bits_per_byte() + *update_size)
1736 {
1737 // extracting after the update
1738 auto tmp = expr;
1739 tmp.op() = bu->op();
1740 return changed(simplify_byte_extract(tmp)); // recursive call
1741 }
1742 else if(
1743 *offset >= *update_offset &&
1744 *offset * expr.get_bits_per_byte() + *el_size <=
1745 *update_offset * bu->get_bits_per_byte() + *update_size)
1746 {
1747 // extracting from the update
1748 auto tmp = expr;
1749 tmp.op() = bu->value();
1750 tmp.offset() =
1751 from_integer(*offset - *update_offset, expr.offset().type());
1752 return changed(simplify_byte_extract(tmp)); // recursive call
1753 }
1754 }
1755 }
1756
1757 // don't do any of the following if endianness doesn't match, as
1758 // bytes need to be swapped
1759 if(
1760 offset.has_value() && *offset == 0 &&
1761 ((expr.id() == ID_byte_extract_little_endian &&
1762 config.ansi_c.endianness ==
1764 (expr.id() == ID_byte_extract_big_endian &&
1765 config.ansi_c.endianness ==
1767 {
1768 // byte extract of full object is object
1769 if(expr.type() == expr.op().type())
1770 {
1771 return expr.op();
1772 }
1773 else if(
1774 expr.type().id() == ID_pointer && expr.op().type().id() == ID_pointer)
1775 {
1776 return typecast_exprt(expr.op(), expr.type());
1777 }
1778 }
1779
1780 if(
1781 (expr.type().id() == ID_union &&
1782 to_union_type(expr.type()).components().empty()) ||
1783 (expr.type().id() == ID_union_tag &&
1784 ns.follow_tag(to_union_tag_type(expr.type())).components().empty()))
1785 {
1786 return empty_union_exprt{expr.type()};
1787 }
1788 else if(
1789 (expr.type().id() == ID_struct &&
1790 to_struct_type(expr.type()).components().empty()) ||
1791 (expr.type().id() == ID_struct_tag &&
1792 ns.follow_tag(to_struct_tag_type(expr.type())).components().empty()))
1793 {
1794 return struct_exprt{{}, expr.type()};
1795 }
1796
1797 // no proper simplification for expr.type()==void
1798 // or types of unknown size
1799 if(!el_size.has_value() || *el_size == 0)
1800 return unchanged(expr);
1801
1802 if(
1803 offset.has_value() && expr.op().id() == ID_array_of &&
1804 to_array_of_expr(expr.op()).op().is_constant())
1805 {
1806 const auto const_bits_opt = expr2bits(
1807 to_array_of_expr(expr.op()).op(),
1808 config.ansi_c.endianness ==
1810 ns);
1811
1812 if(!const_bits_opt.has_value())
1813 return unchanged(expr);
1814
1815 std::string const_bits=const_bits_opt.value();
1816
1817 DATA_INVARIANT(!const_bits.empty(), "bit representation must be non-empty");
1818
1819 // double the string until we have sufficiently many bits
1820 while(mp_integer(const_bits.size()) <
1821 *offset * expr.get_bits_per_byte() + *el_size)
1822 {
1823 const_bits+=const_bits;
1824 }
1825
1826 std::string el_bits = std::string(
1827 const_bits,
1829 numeric_cast_v<std::size_t>(*el_size));
1830
1831 auto tmp = bits2expr(
1832 el_bits, expr.type(), expr.id() == ID_byte_extract_little_endian, ns);
1833
1834 if(tmp.has_value())
1835 return std::move(*tmp);
1836 }
1837
1838 // in some cases we even handle non-const array_of
1839 if(
1840 offset.has_value() && expr.op().id() == ID_array_of &&
1841 (*offset * expr.get_bits_per_byte()) % (*el_size) == 0 &&
1842 *el_size <=
1844 {
1845 auto tmp = expr;
1846 tmp.op() = simplify_index(index_exprt(expr.op(), expr.offset()));
1847 tmp.offset() = from_integer(0, expr.offset().type());
1848 return changed(simplify_byte_extract(tmp));
1849 }
1850
1851 // extract bits of a constant
1852 const auto bits =
1853 expr2bits(expr.op(), expr.id() == ID_byte_extract_little_endian, ns);
1854
1855 if(
1856 offset.has_value() && bits.has_value() &&
1857 mp_integer(bits->size()) >= *el_size + *offset * expr.get_bits_per_byte())
1858 {
1859 // make sure we don't lose bits with structs containing flexible array
1860 // members
1861 const bool struct_has_flexible_array_member = has_subtype(
1862 expr.type(),
1863 [&](const typet &type) {
1864 if(type.id() != ID_struct && type.id() != ID_struct_tag)
1865 return false;
1866
1867 const struct_typet &st = type.id() == ID_struct_tag
1868 ? ns.follow_tag(to_struct_tag_type(type))
1869 : to_struct_type(type);
1870 const auto &comps = st.components();
1871 if(comps.empty() || comps.back().type().id() != ID_array)
1872 return false;
1873
1874 if(comps.back().type().get_bool(ID_C_flexible_array_member))
1875 return true;
1876
1877 const auto size =
1878 numeric_cast<mp_integer>(to_array_type(comps.back().type()).size());
1879 return !size.has_value() || *size <= 1;
1880 },
1881 ns);
1882 if(!struct_has_flexible_array_member)
1883 {
1884 std::string bits_cut = std::string(
1885 bits.value(),
1887 numeric_cast_v<std::size_t>(*el_size));
1888
1889 auto tmp = bits2expr(
1890 bits_cut, expr.type(), expr.id() == ID_byte_extract_little_endian, ns);
1891
1892 if(tmp.has_value())
1893 return std::move(*tmp);
1894 }
1895 }
1896
1897 // push byte extracts into struct or union expressions, just like
1898 // lower_byte_extract does (this is the same code, except recursive calls use
1899 // simplify rather than lower_byte_extract)
1900 if(expr.op().id() == ID_struct || expr.op().id() == ID_union)
1901 {
1902 if(expr.type().id() == ID_struct || expr.type().id() == ID_struct_tag)
1903 {
1904 const struct_typet &struct_type =
1905 expr.type().id() == ID_struct_tag
1906 ? ns.follow_tag(to_struct_tag_type(expr.type()))
1907 : to_struct_type(expr.type());
1908 const struct_typet::componentst &components = struct_type.components();
1909
1910 bool failed = false;
1911 struct_exprt s({}, expr.type());
1912
1913 for(const auto &comp : components)
1914 {
1915 auto component_bits = pointer_offset_bits(comp.type(), ns);
1916
1917 // the next member would be misaligned, abort
1918 if(
1919 !component_bits.has_value() || *component_bits == 0 ||
1920 *component_bits % expr.get_bits_per_byte() != 0)
1921 {
1922 failed = true;
1923 break;
1924 }
1925
1926 auto member_offset_opt =
1927 member_offset_expr(struct_type, comp.get_name(), ns);
1928
1929 if(!member_offset_opt.has_value())
1930 {
1931 failed = true;
1932 break;
1933 }
1934
1935 exprt new_offset = simplify_rec(
1936 plus_exprt{expr.offset(),
1938 member_offset_opt.value(), expr.offset().type())});
1939
1940 byte_extract_exprt tmp = expr;
1941 tmp.type() = comp.type();
1942 tmp.offset() = new_offset;
1943
1945 }
1946
1947 if(!failed)
1948 return s;
1949 }
1950 else if(expr.type().id() == ID_union || expr.type().id() == ID_union_tag)
1951 {
1952 const union_typet &union_type =
1953 expr.type().id() == ID_union_tag
1954 ? ns.follow_tag(to_union_tag_type(expr.type()))
1955 : to_union_type(expr.type());
1956 auto widest_member_opt = union_type.find_widest_union_component(ns);
1957 if(widest_member_opt.has_value())
1958 {
1959 byte_extract_exprt be = expr;
1960 be.type() = widest_member_opt->first.type();
1961 return union_exprt{widest_member_opt->first.get_name(),
1963 expr.type()};
1964 }
1965 }
1966 }
1967 else if(expr.op().id() == ID_array)
1968 {
1969 const array_typet &array_type = to_array_type(expr.op().type());
1970 const auto &element_bit_width =
1971 pointer_offset_bits(array_type.element_type(), ns);
1972 if(
1973 offset.has_value() && element_bit_width.has_value() &&
1974 *element_bit_width > 0)
1975 {
1976 if(
1977 *offset > 0 &&
1978 *offset * expr.get_bits_per_byte() % *element_bit_width == 0)
1979 {
1980 const auto elements_to_erase = numeric_cast_v<std::size_t>(
1981 (*offset * expr.get_bits_per_byte()) / *element_bit_width);
1983 slice.operands().erase(
1984 slice.operands().begin(),
1985 slice.operands().begin() +
1986 std::min(elements_to_erase, slice.operands().size()));
1987 slice.type().size() =
1988 from_integer(slice.operands().size(), slice.type().size().type());
1989 byte_extract_exprt be = expr;
1990 be.op() = slice;
1991 be.offset() = from_integer(0, expr.offset().type());
1992 return changed(simplify_byte_extract(be));
1993 }
1994 else if(*offset == 0 && *el_size % *element_bit_width == 0)
1995 {
1996 const auto elements_to_keep =
1997 numeric_cast_v<std::size_t>(*el_size / *element_bit_width);
1999 if(slice.operands().size() > elements_to_keep)
2000 {
2001 slice.operands().resize(elements_to_keep);
2002 slice.type().size() =
2003 from_integer(slice.operands().size(), slice.type().size().type());
2004 byte_extract_exprt be = expr;
2005 be.op() = slice;
2006 return changed(simplify_byte_extract(be));
2007 }
2008 }
2009 }
2010 }
2011
2012 // try to refine it down to extracting from a member or an index in an array
2013 auto subexpr =
2014 get_subexpression_at_offset(expr.op(), expr.offset(), expr.type(), ns);
2015 if(subexpr.has_value() && subexpr.value() != expr)
2016 return changed(simplify_rec(subexpr.value())); // recursive call
2017
2018 if(can_forward_propagatet(ns)(expr))
2019 return changed(simplify_rec(lower_byte_extract(expr, ns)));
2020
2021 return unchanged(expr);
2022}
2023
2026{
2027 // lift up any ID_if on the object
2028 if(expr.op().id() == ID_if)
2029 {
2030 if_exprt if_expr = lift_if(expr, 0);
2031 return changed(simplify_if_preorder(if_expr));
2032 }
2033 else
2034 {
2035 std::optional<exprt::operandst> new_operands;
2036
2037 for(std::size_t i = 0; i < expr.operands().size(); ++i)
2038 {
2039 auto r_it = simplify_rec(expr.operands()[i]); // recursive call
2040 if(r_it.has_changed())
2041 {
2042 if(!new_operands.has_value())
2043 new_operands = expr.operands();
2044 (*new_operands)[i] = std::move(r_it.expr);
2045 }
2046 }
2047
2048 if(new_operands.has_value())
2049 {
2050 exprt result = expr;
2051 std::swap(result.operands(), *new_operands);
2052 return result;
2053 }
2054 }
2055
2056 return unchanged(expr);
2057}
2058
2061{
2062 // byte_update(byte_update(root, offset, value), offset, value2) =>
2063 // byte_update(root, offset, value2)
2064 if(
2065 expr.id() == expr.op().id() &&
2066 expr.offset() == to_byte_update_expr(expr.op()).offset() &&
2067 expr.value().type() == to_byte_update_expr(expr.op()).value().type())
2068 {
2069 auto tmp = expr;
2070 tmp.set_op(to_byte_update_expr(expr.op()).op());
2071 return std::move(tmp);
2072 }
2073
2074 const exprt &root = expr.op();
2075 const exprt &offset = expr.offset();
2076 const exprt &value = expr.value();
2077 const auto val_size = pointer_offset_bits(value.type(), ns);
2078 const auto root_size = pointer_offset_bits(root.type(), ns);
2079
2080 const auto matching_byte_extract_id =
2081 expr.id() == ID_byte_update_little_endian ? ID_byte_extract_little_endian
2082 : ID_byte_extract_big_endian;
2083
2084 // byte update of full object is byte_extract(new value)
2085 if(
2086 offset.is_zero() && val_size.has_value() && *val_size > 0 &&
2087 root_size.has_value() && *root_size > 0 && *val_size >= *root_size)
2088 {
2090 matching_byte_extract_id,
2091 value,
2092 offset,
2093 expr.get_bits_per_byte(),
2094 expr.type());
2095
2096 return changed(simplify_byte_extract(be));
2097 }
2098
2099 // update bits in a constant
2100 const auto offset_int = numeric_cast<mp_integer>(offset);
2101 if(
2102 root_size.has_value() && *root_size >= 0 && val_size.has_value() &&
2103 *val_size >= 0 && offset_int.has_value() && *offset_int >= 0 &&
2104 *offset_int * expr.get_bits_per_byte() + *val_size <= *root_size)
2105 {
2106 auto root_bits =
2107 expr2bits(root, expr.id() == ID_byte_update_little_endian, ns);
2108
2109 if(root_bits.has_value())
2110 {
2111 const auto val_bits =
2112 expr2bits(value, expr.id() == ID_byte_update_little_endian, ns);
2113
2114 if(val_bits.has_value())
2115 {
2116 root_bits->replace(
2117 numeric_cast_v<std::size_t>(*offset_int * expr.get_bits_per_byte()),
2118 numeric_cast_v<std::size_t>(*val_size),
2119 *val_bits);
2120
2121 auto tmp = bits2expr(
2122 *root_bits,
2123 expr.type(),
2124 expr.id() == ID_byte_update_little_endian,
2125 ns);
2126
2127 if(tmp.has_value())
2128 return std::move(*tmp);
2129 }
2130 }
2131 }
2132
2133 /*
2134 * byte_update(root, offset,
2135 * extract(root, offset) WITH component:=value)
2136 * =>
2137 * byte_update(root, offset + component offset,
2138 * value)
2139 */
2140
2141 if(value.id()==ID_with)
2142 {
2143 const with_exprt &with=to_with_expr(value);
2144
2145 if(with.old().id() == matching_byte_extract_id)
2146 {
2147 const byte_extract_exprt &extract=to_byte_extract_expr(with.old());
2148
2149 /* the simplification can be used only if
2150 root and offset of update and extract
2151 are the same */
2152 if(!(root==extract.op()))
2153 return unchanged(expr);
2154 if(!(offset==extract.offset()))
2155 return unchanged(expr);
2156
2157 if(with.type().id() == ID_struct || with.type().id() == ID_struct_tag)
2158 {
2159 const struct_typet &struct_type =
2160 with.type().id() == ID_struct_tag
2161 ? ns.follow_tag(to_struct_tag_type(with.type()))
2162 : to_struct_type(with.type());
2163 const irep_idt &component_name=with.where().get(ID_component_name);
2164 const typet &c_type = struct_type.get_component(component_name).type();
2165
2166 // is this a bit field?
2167 if(c_type.id() == ID_c_bit_field || c_type.id() == ID_bool)
2168 {
2169 // don't touch -- might not be byte-aligned
2170 }
2171 else
2172 {
2173 // new offset = offset + component offset
2174 auto i = member_offset(struct_type, component_name, ns);
2175 if(i.has_value())
2176 {
2177 exprt compo_offset = from_integer(*i, offset.type());
2178 plus_exprt new_offset(offset, compo_offset);
2179 exprt new_value(with.new_value());
2180 auto tmp = expr;
2181 tmp.set_offset(simplify_node(std::move(new_offset)));
2182 tmp.set_value(std::move(new_value));
2183 return changed(simplify_byte_update(tmp)); // recursive call
2184 }
2185 }
2186 }
2187 else if(with.type().id() == ID_array)
2188 {
2189 auto i =
2191 if(i.has_value())
2192 {
2193 const exprt &index=with.where();
2194 exprt index_offset =
2195 simplify_mult(mult_exprt(index, from_integer(*i, index.type())));
2196
2197 // index_offset may need a typecast
2198 if(offset.type() != index.type())
2199 {
2200 index_offset =
2201 simplify_typecast(typecast_exprt(index_offset, offset.type()));
2202 }
2203
2204 plus_exprt new_offset(offset, index_offset);
2205 exprt new_value(with.new_value());
2206 auto tmp = expr;
2207 tmp.set_offset(simplify_plus(std::move(new_offset)));
2208 tmp.set_value(std::move(new_value));
2209 return changed(simplify_byte_update(tmp)); // recursive call
2210 }
2211 }
2212 }
2213 }
2214
2215 // size must be known
2216 if(!val_size.has_value() || *val_size == 0)
2217 return unchanged(expr);
2218
2219 // byte_update(root, offset, value) is with(root, index, value) when root is
2220 // array-typed, the size of value matches the array-element width, and offset
2221 // is guaranteed to be a multiple of the array-element width
2222 if(auto array_type = type_try_dynamic_cast<array_typet>(root.type()))
2223 {
2224 auto el_size = pointer_offset_bits(array_type->element_type(), ns);
2225
2226 if(el_size.has_value() && *el_size > 0 && *val_size % *el_size == 0)
2227 {
2228 if(
2229 offset_int.has_value() &&
2230 (*offset_int * expr.get_bits_per_byte()) % *el_size == 0)
2231 {
2232 mp_integer base_offset =
2233 (*offset_int * expr.get_bits_per_byte()) / *el_size;
2234 with_exprt result_expr{
2235 root,
2236 from_integer(base_offset, array_type->index_type()),
2238 matching_byte_extract_id,
2239 value,
2240 from_integer(0, offset.type()),
2241 expr.get_bits_per_byte(),
2242 array_type->element_type()}};
2243 mp_integer n_elements = *val_size / *el_size;
2244
2245 for(mp_integer i = 1; i < n_elements; ++i)
2246 {
2247 result_expr = with_exprt{
2248 result_expr,
2249 from_integer(base_offset + i, array_type->index_type()),
2251 matching_byte_extract_id,
2252 value,
2254 i * (*el_size / expr.get_bits_per_byte()), offset.type()),
2255 expr.get_bits_per_byte(),
2256 array_type->element_type()}};
2257 }
2258
2259 return changed(simplify_rec(result_expr));
2260 }
2261 // if we have an offset C + x (where C is a constant) we can try to
2262 // recurse by first looking at the member at offset C
2263 else if(
2264 offset.id() == ID_plus && offset.operands().size() == 2 &&
2265 (to_multi_ary_expr(offset).op0().is_constant() ||
2266 to_multi_ary_expr(offset).op1().is_constant()))
2267 {
2268 const plus_exprt &offset_plus = to_plus_expr(offset);
2269 const auto &const_factor = offset_plus.op0().is_constant()
2270 ? offset_plus.op0()
2271 : offset_plus.op1();
2272 const exprt &other_factor = offset_plus.op0().is_constant()
2273 ? offset_plus.op1()
2274 : offset_plus.op0();
2275
2276 auto tmp = expr;
2277 tmp.set_offset(const_factor);
2278 exprt expr_at_offset_C = simplify_byte_update(tmp);
2279
2280 if(
2281 expr_at_offset_C.id() == ID_with &&
2282 to_with_expr(expr_at_offset_C).where().is_zero())
2283 {
2284 tmp.set_op(to_with_expr(expr_at_offset_C).old());
2285 tmp.set_offset(other_factor);
2286 return changed(simplify_byte_update(tmp));
2287 }
2288 }
2289 else if(
2290 offset.id() == ID_mult && offset.operands().size() == 2 &&
2291 (to_multi_ary_expr(offset).op0().is_constant() ||
2292 to_multi_ary_expr(offset).op1().is_constant()))
2293 {
2294 const mult_exprt &offset_mult = to_mult_expr(offset);
2295 const auto &const_factor = numeric_cast_v<mp_integer>(to_constant_expr(
2296 offset_mult.op0().is_constant() ? offset_mult.op0()
2297 : offset_mult.op1()));
2298 const exprt &other_factor = offset_mult.op0().is_constant()
2299 ? offset_mult.op1()
2300 : offset_mult.op0();
2301
2302 if((const_factor * expr.get_bits_per_byte()) % *el_size == 0)
2303 {
2304 exprt base_offset = mult_exprt{
2305 other_factor,
2307 (const_factor * expr.get_bits_per_byte()) / *el_size,
2308 other_factor.type())};
2309 with_exprt result_expr{
2310 root,
2312 base_offset, array_type->index_type()),
2314 matching_byte_extract_id,
2315 value,
2316 from_integer(0, offset.type()),
2317 expr.get_bits_per_byte(),
2318 array_type->element_type()}};
2319 mp_integer n_elements = *val_size / *el_size;
2320 for(mp_integer i = 1; i < n_elements; ++i)
2321 {
2322 result_expr = with_exprt{
2323 result_expr,
2325 plus_exprt{base_offset, from_integer(i, base_offset.type())},
2326 array_type->index_type()),
2328 matching_byte_extract_id,
2329 value,
2331 i * (*el_size / expr.get_bits_per_byte()), offset.type()),
2332 expr.get_bits_per_byte(),
2333 array_type->element_type()}};
2334 }
2335 return changed(simplify_rec(result_expr));
2336 }
2337 }
2338 }
2339 }
2340
2341 // the following require a constant offset
2342 if(!offset_int.has_value() || *offset_int < 0)
2343 return unchanged(expr);
2344
2345 // Are we updating (parts of) a struct? Do individual member updates
2346 // instead, unless there are non-byte-sized bit fields
2347 if(root.type().id() == ID_struct || root.type().id() == ID_struct_tag)
2348 {
2349 exprt result_expr;
2350 result_expr.make_nil();
2351
2352 auto update_size = pointer_offset_size(value.type(), ns);
2353
2354 const struct_typet &struct_type =
2355 root.type().id() == ID_struct_tag
2356 ? ns.follow_tag(to_struct_tag_type(root.type()))
2357 : to_struct_type(root.type());
2358 const struct_typet::componentst &components=
2359 struct_type.components();
2360
2361 for(const auto &component : components)
2362 {
2363 auto m_offset = member_offset(struct_type, component.get_name(), ns);
2364
2365 auto m_size_bits = pointer_offset_bits(component.type(), ns);
2366
2367 // can we determine the current offset?
2368 if(!m_offset.has_value())
2369 {
2370 result_expr.make_nil();
2371 break;
2372 }
2373
2374 // is it a byte-sized member?
2375 if(
2376 !m_size_bits.has_value() || *m_size_bits == 0 ||
2377 (*m_size_bits) % expr.get_bits_per_byte() != 0)
2378 {
2379 result_expr.make_nil();
2380 break;
2381 }
2382
2383 mp_integer m_size_bytes = (*m_size_bits) / expr.get_bits_per_byte();
2384
2385 // is that member part of the update?
2386 if(*m_offset + m_size_bytes <= *offset_int)
2387 continue;
2388 // are we done updating?
2389 else if(
2390 update_size.has_value() && *update_size > 0 &&
2391 *m_offset >= *offset_int + *update_size)
2392 {
2393 break;
2394 }
2395
2396 if(result_expr.is_nil())
2397 result_expr = as_const(expr).op();
2398
2399 exprt member_name(ID_member_name);
2400 member_name.set(ID_component_name, component.get_name());
2401 result_expr=with_exprt(result_expr, member_name, nil_exprt());
2402
2403 // are we updating on member boundaries?
2404 if(
2405 *m_offset < *offset_int ||
2406 (*m_offset == *offset_int && update_size.has_value() &&
2407 *update_size > 0 && m_size_bytes > *update_size))
2408 {
2410 expr.id(),
2411 member_exprt(root, component.get_name(), component.type()),
2412 from_integer(*offset_int - *m_offset, offset.type()),
2413 value,
2414 expr.get_bits_per_byte());
2415
2416 to_with_expr(result_expr).new_value().swap(v);
2417 }
2418 else if(
2419 update_size.has_value() && *update_size > 0 &&
2420 *m_offset + m_size_bytes > *offset_int + *update_size)
2421 {
2422 // we don't handle this for the moment
2423 result_expr.make_nil();
2424 break;
2425 }
2426 else
2427 {
2429 matching_byte_extract_id,
2430 value,
2431 from_integer(*m_offset - *offset_int, offset.type()),
2432 expr.get_bits_per_byte(),
2433 component.type());
2434
2435 to_with_expr(result_expr).new_value().swap(v);
2436 }
2437 }
2438
2439 if(result_expr.is_not_nil())
2440 return changed(simplify_rec(result_expr));
2441 }
2442
2443 // replace elements of array or struct expressions, possibly using
2444 // byte_extract
2445 if(root.id()==ID_array)
2446 {
2447 auto el_size =
2449
2450 if(
2451 !el_size.has_value() || *el_size == 0 ||
2452 (*el_size) % expr.get_bits_per_byte() != 0 ||
2453 (*val_size) % expr.get_bits_per_byte() != 0)
2454 {
2455 return unchanged(expr);
2456 }
2457
2458 exprt result=root;
2459
2460 mp_integer m_offset_bits=0, val_offset=0;
2461 Forall_operands(it, result)
2462 {
2463 if(*offset_int * expr.get_bits_per_byte() + (*val_size) <= m_offset_bits)
2464 break;
2465
2466 if(*offset_int * expr.get_bits_per_byte() < m_offset_bits + *el_size)
2467 {
2468 mp_integer bytes_req =
2469 (m_offset_bits + *el_size) / expr.get_bits_per_byte() - *offset_int;
2470 bytes_req-=val_offset;
2471 if(val_offset + bytes_req > (*val_size) / expr.get_bits_per_byte())
2472 bytes_req = (*val_size) / expr.get_bits_per_byte() - val_offset;
2473
2474 byte_extract_exprt new_val(
2475 matching_byte_extract_id,
2476 value,
2477 from_integer(val_offset, offset.type()),
2478 expr.get_bits_per_byte(),
2481 from_integer(bytes_req, offset.type())));
2482
2483 *it = byte_update_exprt(
2484 expr.id(),
2485 *it,
2487 *offset_int + val_offset - m_offset_bits / expr.get_bits_per_byte(),
2488 offset.type()),
2489 new_val,
2490 expr.get_bits_per_byte());
2491
2492 *it = simplify_rec(*it); // recursive call
2493
2494 val_offset+=bytes_req;
2495 }
2496
2497 m_offset_bits += *el_size;
2498 }
2499
2500 return std::move(result);
2501 }
2502
2503 return unchanged(expr);
2504}
2505
2508{
2509 if(expr.id() == ID_complex_real)
2510 {
2511 auto &complex_real_expr = to_complex_real_expr(expr);
2512
2513 if(complex_real_expr.op().id() == ID_complex)
2514 return to_complex_expr(complex_real_expr.op()).real();
2515 }
2516 else if(expr.id() == ID_complex_imag)
2517 {
2518 auto &complex_imag_expr = to_complex_imag_expr(expr);
2519
2520 if(complex_imag_expr.op().id() == ID_complex)
2521 return to_complex_expr(complex_imag_expr.op()).imag();
2522 }
2523
2524 return unchanged(expr);
2525}
2526
2529{
2530 // When one operand is zero, an overflow can only occur for a subtraction from
2531 // zero.
2532 if(
2533 expr.op1().is_zero() ||
2534 (expr.op0().is_zero() && !can_cast_expr<minus_overflow_exprt>(expr)))
2535 {
2536 return false_exprt{};
2537 }
2538
2539 // One is neutral element for multiplication
2540 if(
2542 (expr.op0().is_one() || expr.op1().is_one()))
2543 {
2544 return false_exprt{};
2545 }
2546
2547 // we only handle the case of same operand types
2548 if(expr.op0().type() != expr.op1().type())
2549 return unchanged(expr);
2550
2551 // catch some cases over mathematical types
2552 const irep_idt &op_type_id = expr.op0().type().id();
2553 if(
2554 op_type_id == ID_integer || op_type_id == ID_rational ||
2555 op_type_id == ID_real)
2556 {
2557 return false_exprt{};
2558 }
2559
2560 if(op_type_id == ID_natural && !can_cast_expr<minus_overflow_exprt>(expr))
2561 return false_exprt{};
2562
2563 // we only handle constants over signedbv/unsignedbv for the remaining cases
2564 if(op_type_id != ID_signedbv && op_type_id != ID_unsignedbv)
2565 return unchanged(expr);
2566
2567 if(!expr.op0().is_constant() || !expr.op1().is_constant())
2568 return unchanged(expr);
2569
2570 const auto op0_value = numeric_cast<mp_integer>(expr.op0());
2571 const auto op1_value = numeric_cast<mp_integer>(expr.op1());
2572 if(!op0_value.has_value() || !op1_value.has_value())
2573 return unchanged(expr);
2574
2575 mp_integer no_overflow_result;
2577 no_overflow_result = *op0_value + *op1_value;
2579 no_overflow_result = *op0_value - *op1_value;
2581 no_overflow_result = *op0_value * *op1_value;
2583 no_overflow_result = *op0_value << *op1_value;
2584 else
2586
2587 const std::size_t width = to_bitvector_type(expr.op0().type()).get_width();
2588 const integer_bitvector_typet bv_type{op_type_id, width};
2589 if(
2590 no_overflow_result < bv_type.smallest() ||
2591 no_overflow_result > bv_type.largest())
2592 {
2593 return true_exprt{};
2594 }
2595 else
2596 return false_exprt{};
2597}
2598
2601{
2602 // zero is a neutral element for all operations supported here
2603 if(expr.op().is_zero())
2604 return false_exprt{};
2605
2606 // catch some cases over mathematical types
2607 const irep_idt &op_type_id = expr.op().type().id();
2608 if(
2609 op_type_id == ID_integer || op_type_id == ID_rational ||
2610 op_type_id == ID_real)
2611 {
2612 return false_exprt{};
2613 }
2614
2615 if(op_type_id == ID_natural)
2616 return true_exprt{};
2617
2618 // we only handle constants over signedbv/unsignedbv for the remaining cases
2619 if(op_type_id != ID_signedbv && op_type_id != ID_unsignedbv)
2620 return unchanged(expr);
2621
2622 if(!expr.op().is_constant())
2623 return unchanged(expr);
2624
2625 const auto op_value = numeric_cast<mp_integer>(expr.op());
2626 if(!op_value.has_value())
2627 return unchanged(expr);
2628
2629 mp_integer no_overflow_result;
2631 no_overflow_result = -*op_value;
2632 else
2634
2635 const std::size_t width = to_bitvector_type(expr.op().type()).get_width();
2636 const integer_bitvector_typet bv_type{op_type_id, width};
2637 if(
2638 no_overflow_result < bv_type.smallest() ||
2639 no_overflow_result > bv_type.largest())
2640 {
2641 return true_exprt{};
2642 }
2643 else
2644 return false_exprt{};
2645}
2646
2649{
2650 if(expr.id() == ID_overflow_result_unary_minus)
2651 {
2652 // zero is a neutral element
2653 if(expr.op0().is_zero())
2654 return struct_exprt{{expr.op0(), false_exprt{}}, expr.type()};
2655
2656 // catch some cases over mathematical types
2657 const irep_idt &op_type_id = expr.op0().type().id();
2658 if(
2659 op_type_id == ID_integer || op_type_id == ID_rational ||
2660 op_type_id == ID_real)
2661 {
2662 return struct_exprt{{expr.op0(), false_exprt{}}, expr.type()};
2663 }
2664
2665 // always an overflow for natural numbers, but the result is not
2666 // representable
2667 if(op_type_id == ID_natural)
2668 return unchanged(expr);
2669
2670 // we only handle constants over signedbv/unsignedbv for the remaining cases
2671 if(op_type_id != ID_signedbv && op_type_id != ID_unsignedbv)
2672 return unchanged(expr);
2673
2674 if(!expr.op0().is_constant())
2675 return unchanged(expr);
2676
2677 const auto op_value = numeric_cast<mp_integer>(expr.op0());
2678 if(!op_value.has_value())
2679 return unchanged(expr);
2680
2681 mp_integer no_overflow_result = -*op_value;
2682
2683 const std::size_t width = to_bitvector_type(expr.op0().type()).get_width();
2684 const integer_bitvector_typet bv_type{op_type_id, width};
2685 if(
2686 no_overflow_result < bv_type.smallest() ||
2687 no_overflow_result > bv_type.largest())
2688 {
2689 return struct_exprt{
2690 {from_integer(no_overflow_result, expr.op0().type()), true_exprt{}},
2691 expr.type()};
2692 }
2693 else
2694 {
2695 return struct_exprt{
2696 {from_integer(no_overflow_result, expr.op0().type()), false_exprt{}},
2697 expr.type()};
2698 }
2699 }
2700 else
2701 {
2702 // When one operand is zero, an overflow can only occur for a subtraction
2703 // from zero.
2704 if(expr.op0().is_zero())
2705 {
2706 if(
2707 expr.id() == ID_overflow_result_plus ||
2708 expr.id() == ID_overflow_result_shl)
2709 {
2710 return struct_exprt{{expr.op1(), false_exprt{}}, expr.type()};
2711 }
2712 else if(expr.id() == ID_overflow_result_mult)
2713 {
2714 return struct_exprt{
2715 {from_integer(0, expr.op0().type()), false_exprt{}}, expr.type()};
2716 }
2717 }
2718 else if(expr.op1().is_zero())
2719 {
2720 if(
2721 expr.id() == ID_overflow_result_plus ||
2722 expr.id() == ID_overflow_result_minus ||
2723 expr.id() == ID_overflow_result_shl)
2724 {
2725 return struct_exprt{{expr.op0(), false_exprt{}}, expr.type()};
2726 }
2727 else
2728 {
2729 return struct_exprt{
2730 {from_integer(0, expr.op0().type()), false_exprt{}}, expr.type()};
2731 }
2732 }
2733
2734 // One is neutral element for multiplication
2735 if(
2736 expr.id() == ID_overflow_result_mult &&
2737 (expr.op0().is_one() || expr.op1().is_one()))
2738 {
2739 return struct_exprt{
2740 {expr.op0().is_one() ? expr.op1() : expr.op0(), false_exprt{}},
2741 expr.type()};
2742 }
2743
2744 // we only handle the case of same operand types
2745 if(
2746 expr.id() != ID_overflow_result_shl &&
2747 expr.op0().type() != expr.op1().type())
2748 {
2749 return unchanged(expr);
2750 }
2751
2752 // catch some cases over mathematical types
2753 const irep_idt &op_type_id = expr.op0().type().id();
2754 if(
2755 expr.id() != ID_overflow_result_shl &&
2756 (op_type_id == ID_integer || op_type_id == ID_rational ||
2757 op_type_id == ID_real))
2758 {
2759 irep_idt id =
2760 expr.id() == ID_overflow_result_plus
2761 ? ID_plus
2762 : expr.id() == ID_overflow_result_minus ? ID_minus : ID_mult;
2763 return struct_exprt{
2764 {simplify_node(binary_exprt{expr.op0(), id, expr.op1()}),
2765 false_exprt{}},
2766 expr.type()};
2767 }
2768
2769 if(
2770 (expr.id() == ID_overflow_result_plus ||
2771 expr.id() == ID_overflow_result_mult) &&
2772 op_type_id == ID_natural)
2773 {
2774 return struct_exprt{
2776 expr.op0(),
2777 expr.id() == ID_overflow_result_plus ? ID_plus : ID_mult,
2778 expr.op1()}),
2779 false_exprt{}},
2780 expr.type()};
2781 }
2782
2783 // we only handle constants over signedbv/unsignedbv for the remaining cases
2784 if(op_type_id != ID_signedbv && op_type_id != ID_unsignedbv)
2785 return unchanged(expr);
2786
2787 // a special case of overflow-minus checking with operands (X + n) and X
2788 if(expr.id() == ID_overflow_result_minus)
2789 {
2790 const exprt &tc_op0 = skip_typecast(expr.op0());
2791 const exprt &tc_op1 = skip_typecast(expr.op1());
2792
2793 if(auto sum = expr_try_dynamic_cast<plus_exprt>(tc_op0))
2794 {
2795 if(skip_typecast(sum->op0()) == tc_op1 && sum->operands().size() == 2)
2796 {
2797 std::optional<exprt> offset;
2798 if(sum->type().id() == ID_pointer)
2799 {
2800 offset = std::move(simplify_pointer_offset(
2801 pointer_offset_exprt{*sum, expr.op0().type()})
2802 .expr);
2803 if(offset->id() == ID_pointer_offset)
2804 return unchanged(expr);
2805 }
2806 else
2807 offset = std::move(
2808 simplify_typecast(typecast_exprt{sum->op1(), expr.op0().type()})
2809 .expr);
2810
2811 exprt offset_op = skip_typecast(*offset);
2812 if(
2813 offset_op.type().id() != ID_signedbv &&
2814 offset_op.type().id() != ID_unsignedbv)
2815 {
2816 return unchanged(expr);
2817 }
2818
2819 const std::size_t width =
2820 to_bitvector_type(expr.op0().type()).get_width();
2821 const integer_bitvector_typet bv_type{op_type_id, width};
2822
2823 or_exprt not_representable{
2825 offset_op,
2826 ID_lt,
2827 from_integer(bv_type.smallest(), offset_op.type())},
2829 offset_op,
2830 ID_gt,
2831 from_integer(bv_type.largest(), offset_op.type())}};
2832
2833 return struct_exprt{
2834 {*offset, simplify_rec(not_representable)}, expr.type()};
2835 }
2836 }
2837 }
2838
2839 if(!expr.op0().is_constant() || !expr.op1().is_constant())
2840 return unchanged(expr);
2841
2842 // preserve the sizeof type annotation
2843 std::optional<typet> c_sizeof_type;
2844 for(const auto &op : expr.operands())
2845 {
2846 const typet &sizeof_type =
2847 static_cast<const typet &>(op.find(ID_C_c_sizeof_type));
2848 if(sizeof_type.is_not_nil())
2849 {
2850 c_sizeof_type = sizeof_type;
2851 break;
2852 }
2853 }
2854
2855 const auto op0_value = numeric_cast<mp_integer>(expr.op0());
2856 const auto op1_value = numeric_cast<mp_integer>(expr.op1());
2857 if(!op0_value.has_value() || !op1_value.has_value())
2858 return unchanged(expr);
2859
2860 mp_integer no_overflow_result;
2861 if(expr.id() == ID_overflow_result_plus)
2862 no_overflow_result = *op0_value + *op1_value;
2863 else if(expr.id() == ID_overflow_result_minus)
2864 no_overflow_result = *op0_value - *op1_value;
2865 else if(expr.id() == ID_overflow_result_mult)
2866 no_overflow_result = *op0_value * *op1_value;
2867 else if(expr.id() == ID_overflow_result_shl)
2868 no_overflow_result = *op0_value << *op1_value;
2869 else
2871
2872 exprt no_overflow_result_expr =
2873 from_integer(no_overflow_result, expr.op0().type());
2874 if(c_sizeof_type.has_value())
2875 no_overflow_result_expr.set(ID_C_c_sizeof_type, *c_sizeof_type);
2876
2877 const std::size_t width = to_bitvector_type(expr.op0().type()).get_width();
2878 const integer_bitvector_typet bv_type{op_type_id, width};
2879 if(
2880 no_overflow_result < bv_type.smallest() ||
2881 no_overflow_result > bv_type.largest())
2882 {
2883 return struct_exprt{
2884 {std::move(no_overflow_result_expr), true_exprt{}}, expr.type()};
2885 }
2886 else
2887 {
2888 return struct_exprt{
2889 {std::move(no_overflow_result_expr), false_exprt{}}, expr.type()};
2890 }
2891 }
2892}
2893
2896{
2897 auto result = unchanged(expr);
2898
2899 // The ifs below could one day be replaced by a switch()
2900
2901 if(expr.id()==ID_address_of)
2902 {
2903 // the argument of this expression needs special treatment
2904 }
2905 else if(expr.id()==ID_if)
2906 {
2907 result = simplify_if_preorder(to_if_expr(expr));
2908 }
2909 else if(expr.id() == ID_typecast)
2910 {
2912 }
2913 else if(
2914 expr.id() == ID_byte_extract_little_endian ||
2915 expr.id() == ID_byte_extract_big_endian)
2916 {
2918 }
2919 else if(expr.id() == ID_dereference)
2920 {
2922 }
2923 else if(expr.id() == ID_index)
2924 {
2925 result = simplify_index_preorder(to_index_expr(expr));
2926 }
2927 else if(expr.id() == ID_member)
2928 {
2930 }
2931 else if(
2932 expr.id() == ID_is_dynamic_object || expr.id() == ID_is_invalid_pointer ||
2933 expr.id() == ID_object_size || expr.id() == ID_pointer_object ||
2934 expr.id() == ID_pointer_offset)
2935 {
2937 }
2938 else if(expr.has_operands())
2939 {
2940 std::optional<exprt::operandst> new_operands;
2941
2942 for(std::size_t i = 0; i < expr.operands().size(); ++i)
2943 {
2944 auto r_it = simplify_rec(expr.operands()[i]); // recursive call
2945 if(r_it.has_changed())
2946 {
2947 if(!new_operands.has_value())
2948 new_operands = expr.operands();
2949 (*new_operands)[i] = std::move(r_it.expr);
2950 }
2951 }
2952
2953 if(new_operands.has_value())
2954 {
2955 std::swap(result.expr.operands(), *new_operands);
2956 result.expr_changed = resultt<>::CHANGED;
2957 }
2958 }
2959
2960 if(as_const(result.expr).type().id() == ID_array)
2961 {
2962 const array_typet &array_type = to_array_type(as_const(result.expr).type());
2963 resultt<> simp_size = simplify_rec(array_type.size());
2964 if(simp_size.has_changed())
2965 {
2966 to_array_type(result.expr.type()).size() = simp_size.expr;
2967 result.expr_changed = resultt<>::CHANGED;
2968 }
2969 }
2970
2971 return result;
2972}
2973
2975{
2976 if(!node.has_operands())
2977 return unchanged(node); // no change
2978
2979 // #define DEBUGX
2980
2981#ifdef DEBUGX
2982 exprt old(node);
2983#endif
2984
2985 exprt expr = node;
2986 bool no_change_join_operands = join_operands(expr);
2987
2988 resultt<> r = unchanged(expr);
2989
2990 if(expr.id()==ID_typecast)
2991 {
2993 }
2994 else if(expr.id()==ID_equal || expr.id()==ID_notequal ||
2995 expr.id()==ID_gt || expr.id()==ID_lt ||
2996 expr.id()==ID_ge || expr.id()==ID_le)
2997 {
2999 }
3000 else if(expr.id()==ID_if)
3001 {
3002 r = simplify_if(to_if_expr(expr));
3003 }
3004 else if(expr.id()==ID_lambda)
3005 {
3007 }
3008 else if(expr.id()==ID_with)
3009 {
3010 r = simplify_with(to_with_expr(expr));
3011 }
3012 else if(expr.id()==ID_update)
3013 {
3015 }
3016 else if(expr.id()==ID_index)
3017 {
3019 }
3020 else if(expr.id()==ID_member)
3021 {
3023 }
3024 else if(expr.id()==ID_byte_update_little_endian ||
3025 expr.id()==ID_byte_update_big_endian)
3026 {
3028 }
3029 else if(expr.id()==ID_byte_extract_little_endian ||
3030 expr.id()==ID_byte_extract_big_endian)
3031 {
3033 }
3034 else if(expr.id()==ID_pointer_object)
3035 {
3037 }
3038 else if(expr.id() == ID_is_dynamic_object)
3039 {
3041 }
3042 else if(expr.id() == ID_is_invalid_pointer)
3043 {
3045 }
3046 else if(
3048 {
3050 }
3051 else if(expr.id()==ID_div)
3052 {
3053 r = simplify_div(to_div_expr(expr));
3054 }
3055 else if(expr.id()==ID_mod)
3056 {
3057 r = simplify_mod(to_mod_expr(expr));
3058 }
3059 else if(expr.id()==ID_bitnot)
3060 {
3062 }
3063 else if(
3064 expr.id() == ID_bitand || expr.id() == ID_bitor || expr.id() == ID_bitxor ||
3065 expr.id() == ID_bitxnor)
3066 {
3068 }
3069 else if(expr.id()==ID_ashr || expr.id()==ID_lshr || expr.id()==ID_shl)
3070 {
3072 }
3073 else if(expr.id()==ID_power)
3074 {
3076 }
3077 else if(expr.id()==ID_plus)
3078 {
3079 r = simplify_plus(to_plus_expr(expr));
3080 }
3081 else if(expr.id()==ID_minus)
3082 {
3084 }
3085 else if(expr.id()==ID_mult)
3086 {
3087 r = simplify_mult(to_mult_expr(expr));
3088 }
3089 else if(expr.id()==ID_floatbv_plus ||
3090 expr.id()==ID_floatbv_minus ||
3091 expr.id()==ID_floatbv_mult ||
3092 expr.id()==ID_floatbv_div)
3093 {
3095 }
3096 else if(expr.id() == ID_floatbv_round_to_integral)
3097 {
3100 }
3101 else if(expr.id()==ID_floatbv_typecast)
3102 {
3104 }
3105 else if(expr.id()==ID_unary_minus)
3106 {
3108 }
3109 else if(expr.id()==ID_unary_plus)
3110 {
3112 }
3113 else if(expr.id()==ID_not)
3114 {
3115 r = simplify_not(to_not_expr(expr));
3116 }
3117 else if(expr.id()==ID_implies ||
3118 expr.id()==ID_or || expr.id()==ID_xor ||
3119 expr.id()==ID_and)
3120 {
3121 r = simplify_boolean(expr);
3122 }
3123 else if(expr.id()==ID_dereference)
3124 {
3126 }
3127 else if(expr.id()==ID_address_of)
3128 {
3130 }
3131 else if(expr.id()==ID_pointer_offset)
3132 {
3134 }
3135 else if(expr.id()==ID_extractbit)
3136 {
3138 }
3139 else if(expr.id()==ID_concatenation)
3140 {
3142 }
3143 else if(expr.id()==ID_extractbits)
3144 {
3146 }
3147 else if(expr.id() == ID_zero_extend)
3148 {
3150 }
3151 else if(expr.id()==ID_ieee_float_equal ||
3152 expr.id()==ID_ieee_float_notequal)
3153 {
3155 }
3156 else if(expr.id() == ID_bswap)
3157 {
3159 }
3160 else if(expr.id()==ID_isinf)
3161 {
3163 }
3164 else if(expr.id()==ID_isnan)
3165 {
3167 }
3168 else if(expr.id()==ID_isnormal)
3169 {
3171 }
3172 else if(expr.id()==ID_abs)
3173 {
3174 r = simplify_abs(to_abs_expr(expr));
3175 }
3176 else if(expr.id()==ID_sign)
3177 {
3178 r = simplify_sign(to_sign_expr(expr));
3179 }
3180 else if(expr.id() == ID_popcount)
3181 {
3183 }
3184 else if(expr.id() == ID_count_leading_zeros)
3185 {
3187 }
3188 else if(expr.id() == ID_count_trailing_zeros)
3189 {
3191 }
3192 else if(expr.id() == ID_find_first_set)
3193 {
3195 }
3196 else if(expr.id() == ID_function_application)
3197 {
3199 }
3200 else if(expr.id() == ID_complex_real || expr.id() == ID_complex_imag)
3201 {
3203 }
3204 else if(
3205 const auto binary_overflow =
3207 {
3208 r = simplify_overflow_binary(*binary_overflow);
3209 }
3210 else if(
3211 const auto unary_overflow =
3213 {
3214 r = simplify_overflow_unary(*unary_overflow);
3215 }
3216 else if(
3217 const auto overflow_result =
3219 {
3220 r = simplify_overflow_result(*overflow_result);
3221 }
3222 else if(expr.id() == ID_bitreverse)
3223 {
3225 }
3226 else if(
3227 const auto prophecy_r_or_w_ok =
3229 {
3230 r = simplify_prophecy_r_or_w_ok(*prophecy_r_or_w_ok);
3231 }
3232 else if(
3233 const auto prophecy_pointer_in_range =
3235 {
3236 r = simplify_prophecy_pointer_in_range(*prophecy_pointer_in_range);
3237 }
3238 else if(expr.id() == ID_exists || expr.id() == ID_forall)
3239 {
3241 }
3242
3243 if(!no_change_join_operands)
3244 r = changed(r);
3245
3246#ifdef DEBUGX
3247 if(
3248 r.has_changed()
3249# ifdef DEBUG_ON_DEMAND
3250 && debug_on
3251# endif
3252 )
3253 {
3254 std::cout << "===== " << node.id() << ": " << format(node) << '\n'
3255 << " ---> " << format(r.expr) << '\n';
3256 }
3257#endif
3258
3259 return r;
3260}
3261
3263{
3264 // look up in cache
3265
3266 #ifdef USE_CACHE
3267 std::pair<simplify_expr_cachet::containert::iterator, bool>
3268 cache_result=simplify_expr_cache.container().
3269 insert(std::pair<exprt, exprt>(expr, exprt()));
3270
3271 if(!cache_result.second) // found!
3272 {
3273 const exprt &new_expr=cache_result.first->second;
3274
3275 if(new_expr.id().empty())
3276 return true; // no change
3277
3278 expr=new_expr;
3279 return false;
3280 }
3281 #endif
3282
3283 // We work on a copy to prevent unnecessary destruction of sharing.
3284 auto simplify_node_preorder_result = simplify_node_preorder(expr);
3285
3286 auto simplify_node_result = simplify_node(simplify_node_preorder_result.expr);
3287
3288 if(
3289 !simplify_node_result.has_changed() &&
3290 simplify_node_preorder_result.has_changed())
3291 {
3292 simplify_node_result.expr_changed =
3293 simplify_node_preorder_result.expr_changed;
3294 }
3295
3296#ifdef USE_LOCAL_REPLACE_MAP
3297 exprt tmp = simplify_node_result.expr;
3298# if 1
3299 replace_mapt::const_iterator it =
3300 local_replace_map.find(simplify_node_result.expr);
3301 if(it!=local_replace_map.end())
3302 simplify_node_result = changed(it->second);
3303# else
3304 if(
3305 !local_replace_map.empty() &&
3306 !replace_expr(local_replace_map, simplify_node_result.expr))
3307 {
3308 simplify_node_result = changed(simplify_rec(simplify_node_result.expr));
3309 }
3310# endif
3311#endif
3312
3313 if(!simplify_node_result.has_changed())
3314 {
3315 return unchanged(expr);
3316 }
3317 else
3318 {
3320 (as_const(simplify_node_result.expr).type().id() == ID_array &&
3321 expr.type().id() == ID_array) ||
3322 as_const(simplify_node_result.expr).type() == expr.type(),
3323 simplify_node_result.expr.pretty(),
3324 expr.pretty());
3325
3326#ifdef USE_CACHE
3327 // save in cache
3328 cache_result.first->second = simplify_node_result.expr;
3329#endif
3330
3331 return simplify_node_result;
3332 }
3333}
3334
3337{
3338#ifdef DEBUG_ON_DEMAND
3339 if(debug_on)
3340 std::cout << "TO-SIMP " << format(expr) << "\n";
3341#endif
3342 auto result = simplify_rec(expr);
3343#ifdef DEBUG_ON_DEMAND
3344 if(debug_on)
3345 std::cout << "FULLSIMP " << format(result.expr) << "\n";
3346#endif
3347 if(result.has_changed())
3348 {
3349 expr = result.expr;
3350 return false; // change
3351 }
3352 else
3353 return true; // no change
3354}
3355
3357bool simplify(exprt &expr, const namespacet &ns)
3358{
3359 return simplify_exprt(ns).simplify(expr);
3360}
3361
3363{
3364 simplify_exprt(ns).simplify(src);
3365 return src;
3366}
configt config
Definition config.cpp:25
mp_integer bvrep2integer(const irep_idt &src, std::size_t width, bool is_signed)
convert a bit-vector representation (possibly signed) to integer
constant_exprt from_integer(const mp_integer &int_value, const typet &type)
bool to_integer(const constant_exprt &expr, mp_integer &int_value)
Convert a constant expression expr to an arbitrary-precision integer.
bool get_bvrep_bit(const irep_idt &src, std::size_t width, std::size_t bit_index)
Get a bit with given index from bit-vector representation.
mp_integer power(const mp_integer &base, const mp_integer &exponent)
A multi-precision implementation of the power operator.
Target numeric_cast_v(const mp_integer &arg)
Convert an mp_integer to integral type Target An invariant will fail if the conversion is not possibl...
std::optional< Target > numeric_cast(const exprt &arg)
Converts an expression to any integral type.
const T & as_const(T &value)
Return a reference to the same object but ensures the type is const.
Definition as_const.h:14
API to expression classes for bitvectors.
const shift_exprt & to_shift_expr(const exprt &expr)
Cast an exprt to a shift_exprt.
const popcount_exprt & to_popcount_expr(const exprt &expr)
Cast an exprt to a popcount_exprt.
const extractbits_exprt & to_extractbits_expr(const exprt &expr)
Cast an exprt to an extractbits_exprt.
const find_first_set_exprt & to_find_first_set_expr(const exprt &expr)
Cast an exprt to a find_first_set_exprt.
const bitnot_exprt & to_bitnot_expr(const exprt &expr)
Cast an exprt to a bitnot_exprt.
const bswap_exprt & to_bswap_expr(const exprt &expr)
Cast an exprt to a bswap_exprt.
const count_leading_zeros_exprt & to_count_leading_zeros_expr(const exprt &expr)
Cast an exprt to a count_leading_zeros_exprt.
const bitreverse_exprt & to_bitreverse_expr(const exprt &expr)
Cast an exprt to a bitreverse_exprt.
const extractbit_exprt & to_extractbit_expr(const exprt &expr)
Cast an exprt to an extractbit_exprt.
const concatenation_exprt & to_concatenation_expr(const exprt &expr)
Cast an exprt to a concatenation_exprt.
const zero_extend_exprt & to_zero_extend_expr(const exprt &expr)
Cast an exprt to a zero_extend_exprt.
const count_trailing_zeros_exprt & to_count_trailing_zeros_expr(const exprt &expr)
Cast an exprt to a count_trailing_zeros_exprt.
const bv_typet & to_bv_type(const typet &type)
Cast a typet to a bv_typet.
const fixedbv_typet & to_fixedbv_type(const typet &type)
Cast a typet to a fixedbv_typet.
const bitvector_typet & to_bitvector_type(const typet &type)
Cast a typet to a bitvector_typet.
const floatbv_typet & to_floatbv_type(const typet &type)
Cast a typet to a floatbv_typet.
void slice(symex_bmct &symex, symex_target_equationt &symex_target_equation, const namespacet &ns, const optionst &options, ui_message_handlert &ui_message_handler)
Definition bmc_util.cpp:198
Expression classes for byte-level operators.
const byte_update_exprt & to_byte_update_expr(const exprt &expr)
exprt lower_byte_extract(const byte_extract_exprt &src, const namespacet &ns)
Rewrite a byte extract expression to more fundamental operations.
const byte_extract_exprt & to_byte_extract_expr(const exprt &expr)
int16_t s2
int8_t s1
unsignedbv_typet size_type()
Definition c_types.cpp:50
pointer_typet pointer_type(const typet &subtype)
Definition c_types.cpp:235
const c_enum_typet & to_c_enum_type(const typet &type)
Cast a typet to a c_enum_typet.
Definition c_types.h:335
const c_enum_tag_typet & to_c_enum_tag_type(const typet &type)
Cast a typet to a c_enum_tag_typet.
Definition c_types.h:377
const union_typet & to_union_type(const typet &type)
Cast a typet to a union_typet.
Definition c_types.h:184
const union_tag_typet & to_union_tag_type(const typet &type)
Cast a typet to a union_tag_typet.
Definition c_types.h:224
Absolute value.
Definition std_expr.h:442
Operator to return the address of an object.
Array constructor from list of elements.
Definition std_expr.h:1621
exprt & what()
Definition std_expr.h:1575
Arrays with given size.
Definition std_types.h:807
const exprt & size() const
Definition std_types.h:840
const typet & element_type() const
The type of the elements of the array.
Definition std_types.h:827
A base class for binary expressions.
Definition std_expr.h:638
exprt & op0()
Definition expr.h:133
exprt & op1()
Definition expr.h:136
A Boolean expression returning true, iff operation kind would result in an overflow when applied to o...
A base class for relations, i.e., binary predicates whose two operands have the same type.
Definition std_expr.h:762
std::size_t get_width() const
Definition std_types.h:925
Expression of type type extracted from some object op starting at position offset (given in number of...
std::size_t get_bits_per_byte() const
Expression corresponding to op() where the bytes starting at position offset (given in number of byte...
const exprt & offset() const
void set_offset(exprt e)
const exprt & op() const
void set_op(exprt e)
std::size_t get_bits_per_byte() const
const exprt & value() const
The C/C++ Booleans.
Definition c_types.h:97
C enum tag type, i.e., c_enum_typet with an identifier.
Definition c_types.h:352
const typet & underlying_type() const
Definition c_types.h:307
Determine whether an expression is constant.
Definition expr_util.h:87
exprt real()
Definition std_expr.h:1927
exprt imag()
Definition std_expr.h:1937
A constant literal expression.
Definition std_expr.h:3118
const irep_idt & get_value() const
Definition std_expr.h:3126
void set_value(const irep_idt &value)
Definition std_expr.h:3131
The count leading zeros (counting the number of zero bits starting from the most-significant bit) exp...
The count trailing zeros (counting the number of zero bits starting from the least-significant bit) e...
Operator to dereference a pointer.
bool empty() const
Definition dstring.h:89
Union constructor to support unions without any member (a GCC/Clang feature).
Definition std_expr.h:1834
Base class for all expressions.
Definition expr.h:56
std::vector< exprt > operandst
Definition expr.h:58
bool is_one() const
Return whether the expression is a constant representing 1.
Definition expr.cpp:96
bool has_operands() const
Return true if there is at least one operand.
Definition expr.h:91
bool is_true() const
Return whether the expression is a constant representing true.
Definition expr.cpp:27
bool is_false() const
Return whether the expression is a constant representing false.
Definition expr.cpp:34
bool is_zero() const
Return whether the expression is a constant representing 0.
Definition expr.cpp:47
exprt & op0()
Definition expr.h:133
exprt & op1()
Definition expr.h:136
bool is_constant() const
Return whether the expression is a constant.
Definition expr.h:212
typet & type()
Return the type of the expression.
Definition expr.h:84
operandst & operands()
Definition expr.h:94
const source_locationt & source_location() const
Definition expr.h:231
source_locationt & add_source_location()
Definition expr.h:236
void add_to_operands(const exprt &expr)
Add the given argument to the end of exprt's operands.
Definition expr.h:170
Extracts a sub-range of a bit-vector operand.
The Boolean constant false.
Definition std_expr.h:3200
Returns one plus the index of the least-significant one bit, or zero if the operand is zero.
std::size_t get_fraction_bits() const
Definition fixedbv.h:35
Fixed-width bit-vector with signed fixed-point interpretation.
fixedbv_spect spec
Definition fixedbv.h:44
void from_integer(const mp_integer &i)
Definition fixedbv.cpp:32
const mp_integer & get_value() const
Definition fixedbv.h:95
mp_integer to_integer() const
Definition fixedbv.cpp:37
void set_value(const mp_integer &_v)
Definition fixedbv.h:96
void round(const fixedbv_spect &dest_spec)
Definition fixedbv.cpp:52
constant_exprt to_expr() const
Definition fixedbv.cpp:43
Fixed-width bit-vector with IEEE floating-point interpretation.
Application of (mathematical) function.
An IEEE 754 floating-point value, including specificiation.
Definition ieee_float.h:117
void set_sign(bool _sign)
Definition ieee_float.h:160
ieee_float_spect spec
Definition ieee_float.h:119
constant_exprt to_expr() const
mp_integer pack() const
bool get_sign() const
Definition ieee_float.h:254
void unpack(const mp_integer &)
An IEEE 754 value plus a rounding mode, enabling operations with rounding on values.
Definition ieee_float.h:338
mp_integer to_integer() const
void from_integer(const mp_integer &i)
void change_spec(const ieee_float_spect &dest_spec)
The trinary if-then-else operator.
Definition std_expr.h:2502
exprt & false_case()
Definition std_expr.h:2539
exprt & true_case()
Definition std_expr.h:2529
Array index operator.
Definition std_expr.h:1470
exprt & index()
Definition std_expr.h:1510
exprt & array()
Definition std_expr.h:1500
Fixed-width bit-vector representing a signed or unsigned integer.
mp_integer largest() const
Return the largest value that can be represented using this type.
mp_integer smallest() const
Return the smallest value that can be represented using this type.
std::string pretty(unsigned indent=0, unsigned max_indent=0) const
Definition irep.cpp:482
const irept & find(const irep_idt &name) const
Definition irep.cpp:93
const irep_idt & get(const irep_idt &name) const
Definition irep.cpp:44
void set(const irep_idt &name, const irep_idt &value)
Definition irep.h:412
bool is_not_nil() const
Definition irep.h:372
void make_nil()
Definition irep.h:446
void swap(irept &irep)
Definition irep.h:434
const irep_idt & id() const
Definition irep.h:388
bool is_nil() const
Definition irep.h:368
A (mathematical) lambda expression.
exprt application(const operandst &arguments) const
Extract member of struct or union.
Definition std_expr.h:2972
Binary multiplication Associativity is not specified.
Definition std_expr.h:1107
exprt & op1()
Definition std_expr.h:938
exprt & op0()
Definition std_expr.h:932
A namespacet is essentially one or two symbol tables bound together, to allow for symbol lookups in t...
Definition namespace.h:91
The NIL expression.
Definition std_expr.h:3209
The null pointer constant.
Boolean OR.
Definition std_expr.h:2275
An expression returning both the result of the arithmetic operation under wrap-around semantics as we...
exprt & op0()
Definition expr.h:133
exprt & op1()
Definition expr.h:136
The plus expression Associativity is not specified.
Definition std_expr.h:1002
The offset (in bytes) of a pointer relative to the object.
The popcount (counting the number of bits set to 1) expression.
const exprt & length() const
const exprt & content() const
Sign of an expression Predicate is true if _op is negative, false otherwise.
Definition std_expr.h:596
Fixed-width bit-vector with two's complement interpretation.
resultt simplify_isnan(const unary_exprt &)
resultt simplify_bitwise(const multi_ary_exprt &)
const namespacet & ns
resultt simplify_quantifier_expr(const quantifier_exprt &)
Try to simplify exists/forall to a constant expression.
resultt simplify_div(const div_exprt &)
resultt simplify_byte_extract(const byte_extract_exprt &)
resultt simplify_bitreverse(const bitreverse_exprt &)
Try to simplify bit-reversing to a constant expression.
resultt simplify_abs(const abs_exprt &)
resultt simplify_isnormal(const unary_exprt &)
resultt simplify_dereference(const dereference_exprt &)
resultt simplify_bitnot(const bitnot_exprt &)
resultt simplify_zero_extend(const zero_extend_exprt &)
resultt simplify_prophecy_r_or_w_ok(const prophecy_r_or_w_ok_exprt &)
Try to simplify prophecy_{r,w,rw}_ok to a constant expression.
resultt simplify_member_preorder(const member_exprt &)
resultt simplify_popcount(const popcount_exprt &)
static resultt changed(resultt<> result)
resultt simplify_dereference_preorder(const dereference_exprt &)
resultt simplify_unary_pointer_predicate_preorder(const unary_exprt &)
resultt simplify_address_of(const address_of_exprt &)
resultt simplify_if(const if_exprt &)
resultt simplify_node(const exprt &)
resultt simplify_node_preorder(const exprt &)
resultt simplify_prophecy_pointer_in_range(const prophecy_pointer_in_range_exprt &)
Try to simplify prophecy_pointer_in_range to a constant expression.
resultt simplify_overflow_unary(const unary_overflow_exprt &)
Try to simplify overflow-unary-.
resultt simplify_minus(const minus_exprt &)
resultt simplify_extractbit(const extractbit_exprt &)
resultt simplify_rec(const exprt &)
resultt simplify_shifts(const shift_exprt &)
resultt simplify_index_preorder(const index_exprt &)
resultt simplify_typecast(const typecast_exprt &)
resultt simplify_pointer_object(const pointer_object_exprt &)
resultt simplify_boolean(const exprt &)
resultt simplify_object(const exprt &)
resultt simplify_mult(const mult_exprt &)
resultt simplify_floatbv_typecast(const floatbv_typecast_exprt &)
resultt simplify_with(const with_exprt &)
virtual resultt simplify_inequality(const binary_relation_exprt &)
simplifies inequalities !=, <=, <, >=, >, and also ==
resultt simplify_not(const not_exprt &)
resultt simplify_isinf(const unary_exprt &)
resultt simplify_overflow_binary(const binary_overflow_exprt &)
Try to simplify overflow-+, overflow-*, overflow–, overflow-shl.
resultt simplify_function_application(const function_application_exprt &)
Attempt to simplify mathematical function applications if we have enough information to do so.
resultt simplify_index(const index_exprt &)
resultt simplify_bswap(const bswap_exprt &)
resultt simplify_member(const member_exprt &)
static resultt unchanged(exprt expr)
resultt simplify_byte_update(const byte_update_exprt &)
resultt simplify_extractbits(const extractbits_exprt &)
Simplifies extracting of bits from a constant.
resultt simplify_update(const update_exprt &)
resultt simplify_is_invalid_pointer(const unary_exprt &)
resultt simplify_mod(const mod_exprt &)
resultt simplify_complex(const unary_exprt &)
virtual resultt simplify_pointer_offset(const pointer_offset_exprt &)
resultt simplify_plus(const plus_exprt &)
virtual bool simplify(exprt &expr)
resultt simplify_unary_plus(const unary_plus_exprt &)
resultt simplify_overflow_result(const overflow_result_exprt &)
Try to simplify overflow_result-+, overflow_result-*, overflow_result–, overflow_result-shl,...
resultt simplify_ffs(const find_first_set_exprt &)
Try to simplify find-first-set to a constant expression.
resultt simplify_if_preorder(const if_exprt &expr)
resultt simplify_byte_extract_preorder(const byte_extract_exprt &)
resultt simplify_is_dynamic_object(const unary_exprt &)
resultt simplify_power(const power_exprt &)
resultt simplify_object_size(const object_size_exprt &)
resultt simplify_lambda(const lambda_exprt &)
resultt simplify_concatenation(const concatenation_exprt &)
resultt simplify_floatbv_op(const ieee_float_op_exprt &)
resultt simplify_ctz(const count_trailing_zeros_exprt &)
Try to simplify count-trailing-zeros to a constant expression.
resultt simplify_clz(const count_leading_zeros_exprt &)
Try to simplify count-leading-zeros to a constant expression.
resultt simplify_ieee_float_relation(const binary_relation_exprt &)
resultt simplify_typecast_preorder(const typecast_exprt &)
resultt simplify_sign(const sign_exprt &)
resultt simplify_unary_minus(const unary_minus_exprt &)
resultt simplify_floatbv_round_to_integral(const floatbv_round_to_integral_exprt &)
Struct constructor from list of elements.
Definition std_expr.h:1877
Structure type, corresponds to C style structs.
Definition std_types.h:231
const componentst & components() const
Definition std_types.h:147
const componentt & get_component(const irep_idt &component_name) const
Get the reference to a component with given name.
Definition std_types.cpp:64
bool has_component(const irep_idt &component_name) const
Definition std_types.h:157
std::size_t component_number(const irep_idt &component_name) const
Return the sequence number of the component with given name.
Definition std_types.cpp:47
std::vector< componentt > componentst
Definition std_types.h:140
const irep_idt & get_identifier() const
Definition std_expr.h:160
The Boolean constant true.
Definition std_expr.h:3191
const typet & subtype() const
Definition type.h:187
Semantic type conversion.
Definition std_expr.h:2073
static exprt conditional_cast(const exprt &expr, const typet &type)
Definition std_expr.h:2081
The type of an expression, extends irept.
Definition type.h:29
Generic base class for unary expressions.
Definition std_expr.h:361
const exprt & op() const
Definition std_expr.h:391
A Boolean expression returning true, iff operation kind would result in an overflow when applied to t...
Union constructor from single element.
Definition std_expr.h:1770
The union type.
Definition c_types.h:147
std::optional< std::pair< struct_union_typet::componentt, mp_integer > > find_widest_union_component(const namespacet &ns) const
Determine the member of maximum bit width in a union type.
Definition c_types.cpp:300
Fixed-width bit-vector with unsigned binary interpretation.
Operator to update elements in structs and arrays.
Definition std_expr.h:2783
exprt & old()
Definition std_expr.h:2795
exprt::operandst & designator()
Definition std_expr.h:2809
exprt & new_value()
Definition std_expr.h:2819
Operator to update elements in structs and arrays.
Definition std_expr.h:2603
exprt & new_value()
Definition std_expr.h:2633
exprt & where()
Definition std_expr.h:2623
exprt & old()
Definition std_expr.h:2613
#define Forall_operands(it, expr)
Definition expr.h:27
auto expr_checked_cast(TExpr &base) -> typename detail::expr_dynamic_cast_return_typet< T, TExpr >::type
Cast a reference to a generic exprt to a specific derived class.
Definition expr_cast.h:227
bool can_cast_expr(const exprt &base)
Check whether a reference to a generic exprt is of a specific derived class.
auto type_try_dynamic_cast(TType &base) -> typename detail::expr_try_dynamic_cast_return_typet< T, TType >::type
Try to cast a reference to a generic typet to a specific derived class.
Definition expr_cast.h:135
bool can_cast_type(const typet &base)
Check whether a reference to a generic typet is of a specific derived class.
auto expr_try_dynamic_cast(TExpr &base) -> typename detail::expr_try_dynamic_cast_return_typet< T, TExpr >::type
Try to cast a reference to a generic exprt to a specific derived class.
Definition expr_cast.h:81
constant_exprt make_boolean_expr(bool value)
returns true_exprt if given true and false_exprt otherwise
exprt is_not_zero(const exprt &src, const namespacet &ns)
converts a scalar/float expression to C/C++ Booleans
Definition expr_util.cpp:69
const exprt & skip_typecast(const exprt &expr)
find the expression nested inside typecasts, if any
if_exprt lift_if(const exprt &src, std::size_t operand_number)
lift up an if_exprt one level
bool has_subtype(const typet &type, const std::function< bool(const typet &)> &pred, const namespacet &ns)
returns true if any of the contained types satisfies pred
Deprecated expression utility functions.
API to expression classes for floating-point arithmetic.
const ieee_float_op_exprt & to_ieee_float_op_expr(const exprt &expr)
Cast an exprt to an ieee_float_op_exprt.
const floatbv_round_to_integral_exprt & to_floatbv_round_to_integral_expr(const exprt &expr)
Cast an exprt to a floatbv_round_to_integral_exprt.
const floatbv_typecast_exprt & to_floatbv_typecast_expr(const exprt &expr)
Cast an exprt to a floatbv_typecast_exprt.
static format_containert< T > format(const T &o)
Definition format.h:37
const std::string & id2string(const irep_idt &d)
Definition irep.h:44
static int8_t r
Definition irep_hash.h:60
API to expression classes for 'mathematical' expressions.
const quantifier_exprt & to_quantifier_expr(const exprt &expr)
Cast an exprt to a quantifier_exprt.
const power_exprt & to_power_expr(const exprt &expr)
Cast an exprt to a power_exprt.
const function_application_exprt & to_function_application_expr(const exprt &expr)
Cast an exprt to a function_application_exprt.
const lambda_exprt & to_lambda_expr(const exprt &expr)
Cast an exprt to a lambda_exprt.
const mp_integer string2integer(const std::string &n, unsigned base)
Definition mp_arith.cpp:54
API to expression classes for Pointers.
const address_of_exprt & to_address_of_expr(const exprt &expr)
Cast an exprt to an address_of_exprt.
const pointer_typet & to_pointer_type(const typet &type)
Cast a typet to a pointer_typet.
const dereference_exprt & to_dereference_expr(const exprt &expr)
Cast an exprt to a dereference_exprt.
const pointer_offset_exprt & to_pointer_offset_expr(const exprt &expr)
Cast an exprt to a pointer_offset_exprt.
const pointer_object_exprt & to_pointer_object_expr(const exprt &expr)
Cast an exprt to a pointer_object_exprt.
std::optional< mp_integer > pointer_offset_size(const typet &type, const namespacet &ns)
Compute the size of a type in bytes, rounding up to full bytes.
std::optional< exprt > get_subexpression_at_offset(const exprt &expr, const mp_integer &offset_bytes, const typet &target_type_raw, const namespacet &ns)
std::optional< mp_integer > pointer_offset_bits(const typet &type, const namespacet &ns)
std::optional< mp_integer > member_offset(const struct_typet &type, const irep_idt &member, const namespacet &ns)
std::optional< exprt > member_offset_expr(const member_exprt &member_expr, const namespacet &ns)
Pointer Logic.
exprt pointer_offset_sum(const exprt &a, const exprt &b)
Pointer Dereferencing.
exprt object_size(const exprt &pointer)
constant_exprt from_rational(const rationalt &a)
bool replace_expr(const exprt &what, const exprt &by, exprt &dest)
const std::size_t sharing_mapt< keyT, valueT, fail_if_equal, hashT, equalT >::bits
bool simplify(exprt &expr, const namespacet &ns)
static simplify_exprt::resultt simplify_string_compare_to(const function_application_exprt &expr, const namespacet &ns)
Simplify String.compareTo function when arguments are constant.
static simplify_exprt::resultt simplify_string_contains(const function_application_exprt &expr, const namespacet &ns)
Simplify String.contains function when arguments are constant.
static simplify_exprt::resultt simplify_string_endswith(const function_application_exprt &expr, const namespacet &ns)
Simplify String.endsWith function when arguments are constant.
static simplify_exprt::resultt simplify_string_char_at(const function_application_exprt &expr, const namespacet &ns)
Simplify String.charAt function when arguments are constant.
static simplify_exprt::resultt simplify_string_startswith(const function_application_exprt &expr, const namespacet &ns)
Simplify String.startsWith function when arguments are constant.
static simplify_exprt::resultt simplify_string_is_empty(const function_application_exprt &expr, const namespacet &ns)
Simplify String.isEmpty function when arguments are constant.
static bool lower_case_string_expression(array_exprt &string_data)
Take the passed-in constant string array and lower-case every character.
static simplify_exprt::resultt simplify_string_index_of(const function_application_exprt &expr, const namespacet &ns, const bool search_from_end)
Simplify String.indexOf function when arguments are constant.
static simplify_exprt::resultt simplify_string_equals_ignore_case(const function_application_exprt &expr, const namespacet &ns)
Simplify String.equalsIgnorecase function when arguments are constant.
exprt simplify_expr(exprt src, const namespacet &ns)
std::optional< exprt > bits2expr(const std::string &bits, const typet &type, bool little_endian, const namespacet &ns)
std::optional< std::string > expr2bits(const exprt &expr, bool little_endian, const namespacet &ns)
std::optional< std::reference_wrapper< const array_exprt > > try_get_string_data_array(const exprt &content, const namespacet &ns)
Get char sequence from content field of a refined string expression.
bool join_operands(exprt &expr)
BigInt mp_integer
Definition smt_terms.h:17
#define CHECK_RETURN(CONDITION)
Definition invariant.h:495
#define UNREACHABLE
This should be used to mark dead code.
Definition invariant.h:525
#define DATA_INVARIANT(CONDITION, REASON)
This condition should be used to document that assumptions that are made on goto_functions,...
Definition invariant.h:534
#define POSTCONDITION_WITH_DIAGNOSTICS(CONDITION,...)
Definition invariant.h:480
auto component(T &struct_expr, const irep_idt &name, const namespacet &ns) -> decltype(struct_expr.op0())
Definition std_expr.cpp:122
API to expression classes.
const struct_exprt & to_struct_expr(const exprt &expr)
Cast an exprt to a struct_exprt.
Definition std_expr.h:1900
const array_of_exprt & to_array_of_expr(const exprt &expr)
Cast an exprt to an array_of_exprt.
Definition std_expr.h:1603
const binary_relation_exprt & to_binary_relation_expr(const exprt &expr)
Cast an exprt to a binary_relation_exprt.
Definition std_expr.h:895
const unary_plus_exprt & to_unary_plus_expr(const exprt &expr)
Cast an exprt to a unary_plus_exprt.
Definition std_expr.h:556
const index_exprt & to_index_expr(const exprt &expr)
Cast an exprt to an index_exprt.
Definition std_expr.h:1538
const mod_exprt & to_mod_expr(const exprt &expr)
Cast an exprt to a mod_exprt.
Definition std_expr.h:1277
const mult_exprt & to_mult_expr(const exprt &expr)
Cast an exprt to a mult_exprt.
Definition std_expr.h:1137
const array_exprt & to_array_expr(const exprt &expr)
Cast an exprt to an array_exprt.
Definition std_expr.h:1665
const typecast_exprt & to_typecast_expr(const exprt &expr)
Cast an exprt to a typecast_exprt.
Definition std_expr.h:2107
const div_exprt & to_div_expr(const exprt &expr)
Cast an exprt to a div_exprt.
Definition std_expr.h:1206
const plus_exprt & to_plus_expr(const exprt &expr)
Cast an exprt to a plus_exprt.
Definition std_expr.h:1041
const unary_exprt & to_unary_expr(const exprt &expr)
Cast an exprt to a unary_exprt.
Definition std_expr.h:426
const multi_ary_exprt & to_multi_ary_expr(const exprt &expr)
Cast an exprt to a multi_ary_exprt.
Definition std_expr.h:987
const abs_exprt & to_abs_expr(const exprt &expr)
Cast an exprt to a abs_exprt.
Definition std_expr.h:466
const if_exprt & to_if_expr(const exprt &expr)
Cast an exprt to an if_exprt.
Definition std_expr.h:2582
const member_exprt & to_member_expr(const exprt &expr)
Cast an exprt to a member_exprt.
Definition std_expr.h:3064
const minus_exprt & to_minus_expr(const exprt &expr)
Cast an exprt to a minus_exprt.
Definition std_expr.h:1086
const complex_imag_exprt & to_complex_imag_expr(const exprt &expr)
Cast an exprt to a complex_imag_exprt.
Definition std_expr.h:2053
const index_designatort & to_index_designator(const exprt &expr)
Cast an exprt to an index_designatort.
Definition std_expr.h:2714
const complex_real_exprt & to_complex_real_expr(const exprt &expr)
Cast an exprt to a complex_real_exprt.
Definition std_expr.h:2010
const constant_exprt & to_constant_expr(const exprt &expr)
Cast an exprt to a constant_exprt.
Definition std_expr.h:3173
const not_exprt & to_not_expr(const exprt &expr)
Cast an exprt to an not_exprt.
Definition std_expr.h:2484
const symbol_exprt & to_symbol_expr(const exprt &expr)
Cast an exprt to a symbol_exprt.
Definition std_expr.h:272
const with_exprt & to_with_expr(const exprt &expr)
Cast an exprt to a with_exprt.
Definition std_expr.h:2661
const complex_exprt & to_complex_expr(const exprt &expr)
Cast an exprt to a complex_exprt.
Definition std_expr.h:1965
const update_exprt & to_update_expr(const exprt &expr)
Cast an exprt to an update_exprt.
Definition std_expr.h:2866
const unary_minus_exprt & to_unary_minus_expr(const exprt &expr)
Cast an exprt to a unary_minus_exprt.
Definition std_expr.h:514
const sign_exprt & to_sign_expr(const exprt &expr)
Cast an exprt to a sign_exprt.
Definition std_expr.h:621
bool is_constant(const typet &type)
This method tests, if the given typet is a constant.
Definition std_types.h:29
const struct_typet & to_struct_type(const typet &type)
Cast a typet to a struct_typet.
Definition std_types.h:308
const struct_tag_typet & to_struct_tag_type(const typet &type)
Cast a typet to a struct_tag_typet.
Definition std_types.h:518
const array_typet & to_array_type(const typet &type)
Cast a typet to an array_typet.
Definition std_types.h:888
String expressions for the string solver.
refined_string_exprt & to_string_expr(exprt &expr)
static bool failed(bool error_indicator)
const type_with_subtypet & to_type_with_subtype(const typet &type)
Definition type.h:208
dstringt irep_idt