Mercurial > hg > CbC > CbC_gcc

comparison gcc/d/dmd/optimize.c @ 145:1830386684a0

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
gcc-9.2.0
author anatofuz
date Thu, 13 Feb 2020 11:34:05 +0900
parents
children
comparison
equal deleted inserted replaced
131:84e7813d76e9 145:1830386684a0
1
2 /* Compiler implementation of the D programming language
3 * Copyright (C) 1999-2019 by The D Language Foundation, All Rights Reserved
4 * written by Walter Bright
5 * http://www.digitalmars.com
6 * Distributed under the Boost Software License, Version 1.0
7 * http://www.boost.org/LICENSE_1_0.txt
8 * https://github.com/D-Programming-Language/dmd/blob/master/src/optimize.c
9 */
10
11 #include "root/dsystem.h"
12
13 #include "root/checkedint.h"
14 #include "lexer.h"
15 #include "mtype.h"
16 #include "expression.h"
17 #include "declaration.h"
18 #include "aggregate.h"
19 #include "init.h"
20 #include "enum.h"
21 #include "ctfe.h"
22
23 Expression *semantic(Expression *e, Scope *sc);
24
25 /*************************************
26 * If variable has a const initializer,
27 * return that initializer.
28 */
29
30 Expression *expandVar(int result, VarDeclaration *v)
31 {
32 //printf("expandVar(result = %d, v = %p, %s)\n", result, v, v ? v->toChars() : "null");
33
34 Expression *e = NULL;
35 if (!v)
36 return e;
37 if (!v->originalType && v->semanticRun < PASSsemanticdone) // semantic() not yet run
38 v->semantic(NULL);
39
40 if (v->isConst() || v->isImmutable() || v->storage_class & STCmanifest)
41 {
42 if (!v->type)
43 {
44 return e;
45 }
46 Type *tb = v->type->toBasetype();
47 if (v->storage_class & STCmanifest ||
48 v->type->toBasetype()->isscalar() ||
49 ((result & WANTexpand) && (tb->ty != Tsarray && tb->ty != Tstruct))
50 )
51 {
52 if (v->_init)
53 {
54 if (v->inuse)
55 {
56 if (v->storage_class & STCmanifest)
57 {
58 v->error("recursive initialization of constant");
59 goto Lerror;
60 }
61 goto L1;
62 }
63 Expression *ei = v->getConstInitializer();
64 if (!ei)
65 {
66 if (v->storage_class & STCmanifest)
67 {
68 v->error("enum cannot be initialized with %s", v->_init->toChars());
69 goto Lerror;
70 }
71 goto L1;
72 }
73 if (ei->op == TOKconstruct || ei->op == TOKblit)
74 {
75 AssignExp *ae = (AssignExp *)ei;
76 ei = ae->e2;
77 if (ei->isConst() == 1)
78 {
79 }
80 else if (ei->op == TOKstring)
81 {
82 // Bugzilla 14459: We should not constfold the string literal
83 // if it's typed as a C string, because the value expansion
84 // will drop the pointer identity.
85 if (!(result & WANTexpand) && ei->type->toBasetype()->ty == Tpointer)
86 goto L1;
87 }
88 else
89 goto L1;
90
91 if (ei->type == v->type)
92 {
93 // const variable initialized with const expression
94 }
95 else if (ei->implicitConvTo(v->type) >= MATCHconst)
96 {
97 // const var initialized with non-const expression
98 ei = ei->implicitCastTo(NULL, v->type);
99 ei = semantic(ei, NULL);
100 }
101 else
102 goto L1;
103 }
104 else if (!(v->storage_class & STCmanifest) &&
105 ei->isConst() != 1 && ei->op != TOKstring &&
106 ei->op != TOKaddress)
107 {
108 goto L1;
109 }
110 if (!ei->type)
111 {
112 goto L1;
113 }
114 else
115 {
116 // Should remove the copy() operation by
117 // making all mods to expressions copy-on-write
118 e = ei->copy();
119 }
120 }
121 else
122 {
123 goto L1;
124 }
125 if (e->type != v->type)
126 {
127 e = e->castTo(NULL, v->type);
128 }
129 v->inuse++;
130 e = e->optimize(result);
131 v->inuse--;
132 }
133 }
134 L1:
135 //if (e) printf("\te = %p, %s, e->type = %d, %s\n", e, e->toChars(), e->type->ty, e->type->toChars());
136 return e;
137
138 Lerror:
139 return new ErrorExp();
140 }
141
142
143 Expression *fromConstInitializer(int result, Expression *e1)
144 {
145 //printf("fromConstInitializer(result = %x, %s)\n", result, e1->toChars());
146 //static int xx; if (xx++ == 10) assert(0);
147 Expression *e = e1;
148 if (e1->op == TOKvar)
149 {
150 VarExp *ve = (VarExp *)e1;
151 VarDeclaration *v = ve->var->isVarDeclaration();
152 e = expandVar(result, v);
153 if (e)
154 {
155 // If it is a comma expression involving a declaration, we mustn't
156 // perform a copy -- we'd get two declarations of the same variable.
157 // See bugzilla 4465.
158 if (e->op == TOKcomma && ((CommaExp *)e)->e1->op == TOKdeclaration)
159 e = e1;
160 else
161
162 if (e->type != e1->type && e1->type && e1->type->ty != Tident)
163 {
164 // Type 'paint' operation
165 e = e->copy();
166 e->type = e1->type;
167 }
168 e->loc = e1->loc;
169 }
170 else
171 {
172 e = e1;
173 }
174 }
175 return e;
176 }
177
178 Expression *Expression_optimize(Expression *e, int result, bool keepLvalue)
179 {
180 class OptimizeVisitor : public Visitor
181 {
182 public:
183 int result;
184 bool keepLvalue;
185 Expression *ret;
186
187 OptimizeVisitor(int result, bool keepLvalue)
188 : result(result), keepLvalue(keepLvalue)
189 {
190 }
191
192 void error()
193 {
194 ret = new ErrorExp();
195 }
196
197 bool expOptimize(Expression *&e, int flags, bool keepLvalue = false)
198 {
199 if (!e)
200 return false;
201 Expression *ex = e->optimize(flags, keepLvalue);
202 if (ex->op == TOKerror)
203 {
204 ret = ex; // store error result
205 return true;
206 }
207 else
208 {
209 e = ex; // modify original
210 return false;
211 }
212 }
213
214 bool unaOptimize(UnaExp *e, int flags)
215 {
216 return expOptimize(e->e1, flags);
217 }
218
219 bool binOptimize(BinExp *e, int flags)
220 {
221 expOptimize(e->e1, flags);
222 expOptimize(e->e2, flags);
223 return ret->op == TOKerror;
224 }
225
226 void visit(Expression *)
227 {
228 //printf("Expression::optimize(result = x%x) %s\n", result, e->toChars());
229 }
230
231 void visit(VarExp *e)
232 {
233 if (keepLvalue)
234 {
235 VarDeclaration *v = e->var->isVarDeclaration();
236 if (v && !(v->storage_class & STCmanifest))
237 return;
238 }
239 ret = fromConstInitializer(result, e);
240 }
241
242 void visit(TupleExp *e)
243 {
244 expOptimize(e->e0, WANTvalue);
245 for (size_t i = 0; i < e->exps->dim; i++)
246 {
247 expOptimize((*e->exps)[i], WANTvalue);
248 }
249 }
250
251 void visit(ArrayLiteralExp *e)
252 {
253 if (e->elements)
254 {
255 expOptimize(e->basis, result & WANTexpand);
256 for (size_t i = 0; i < e->elements->dim; i++)
257 {
258 expOptimize((*e->elements)[i], result & WANTexpand);
259 }
260 }
261 }
262
263 void visit(AssocArrayLiteralExp *e)
264 {
265 assert(e->keys->dim == e->values->dim);
266 for (size_t i = 0; i < e->keys->dim; i++)
267 {
268 expOptimize((*e->keys)[i], result & WANTexpand);
269 expOptimize((*e->values)[i], result & WANTexpand);
270 }
271 }
272
273 void visit(StructLiteralExp *e)
274 {
275 if (e->stageflags & stageOptimize) return;
276 int old = e->stageflags;
277 e->stageflags |= stageOptimize;
278 if (e->elements)
279 {
280 for (size_t i = 0; i < e->elements->dim; i++)
281 {
282 expOptimize((*e->elements)[i], result & WANTexpand);
283 }
284 }
285 e->stageflags = old;
286 }
287
288 void visit(UnaExp *e)
289 {
290 //printf("UnaExp::optimize() %s\n", e->toChars());
291 if (unaOptimize(e, result))
292 return;
293 }
294
295 void visit(NegExp *e)
296 {
297 if (unaOptimize(e, result))
298 return;
299
300 if (e->e1->isConst() == 1)
301 {
302 ret = Neg(e->type, e->e1).copy();
303 }
304 }
305
306 void visit(ComExp *e)
307 {
308 if (unaOptimize(e, result))
309 return;
310
311 if (e->e1->isConst() == 1)
312 {
313 ret = Com(e->type, e->e1).copy();
314 }
315 }
316
317 void visit(NotExp *e)
318 {
319 if (unaOptimize(e, result))
320 return;
321
322 if (e->e1->isConst() == 1)
323 {
324 ret = Not(e->type, e->e1).copy();
325 }
326 }
327
328 void visit(SymOffExp *e)
329 {
330 assert(e->var);
331 }
332
333 void visit(AddrExp *e)
334 {
335 //printf("AddrExp::optimize(result = %d) %s\n", result, e->toChars());
336
337 /* Rewrite &(a,b) as (a,&b)
338 */
339 if (e->e1->op == TOKcomma)
340 {
341 CommaExp *ce = (CommaExp *)e->e1;
342 AddrExp *ae = new AddrExp(e->loc, ce->e2, e->type);
343 ret = new CommaExp(ce->loc, ce->e1, ae);
344 ret->type = e->type;
345 return;
346 }
347
348 // Keep lvalue-ness
349 if (expOptimize(e->e1, result, true))
350 return;
351
352 // Convert &*ex to ex
353 if (e->e1->op == TOKstar)
354 {
355 Expression *ex = ((PtrExp *)e->e1)->e1;
356 if (e->type->equals(ex->type))
357 ret = ex;
358 else if (e->type->toBasetype()->equivalent(ex->type->toBasetype()))
359 {
360 ret = ex->copy();
361 ret->type = e->type;
362 }
363 return;
364 }
365 if (e->e1->op == TOKvar)
366 {
367 VarExp *ve = (VarExp *)e->e1;
368 if (!ve->var->isOut() && !ve->var->isRef() &&
369 !ve->var->isImportedSymbol())
370 {
371 ret = new SymOffExp(e->loc, ve->var, 0, ve->hasOverloads);
372 ret->type = e->type;
373 return;
374 }
375 }
376 if (e->e1->op == TOKindex)
377 {
378 // Convert &array[n] to &array+n
379 IndexExp *ae = (IndexExp *)e->e1;
380
381 if (ae->e2->op == TOKint64 && ae->e1->op == TOKvar)
382 {
383 sinteger_t index = ae->e2->toInteger();
384 VarExp *ve = (VarExp *)ae->e1;
385 if (ve->type->ty == Tsarray
386 && !ve->var->isImportedSymbol())
387 {
388 TypeSArray *ts = (TypeSArray *)ve->type;
389 sinteger_t dim = ts->dim->toInteger();
390 if (index < 0 || index >= dim)
391 {
392 e->error("array index %lld is out of bounds [0..%lld]", index, dim);
393 return error();
394 }
395
396 bool overflow = false;
397 const d_uns64 offset = mulu(index, ts->nextOf()->size(e->loc), overflow);
398 if (overflow)
399 {
400 e->error("array offset overflow");
401 return error();
402 }
403
404 ret = new SymOffExp(e->loc, ve->var, offset);
405 ret->type = e->type;
406 return;
407 }
408 }
409 }
410 }
411
412 void visit(PtrExp *e)
413 {
414 //printf("PtrExp::optimize(result = x%x) %s\n", result, e->toChars());
415 if (expOptimize(e->e1, result))
416 return;
417 // Convert *&ex to ex
418 // But only if there is no type punning involved
419 if (e->e1->op == TOKaddress)
420 {
421 Expression *ex = ((AddrExp *)e->e1)->e1;
422 if (e->type->equals(ex->type))
423 ret = ex;
424 else if (e->type->toBasetype()->equivalent(ex->type->toBasetype()))
425 {
426 ret = ex->copy();
427 ret->type = e->type;
428 }
429 }
430 if (keepLvalue)
431 return;
432
433 // Constant fold *(&structliteral + offset)
434 if (e->e1->op == TOKadd)
435 {
436 Expression *ex = Ptr(e->type, e->e1).copy();
437 if (!CTFEExp::isCantExp(ex))
438 {
439 ret = ex;
440 return;
441 }
442 }
443
444 if (e->e1->op == TOKsymoff)
445 {
446 SymOffExp *se = (SymOffExp *)e->e1;
447 VarDeclaration *v = se->var->isVarDeclaration();
448 Expression *ex = expandVar(result, v);
449 if (ex && ex->op == TOKstructliteral)
450 {
451 StructLiteralExp *sle = (StructLiteralExp *)ex;
452 ex = sle->getField(e->type, (unsigned)se->offset);
453 if (ex && !CTFEExp::isCantExp(ex))
454 {
455 ret = ex;
456 return;
457 }
458 }
459 }
460 }
461
462 void visit(DotVarExp *e)
463 {
464 //printf("DotVarExp::optimize(result = x%x) %s\n", result, e->toChars());
465 if (expOptimize(e->e1, result))
466 return;
467 if (keepLvalue)
468 return;
469
470 Expression *ex = e->e1;
471
472 if (ex->op == TOKvar)
473 {
474 VarExp *ve = (VarExp *)ex;
475 VarDeclaration *v = ve->var->isVarDeclaration();
476 ex = expandVar(result, v);
477 }
478
479 if (ex && ex->op == TOKstructliteral)
480 {
481 StructLiteralExp *sle = (StructLiteralExp *)ex;
482 VarDeclaration *vf = e->var->isVarDeclaration();
483 if (vf && !vf->overlapped)
484 {
485 /* Bugzilla 13021: Prevent optimization if vf has overlapped fields.
486 */
487 ex = sle->getField(e->type, vf->offset);
488 if (ex && !CTFEExp::isCantExp(ex))
489 {
490 ret = ex;
491 return;
492 }
493 }
494 }
495 }
496
497 void visit(NewExp *e)
498 {
499 expOptimize(e->thisexp, WANTvalue);
500
501 // Optimize parameters
502 if (e->newargs)
503 {
504 for (size_t i = 0; i < e->newargs->dim; i++)
505 {
506 expOptimize((*e->newargs)[i], WANTvalue);
507 }
508 }
509
510 if (e->arguments)
511 {
512 for (size_t i = 0; i < e->arguments->dim; i++)
513 {
514 expOptimize((*e->arguments)[i], WANTvalue);
515 }
516 }
517 }
518
519 void visit(CallExp *e)
520 {
521 //printf("CallExp::optimize(result = %d) %s\n", result, e->toChars());
522
523 // Optimize parameters with keeping lvalue-ness
524 if (expOptimize(e->e1, result))
525 return;
526 if (e->arguments)
527 {
528 Type *t1 = e->e1->type->toBasetype();
529 if (t1->ty == Tdelegate) t1 = t1->nextOf();
530 assert(t1->ty == Tfunction);
531 TypeFunction *tf = (TypeFunction *)t1;
532 for (size_t i = 0; i < e->arguments->dim; i++)
533 {
534 Parameter *p = Parameter::getNth(tf->parameters, i);
535 bool keep = p && (p->storageClass & (STCref | STCout)) != 0;
536 expOptimize((*e->arguments)[i], WANTvalue, keep);
537 }
538 }
539 }
540
541 void visit(CastExp *e)
542 {
543 //printf("CastExp::optimize(result = %d) %s\n", result, e->toChars());
544 //printf("from %s to %s\n", e->type->toChars(), e->to->toChars());
545 //printf("from %s\n", e->type->toChars());
546 //printf("e1->type %s\n", e->e1->type->toChars());
547 //printf("type = %p\n", e->type);
548 assert(e->type);
549 TOK op1 = e->e1->op;
550
551 Expression *e1old = e->e1;
552 if (expOptimize(e->e1, result))
553 return;
554 e->e1 = fromConstInitializer(result, e->e1);
555
556 if (e->e1 == e1old &&
557 e->e1->op == TOKarrayliteral &&
558 e->type->toBasetype()->ty == Tpointer &&
559 e->e1->type->toBasetype()->ty != Tsarray)
560 {
561 // Casting this will result in the same expression, and
562 // infinite loop because of Expression::implicitCastTo()
563 return; // no change
564 }
565
566 if ((e->e1->op == TOKstring || e->e1->op == TOKarrayliteral) &&
567 (e->type->ty == Tpointer || e->type->ty == Tarray))
568 {
569 const d_uns64 esz = e->type->nextOf()->size(e->loc);
570 const d_uns64 e1sz = e->e1->type->toBasetype()->nextOf()->size(e->e1->loc);
571 if (esz == SIZE_INVALID || e1sz == SIZE_INVALID)
572 return error();
573
574 if (e1sz == esz)
575 {
576 // Bugzilla 12937: If target type is void array, trying to paint
577 // e->e1 with that type will cause infinite recursive optimization.
578 if (e->type->nextOf()->ty == Tvoid)
579 return;
580
581 ret = e->e1->castTo(NULL, e->type);
582 //printf(" returning1 %s\n", ret->toChars());
583 return;
584 }
585 }
586
587 if (e->e1->op == TOKstructliteral &&
588 e->e1->type->implicitConvTo(e->type) >= MATCHconst)
589 {
590 //printf(" returning2 %s\n", e->e1->toChars());
591 L1: // Returning e1 with changing its type
592 ret = (e1old == e->e1 ? e->e1->copy() : e->e1);
593 ret->type = e->type;
594 return;
595 }
596
597 /* The first test here is to prevent infinite loops
598 */
599 if (op1 != TOKarrayliteral && e->e1->op == TOKarrayliteral)
600 {
601 ret = e->e1->castTo(NULL, e->to);
602 return;
603 }
604 if (e->e1->op == TOKnull &&
605 (e->type->ty == Tpointer || e->type->ty == Tclass || e->type->ty == Tarray))
606 {
607 //printf(" returning3 %s\n", e->e1->toChars());
608 goto L1;
609 }
610
611 if (e->type->ty == Tclass && e->e1->type->ty == Tclass)
612 {
613 // See if we can remove an unnecessary cast
614 ClassDeclaration *cdfrom = e->e1->type->isClassHandle();
615 ClassDeclaration *cdto = e->type->isClassHandle();
616 if (cdto == ClassDeclaration::object && !cdfrom->isInterfaceDeclaration())
617 goto L1; // can always convert a class to Object
618 // Need to determine correct offset before optimizing away the cast.
619 // https://issues.dlang.org/show_bug.cgi?id=16980
620 cdfrom->size(e->loc);
621 assert(cdfrom->sizeok == SIZEOKdone);
622 assert(cdto->sizeok == SIZEOKdone || !cdto->isBaseOf(cdfrom, NULL));
623 int offset;
624 if (cdto->isBaseOf(cdfrom, &offset) && offset == 0)
625 {
626 //printf(" returning4 %s\n", e->e1->toChars());
627 goto L1;
628 }
629 }
630
631 // We can convert 'head const' to mutable
632 if (e->to->mutableOf()->constOf()->equals(e->e1->type->mutableOf()->constOf()))
633 {
634 //printf(" returning5 %s\n", e->e1->toChars());
635 goto L1;
636 }
637
638 if (e->e1->isConst())
639 {
640 if (e->e1->op == TOKsymoff)
641 {
642 if (e->type->toBasetype()->ty != Tsarray)
643 {
644 const d_uns64 esz = e->type->size(e->loc);
645 const d_uns64 e1sz = e->e1->type->size(e->e1->loc);
646 if (esz == SIZE_INVALID ||
647 e1sz == SIZE_INVALID)
648 return error();
649
650 if (esz == e1sz)
651 goto L1;
652 }
653 return;
654 }
655 if (e->to->toBasetype()->ty != Tvoid)
656 {
657 if (e->e1->type->equals(e->type) && e->type->equals(e->to))
658 ret = e->e1;
659 else
660 ret = Cast(e->loc, e->type, e->to, e->e1).copy();
661 }
662 }
663 //printf(" returning6 %s\n", ret->toChars());
664 }
665
666 void visit(BinExp *e)
667 {
668 //printf("BinExp::optimize(result = %d) %s\n", result, e->toChars());
669 // don't replace const variable with its initializer in e1
670 bool e2only = (e->op == TOKconstruct || e->op == TOKblit);
671 if (e2only ? expOptimize(e->e2, result) : binOptimize(e, result))
672 return;
673
674 if (e->op == TOKshlass || e->op == TOKshrass || e->op == TOKushrass)
675 {
676 if (e->e2->isConst() == 1)
677 {
678 sinteger_t i2 = e->e2->toInteger();
679 d_uns64 sz = e->e1->type->size(e->e1->loc);
680 assert(sz != SIZE_INVALID);
681 sz *= 8;
682 if (i2 < 0 || (d_uns64)i2 >= sz)
683 {
684 e->error("shift assign by %lld is outside the range 0..%llu", i2, (ulonglong)sz - 1);
685 return error();
686 }
687 }
688 }
689 }
690
691 void visit(AddExp *e)
692 {
693 //printf("AddExp::optimize(%s)\n", e->toChars());
694
695 if (binOptimize(e, result))
696 return;
697
698 if (e->e1->isConst() && e->e2->isConst())
699 {
700 if (e->e1->op == TOKsymoff && e->e2->op == TOKsymoff)
701 return;
702 ret = Add(e->loc, e->type, e->e1, e->e2).copy();
703 }
704 }
705
706 void visit(MinExp *e)
707 {
708 if (binOptimize(e, result))
709 return;
710
711 if (e->e1->isConst() && e->e2->isConst())
712 {
713 if (e->e2->op == TOKsymoff)
714 return;
715 ret = Min(e->loc, e->type, e->e1, e->e2).copy();
716 }
717 }
718
719 void visit(MulExp *e)
720 {
721 //printf("MulExp::optimize(result = %d) %s\n", result, e->toChars());
722
723 if (binOptimize(e, result))
724 return;
725
726 if (e->e1->isConst() == 1 && e->e2->isConst() == 1)
727 {
728 ret = Mul(e->loc, e->type, e->e1, e->e2).copy();
729 }
730 }
731
732 void visit(DivExp *e)
733 {
734 //printf("DivExp::optimize(%s)\n", e->toChars());
735
736 if (binOptimize(e, result))
737 return;
738
739 if (e->e1->isConst() == 1 && e->e2->isConst() == 1)
740 {
741 ret = Div(e->loc, e->type, e->e1, e->e2).copy();
742 }
743 }
744
745 void visit(ModExp *e)
746 {
747 if (binOptimize(e, result))
748 return;
749
750 if (e->e1->isConst() == 1 && e->e2->isConst() == 1)
751 {
752 ret = Mod(e->loc, e->type, e->e1, e->e2).copy();
753 }
754 }
755
756 void shift_optimize(BinExp *e, UnionExp (*shift)(Loc, Type *, Expression *, Expression *))
757 {
758 if (binOptimize(e, result))
759 return;
760
761 if (e->e2->isConst() == 1)
762 {
763 sinteger_t i2 = e->e2->toInteger();
764 d_uns64 sz = e->e1->type->size();
765 assert(sz != SIZE_INVALID);
766 sz *= 8;
767 if (i2 < 0 || (d_uns64)i2 >= sz)
768 {
769 e->error("shift by %lld is outside the range 0..%llu", i2, (ulonglong)sz - 1);
770 return error();
771 }
772 if (e->e1->isConst() == 1)
773 ret = (*shift)(e->loc, e->type, e->e1, e->e2).copy();
774 }
775 }
776
777 void visit(ShlExp *e)
778 {
779 //printf("ShlExp::optimize(result = %d) %s\n", result, e->toChars());
780 shift_optimize(e, &Shl);
781 }
782
783 void visit(ShrExp *e)
784 {
785 //printf("ShrExp::optimize(result = %d) %s\n", result, e->toChars());
786 shift_optimize(e, &Shr);
787 }
788
789 void visit(UshrExp *e)
790 {
791 //printf("UshrExp::optimize(result = %d) %s\n", result, toChars());
792 shift_optimize(e, &Ushr);
793 }
794
795 void visit(AndExp *e)
796 {
797 if (binOptimize(e, result))
798 return;
799
800 if (e->e1->isConst() == 1 && e->e2->isConst() == 1)
801 ret = And(e->loc, e->type, e->e1, e->e2).copy();
802 }
803
804 void visit(OrExp *e)
805 {
806 if (binOptimize(e, result))
807 return;
808
809 if (e->e1->isConst() == 1 && e->e2->isConst() == 1)
810 ret = Or(e->loc, e->type, e->e1, e->e2).copy();
811 }
812
813 void visit(XorExp *e)
814 {
815 if (binOptimize(e, result))
816 return;
817
818 if (e->e1->isConst() == 1 && e->e2->isConst() == 1)
819 ret = Xor(e->loc, e->type, e->e1, e->e2).copy();
820 }
821
822 void visit(PowExp *e)
823 {
824 if (binOptimize(e, result))
825 return;
826
827 // Replace 1 ^^ x or 1.0^^x by (x, 1)
828 if ((e->e1->op == TOKint64 && e->e1->toInteger() == 1) ||
829 (e->e1->op == TOKfloat64 && e->e1->toReal() == CTFloat::one))
830 {
831 ret = new CommaExp(e->loc, e->e2, e->e1);
832 ret->type = e->type;
833 return;
834 }
835
836 // Replace -1 ^^ x by (x&1) ? -1 : 1, where x is integral
837 if (e->e2->type->isintegral() && e->e1->op == TOKint64 && (sinteger_t)e->e1->toInteger() == -1L)
838 {
839 ret = new AndExp(e->loc, e->e2, new IntegerExp(e->loc, 1, e->e2->type));
840 ret->type = e->e2->type;
841 ret = new CondExp(e->loc, ret, new IntegerExp(e->loc, -1L, e->type), new IntegerExp(e->loc, 1L, e->type));
842 ret->type = e->type;
843 return;
844 }
845
846 // Replace x ^^ 0 or x^^0.0 by (x, 1)
847 if ((e->e2->op == TOKint64 && e->e2->toInteger() == 0) ||
848 (e->e2->op == TOKfloat64 && e->e2->toReal() == CTFloat::zero))
849 {
850 if (e->e1->type->isintegral())
851 ret = new IntegerExp(e->loc, 1, e->e1->type);
852 else
853 ret = new RealExp(e->loc, CTFloat::one, e->e1->type);
854
855 ret = new CommaExp(e->loc, e->e1, ret);
856 ret->type = e->type;
857 return;
858 }
859
860 // Replace x ^^ 1 or x^^1.0 by (x)
861 if ((e->e2->op == TOKint64 && e->e2->toInteger() == 1) ||
862 (e->e2->op == TOKfloat64 && e->e2->toReal() == CTFloat::one))
863 {
864 ret = e->e1;
865 return;
866 }
867
868 // Replace x ^^ -1.0 by (1.0 / x)
869 if ((e->e2->op == TOKfloat64 && e->e2->toReal() == CTFloat::minusone))
870 {
871 ret = new DivExp(e->loc, new RealExp(e->loc, CTFloat::one, e->e2->type), e->e1);
872 ret->type = e->type;
873 return;
874 }
875
876 // All other negative integral powers are illegal
877 if ((e->e1->type->isintegral()) && (e->e2->op == TOKint64) && (sinteger_t)e->e2->toInteger() < 0)
878 {
879 e->error("cannot raise %s to a negative integer power. Did you mean (cast(real)%s)^^%s ?",
880 e->e1->type->toBasetype()->toChars(), e->e1->toChars(), e->e2->toChars());
881 return error();
882 }
883
884 // If e2 *could* have been an integer, make it one.
885 if (e->e2->op == TOKfloat64 && (e->e2->toReal() == ldouble((sinteger_t)e->e2->toReal())))
886 e->e2 = new IntegerExp(e->loc, e->e2->toInteger(), Type::tint64);
887
888 if (e->e1->isConst() == 1 && e->e2->isConst() == 1)
889 {
890 Expression *ex = Pow(e->loc, e->type, e->e1, e->e2).copy();
891 if (!CTFEExp::isCantExp(ex))
892 {
893 ret = ex;
894 return;
895 }
896 }
897
898 // (2 ^^ n) ^^ p -> 1 << n * p
899 if (e->e1->op == TOKint64 && e->e1->toInteger() > 0 &&
900 !((e->e1->toInteger() - 1) & e->e1->toInteger()) &&
901 e->e2->type->isintegral() && e->e2->type->isunsigned())
902 {
903 dinteger_t i = e->e1->toInteger();
904 dinteger_t mul = 1;
905 while ((i >>= 1) > 1)
906 mul++;
907 Expression *shift = new MulExp(e->loc, e->e2, new IntegerExp(e->loc, mul, e->e2->type));
908 shift->type = e->e2->type;
909 shift = shift->castTo(NULL, Type::tshiftcnt);
910 ret = new ShlExp(e->loc, new IntegerExp(e->loc, 1, e->e1->type), shift);
911 ret->type = e->type;
912 return;
913 }
914 }
915
916 void visit(CommaExp *e)
917 {
918 //printf("CommaExp::optimize(result = %d) %s\n", result, e->toChars());
919 // Comma needs special treatment, because it may
920 // contain compiler-generated declarations. We can interpret them, but
921 // otherwise we must NOT attempt to constant-fold them.
922 // In particular, if the comma returns a temporary variable, it needs
923 // to be an lvalue (this is particularly important for struct constructors)
924
925 expOptimize(e->e1, WANTvalue);
926 expOptimize(e->e2, result, keepLvalue);
927 if (ret->op == TOKerror)
928 return;
929
930 if (!e->e1 || e->e1->op == TOKint64 || e->e1->op == TOKfloat64 || !hasSideEffect(e->e1))
931 {
932 ret = e->e2;
933 if (ret)
934 ret->type = e->type;
935 }
936
937 //printf("-CommaExp::optimize(result = %d) %s\n", result, e->e->toChars());
938 }
939
940 void visit(ArrayLengthExp *e)
941 {
942 //printf("ArrayLengthExp::optimize(result = %d) %s\n", result, e->toChars());
943
944 if (unaOptimize(e, WANTexpand))
945 return;
946
947 // CTFE interpret static immutable arrays (to get better diagnostics)
948 if (e->e1->op == TOKvar)
949 {
950 VarDeclaration *v = ((VarExp *)e->e1)->var->isVarDeclaration();
951 if (v && (v->storage_class & STCstatic) && (v->storage_class & STCimmutable) && v->_init)
952 {
953 if (Expression *ci = v->getConstInitializer())
954 e->e1 = ci;
955 }
956 }
957
958 if (e->e1->op == TOKstring || e->e1->op == TOKarrayliteral || e->e1->op == TOKassocarrayliteral ||
959 e->e1->type->toBasetype()->ty == Tsarray)
960 {
961 ret = ArrayLength(e->type, e->e1).copy();
962 }
963 }
964
965 void visit(EqualExp *e)
966 {
967 //printf("EqualExp::optimize(result = %x) %s\n", result, e->toChars());
968 if (binOptimize(e, WANTvalue))
969 return;
970
971 Expression *e1 = fromConstInitializer(result, e->e1);
972 Expression *e2 = fromConstInitializer(result, e->e2);
973 if (e1->op == TOKerror)
974 {
975 ret = e1;
976 return;
977 }
978 if (e2->op == TOKerror)
979 {
980 ret = e2;
981 return;
982 }
983
984 ret = Equal(e->op, e->loc, e->type, e1, e2).copy();
985 if (CTFEExp::isCantExp(ret))
986 ret = e;
987 }
988
989 void visit(IdentityExp *e)
990 {
991 //printf("IdentityExp::optimize(result = %d) %s\n", result, e->toChars());
992
993 if (binOptimize(e, WANTvalue))
994 return;
995
996 if ((e->e1->isConst() && e->e2->isConst()) ||
997 (e->e1->op == TOKnull && e->e2->op == TOKnull)
998 )
999 {
1000 ret = Identity(e->op, e->loc, e->type, e->e1, e->e2).copy();
1001 if (CTFEExp::isCantExp(ret))
1002 ret = e;
1003 }
1004 }
1005
1006 /* It is possible for constant folding to change an array expression of
1007 * unknown length, into one where the length is known.
1008 * If the expression 'arr' is a literal, set lengthVar to be its length.
1009 */
1010 static void setLengthVarIfKnown(VarDeclaration *lengthVar, Expression *arr)
1011 {
1012 if (!lengthVar)
1013 return;
1014 if (lengthVar->_init && !lengthVar->_init->isVoidInitializer())
1015 return; // we have previously calculated the length
1016 size_t len;
1017 if (arr->op == TOKstring)
1018 len = ((StringExp *)arr)->len;
1019 else if (arr->op == TOKarrayliteral)
1020 len = ((ArrayLiteralExp *)arr)->elements->dim;
1021 else
1022 {
1023 Type *t = arr->type->toBasetype();
1024 if (t->ty == Tsarray)
1025 len = (size_t)((TypeSArray *)t)->dim->toInteger();
1026 else
1027 return; // we don't know the length yet
1028 }
1029
1030 Expression *dollar = new IntegerExp(Loc(), len, Type::tsize_t);
1031 lengthVar->_init = new ExpInitializer(Loc(), dollar);
1032 lengthVar->storage_class |= STCstatic | STCconst;
1033 }
1034
1035 void visit(IndexExp *e)
1036 {
1037 //printf("IndexExp::optimize(result = %d) %s\n", result, e->toChars());
1038 if (expOptimize(e->e1, result & WANTexpand))
1039 return;
1040
1041 Expression *ex = fromConstInitializer(result, e->e1);
1042
1043 // We might know $ now
1044 setLengthVarIfKnown(e->lengthVar, ex);
1045
1046 if (expOptimize(e->e2, WANTvalue))
1047 return;
1048 if (keepLvalue)
1049 return;
1050 ret = Index(e->type, ex, e->e2).copy();
1051 if (CTFEExp::isCantExp(ret))
1052 ret = e;
1053 }
1054
1055 void visit(SliceExp *e)
1056 {
1057 //printf("SliceExp::optimize(result = %d) %s\n", result, e->toChars());
1058 if (expOptimize(e->e1, result & WANTexpand))
1059 return;
1060 if (!e->lwr)
1061 {
1062 if (e->e1->op == TOKstring)
1063 {
1064 // Convert slice of string literal into dynamic array
1065 Type *t = e->e1->type->toBasetype();
1066 if (Type *tn = t->nextOf())
1067 ret = e->e1->castTo(NULL, tn->arrayOf());
1068 }
1069 }
1070 else
1071 {
1072 e->e1 = fromConstInitializer(result, e->e1);
1073 // We might know $ now
1074 setLengthVarIfKnown(e->lengthVar, e->e1);
1075 expOptimize(e->lwr, WANTvalue);
1076 expOptimize(e->upr, WANTvalue);
1077 if (ret->op == TOKerror)
1078 return;
1079 ret = Slice(e->type, e->e1, e->lwr, e->upr).copy();
1080 if (CTFEExp::isCantExp(ret))
1081 ret = e;
1082 }
1083
1084 // Bugzilla 14649: We need to leave the slice form so it might be
1085 // a part of array operation.
1086 // Assume that the backend codegen will handle the form `e[]`
1087 // as an equal to `e` itself.
1088 if (ret->op == TOKstring)
1089 {
1090 e->e1 = ret;
1091 e->lwr = NULL;
1092 e->upr = NULL;
1093 ret = e;
1094 }
1095 //printf("-SliceExp::optimize() %s\n", ret->toChars());
1096 }
1097
1098 void visit(AndAndExp *e)
1099 {
1100 //printf("AndAndExp::optimize(%d) %s\n", result, e->toChars());
1101 if (expOptimize(e->e1, WANTvalue))
1102 return;
1103
1104 if (e->e1->isBool(false))
1105 {
1106 // Replace with (e1, false)
1107 ret = new IntegerExp(e->loc, 0, Type::tbool);
1108 ret = Expression::combine(e->e1, ret);
1109 if (e->type->toBasetype()->ty == Tvoid)
1110 {
1111 ret = new CastExp(e->loc, ret, Type::tvoid);
1112 ret->type = e->type;
1113 }
1114 return;
1115 }
1116
1117 if (expOptimize(e->e2, WANTvalue))
1118 return;
1119
1120 if (e->e1->isConst())
1121 {
1122 if (e->e2->isConst())
1123 {
1124 bool n1 = e->e1->isBool(true);
1125 bool n2 = e->e2->isBool(true);
1126 ret = new IntegerExp(e->loc, n1 && n2, e->type);
1127 }
1128 else if (e->e1->isBool(true))
1129 {
1130 if (e->type->toBasetype()->ty == Tvoid)
1131 ret = e->e2;
1132 else
1133 {
1134 ret = new CastExp(e->loc, e->e2, e->type);
1135 ret->type = e->type;
1136 }
1137 }
1138 }
1139 }
1140
1141 void visit(OrOrExp *e)
1142 {
1143 //printf("OrOrExp::optimize(%d) %s\n", result, e->toChars());
1144 if (expOptimize(e->e1, WANTvalue))
1145 return;
1146
1147 if (e->e1->isBool(true))
1148 {
1149 // Replace with (e1, true)
1150 ret = new IntegerExp(e->loc, 1, Type::tbool);
1151 ret = Expression::combine(e->e1, ret);
1152 if (e->type->toBasetype()->ty == Tvoid)
1153 {
1154 ret = new CastExp(e->loc, ret, Type::tvoid);
1155 ret->type = e->type;
1156 }
1157 return;
1158 }
1159
1160 if (expOptimize(e->e2, WANTvalue))
1161 return;
1162
1163 if (e->e1->isConst())
1164 {
1165 if (e->e2->isConst())
1166 {
1167 bool n1 = e->e1->isBool(true);
1168 bool n2 = e->e2->isBool(true);
1169 ret = new IntegerExp(e->loc, n1 || n2, e->type);
1170 }
1171 else if (e->e1->isBool(false))
1172 {
1173 if (e->type->toBasetype()->ty == Tvoid)
1174 ret = e->e2;
1175 else
1176 {
1177 ret = new CastExp(e->loc, e->e2, e->type);
1178 ret->type = e->type;
1179 }
1180 }
1181 }
1182 }
1183
1184 void visit(CmpExp *e)
1185 {
1186 //printf("CmpExp::optimize() %s\n", e->toChars());
1187 if (binOptimize(e, WANTvalue))
1188 return;
1189
1190 Expression *e1 = fromConstInitializer(result, e->e1);
1191 Expression *e2 = fromConstInitializer(result, e->e2);
1192
1193 ret = Cmp(e->op, e->loc, e->type, e1, e2).copy();
1194 if (CTFEExp::isCantExp(ret))
1195 ret = e;
1196 }
1197
1198 void visit(CatExp *e)
1199 {
1200 //printf("CatExp::optimize(%d) %s\n", result, e->toChars());
1201
1202 if (binOptimize(e, result))
1203 return;
1204
1205 if (e->e1->op == TOKcat)
1206 {
1207 // Bugzilla 12798: optimize ((expr ~ str1) ~ str2)
1208 CatExp *ce1 = (CatExp *)e->e1;
1209 CatExp cex(e->loc, ce1->e2, e->e2);
1210 cex.type = e->type;
1211 Expression *ex = cex.optimize(result);
1212 if (ex != &cex)
1213 {
1214 e->e1 = ce1->e1;
1215 e->e2 = ex;
1216 }
1217 }
1218
1219 // optimize "str"[] -> "str"
1220 if (e->e1->op == TOKslice)
1221 {
1222 SliceExp *se1 = (SliceExp *)e->e1;
1223 if (se1->e1->op == TOKstring && !se1->lwr)
1224 e->e1 = se1->e1;
1225 }
1226 if (e->e2->op == TOKslice)
1227 {
1228 SliceExp *se2 = (SliceExp *)e->e2;
1229 if (se2->e1->op == TOKstring && !se2->lwr)
1230 e->e2 = se2->e1;
1231 }
1232
1233 ret = Cat(e->type, e->e1, e->e2).copy();
1234 if (CTFEExp::isCantExp(ret))
1235 ret = e;
1236 }
1237
1238 void visit(CondExp *e)
1239 {
1240 if (expOptimize(e->econd, WANTvalue))
1241 return;
1242 if (e->econd->isBool(true))
1243 ret = e->e1->optimize(result, keepLvalue);
1244 else if (e->econd->isBool(false))
1245 ret = e->e2->optimize(result, keepLvalue);
1246 else
1247 {
1248 expOptimize(e->e1, result, keepLvalue);
1249 expOptimize(e->e2, result, keepLvalue);
1250 }
1251 }
1252 };
1253
1254 OptimizeVisitor v(result, keepLvalue);
1255 Expression *ex = NULL;
1256 v.ret = e;
1257
1258 // Optimize the expression until it can no longer be simplified.
1259 while (ex != v.ret)
1260 {
1261 ex = v.ret;
1262 ex->accept(&v);
1263 }
1264 return ex;
1265 }