1 //===-- ConstantRange.cpp - ConstantRange implementation ------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Represent a range of possible values that may occur when the program is run
11 // for an integral value. This keeps track of a lower and upper bound for the
12 // constant, which MAY wrap around the end of the numeric range. To do this, it
13 // keeps track of a [lower, upper) bound, which specifies an interval just like
14 // STL iterators. When used with boolean values, the following are important
15 // ranges (other integral ranges use min/max values for special range values):
16 //
17 // [F, F) = {} = Empty set
18 // [T, F) = {T}
19 // [F, T) = {F}
20 // [T, T) = {F, T} = Full set
21 //
22 //===----------------------------------------------------------------------===//
23
24 #include "llvm/IR/InstrTypes.h"
25 #include "llvm/Support/ConstantRange.h"
26 #include "llvm/Support/Debug.h"
27 #include "llvm/Support/raw_ostream.h"
28 using namespace llvm;
29
30 /// Initialize a full (the default) or empty set for the specified type.
31 ///
ConstantRange(uint32_t BitWidth,bool Full)32 ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) {
33 if (Full)
34 Lower = Upper = APInt::getMaxValue(BitWidth);
35 else
36 Lower = Upper = APInt::getMinValue(BitWidth);
37 }
38
39 /// Initialize a range to hold the single specified value.
40 ///
ConstantRange(APIntMoveTy V)41 ConstantRange::ConstantRange(APIntMoveTy V)
42 : Lower(llvm_move(V)), Upper(Lower + 1) {}
43
ConstantRange(APIntMoveTy L,APIntMoveTy U)44 ConstantRange::ConstantRange(APIntMoveTy L, APIntMoveTy U)
45 : Lower(llvm_move(L)), Upper(llvm_move(U)) {
46 assert(Lower.getBitWidth() == Upper.getBitWidth() &&
47 "ConstantRange with unequal bit widths");
48 assert((Lower != Upper || (Lower.isMaxValue() || Lower.isMinValue())) &&
49 "Lower == Upper, but they aren't min or max value!");
50 }
51
makeICmpRegion(unsigned Pred,const ConstantRange & CR)52 ConstantRange ConstantRange::makeICmpRegion(unsigned Pred,
53 const ConstantRange &CR) {
54 if (CR.isEmptySet())
55 return CR;
56
57 uint32_t W = CR.getBitWidth();
58 switch (Pred) {
59 default: llvm_unreachable("Invalid ICmp predicate to makeICmpRegion()");
60 case CmpInst::ICMP_EQ:
61 return CR;
62 case CmpInst::ICMP_NE:
63 if (CR.isSingleElement())
64 return ConstantRange(CR.getUpper(), CR.getLower());
65 return ConstantRange(W);
66 case CmpInst::ICMP_ULT: {
67 APInt UMax(CR.getUnsignedMax());
68 if (UMax.isMinValue())
69 return ConstantRange(W, /* empty */ false);
70 return ConstantRange(APInt::getMinValue(W), UMax);
71 }
72 case CmpInst::ICMP_SLT: {
73 APInt SMax(CR.getSignedMax());
74 if (SMax.isMinSignedValue())
75 return ConstantRange(W, /* empty */ false);
76 return ConstantRange(APInt::getSignedMinValue(W), SMax);
77 }
78 case CmpInst::ICMP_ULE: {
79 APInt UMax(CR.getUnsignedMax());
80 if (UMax.isMaxValue())
81 return ConstantRange(W);
82 return ConstantRange(APInt::getMinValue(W), UMax + 1);
83 }
84 case CmpInst::ICMP_SLE: {
85 APInt SMax(CR.getSignedMax());
86 if (SMax.isMaxSignedValue())
87 return ConstantRange(W);
88 return ConstantRange(APInt::getSignedMinValue(W), SMax + 1);
89 }
90 case CmpInst::ICMP_UGT: {
91 APInt UMin(CR.getUnsignedMin());
92 if (UMin.isMaxValue())
93 return ConstantRange(W, /* empty */ false);
94 return ConstantRange(UMin + 1, APInt::getNullValue(W));
95 }
96 case CmpInst::ICMP_SGT: {
97 APInt SMin(CR.getSignedMin());
98 if (SMin.isMaxSignedValue())
99 return ConstantRange(W, /* empty */ false);
100 return ConstantRange(SMin + 1, APInt::getSignedMinValue(W));
101 }
102 case CmpInst::ICMP_UGE: {
103 APInt UMin(CR.getUnsignedMin());
104 if (UMin.isMinValue())
105 return ConstantRange(W);
106 return ConstantRange(UMin, APInt::getNullValue(W));
107 }
108 case CmpInst::ICMP_SGE: {
109 APInt SMin(CR.getSignedMin());
110 if (SMin.isMinSignedValue())
111 return ConstantRange(W);
112 return ConstantRange(SMin, APInt::getSignedMinValue(W));
113 }
114 }
115 }
116
117 /// isFullSet - Return true if this set contains all of the elements possible
118 /// for this data-type
isFullSet() const119 bool ConstantRange::isFullSet() const {
120 return Lower == Upper && Lower.isMaxValue();
121 }
122
123 /// isEmptySet - Return true if this set contains no members.
124 ///
isEmptySet() const125 bool ConstantRange::isEmptySet() const {
126 return Lower == Upper && Lower.isMinValue();
127 }
128
129 /// isWrappedSet - Return true if this set wraps around the top of the range,
130 /// for example: [100, 8)
131 ///
isWrappedSet() const132 bool ConstantRange::isWrappedSet() const {
133 return Lower.ugt(Upper);
134 }
135
136 /// isSignWrappedSet - Return true if this set wraps around the INT_MIN of
137 /// its bitwidth, for example: i8 [120, 140).
138 ///
isSignWrappedSet() const139 bool ConstantRange::isSignWrappedSet() const {
140 return contains(APInt::getSignedMaxValue(getBitWidth())) &&
141 contains(APInt::getSignedMinValue(getBitWidth()));
142 }
143
144 /// getSetSize - Return the number of elements in this set.
145 ///
getSetSize() const146 APInt ConstantRange::getSetSize() const {
147 if (isEmptySet())
148 return APInt(getBitWidth()+1, 0);
149
150 if (isFullSet()) {
151 APInt Size(getBitWidth()+1, 0);
152 Size.setBit(getBitWidth());
153 return Size;
154 }
155
156 // This is also correct for wrapped sets.
157 return (Upper - Lower).zext(getBitWidth()+1);
158 }
159
160 /// getUnsignedMax - Return the largest unsigned value contained in the
161 /// ConstantRange.
162 ///
getUnsignedMax() const163 APInt ConstantRange::getUnsignedMax() const {
164 if (isFullSet() || isWrappedSet())
165 return APInt::getMaxValue(getBitWidth());
166 return getUpper() - 1;
167 }
168
169 /// getUnsignedMin - Return the smallest unsigned value contained in the
170 /// ConstantRange.
171 ///
getUnsignedMin() const172 APInt ConstantRange::getUnsignedMin() const {
173 if (isFullSet() || (isWrappedSet() && getUpper() != 0))
174 return APInt::getMinValue(getBitWidth());
175 return getLower();
176 }
177
178 /// getSignedMax - Return the largest signed value contained in the
179 /// ConstantRange.
180 ///
getSignedMax() const181 APInt ConstantRange::getSignedMax() const {
182 APInt SignedMax(APInt::getSignedMaxValue(getBitWidth()));
183 if (!isWrappedSet()) {
184 if (getLower().sle(getUpper() - 1))
185 return getUpper() - 1;
186 return SignedMax;
187 }
188 if (getLower().isNegative() == getUpper().isNegative())
189 return SignedMax;
190 return getUpper() - 1;
191 }
192
193 /// getSignedMin - Return the smallest signed value contained in the
194 /// ConstantRange.
195 ///
getSignedMin() const196 APInt ConstantRange::getSignedMin() const {
197 APInt SignedMin(APInt::getSignedMinValue(getBitWidth()));
198 if (!isWrappedSet()) {
199 if (getLower().sle(getUpper() - 1))
200 return getLower();
201 return SignedMin;
202 }
203 if ((getUpper() - 1).slt(getLower())) {
204 if (getUpper() != SignedMin)
205 return SignedMin;
206 }
207 return getLower();
208 }
209
210 /// contains - Return true if the specified value is in the set.
211 ///
contains(const APInt & V) const212 bool ConstantRange::contains(const APInt &V) const {
213 if (Lower == Upper)
214 return isFullSet();
215
216 if (!isWrappedSet())
217 return Lower.ule(V) && V.ult(Upper);
218 return Lower.ule(V) || V.ult(Upper);
219 }
220
221 /// contains - Return true if the argument is a subset of this range.
222 /// Two equal sets contain each other. The empty set contained by all other
223 /// sets.
224 ///
contains(const ConstantRange & Other) const225 bool ConstantRange::contains(const ConstantRange &Other) const {
226 if (isFullSet() || Other.isEmptySet()) return true;
227 if (isEmptySet() || Other.isFullSet()) return false;
228
229 if (!isWrappedSet()) {
230 if (Other.isWrappedSet())
231 return false;
232
233 return Lower.ule(Other.getLower()) && Other.getUpper().ule(Upper);
234 }
235
236 if (!Other.isWrappedSet())
237 return Other.getUpper().ule(Upper) ||
238 Lower.ule(Other.getLower());
239
240 return Other.getUpper().ule(Upper) && Lower.ule(Other.getLower());
241 }
242
243 /// subtract - Subtract the specified constant from the endpoints of this
244 /// constant range.
subtract(const APInt & Val) const245 ConstantRange ConstantRange::subtract(const APInt &Val) const {
246 assert(Val.getBitWidth() == getBitWidth() && "Wrong bit width");
247 // If the set is empty or full, don't modify the endpoints.
248 if (Lower == Upper)
249 return *this;
250 return ConstantRange(Lower - Val, Upper - Val);
251 }
252
253 /// \brief Subtract the specified range from this range (aka relative complement
254 /// of the sets).
difference(const ConstantRange & CR) const255 ConstantRange ConstantRange::difference(const ConstantRange &CR) const {
256 return intersectWith(CR.inverse());
257 }
258
259 /// intersectWith - Return the range that results from the intersection of this
260 /// range with another range. The resultant range is guaranteed to include all
261 /// elements contained in both input ranges, and to have the smallest possible
262 /// set size that does so. Because there may be two intersections with the
263 /// same set size, A.intersectWith(B) might not be equal to B.intersectWith(A).
intersectWith(const ConstantRange & CR) const264 ConstantRange ConstantRange::intersectWith(const ConstantRange &CR) const {
265 assert(getBitWidth() == CR.getBitWidth() &&
266 "ConstantRange types don't agree!");
267
268 // Handle common cases.
269 if ( isEmptySet() || CR.isFullSet()) return *this;
270 if (CR.isEmptySet() || isFullSet()) return CR;
271
272 if (!isWrappedSet() && CR.isWrappedSet())
273 return CR.intersectWith(*this);
274
275 if (!isWrappedSet() && !CR.isWrappedSet()) {
276 if (Lower.ult(CR.Lower)) {
277 if (Upper.ule(CR.Lower))
278 return ConstantRange(getBitWidth(), false);
279
280 if (Upper.ult(CR.Upper))
281 return ConstantRange(CR.Lower, Upper);
282
283 return CR;
284 }
285 if (Upper.ult(CR.Upper))
286 return *this;
287
288 if (Lower.ult(CR.Upper))
289 return ConstantRange(Lower, CR.Upper);
290
291 return ConstantRange(getBitWidth(), false);
292 }
293
294 if (isWrappedSet() && !CR.isWrappedSet()) {
295 if (CR.Lower.ult(Upper)) {
296 if (CR.Upper.ult(Upper))
297 return CR;
298
299 if (CR.Upper.ule(Lower))
300 return ConstantRange(CR.Lower, Upper);
301
302 if (getSetSize().ult(CR.getSetSize()))
303 return *this;
304 return CR;
305 }
306 if (CR.Lower.ult(Lower)) {
307 if (CR.Upper.ule(Lower))
308 return ConstantRange(getBitWidth(), false);
309
310 return ConstantRange(Lower, CR.Upper);
311 }
312 return CR;
313 }
314
315 if (CR.Upper.ult(Upper)) {
316 if (CR.Lower.ult(Upper)) {
317 if (getSetSize().ult(CR.getSetSize()))
318 return *this;
319 return CR;
320 }
321
322 if (CR.Lower.ult(Lower))
323 return ConstantRange(Lower, CR.Upper);
324
325 return CR;
326 }
327 if (CR.Upper.ule(Lower)) {
328 if (CR.Lower.ult(Lower))
329 return *this;
330
331 return ConstantRange(CR.Lower, Upper);
332 }
333 if (getSetSize().ult(CR.getSetSize()))
334 return *this;
335 return CR;
336 }
337
338
339 /// unionWith - Return the range that results from the union of this range with
340 /// another range. The resultant range is guaranteed to include the elements of
341 /// both sets, but may contain more. For example, [3, 9) union [12,15) is
342 /// [3, 15), which includes 9, 10, and 11, which were not included in either
343 /// set before.
344 ///
unionWith(const ConstantRange & CR) const345 ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
346 assert(getBitWidth() == CR.getBitWidth() &&
347 "ConstantRange types don't agree!");
348
349 if ( isFullSet() || CR.isEmptySet()) return *this;
350 if (CR.isFullSet() || isEmptySet()) return CR;
351
352 if (!isWrappedSet() && CR.isWrappedSet()) return CR.unionWith(*this);
353
354 if (!isWrappedSet() && !CR.isWrappedSet()) {
355 if (CR.Upper.ult(Lower) || Upper.ult(CR.Lower)) {
356 // If the two ranges are disjoint, find the smaller gap and bridge it.
357 APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
358 if (d1.ult(d2))
359 return ConstantRange(Lower, CR.Upper);
360 return ConstantRange(CR.Lower, Upper);
361 }
362
363 APInt L = Lower, U = Upper;
364 if (CR.Lower.ult(L))
365 L = CR.Lower;
366 if ((CR.Upper - 1).ugt(U - 1))
367 U = CR.Upper;
368
369 if (L == 0 && U == 0)
370 return ConstantRange(getBitWidth());
371
372 return ConstantRange(L, U);
373 }
374
375 if (!CR.isWrappedSet()) {
376 // ------U L----- and ------U L----- : this
377 // L--U L--U : CR
378 if (CR.Upper.ule(Upper) || CR.Lower.uge(Lower))
379 return *this;
380
381 // ------U L----- : this
382 // L---------U : CR
383 if (CR.Lower.ule(Upper) && Lower.ule(CR.Upper))
384 return ConstantRange(getBitWidth());
385
386 // ----U L---- : this
387 // L---U : CR
388 // <d1> <d2>
389 if (Upper.ule(CR.Lower) && CR.Upper.ule(Lower)) {
390 APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
391 if (d1.ult(d2))
392 return ConstantRange(Lower, CR.Upper);
393 return ConstantRange(CR.Lower, Upper);
394 }
395
396 // ----U L----- : this
397 // L----U : CR
398 if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper))
399 return ConstantRange(CR.Lower, Upper);
400
401 // ------U L---- : this
402 // L-----U : CR
403 assert(CR.Lower.ult(Upper) && CR.Upper.ult(Lower) &&
404 "ConstantRange::unionWith missed a case with one range wrapped");
405 return ConstantRange(Lower, CR.Upper);
406 }
407
408 // ------U L---- and ------U L---- : this
409 // -U L----------- and ------------U L : CR
410 if (CR.Lower.ule(Upper) || Lower.ule(CR.Upper))
411 return ConstantRange(getBitWidth());
412
413 APInt L = Lower, U = Upper;
414 if (CR.Upper.ugt(U))
415 U = CR.Upper;
416 if (CR.Lower.ult(L))
417 L = CR.Lower;
418
419 return ConstantRange(L, U);
420 }
421
422 /// zeroExtend - Return a new range in the specified integer type, which must
423 /// be strictly larger than the current type. The returned range will
424 /// correspond to the possible range of values as if the source range had been
425 /// zero extended.
zeroExtend(uint32_t DstTySize) const426 ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
427 if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
428
429 unsigned SrcTySize = getBitWidth();
430 assert(SrcTySize < DstTySize && "Not a value extension");
431 if (isFullSet() || isWrappedSet()) {
432 // Change into [0, 1 << src bit width)
433 APInt LowerExt(DstTySize, 0);
434 if (!Upper) // special case: [X, 0) -- not really wrapping around
435 LowerExt = Lower.zext(DstTySize);
436 return ConstantRange(LowerExt, APInt::getOneBitSet(DstTySize, SrcTySize));
437 }
438
439 return ConstantRange(Lower.zext(DstTySize), Upper.zext(DstTySize));
440 }
441
442 /// signExtend - Return a new range in the specified integer type, which must
443 /// be strictly larger than the current type. The returned range will
444 /// correspond to the possible range of values as if the source range had been
445 /// sign extended.
signExtend(uint32_t DstTySize) const446 ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const {
447 if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
448
449 unsigned SrcTySize = getBitWidth();
450 assert(SrcTySize < DstTySize && "Not a value extension");
451 if (isFullSet() || isSignWrappedSet()) {
452 return ConstantRange(APInt::getHighBitsSet(DstTySize,DstTySize-SrcTySize+1),
453 APInt::getLowBitsSet(DstTySize, SrcTySize-1) + 1);
454 }
455
456 return ConstantRange(Lower.sext(DstTySize), Upper.sext(DstTySize));
457 }
458
459 /// truncate - Return a new range in the specified integer type, which must be
460 /// strictly smaller than the current type. The returned range will
461 /// correspond to the possible range of values as if the source range had been
462 /// truncated to the specified type.
truncate(uint32_t DstTySize) const463 ConstantRange ConstantRange::truncate(uint32_t DstTySize) const {
464 assert(getBitWidth() > DstTySize && "Not a value truncation");
465 if (isEmptySet())
466 return ConstantRange(DstTySize, /*isFullSet=*/false);
467 if (isFullSet())
468 return ConstantRange(DstTySize, /*isFullSet=*/true);
469
470 APInt MaxValue = APInt::getMaxValue(DstTySize).zext(getBitWidth());
471 APInt MaxBitValue(getBitWidth(), 0);
472 MaxBitValue.setBit(DstTySize);
473
474 APInt LowerDiv(Lower), UpperDiv(Upper);
475 ConstantRange Union(DstTySize, /*isFullSet=*/false);
476
477 // Analyze wrapped sets in their two parts: [0, Upper) \/ [Lower, MaxValue]
478 // We use the non-wrapped set code to analyze the [Lower, MaxValue) part, and
479 // then we do the union with [MaxValue, Upper)
480 if (isWrappedSet()) {
481 // if Upper is greater than Max Value, it covers the whole truncated range.
482 if (Upper.uge(MaxValue))
483 return ConstantRange(DstTySize, /*isFullSet=*/true);
484
485 Union = ConstantRange(APInt::getMaxValue(DstTySize),Upper.trunc(DstTySize));
486 UpperDiv = APInt::getMaxValue(getBitWidth());
487
488 // Union covers the MaxValue case, so return if the remaining range is just
489 // MaxValue.
490 if (LowerDiv == UpperDiv)
491 return Union;
492 }
493
494 // Chop off the most significant bits that are past the destination bitwidth.
495 if (LowerDiv.uge(MaxValue)) {
496 APInt Div(getBitWidth(), 0);
497 APInt::udivrem(LowerDiv, MaxBitValue, Div, LowerDiv);
498 UpperDiv = UpperDiv - MaxBitValue * Div;
499 }
500
501 if (UpperDiv.ule(MaxValue))
502 return ConstantRange(LowerDiv.trunc(DstTySize),
503 UpperDiv.trunc(DstTySize)).unionWith(Union);
504
505 // The truncated value wrapps around. Check if we can do better than fullset.
506 APInt UpperModulo = UpperDiv - MaxBitValue;
507 if (UpperModulo.ult(LowerDiv))
508 return ConstantRange(LowerDiv.trunc(DstTySize),
509 UpperModulo.trunc(DstTySize)).unionWith(Union);
510
511 return ConstantRange(DstTySize, /*isFullSet=*/true);
512 }
513
514 /// zextOrTrunc - make this range have the bit width given by \p DstTySize. The
515 /// value is zero extended, truncated, or left alone to make it that width.
zextOrTrunc(uint32_t DstTySize) const516 ConstantRange ConstantRange::zextOrTrunc(uint32_t DstTySize) const {
517 unsigned SrcTySize = getBitWidth();
518 if (SrcTySize > DstTySize)
519 return truncate(DstTySize);
520 if (SrcTySize < DstTySize)
521 return zeroExtend(DstTySize);
522 return *this;
523 }
524
525 /// sextOrTrunc - make this range have the bit width given by \p DstTySize. The
526 /// value is sign extended, truncated, or left alone to make it that width.
sextOrTrunc(uint32_t DstTySize) const527 ConstantRange ConstantRange::sextOrTrunc(uint32_t DstTySize) const {
528 unsigned SrcTySize = getBitWidth();
529 if (SrcTySize > DstTySize)
530 return truncate(DstTySize);
531 if (SrcTySize < DstTySize)
532 return signExtend(DstTySize);
533 return *this;
534 }
535
536 ConstantRange
add(const ConstantRange & Other) const537 ConstantRange::add(const ConstantRange &Other) const {
538 if (isEmptySet() || Other.isEmptySet())
539 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
540 if (isFullSet() || Other.isFullSet())
541 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
542
543 APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
544 APInt NewLower = getLower() + Other.getLower();
545 APInt NewUpper = getUpper() + Other.getUpper() - 1;
546 if (NewLower == NewUpper)
547 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
548
549 ConstantRange X = ConstantRange(NewLower, NewUpper);
550 if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y))
551 // We've wrapped, therefore, full set.
552 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
553
554 return X;
555 }
556
557 ConstantRange
sub(const ConstantRange & Other) const558 ConstantRange::sub(const ConstantRange &Other) const {
559 if (isEmptySet() || Other.isEmptySet())
560 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
561 if (isFullSet() || Other.isFullSet())
562 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
563
564 APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
565 APInt NewLower = getLower() - Other.getUpper() + 1;
566 APInt NewUpper = getUpper() - Other.getLower();
567 if (NewLower == NewUpper)
568 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
569
570 ConstantRange X = ConstantRange(NewLower, NewUpper);
571 if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y))
572 // We've wrapped, therefore, full set.
573 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
574
575 return X;
576 }
577
578 ConstantRange
multiply(const ConstantRange & Other) const579 ConstantRange::multiply(const ConstantRange &Other) const {
580 // TODO: If either operand is a single element and the multiply is known to
581 // be non-wrapping, round the result min and max value to the appropriate
582 // multiple of that element. If wrapping is possible, at least adjust the
583 // range according to the greatest power-of-two factor of the single element.
584
585 if (isEmptySet() || Other.isEmptySet())
586 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
587
588 APInt this_min = getUnsignedMin().zext(getBitWidth() * 2);
589 APInt this_max = getUnsignedMax().zext(getBitWidth() * 2);
590 APInt Other_min = Other.getUnsignedMin().zext(getBitWidth() * 2);
591 APInt Other_max = Other.getUnsignedMax().zext(getBitWidth() * 2);
592
593 ConstantRange Result_zext = ConstantRange(this_min * Other_min,
594 this_max * Other_max + 1);
595 return Result_zext.truncate(getBitWidth());
596 }
597
598 ConstantRange
smax(const ConstantRange & Other) const599 ConstantRange::smax(const ConstantRange &Other) const {
600 // X smax Y is: range(smax(X_smin, Y_smin),
601 // smax(X_smax, Y_smax))
602 if (isEmptySet() || Other.isEmptySet())
603 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
604 APInt NewL = APIntOps::smax(getSignedMin(), Other.getSignedMin());
605 APInt NewU = APIntOps::smax(getSignedMax(), Other.getSignedMax()) + 1;
606 if (NewU == NewL)
607 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
608 return ConstantRange(NewL, NewU);
609 }
610
611 ConstantRange
umax(const ConstantRange & Other) const612 ConstantRange::umax(const ConstantRange &Other) const {
613 // X umax Y is: range(umax(X_umin, Y_umin),
614 // umax(X_umax, Y_umax))
615 if (isEmptySet() || Other.isEmptySet())
616 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
617 APInt NewL = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
618 APInt NewU = APIntOps::umax(getUnsignedMax(), Other.getUnsignedMax()) + 1;
619 if (NewU == NewL)
620 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
621 return ConstantRange(NewL, NewU);
622 }
623
624 ConstantRange
udiv(const ConstantRange & RHS) const625 ConstantRange::udiv(const ConstantRange &RHS) const {
626 if (isEmptySet() || RHS.isEmptySet() || RHS.getUnsignedMax() == 0)
627 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
628 if (RHS.isFullSet())
629 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
630
631 APInt Lower = getUnsignedMin().udiv(RHS.getUnsignedMax());
632
633 APInt RHS_umin = RHS.getUnsignedMin();
634 if (RHS_umin == 0) {
635 // We want the lowest value in RHS excluding zero. Usually that would be 1
636 // except for a range in the form of [X, 1) in which case it would be X.
637 if (RHS.getUpper() == 1)
638 RHS_umin = RHS.getLower();
639 else
640 RHS_umin = APInt(getBitWidth(), 1);
641 }
642
643 APInt Upper = getUnsignedMax().udiv(RHS_umin) + 1;
644
645 // If the LHS is Full and the RHS is a wrapped interval containing 1 then
646 // this could occur.
647 if (Lower == Upper)
648 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
649
650 return ConstantRange(Lower, Upper);
651 }
652
653 ConstantRange
binaryAnd(const ConstantRange & Other) const654 ConstantRange::binaryAnd(const ConstantRange &Other) const {
655 if (isEmptySet() || Other.isEmptySet())
656 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
657
658 // TODO: replace this with something less conservative
659
660 APInt umin = APIntOps::umin(Other.getUnsignedMax(), getUnsignedMax());
661 if (umin.isAllOnesValue())
662 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
663 return ConstantRange(APInt::getNullValue(getBitWidth()), umin + 1);
664 }
665
666 ConstantRange
binaryOr(const ConstantRange & Other) const667 ConstantRange::binaryOr(const ConstantRange &Other) const {
668 if (isEmptySet() || Other.isEmptySet())
669 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
670
671 // TODO: replace this with something less conservative
672
673 APInt umax = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
674 if (umax.isMinValue())
675 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
676 return ConstantRange(umax, APInt::getNullValue(getBitWidth()));
677 }
678
679 ConstantRange
shl(const ConstantRange & Other) const680 ConstantRange::shl(const ConstantRange &Other) const {
681 if (isEmptySet() || Other.isEmptySet())
682 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
683
684 APInt min = getUnsignedMin().shl(Other.getUnsignedMin());
685 APInt max = getUnsignedMax().shl(Other.getUnsignedMax());
686
687 // there's no overflow!
688 APInt Zeros(getBitWidth(), getUnsignedMax().countLeadingZeros());
689 if (Zeros.ugt(Other.getUnsignedMax()))
690 return ConstantRange(min, max + 1);
691
692 // FIXME: implement the other tricky cases
693 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
694 }
695
696 ConstantRange
lshr(const ConstantRange & Other) const697 ConstantRange::lshr(const ConstantRange &Other) const {
698 if (isEmptySet() || Other.isEmptySet())
699 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
700
701 APInt max = getUnsignedMax().lshr(Other.getUnsignedMin());
702 APInt min = getUnsignedMin().lshr(Other.getUnsignedMax());
703 if (min == max + 1)
704 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
705
706 return ConstantRange(min, max + 1);
707 }
708
inverse() const709 ConstantRange ConstantRange::inverse() const {
710 if (isFullSet())
711 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
712 if (isEmptySet())
713 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
714 return ConstantRange(Upper, Lower);
715 }
716
717 /// print - Print out the bounds to a stream...
718 ///
print(raw_ostream & OS) const719 void ConstantRange::print(raw_ostream &OS) const {
720 if (isFullSet())
721 OS << "full-set";
722 else if (isEmptySet())
723 OS << "empty-set";
724 else
725 OS << "[" << Lower << "," << Upper << ")";
726 }
727
728 /// dump - Allow printing from a debugger easily...
729 ///
dump() const730 void ConstantRange::dump() const {
731 print(dbgs());
732 }
733