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/InstrTypes.h"
25#include "llvm/Support/ConstantRange.h"
26#include "llvm/Support/Debug.h"
27#include "llvm/Support/raw_ostream.h"
28using namespace llvm;
29
30/// Initialize a full (the default) or empty set for the specified type.
31///
32ConstantRange::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///
41ConstantRange::ConstantRange(const APInt &V) : Lower(V), Upper(V + 1) {}
42
43ConstantRange::ConstantRange(const APInt &L, const APInt &U) :
44  Lower(L), Upper(U) {
45  assert(L.getBitWidth() == U.getBitWidth() &&
46         "ConstantRange with unequal bit widths");
47  assert((L != U || (L.isMaxValue() || L.isMinValue())) &&
48         "Lower == Upper, but they aren't min or max value!");
49}
50
51ConstantRange ConstantRange::makeICmpRegion(unsigned Pred,
52                                            const ConstantRange &CR) {
53  if (CR.isEmptySet())
54    return CR;
55
56  uint32_t W = CR.getBitWidth();
57  switch (Pred) {
58    default: llvm_unreachable("Invalid ICmp predicate to makeICmpRegion()");
59    case CmpInst::ICMP_EQ:
60      return CR;
61    case CmpInst::ICMP_NE:
62      if (CR.isSingleElement())
63        return ConstantRange(CR.getUpper(), CR.getLower());
64      return ConstantRange(W);
65    case CmpInst::ICMP_ULT: {
66      APInt UMax(CR.getUnsignedMax());
67      if (UMax.isMinValue())
68        return ConstantRange(W, /* empty */ false);
69      return ConstantRange(APInt::getMinValue(W), UMax);
70    }
71    case CmpInst::ICMP_SLT: {
72      APInt SMax(CR.getSignedMax());
73      if (SMax.isMinSignedValue())
74        return ConstantRange(W, /* empty */ false);
75      return ConstantRange(APInt::getSignedMinValue(W), SMax);
76    }
77    case CmpInst::ICMP_ULE: {
78      APInt UMax(CR.getUnsignedMax());
79      if (UMax.isMaxValue())
80        return ConstantRange(W);
81      return ConstantRange(APInt::getMinValue(W), UMax + 1);
82    }
83    case CmpInst::ICMP_SLE: {
84      APInt SMax(CR.getSignedMax());
85      if (SMax.isMaxSignedValue())
86        return ConstantRange(W);
87      return ConstantRange(APInt::getSignedMinValue(W), SMax + 1);
88    }
89    case CmpInst::ICMP_UGT: {
90      APInt UMin(CR.getUnsignedMin());
91      if (UMin.isMaxValue())
92        return ConstantRange(W, /* empty */ false);
93      return ConstantRange(UMin + 1, APInt::getNullValue(W));
94    }
95    case CmpInst::ICMP_SGT: {
96      APInt SMin(CR.getSignedMin());
97      if (SMin.isMaxSignedValue())
98        return ConstantRange(W, /* empty */ false);
99      return ConstantRange(SMin + 1, APInt::getSignedMinValue(W));
100    }
101    case CmpInst::ICMP_UGE: {
102      APInt UMin(CR.getUnsignedMin());
103      if (UMin.isMinValue())
104        return ConstantRange(W);
105      return ConstantRange(UMin, APInt::getNullValue(W));
106    }
107    case CmpInst::ICMP_SGE: {
108      APInt SMin(CR.getSignedMin());
109      if (SMin.isMinSignedValue())
110        return ConstantRange(W);
111      return ConstantRange(SMin, APInt::getSignedMinValue(W));
112    }
113  }
114}
115
116/// isFullSet - Return true if this set contains all of the elements possible
117/// for this data-type
118bool ConstantRange::isFullSet() const {
119  return Lower == Upper && Lower.isMaxValue();
120}
121
122/// isEmptySet - Return true if this set contains no members.
123///
124bool ConstantRange::isEmptySet() const {
125  return Lower == Upper && Lower.isMinValue();
126}
127
128/// isWrappedSet - Return true if this set wraps around the top of the range,
129/// for example: [100, 8)
130///
131bool ConstantRange::isWrappedSet() const {
132  return Lower.ugt(Upper);
133}
134
135/// isSignWrappedSet - Return true if this set wraps around the INT_MIN of
136/// its bitwidth, for example: i8 [120, 140).
137///
138bool ConstantRange::isSignWrappedSet() const {
139  return contains(APInt::getSignedMaxValue(getBitWidth())) &&
140         contains(APInt::getSignedMinValue(getBitWidth()));
141}
142
143/// getSetSize - Return the number of elements in this set.
144///
145APInt ConstantRange::getSetSize() const {
146  if (isEmptySet())
147    return APInt(getBitWidth(), 0);
148  if (getBitWidth() == 1) {
149    if (Lower != Upper)  // One of T or F in the set...
150      return APInt(2, 1);
151    return APInt(2, 2);      // Must be full set...
152  }
153
154  // Simply subtract the bounds...
155  return Upper - Lower;
156}
157
158/// getUnsignedMax - Return the largest unsigned value contained in the
159/// ConstantRange.
160///
161APInt ConstantRange::getUnsignedMax() const {
162  if (isFullSet() || isWrappedSet())
163    return APInt::getMaxValue(getBitWidth());
164  return getUpper() - 1;
165}
166
167/// getUnsignedMin - Return the smallest unsigned value contained in the
168/// ConstantRange.
169///
170APInt ConstantRange::getUnsignedMin() const {
171  if (isFullSet() || (isWrappedSet() && getUpper() != 0))
172    return APInt::getMinValue(getBitWidth());
173  return getLower();
174}
175
176/// getSignedMax - Return the largest signed value contained in the
177/// ConstantRange.
178///
179APInt ConstantRange::getSignedMax() const {
180  APInt SignedMax(APInt::getSignedMaxValue(getBitWidth()));
181  if (!isWrappedSet()) {
182    if (getLower().sle(getUpper() - 1))
183      return getUpper() - 1;
184    return SignedMax;
185  }
186  if (getLower().isNegative() == getUpper().isNegative())
187    return SignedMax;
188  return getUpper() - 1;
189}
190
191/// getSignedMin - Return the smallest signed value contained in the
192/// ConstantRange.
193///
194APInt ConstantRange::getSignedMin() const {
195  APInt SignedMin(APInt::getSignedMinValue(getBitWidth()));
196  if (!isWrappedSet()) {
197    if (getLower().sle(getUpper() - 1))
198      return getLower();
199    return SignedMin;
200  }
201  if ((getUpper() - 1).slt(getLower())) {
202    if (getUpper() != SignedMin)
203      return SignedMin;
204  }
205  return getLower();
206}
207
208/// contains - Return true if the specified value is in the set.
209///
210bool ConstantRange::contains(const APInt &V) const {
211  if (Lower == Upper)
212    return isFullSet();
213
214  if (!isWrappedSet())
215    return Lower.ule(V) && V.ult(Upper);
216  return Lower.ule(V) || V.ult(Upper);
217}
218
219/// contains - Return true if the argument is a subset of this range.
220/// Two equal sets contain each other. The empty set contained by all other
221/// sets.
222///
223bool ConstantRange::contains(const ConstantRange &Other) const {
224  if (isFullSet() || Other.isEmptySet()) return true;
225  if (isEmptySet() || Other.isFullSet()) return false;
226
227  if (!isWrappedSet()) {
228    if (Other.isWrappedSet())
229      return false;
230
231    return Lower.ule(Other.getLower()) && Other.getUpper().ule(Upper);
232  }
233
234  if (!Other.isWrappedSet())
235    return Other.getUpper().ule(Upper) ||
236           Lower.ule(Other.getLower());
237
238  return Other.getUpper().ule(Upper) && Lower.ule(Other.getLower());
239}
240
241/// subtract - Subtract the specified constant from the endpoints of this
242/// constant range.
243ConstantRange ConstantRange::subtract(const APInt &Val) const {
244  assert(Val.getBitWidth() == getBitWidth() && "Wrong bit width");
245  // If the set is empty or full, don't modify the endpoints.
246  if (Lower == Upper)
247    return *this;
248  return ConstantRange(Lower - Val, Upper - Val);
249}
250
251/// intersectWith - Return the range that results from the intersection of this
252/// range with another range.  The resultant range is guaranteed to include all
253/// elements contained in both input ranges, and to have the smallest possible
254/// set size that does so.  Because there may be two intersections with the
255/// same set size, A.intersectWith(B) might not be equal to B.intersectWith(A).
256ConstantRange ConstantRange::intersectWith(const ConstantRange &CR) const {
257  assert(getBitWidth() == CR.getBitWidth() &&
258         "ConstantRange types don't agree!");
259
260  // Handle common cases.
261  if (   isEmptySet() || CR.isFullSet()) return *this;
262  if (CR.isEmptySet() ||    isFullSet()) return CR;
263
264  if (!isWrappedSet() && CR.isWrappedSet())
265    return CR.intersectWith(*this);
266
267  if (!isWrappedSet() && !CR.isWrappedSet()) {
268    if (Lower.ult(CR.Lower)) {
269      if (Upper.ule(CR.Lower))
270        return ConstantRange(getBitWidth(), false);
271
272      if (Upper.ult(CR.Upper))
273        return ConstantRange(CR.Lower, Upper);
274
275      return CR;
276    }
277    if (Upper.ult(CR.Upper))
278      return *this;
279
280    if (Lower.ult(CR.Upper))
281      return ConstantRange(Lower, CR.Upper);
282
283    return ConstantRange(getBitWidth(), false);
284  }
285
286  if (isWrappedSet() && !CR.isWrappedSet()) {
287    if (CR.Lower.ult(Upper)) {
288      if (CR.Upper.ult(Upper))
289        return CR;
290
291      if (CR.Upper.ult(Lower))
292        return ConstantRange(CR.Lower, Upper);
293
294      if (getSetSize().ult(CR.getSetSize()))
295        return *this;
296      return CR;
297    }
298    if (CR.Lower.ult(Lower)) {
299      if (CR.Upper.ule(Lower))
300        return ConstantRange(getBitWidth(), false);
301
302      return ConstantRange(Lower, CR.Upper);
303    }
304    return CR;
305  }
306
307  if (CR.Upper.ult(Upper)) {
308    if (CR.Lower.ult(Upper)) {
309      if (getSetSize().ult(CR.getSetSize()))
310        return *this;
311      return CR;
312    }
313
314    if (CR.Lower.ult(Lower))
315      return ConstantRange(Lower, CR.Upper);
316
317    return CR;
318  }
319  if (CR.Upper.ult(Lower)) {
320    if (CR.Lower.ult(Lower))
321      return *this;
322
323    return ConstantRange(CR.Lower, Upper);
324  }
325  if (getSetSize().ult(CR.getSetSize()))
326    return *this;
327  return CR;
328}
329
330
331/// unionWith - Return the range that results from the union of this range with
332/// another range.  The resultant range is guaranteed to include the elements of
333/// both sets, but may contain more.  For example, [3, 9) union [12,15) is
334/// [3, 15), which includes 9, 10, and 11, which were not included in either
335/// set before.
336///
337ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
338  assert(getBitWidth() == CR.getBitWidth() &&
339         "ConstantRange types don't agree!");
340
341  if (   isFullSet() || CR.isEmptySet()) return *this;
342  if (CR.isFullSet() ||    isEmptySet()) return CR;
343
344  if (!isWrappedSet() && CR.isWrappedSet()) return CR.unionWith(*this);
345
346  if (!isWrappedSet() && !CR.isWrappedSet()) {
347    if (CR.Upper.ult(Lower) || Upper.ult(CR.Lower)) {
348      // If the two ranges are disjoint, find the smaller gap and bridge it.
349      APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
350      if (d1.ult(d2))
351        return ConstantRange(Lower, CR.Upper);
352      return ConstantRange(CR.Lower, Upper);
353    }
354
355    APInt L = Lower, U = Upper;
356    if (CR.Lower.ult(L))
357      L = CR.Lower;
358    if ((CR.Upper - 1).ugt(U - 1))
359      U = CR.Upper;
360
361    if (L == 0 && U == 0)
362      return ConstantRange(getBitWidth());
363
364    return ConstantRange(L, U);
365  }
366
367  if (!CR.isWrappedSet()) {
368    // ------U   L-----  and  ------U   L----- : this
369    //   L--U                            L--U  : CR
370    if (CR.Upper.ule(Upper) || CR.Lower.uge(Lower))
371      return *this;
372
373    // ------U   L----- : this
374    //    L---------U   : CR
375    if (CR.Lower.ule(Upper) && Lower.ule(CR.Upper))
376      return ConstantRange(getBitWidth());
377
378    // ----U       L---- : this
379    //       L---U       : CR
380    //    <d1>  <d2>
381    if (Upper.ule(CR.Lower) && CR.Upper.ule(Lower)) {
382      APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
383      if (d1.ult(d2))
384        return ConstantRange(Lower, CR.Upper);
385      return ConstantRange(CR.Lower, Upper);
386    }
387
388    // ----U     L----- : this
389    //        L----U    : CR
390    if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper))
391      return ConstantRange(CR.Lower, Upper);
392
393    // ------U    L---- : this
394    //    L-----U       : CR
395    assert(CR.Lower.ult(Upper) && CR.Upper.ult(Lower) &&
396           "ConstantRange::unionWith missed a case with one range wrapped");
397    return ConstantRange(Lower, CR.Upper);
398  }
399
400  // ------U    L----  and  ------U    L---- : this
401  // -U  L-----------  and  ------------U  L : CR
402  if (CR.Lower.ule(Upper) || Lower.ule(CR.Upper))
403    return ConstantRange(getBitWidth());
404
405  APInt L = Lower, U = Upper;
406  if (CR.Upper.ugt(U))
407    U = CR.Upper;
408  if (CR.Lower.ult(L))
409    L = CR.Lower;
410
411  return ConstantRange(L, U);
412}
413
414/// zeroExtend - Return a new range in the specified integer type, which must
415/// be strictly larger than the current type.  The returned range will
416/// correspond to the possible range of values as if the source range had been
417/// zero extended.
418ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
419  if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
420
421  unsigned SrcTySize = getBitWidth();
422  assert(SrcTySize < DstTySize && "Not a value extension");
423  if (isFullSet() || isWrappedSet())
424    // Change into [0, 1 << src bit width)
425    return ConstantRange(APInt(DstTySize,0), APInt(DstTySize,1).shl(SrcTySize));
426
427  return ConstantRange(Lower.zext(DstTySize), Upper.zext(DstTySize));
428}
429
430/// signExtend - Return a new range in the specified integer type, which must
431/// be strictly larger than the current type.  The returned range will
432/// correspond to the possible range of values as if the source range had been
433/// sign extended.
434ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const {
435  if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
436
437  unsigned SrcTySize = getBitWidth();
438  assert(SrcTySize < DstTySize && "Not a value extension");
439  if (isFullSet() || isSignWrappedSet()) {
440    return ConstantRange(APInt::getHighBitsSet(DstTySize,DstTySize-SrcTySize+1),
441                         APInt::getLowBitsSet(DstTySize, SrcTySize-1) + 1);
442  }
443
444  return ConstantRange(Lower.sext(DstTySize), Upper.sext(DstTySize));
445}
446
447/// truncate - Return a new range in the specified integer type, which must be
448/// strictly smaller than the current type.  The returned range will
449/// correspond to the possible range of values as if the source range had been
450/// truncated to the specified type.
451ConstantRange ConstantRange::truncate(uint32_t DstTySize) const {
452  assert(getBitWidth() > DstTySize && "Not a value truncation");
453  if (isFullSet() || getSetSize().getActiveBits() > DstTySize)
454    return ConstantRange(DstTySize, /*isFullSet=*/true);
455
456  return ConstantRange(Lower.trunc(DstTySize), Upper.trunc(DstTySize));
457}
458
459/// zextOrTrunc - make this range have the bit width given by \p DstTySize. The
460/// value is zero extended, truncated, or left alone to make it that width.
461ConstantRange ConstantRange::zextOrTrunc(uint32_t DstTySize) const {
462  unsigned SrcTySize = getBitWidth();
463  if (SrcTySize > DstTySize)
464    return truncate(DstTySize);
465  if (SrcTySize < DstTySize)
466    return zeroExtend(DstTySize);
467  return *this;
468}
469
470/// sextOrTrunc - make this range have the bit width given by \p DstTySize. The
471/// value is sign extended, truncated, or left alone to make it that width.
472ConstantRange ConstantRange::sextOrTrunc(uint32_t DstTySize) const {
473  unsigned SrcTySize = getBitWidth();
474  if (SrcTySize > DstTySize)
475    return truncate(DstTySize);
476  if (SrcTySize < DstTySize)
477    return signExtend(DstTySize);
478  return *this;
479}
480
481ConstantRange
482ConstantRange::add(const ConstantRange &Other) const {
483  if (isEmptySet() || Other.isEmptySet())
484    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
485  if (isFullSet() || Other.isFullSet())
486    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
487
488  APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
489  APInt NewLower = getLower() + Other.getLower();
490  APInt NewUpper = getUpper() + Other.getUpper() - 1;
491  if (NewLower == NewUpper)
492    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
493
494  ConstantRange X = ConstantRange(NewLower, NewUpper);
495  if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y))
496    // We've wrapped, therefore, full set.
497    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
498
499  return X;
500}
501
502ConstantRange
503ConstantRange::sub(const ConstantRange &Other) const {
504  if (isEmptySet() || Other.isEmptySet())
505    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
506  if (isFullSet() || Other.isFullSet())
507    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
508
509  APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
510  APInt NewLower = getLower() - Other.getUpper() + 1;
511  APInt NewUpper = getUpper() - Other.getLower();
512  if (NewLower == NewUpper)
513    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
514
515  ConstantRange X = ConstantRange(NewLower, NewUpper);
516  if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y))
517    // We've wrapped, therefore, full set.
518    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
519
520  return X;
521}
522
523ConstantRange
524ConstantRange::multiply(const ConstantRange &Other) const {
525  // TODO: If either operand is a single element and the multiply is known to
526  // be non-wrapping, round the result min and max value to the appropriate
527  // multiple of that element. If wrapping is possible, at least adjust the
528  // range according to the greatest power-of-two factor of the single element.
529
530  if (isEmptySet() || Other.isEmptySet())
531    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
532  if (isFullSet() || Other.isFullSet())
533    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
534
535  APInt this_min = getUnsignedMin().zext(getBitWidth() * 2);
536  APInt this_max = getUnsignedMax().zext(getBitWidth() * 2);
537  APInt Other_min = Other.getUnsignedMin().zext(getBitWidth() * 2);
538  APInt Other_max = Other.getUnsignedMax().zext(getBitWidth() * 2);
539
540  ConstantRange Result_zext = ConstantRange(this_min * Other_min,
541                                            this_max * Other_max + 1);
542  return Result_zext.truncate(getBitWidth());
543}
544
545ConstantRange
546ConstantRange::smax(const ConstantRange &Other) const {
547  // X smax Y is: range(smax(X_smin, Y_smin),
548  //                    smax(X_smax, Y_smax))
549  if (isEmptySet() || Other.isEmptySet())
550    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
551  APInt NewL = APIntOps::smax(getSignedMin(), Other.getSignedMin());
552  APInt NewU = APIntOps::smax(getSignedMax(), Other.getSignedMax()) + 1;
553  if (NewU == NewL)
554    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
555  return ConstantRange(NewL, NewU);
556}
557
558ConstantRange
559ConstantRange::umax(const ConstantRange &Other) const {
560  // X umax Y is: range(umax(X_umin, Y_umin),
561  //                    umax(X_umax, Y_umax))
562  if (isEmptySet() || Other.isEmptySet())
563    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
564  APInt NewL = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
565  APInt NewU = APIntOps::umax(getUnsignedMax(), Other.getUnsignedMax()) + 1;
566  if (NewU == NewL)
567    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
568  return ConstantRange(NewL, NewU);
569}
570
571ConstantRange
572ConstantRange::udiv(const ConstantRange &RHS) const {
573  if (isEmptySet() || RHS.isEmptySet() || RHS.getUnsignedMax() == 0)
574    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
575  if (RHS.isFullSet())
576    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
577
578  APInt Lower = getUnsignedMin().udiv(RHS.getUnsignedMax());
579
580  APInt RHS_umin = RHS.getUnsignedMin();
581  if (RHS_umin == 0) {
582    // We want the lowest value in RHS excluding zero. Usually that would be 1
583    // except for a range in the form of [X, 1) in which case it would be X.
584    if (RHS.getUpper() == 1)
585      RHS_umin = RHS.getLower();
586    else
587      RHS_umin = APInt(getBitWidth(), 1);
588  }
589
590  APInt Upper = getUnsignedMax().udiv(RHS_umin) + 1;
591
592  // If the LHS is Full and the RHS is a wrapped interval containing 1 then
593  // this could occur.
594  if (Lower == Upper)
595    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
596
597  return ConstantRange(Lower, Upper);
598}
599
600ConstantRange
601ConstantRange::binaryAnd(const ConstantRange &Other) const {
602  if (isEmptySet() || Other.isEmptySet())
603    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
604
605  // TODO: replace this with something less conservative
606
607  APInt umin = APIntOps::umin(Other.getUnsignedMax(), getUnsignedMax());
608  if (umin.isAllOnesValue())
609    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
610  return ConstantRange(APInt::getNullValue(getBitWidth()), umin + 1);
611}
612
613ConstantRange
614ConstantRange::binaryOr(const ConstantRange &Other) const {
615  if (isEmptySet() || Other.isEmptySet())
616    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
617
618  // TODO: replace this with something less conservative
619
620  APInt umax = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
621  if (umax.isMinValue())
622    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
623  return ConstantRange(umax, APInt::getNullValue(getBitWidth()));
624}
625
626ConstantRange
627ConstantRange::shl(const ConstantRange &Other) const {
628  if (isEmptySet() || Other.isEmptySet())
629    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
630
631  APInt min = getUnsignedMin().shl(Other.getUnsignedMin());
632  APInt max = getUnsignedMax().shl(Other.getUnsignedMax());
633
634  // there's no overflow!
635  APInt Zeros(getBitWidth(), getUnsignedMax().countLeadingZeros());
636  if (Zeros.ugt(Other.getUnsignedMax()))
637    return ConstantRange(min, max + 1);
638
639  // FIXME: implement the other tricky cases
640  return ConstantRange(getBitWidth(), /*isFullSet=*/true);
641}
642
643ConstantRange
644ConstantRange::lshr(const ConstantRange &Other) const {
645  if (isEmptySet() || Other.isEmptySet())
646    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
647
648  APInt max = getUnsignedMax().lshr(Other.getUnsignedMin());
649  APInt min = getUnsignedMin().lshr(Other.getUnsignedMax());
650  if (min == max + 1)
651    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
652
653  return ConstantRange(min, max + 1);
654}
655
656ConstantRange ConstantRange::inverse() const {
657  if (isFullSet())
658    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
659  if (isEmptySet())
660    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
661  return ConstantRange(Upper, Lower);
662}
663
664/// print - Print out the bounds to a stream...
665///
666void ConstantRange::print(raw_ostream &OS) const {
667  if (isFullSet())
668    OS << "full-set";
669  else if (isEmptySet())
670    OS << "empty-set";
671  else
672    OS << "[" << Lower << "," << Upper << ")";
673}
674
675/// dump - Allow printing from a debugger easily...
676///
677void ConstantRange::dump() const {
678  print(dbgs());
679}
680