lib/Support/ConstantRange.cpp

   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/Support/ConstantRange.h"
  25 #include "llvm/Support/raw_ostream.h"
  26 #include "llvm/Instructions.h"
  27 using namespace llvm;
  28
  29 /// Initialize a full (the default) or empty set for the specified type.
  30 ///
  31 ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) {
  32   if (Full)
  33     Lower = Upper = APInt::getMaxValue(BitWidth);
  34   else
  35     Lower = Upper = APInt::getMinValue(BitWidth);
  36 }
  37
  38 /// Initialize a range to hold the single specified value.
  39 ///
  40 ConstantRange::ConstantRange(const APInt & V) : Lower(V), Upper(V + 1) {}
  41
  42 ConstantRange::ConstantRange(const APInt &L, const APInt &U) :
  43   Lower(L), Upper(U) {
  44   assert(L.getBitWidth() == U.getBitWidth() &&
  45          "ConstantRange with unequal bit widths");
  46   assert((L != U || (L.isMaxValue() || L.isMinValue())) &&
  47          "Lower == Upper, but they aren't min or max value!");
  48 }
  49
  50 ConstantRange ConstantRange::makeICmpRegion(unsigned Pred,
  51                                             const ConstantRange &CR) {
  52   uint32_t W = CR.getBitWidth();
  53   switch (Pred) {
  54     default: assert(!"Invalid ICmp predicate to makeICmpRegion()");
  55     case ICmpInst::ICMP_EQ:
  56       return CR;
  57     case ICmpInst::ICMP_NE:
  58       if (CR.isSingleElement())
  59         return ConstantRange(CR.getUpper(), CR.getLower());
  60       return ConstantRange(W);
  61     case ICmpInst::ICMP_ULT:
  62       return ConstantRange(APInt::getMinValue(W), CR.getUnsignedMax());
  63     case ICmpInst::ICMP_SLT:
  64       return ConstantRange(APInt::getSignedMinValue(W), CR.getSignedMax());
  65     case ICmpInst::ICMP_ULE: {
  66       APInt UMax(CR.getUnsignedMax());
  67       if (UMax.isMaxValue())
  68         return ConstantRange(W);
  69       return ConstantRange(APInt::getMinValue(W), UMax + 1);
  70     }
  71     case ICmpInst::ICMP_SLE: {
  72       APInt SMax(CR.getSignedMax());
  73       if (SMax.isMaxSignedValue() || (SMax+1).isMaxSignedValue())
  74         return ConstantRange(W);
  75       return ConstantRange(APInt::getSignedMinValue(W), SMax + 1);
  76     }
  77     case ICmpInst::ICMP_UGT:
  78       return ConstantRange(CR.getUnsignedMin() + 1, APInt::getNullValue(W));
  79     case ICmpInst::ICMP_SGT:
  80       return ConstantRange(CR.getSignedMin() + 1,
  81                            APInt::getSignedMinValue(W));
  82     case ICmpInst::ICMP_UGE: {
  83       APInt UMin(CR.getUnsignedMin());
  84       if (UMin.isMinValue())
  85         return ConstantRange(W);
  86       return ConstantRange(UMin, APInt::getNullValue(W));
  87     }
  88     case ICmpInst::ICMP_SGE: {
  89       APInt SMin(CR.getSignedMin());
  90       if (SMin.isMinSignedValue())
  91         return ConstantRange(W);
  92       return ConstantRange(SMin, APInt::getSignedMinValue(W));
  93     }
  94   }
  95 }
  96
  97 /// isFullSet - Return true if this set contains all of the elements possible
  98 /// for this data-type
  99 bool ConstantRange::isFullSet() const {
 100   return Lower == Upper && Lower.isMaxValue();
 101 }
 102
 103 /// isEmptySet - Return true if this set contains no members.
 104 ///
 105 bool ConstantRange::isEmptySet() const {
 106   return Lower == Upper && Lower.isMinValue();
 107 }
 108
 109 /// isWrappedSet - Return true if this set wraps around the top of the range,
 110 /// for example: [100, 8)
 111 ///
 112 bool ConstantRange::isWrappedSet() const {
 113   return Lower.ugt(Upper);
 114 }
 115
 116 /// getSetSize - Return the number of elements in this set.
 117 ///
 118 APInt ConstantRange::getSetSize() const {
 119   if (isEmptySet())
 120     return APInt(getBitWidth(), 0);
 121   if (getBitWidth() == 1) {
 122     if (Lower != Upper)  // One of T or F in the set...
 123       return APInt(2, 1);
 124     return APInt(2, 2);      // Must be full set...
 125   }
 126
 127   // Simply subtract the bounds...
 128   return Upper - Lower;
 129 }
 130
 131 /// getUnsignedMax - Return the largest unsigned value contained in the
 132 /// ConstantRange.
 133 ///
 134 APInt ConstantRange::getUnsignedMax() const {
 135   if (isFullSet() || isWrappedSet())
 136     return APInt::getMaxValue(getBitWidth());
 137   else
 138     return getUpper() - 1;
 139 }
 140
 141 /// getUnsignedMin - Return the smallest unsigned value contained in the
 142 /// ConstantRange.
 143 ///
 144 APInt ConstantRange::getUnsignedMin() const {
 145   if (isFullSet() || (isWrappedSet() && getUpper() != 0))
 146     return APInt::getMinValue(getBitWidth());
 147   else
 148     return getLower();
 149 }
 150
 151 /// getSignedMax - Return the largest signed value contained in the
 152 /// ConstantRange.
 153 ///
 154 APInt ConstantRange::getSignedMax() const {
 155   APInt SignedMax(APInt::getSignedMaxValue(getBitWidth()));
 156   if (!isWrappedSet()) {
 157     if (getLower().sle(getUpper() - 1))
 158       return getUpper() - 1;
 159     else
 160       return SignedMax;
 161   } else {
 162     if (getLower().isNegative() == getUpper().isNegative())
 163       return SignedMax;
 164     else
 165       return getUpper() - 1;
 166   }
 167 }
 168
 169 /// getSignedMin - Return the smallest signed value contained in the
 170 /// ConstantRange.
 171 ///
 172 APInt ConstantRange::getSignedMin() const {
 173   APInt SignedMin(APInt::getSignedMinValue(getBitWidth()));
 174   if (!isWrappedSet()) {
 175     if (getLower().sle(getUpper() - 1))
 176       return getLower();
 177     else
 178       return SignedMin;
 179   } else {
 180     if ((getUpper() - 1).slt(getLower())) {
 181       if (getUpper() != SignedMin)
 182         return SignedMin;
 183       else
 184         return getLower();
 185     } else {
 186       return getLower();
 187     }
 188   }
 189 }
 190
 191 /// contains - Return true if the specified value is in the set.
 192 ///
 193 bool ConstantRange::contains(const APInt &V) const {
 194   if (Lower == Upper)
 195     return isFullSet();
 196
 197   if (!isWrappedSet())
 198     return Lower.ule(V) && V.ult(Upper);
 199   else
 200     return Lower.ule(V) || V.ult(Upper);
 201 }
 202
 203 /// contains - Return true if the argument is a subset of this range.
 204 /// Two equal set contain each other. The empty set is considered to be
 205 /// contained by all other sets.
 206 ///
 207 bool ConstantRange::contains(const ConstantRange &Other) const {
 208   if (isFullSet()) return true;
 209   if (Other.isFullSet()) return false;
 210   if (Other.isEmptySet()) return true;
 211   if (isEmptySet()) return false;
 212
 213   if (!isWrappedSet()) {
 214     if (Other.isWrappedSet())
 215       return false;
 216
 217     return Lower.ule(Other.getLower()) && Other.getUpper().ule(Upper);
 218   }
 219
 220   if (!Other.isWrappedSet())
 221     return Other.getUpper().ule(Upper) ||
 222            Lower.ule(Other.getLower());
 223
 224   return Other.getUpper().ule(Upper) && Lower.ule(Other.getLower());
 225 }
 226
 227 /// subtract - Subtract the specified constant from the endpoints of this
 228 /// constant range.
 229 ConstantRange ConstantRange::subtract(const APInt &Val) const {
 230   assert(Val.getBitWidth() == getBitWidth() && "Wrong bit width");
 231   // If the set is empty or full, don't modify the endpoints.
 232   if (Lower == Upper)
 233     return *this;
 234   return ConstantRange(Lower - Val, Upper - Val);
 235 }
 236
 237
 238 // intersect1Wrapped - This helper function is used to intersect two ranges when
 239 // it is known that LHS is wrapped and RHS isn't.
 240 //
 241 ConstantRange
 242 ConstantRange::intersect1Wrapped(const ConstantRange &LHS,
 243                                  const ConstantRange &RHS) {
 244   assert(LHS.isWrappedSet() && !RHS.isWrappedSet());
 245
 246   // Check to see if we overlap on the Left side of RHS...
 247   //
 248   if (RHS.Lower.ult(LHS.Upper)) {
 249     // We do overlap on the left side of RHS, see if we overlap on the right of
 250     // RHS...
 251     if (RHS.Upper.ugt(LHS.Lower)) {
 252       // Ok, the result overlaps on both the left and right sides.  See if the
 253       // resultant interval will be smaller if we wrap or not...
 254       //
 255       if (LHS.getSetSize().ult(RHS.getSetSize()))
 256         return LHS;
 257       else
 258         return RHS;
 259
 260     } else {
 261       // No overlap on the right, just on the left.
 262       return ConstantRange(RHS.Lower, LHS.Upper);
 263     }
 264   } else {
 265     // We don't overlap on the left side of RHS, see if we overlap on the right
 266     // of RHS...
 267     if (RHS.Upper.ugt(LHS.Lower)) {
 268       // Simple overlap...
 269       return ConstantRange(LHS.Lower, RHS.Upper);
 270     } else {
 271       // No overlap...
 272       return ConstantRange(LHS.getBitWidth(), false);
 273     }
 274   }
 275 }
 276
 277 /// intersectWith - Return the range that results from the intersection of this
 278 /// range with another range.  The resultant range is guaranteed to include all
 279 /// elements contained in both input ranges, and to have the smallest possible
 280 /// set size that does so.  Because there may be two intersections with the
 281 /// same set size, A.intersectWith(B) might not be equal to B.intersectWith(A).
 282 ConstantRange ConstantRange::intersectWith(const ConstantRange &CR) const {
 283   assert(getBitWidth() == CR.getBitWidth() &&
 284          "ConstantRange types don't agree!");
 285
 286   // Handle common cases.
 287   if (   isEmptySet() || CR.isFullSet()) return *this;
 288   if (CR.isEmptySet() ||    isFullSet()) return CR;
 289
 290   if (!isWrappedSet() && CR.isWrappedSet())
 291     return CR.intersectWith(*this);
 292
 293   if (!isWrappedSet() && !CR.isWrappedSet()) {
 294     if (Lower.ult(CR.Lower)) {
 295       if (Upper.ule(CR.Lower))
 296         return ConstantRange(getBitWidth(), false);
 297
 298       if (Upper.ult(CR.Upper))
 299         return ConstantRange(CR.Lower, Upper);
 300
 301       return CR;
 302     } else {
 303       if (Upper.ult(CR.Upper))
 304         return *this;
 305
 306       if (Lower.ult(CR.Upper))
 307         return ConstantRange(Lower, CR.Upper);
 308
 309       return ConstantRange(getBitWidth(), false);
 310     }
 311   }
 312
 313   if (isWrappedSet() && !CR.isWrappedSet()) {
 314     if (CR.Lower.ult(Upper)) {
 315       if (CR.Upper.ult(Upper))
 316         return CR;
 317
 318       if (CR.Upper.ult(Lower))
 319         return ConstantRange(CR.Lower, Upper);
 320
 321       if (getSetSize().ult(CR.getSetSize()))
 322         return *this;
 323       else
 324         return CR;
 325     } else if (CR.Lower.ult(Lower)) {
 326       if (CR.Upper.ule(Lower))
 327         return ConstantRange(getBitWidth(), false);
 328
 329       return ConstantRange(Lower, CR.Upper);
 330     }
 331     return CR;
 332   }
 333
 334   if (CR.Upper.ult(Upper)) {
 335     if (CR.Lower.ult(Upper)) {
 336       if (getSetSize().ult(CR.getSetSize()))
 337         return *this;
 338       else
 339         return CR;
 340     }
 341
 342     if (CR.Lower.ult(Lower))
 343       return ConstantRange(Lower, CR.Upper);
 344
 345     return CR;
 346   } else if (CR.Upper.ult(Lower)) {
 347     if (CR.Lower.ult(Lower))
 348       return *this;
 349
 350     return ConstantRange(CR.Lower, Upper);
 351   }
 352   if (getSetSize().ult(CR.getSetSize()))
 353     return *this;
 354   else
 355     return CR;
 356 }
 357
 358
 359 /// unionWith - Return the range that results from the union of this range with
 360 /// another range.  The resultant range is guaranteed to include the elements of
 361 /// both sets, but may contain more.  For example, [3, 9) union [12,15) is
 362 /// [3, 15), which includes 9, 10, and 11, which were not included in either
 363 /// set before.
 364 ///
 365 ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
 366   assert(getBitWidth() == CR.getBitWidth() &&
 367          "ConstantRange types don't agree!");
 368
 369   if (   isFullSet() || CR.isEmptySet()) return *this;
 370   if (CR.isFullSet() ||    isEmptySet()) return CR;
 371
 372   if (!isWrappedSet() && CR.isWrappedSet()) return CR.unionWith(*this);
 373
 374   if (!isWrappedSet() && !CR.isWrappedSet()) {
 375     if (CR.Upper.ult(Lower) || Upper.ult(CR.Lower)) {
 376       // If the two ranges are disjoint, find the smaller gap and bridge it.
 377       APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
 378       if (d1.ult(d2))
 379         return ConstantRange(Lower, CR.Upper);
 380       else
 381         return ConstantRange(CR.Lower, Upper);
 382     }
 383
 384     APInt L = Lower, U = Upper;
 385     if (CR.Lower.ult(L))
 386       L = CR.Lower;
 387     if ((CR.Upper - 1).ugt(U - 1))
 388       U = CR.Upper;
 389
 390     if (L == 0 && U == 0)
 391       return ConstantRange(getBitWidth());
 392
 393     return ConstantRange(L, U);
 394   }
 395
 396   if (!CR.isWrappedSet()) {
 397     // ------U   L-----  and  ------U   L----- : this
 398     //   L--U                            L--U  : CR
 399     if (CR.Upper.ule(Upper) || CR.Lower.uge(Lower))
 400       return *this;
 401
 402     // ------U   L----- : this
 403     //    L---------U   : CR
 404     if (CR.Lower.ule(Upper) && Lower.ule(CR.Upper))
 405       return ConstantRange(getBitWidth());
 406
 407     // ----U       L---- : this
 408     //       L---U       : CR
 409     //    <d1>  <d2>
 410     if (Upper.ule(CR.Lower) && CR.Upper.ule(Lower)) {
 411       APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
 412       if (d1.ult(d2))
 413         return ConstantRange(Lower, CR.Upper);
 414       else
 415         return ConstantRange(CR.Lower, Upper);
 416     }
 417
 418     // ----U     L----- : this
 419     //        L----U    : CR
 420     if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper))
 421       return ConstantRange(CR.Lower, Upper);
 422
 423     // ------U    L---- : this
 424     //    L-----U       : CR
 425     if (CR.Lower.ult(Upper) && CR.Upper.ult(Lower))
 426       return ConstantRange(Lower, CR.Upper);
 427   }
 428
 429   assert(isWrappedSet() && CR.isWrappedSet() &&
 430          "ConstantRange::unionWith missed wrapped union unwrapped case");
 431
 432   // ------U    L----  and  ------U    L---- : this
 433   // -U  L-----------  and  ------------U  L : CR
 434   if (CR.Lower.ule(Upper) || Lower.ule(CR.Upper))
 435     return ConstantRange(getBitWidth());
 436
 437   APInt L = Lower, U = Upper;
 438   if (CR.Upper.ugt(U))
 439     U = CR.Upper;
 440   if (CR.Lower.ult(L))
 441     L = CR.Lower;
 442
 443   return ConstantRange(L, U);
 444 }
 445
 446 /// zeroExtend - Return a new range in the specified integer type, which must
 447 /// be strictly larger than the current type.  The returned range will
 448 /// correspond to the possible range of values as if the source range had been
 449 /// zero extended.
 450 ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
 451   unsigned SrcTySize = getBitWidth();
 452   assert(SrcTySize < DstTySize && "Not a value extension");
 453   if (isFullSet())
 454     // Change a source full set into [0, 1 << 8*numbytes)
 455     return ConstantRange(APInt(DstTySize,0), APInt(DstTySize,1).shl(SrcTySize));
 456
 457   APInt L = Lower; L.zext(DstTySize);
 458   APInt U = Upper; U.zext(DstTySize);
 459   return ConstantRange(L, U);
 460 }
 461
 462 /// signExtend - Return a new range in the specified integer type, which must
 463 /// be strictly larger than the current type.  The returned range will
 464 /// correspond to the possible range of values as if the source range had been
 465 /// sign extended.
 466 ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const {
 467   unsigned SrcTySize = getBitWidth();
 468   assert(SrcTySize < DstTySize && "Not a value extension");
 469   if (isFullSet()) {
 470     return ConstantRange(APInt::getHighBitsSet(DstTySize,DstTySize-SrcTySize+1),
 471                          APInt::getLowBitsSet(DstTySize, SrcTySize-1) + 1);
 472   }
 473
 474   APInt L = Lower; L.sext(DstTySize);
 475   APInt U = Upper; U.sext(DstTySize);
 476   return ConstantRange(L, U);
 477 }
 478
 479 /// truncate - Return a new range in the specified integer type, which must be
 480 /// strictly smaller than the current type.  The returned range will
 481 /// correspond to the possible range of values as if the source range had been
 482 /// truncated to the specified type.
 483 ConstantRange ConstantRange::truncate(uint32_t DstTySize) const {
 484   unsigned SrcTySize = getBitWidth();
 485   assert(SrcTySize > DstTySize && "Not a value truncation");
 486   APInt Size(APInt::getLowBitsSet(SrcTySize, DstTySize));
 487   if (isFullSet() || getSetSize().ugt(Size))
 488     return ConstantRange(DstTySize);
 489
 490   APInt L = Lower; L.trunc(DstTySize);
 491   APInt U = Upper; U.trunc(DstTySize);
 492   return ConstantRange(L, U);
 493 }
 494
 495 ConstantRange
 496 ConstantRange::add(const ConstantRange &Other) const {
 497   if (isEmptySet() || Other.isEmptySet())
 498     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 499   if (isFullSet() || Other.isFullSet())
 500     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 501
 502   APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
 503   APInt NewLower = getLower() + Other.getLower();
 504   APInt NewUpper = getUpper() + Other.getUpper() - 1;
 505   if (NewLower == NewUpper)
 506     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 507
 508   ConstantRange X = ConstantRange(NewLower, NewUpper);
 509   if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y))
 510     // We've wrapped, therefore, full set.
 511     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 512
 513   return X;
 514 }
 515
 516 ConstantRange
 517 ConstantRange::multiply(const ConstantRange &Other) const {
 518   if (isEmptySet() || Other.isEmptySet())
 519     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 520   if (isFullSet() || Other.isFullSet())
 521     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 522
 523   APInt this_min = getUnsignedMin().zext(getBitWidth() * 2);
 524   APInt this_max = getUnsignedMax().zext(getBitWidth() * 2);
 525   APInt Other_min = Other.getUnsignedMin().zext(getBitWidth() * 2);
 526   APInt Other_max = Other.getUnsignedMax().zext(getBitWidth() * 2);
 527
 528   ConstantRange Result_zext = ConstantRange(this_min * Other_min,
 529                                             this_max * Other_max + 1);
 530   return Result_zext.truncate(getBitWidth());
 531 }
 532
 533 ConstantRange
 534 ConstantRange::smax(const ConstantRange &Other) const {
 535   // X smax Y is: range(smax(X_smin, Y_smin),
 536   //                    smax(X_smax, Y_smax))
 537   if (isEmptySet() || Other.isEmptySet())
 538     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 539   APInt NewL = APIntOps::smax(getSignedMin(), Other.getSignedMin());
 540   APInt NewU = APIntOps::smax(getSignedMax(), Other.getSignedMax()) + 1;
 541   if (NewU == NewL)
 542     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 543   return ConstantRange(NewL, NewU);
 544 }
 545
 546 ConstantRange
 547 ConstantRange::umax(const ConstantRange &Other) const {
 548   // X umax Y is: range(umax(X_umin, Y_umin),
 549   //                    umax(X_umax, Y_umax))
 550   if (isEmptySet() || Other.isEmptySet())
 551     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 552   APInt NewL = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
 553   APInt NewU = APIntOps::umax(getUnsignedMax(), Other.getUnsignedMax()) + 1;
 554   if (NewU == NewL)
 555     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 556   return ConstantRange(NewL, NewU);
 557 }
 558
 559 ConstantRange
 560 ConstantRange::udiv(const ConstantRange &RHS) const {
 561   if (isEmptySet() || RHS.isEmptySet() || RHS.getUnsignedMax() == 0)
 562     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 563   if (RHS.isFullSet())
 564     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 565
 566   APInt Lower = getUnsignedMin().udiv(RHS.getUnsignedMax());
 567
 568   APInt RHS_umin = RHS.getUnsignedMin();
 569   if (RHS_umin == 0) {
 570     // We want the lowest value in RHS excluding zero. Usually that would be 1
 571     // except for a range in the form of [X, 1) in which case it would be X.
 572     if (RHS.getUpper() == 1)
 573       RHS_umin = RHS.getLower();
 574     else
 575       RHS_umin = APInt(getBitWidth(), 1);
 576   }
 577
 578   APInt Upper = getUnsignedMax().udiv(RHS_umin) + 1;
 579
 580   // If the LHS is Full and the RHS is a wrapped interval containing 1 then
 581   // this could occur.
 582   if (Lower == Upper)
 583     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 584
 585   return ConstantRange(Lower, Upper);
 586 }
 587
 588 /// print - Print out the bounds to a stream...
 589 ///
 590 void ConstantRange::print(raw_ostream &OS) const {
 591   OS << "[" << Lower << "," << Upper << ")";
 592 }
 593
 594 /// dump - Allow printing from a debugger easily...
 595 ///
 596 void ConstantRange::dump() const {
 597   print(errs());
 598 }
 599
 600