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/Constants.h"
  25 #include "llvm/Support/ConstantRange.h"
  26 #include "llvm/Support/Debug.h"
  27 #include "llvm/Support/raw_ostream.h"
  28 #include "llvm/Instructions.h"
  29 using namespace llvm;
  30
  31 /// Initialize a full (the default) or empty set for the specified type.
  32 ///
  33 ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) {
  34   if (Full)
  35     Lower = Upper = APInt::getMaxValue(BitWidth);
  36   else
  37     Lower = Upper = APInt::getMinValue(BitWidth);
  38 }
  39
  40 /// Initialize a range to hold the single specified value.
  41 ///
  42 ConstantRange::ConstantRange(const APInt &V) : Lower(V), Upper(V + 1) {}
  43
  44 ConstantRange::ConstantRange(const APInt &L, const APInt &U) :
  45   Lower(L), Upper(U) {
  46   assert(L.getBitWidth() == U.getBitWidth() &&
  47          "ConstantRange with unequal bit widths");
  48   assert((L != U || (L.isMaxValue() || L.isMinValue())) &&
  49          "Lower == Upper, but they aren't min or max value!");
  50 }
  51
  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: assert(!"Invalid ICmp predicate to makeICmpRegion()");
  60     case ICmpInst::ICMP_EQ:
  61       return CR;
  62     case ICmpInst::ICMP_NE:
  63       if (CR.isSingleElement())
  64         return ConstantRange(CR.getUpper(), CR.getLower());
  65       return ConstantRange(W);
  66     case ICmpInst::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 ICmpInst::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 ICmpInst::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 ICmpInst::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 ICmpInst::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 ICmpInst::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 ICmpInst::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 ICmpInst::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
 119 bool ConstantRange::isFullSet() const {
 120   return Lower == Upper && Lower.isMaxValue();
 121 }
 122
 123 /// isEmptySet - Return true if this set contains no members.
 124 ///
 125 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 ///
 132 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 ///
 139 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 ///
 146 APInt ConstantRange::getSetSize() const {
 147   if (isEmptySet())
 148     return APInt(getBitWidth(), 0);
 149   if (getBitWidth() == 1) {
 150     if (Lower != Upper)  // One of T or F in the set...
 151       return APInt(2, 1);
 152     return APInt(2, 2);      // Must be full set...
 153   }
 154
 155   // Simply subtract the bounds...
 156   return Upper - Lower;
 157 }
 158
 159 /// getUnsignedMax - Return the largest unsigned value contained in the
 160 /// ConstantRange.
 161 ///
 162 APInt ConstantRange::getUnsignedMax() const {
 163   if (isFullSet() || isWrappedSet())
 164     return APInt::getMaxValue(getBitWidth());
 165   else
 166     return getUpper() - 1;
 167 }
 168
 169 /// getUnsignedMin - Return the smallest unsigned value contained in the
 170 /// ConstantRange.
 171 ///
 172 APInt ConstantRange::getUnsignedMin() const {
 173   if (isFullSet() || (isWrappedSet() && getUpper() != 0))
 174     return APInt::getMinValue(getBitWidth());
 175   else
 176     return getLower();
 177 }
 178
 179 /// getSignedMax - Return the largest signed value contained in the
 180 /// ConstantRange.
 181 ///
 182 APInt ConstantRange::getSignedMax() const {
 183   APInt SignedMax(APInt::getSignedMaxValue(getBitWidth()));
 184   if (!isWrappedSet()) {
 185     if (getLower().sle(getUpper() - 1))
 186       return getUpper() - 1;
 187     else
 188       return SignedMax;
 189   } else {
 190     if (getLower().isNegative() == getUpper().isNegative())
 191       return SignedMax;
 192     else
 193       return getUpper() - 1;
 194   }
 195 }
 196
 197 /// getSignedMin - Return the smallest signed value contained in the
 198 /// ConstantRange.
 199 ///
 200 APInt ConstantRange::getSignedMin() const {
 201   APInt SignedMin(APInt::getSignedMinValue(getBitWidth()));
 202   if (!isWrappedSet()) {
 203     if (getLower().sle(getUpper() - 1))
 204       return getLower();
 205     else
 206       return SignedMin;
 207   } else {
 208     if ((getUpper() - 1).slt(getLower())) {
 209       if (getUpper() != SignedMin)
 210         return SignedMin;
 211       else
 212         return getLower();
 213     } else {
 214       return getLower();
 215     }
 216   }
 217 }
 218
 219 /// contains - Return true if the specified value is in the set.
 220 ///
 221 bool ConstantRange::contains(const APInt &V) const {
 222   if (Lower == Upper)
 223     return isFullSet();
 224
 225   if (!isWrappedSet())
 226     return Lower.ule(V) && V.ult(Upper);
 227   else
 228     return Lower.ule(V) || V.ult(Upper);
 229 }
 230
 231 /// contains - Return true if the argument is a subset of this range.
 232 /// Two equal sets contain each other. The empty set contained by all other
 233 /// sets.
 234 ///
 235 bool ConstantRange::contains(const ConstantRange &Other) const {
 236   if (isFullSet() || Other.isEmptySet()) return true;
 237   if (isEmptySet() || Other.isFullSet()) return false;
 238
 239   if (!isWrappedSet()) {
 240     if (Other.isWrappedSet())
 241       return false;
 242
 243     return Lower.ule(Other.getLower()) && Other.getUpper().ule(Upper);
 244   }
 245
 246   if (!Other.isWrappedSet())
 247     return Other.getUpper().ule(Upper) ||
 248            Lower.ule(Other.getLower());
 249
 250   return Other.getUpper().ule(Upper) && Lower.ule(Other.getLower());
 251 }
 252
 253 /// subtract - Subtract the specified constant from the endpoints of this
 254 /// constant range.
 255 ConstantRange ConstantRange::subtract(const APInt &Val) const {
 256   assert(Val.getBitWidth() == getBitWidth() && "Wrong bit width");
 257   // If the set is empty or full, don't modify the endpoints.
 258   if (Lower == Upper)
 259     return *this;
 260   return ConstantRange(Lower - Val, Upper - Val);
 261 }
 262
 263 /// intersectWith - Return the range that results from the intersection of this
 264 /// range with another range.  The resultant range is guaranteed to include all
 265 /// elements contained in both input ranges, and to have the smallest possible
 266 /// set size that does so.  Because there may be two intersections with the
 267 /// same set size, A.intersectWith(B) might not be equal to B.intersectWith(A).
 268 ConstantRange ConstantRange::intersectWith(const ConstantRange &CR) const {
 269   assert(getBitWidth() == CR.getBitWidth() &&
 270          "ConstantRange types don't agree!");
 271
 272   // Handle common cases.
 273   if (   isEmptySet() || CR.isFullSet()) return *this;
 274   if (CR.isEmptySet() ||    isFullSet()) return CR;
 275
 276   if (!isWrappedSet() && CR.isWrappedSet())
 277     return CR.intersectWith(*this);
 278
 279   if (!isWrappedSet() && !CR.isWrappedSet()) {
 280     if (Lower.ult(CR.Lower)) {
 281       if (Upper.ule(CR.Lower))
 282         return ConstantRange(getBitWidth(), false);
 283
 284       if (Upper.ult(CR.Upper))
 285         return ConstantRange(CR.Lower, Upper);
 286
 287       return CR;
 288     } else {
 289       if (Upper.ult(CR.Upper))
 290         return *this;
 291
 292       if (Lower.ult(CR.Upper))
 293         return ConstantRange(Lower, CR.Upper);
 294
 295       return ConstantRange(getBitWidth(), false);
 296     }
 297   }
 298
 299   if (isWrappedSet() && !CR.isWrappedSet()) {
 300     if (CR.Lower.ult(Upper)) {
 301       if (CR.Upper.ult(Upper))
 302         return CR;
 303
 304       if (CR.Upper.ult(Lower))
 305         return ConstantRange(CR.Lower, Upper);
 306
 307       if (getSetSize().ult(CR.getSetSize()))
 308         return *this;
 309       else
 310         return CR;
 311     } else if (CR.Lower.ult(Lower)) {
 312       if (CR.Upper.ule(Lower))
 313         return ConstantRange(getBitWidth(), false);
 314
 315       return ConstantRange(Lower, CR.Upper);
 316     }
 317     return CR;
 318   }
 319
 320   if (CR.Upper.ult(Upper)) {
 321     if (CR.Lower.ult(Upper)) {
 322       if (getSetSize().ult(CR.getSetSize()))
 323         return *this;
 324       else
 325         return CR;
 326     }
 327
 328     if (CR.Lower.ult(Lower))
 329       return ConstantRange(Lower, CR.Upper);
 330
 331     return CR;
 332   } else if (CR.Upper.ult(Lower)) {
 333     if (CR.Lower.ult(Lower))
 334       return *this;
 335
 336     return ConstantRange(CR.Lower, Upper);
 337   }
 338   if (getSetSize().ult(CR.getSetSize()))
 339     return *this;
 340   else
 341     return CR;
 342 }
 343
 344
 345 /// unionWith - Return the range that results from the union of this range with
 346 /// another range.  The resultant range is guaranteed to include the elements of
 347 /// both sets, but may contain more.  For example, [3, 9) union [12,15) is
 348 /// [3, 15), which includes 9, 10, and 11, which were not included in either
 349 /// set before.
 350 ///
 351 ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
 352   assert(getBitWidth() == CR.getBitWidth() &&
 353          "ConstantRange types don't agree!");
 354
 355   if (   isFullSet() || CR.isEmptySet()) return *this;
 356   if (CR.isFullSet() ||    isEmptySet()) return CR;
 357
 358   if (!isWrappedSet() && CR.isWrappedSet()) return CR.unionWith(*this);
 359
 360   if (!isWrappedSet() && !CR.isWrappedSet()) {
 361     if (CR.Upper.ult(Lower) || Upper.ult(CR.Lower)) {
 362       // If the two ranges are disjoint, find the smaller gap and bridge it.
 363       APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
 364       if (d1.ult(d2))
 365         return ConstantRange(Lower, CR.Upper);
 366       else
 367         return ConstantRange(CR.Lower, Upper);
 368     }
 369
 370     APInt L = Lower, U = Upper;
 371     if (CR.Lower.ult(L))
 372       L = CR.Lower;
 373     if ((CR.Upper - 1).ugt(U - 1))
 374       U = CR.Upper;
 375
 376     if (L == 0 && U == 0)
 377       return ConstantRange(getBitWidth());
 378
 379     return ConstantRange(L, U);
 380   }
 381
 382   if (!CR.isWrappedSet()) {
 383     // ------U   L-----  and  ------U   L----- : this
 384     //   L--U                            L--U  : CR
 385     if (CR.Upper.ule(Upper) || CR.Lower.uge(Lower))
 386       return *this;
 387
 388     // ------U   L----- : this
 389     //    L---------U   : CR
 390     if (CR.Lower.ule(Upper) && Lower.ule(CR.Upper))
 391       return ConstantRange(getBitWidth());
 392
 393     // ----U       L---- : this
 394     //       L---U       : CR
 395     //    <d1>  <d2>
 396     if (Upper.ule(CR.Lower) && CR.Upper.ule(Lower)) {
 397       APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
 398       if (d1.ult(d2))
 399         return ConstantRange(Lower, CR.Upper);
 400       else
 401         return ConstantRange(CR.Lower, Upper);
 402     }
 403
 404     // ----U     L----- : this
 405     //        L----U    : CR
 406     if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper))
 407       return ConstantRange(CR.Lower, Upper);
 408
 409     // ------U    L---- : this
 410     //    L-----U       : CR
 411     if (CR.Lower.ult(Upper) && CR.Upper.ult(Lower))
 412       return ConstantRange(Lower, CR.Upper);
 413   }
 414
 415   assert(isWrappedSet() && CR.isWrappedSet() &&
 416          "ConstantRange::unionWith missed wrapped union unwrapped case");
 417
 418   // ------U    L----  and  ------U    L---- : this
 419   // -U  L-----------  and  ------------U  L : CR
 420   if (CR.Lower.ule(Upper) || Lower.ule(CR.Upper))
 421     return ConstantRange(getBitWidth());
 422
 423   APInt L = Lower, U = Upper;
 424   if (CR.Upper.ugt(U))
 425     U = CR.Upper;
 426   if (CR.Lower.ult(L))
 427     L = CR.Lower;
 428
 429   return ConstantRange(L, U);
 430 }
 431
 432 /// zeroExtend - Return a new range in the specified integer type, which must
 433 /// be strictly larger than the current type.  The returned range will
 434 /// correspond to the possible range of values as if the source range had been
 435 /// zero extended.
 436 ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
 437   if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
 438
 439   unsigned SrcTySize = getBitWidth();
 440   assert(SrcTySize < DstTySize && "Not a value extension");
 441   if (isFullSet() || isWrappedSet())
 442     // Change into [0, 1 << src bit width)
 443     return ConstantRange(APInt(DstTySize,0), APInt(DstTySize,1).shl(SrcTySize));
 444
 445   APInt L = Lower; L.zext(DstTySize);
 446   APInt U = Upper; U.zext(DstTySize);
 447   return ConstantRange(L, U);
 448 }
 449
 450 /// signExtend - Return a new range in the specified integer type, which must
 451 /// be strictly larger than the current type.  The returned range will
 452 /// correspond to the possible range of values as if the source range had been
 453 /// sign extended.
 454 ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const {
 455   if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
 456
 457   unsigned SrcTySize = getBitWidth();
 458   assert(SrcTySize < DstTySize && "Not a value extension");
 459   if (isFullSet() || isSignWrappedSet()) {
 460     return ConstantRange(APInt::getHighBitsSet(DstTySize,DstTySize-SrcTySize+1),
 461                          APInt::getLowBitsSet(DstTySize, SrcTySize-1) + 1);
 462   }
 463
 464   APInt L = Lower; L.sext(DstTySize);
 465   APInt U = Upper; U.sext(DstTySize);
 466   return ConstantRange(L, U);
 467 }
 468
 469 /// truncate - Return a new range in the specified integer type, which must be
 470 /// strictly smaller than the current type.  The returned range will
 471 /// correspond to the possible range of values as if the source range had been
 472 /// truncated to the specified type.
 473 ConstantRange ConstantRange::truncate(uint32_t DstTySize) const {
 474   unsigned SrcTySize = getBitWidth();
 475   assert(SrcTySize > DstTySize && "Not a value truncation");
 476   APInt Size(APInt::getLowBitsSet(SrcTySize, DstTySize));
 477   if (isFullSet() || getSetSize().ugt(Size))
 478     return ConstantRange(DstTySize, /*isFullSet=*/true);
 479
 480   APInt L = Lower; L.trunc(DstTySize);
 481   APInt U = Upper; U.trunc(DstTySize);
 482   return ConstantRange(L, U);
 483 }
 484
 485 /// zextOrTrunc - make this range have the bit width given by \p DstTySize. The
 486 /// value is zero extended, truncated, or left alone to make it that width.
 487 ConstantRange ConstantRange::zextOrTrunc(uint32_t DstTySize) const {
 488   unsigned SrcTySize = getBitWidth();
 489   if (SrcTySize > DstTySize)
 490     return truncate(DstTySize);
 491   else if (SrcTySize < DstTySize)
 492     return zeroExtend(DstTySize);
 493   else
 494     return *this;
 495 }
 496
 497 /// sextOrTrunc - make this range have the bit width given by \p DstTySize. The
 498 /// value is sign extended, truncated, or left alone to make it that width.
 499 ConstantRange ConstantRange::sextOrTrunc(uint32_t DstTySize) const {
 500   unsigned SrcTySize = getBitWidth();
 501   if (SrcTySize > DstTySize)
 502     return truncate(DstTySize);
 503   else if (SrcTySize < DstTySize)
 504     return signExtend(DstTySize);
 505   else
 506     return *this;
 507 }
 508
 509 ConstantRange
 510 ConstantRange::add(const ConstantRange &Other) const {
 511   if (isEmptySet() || Other.isEmptySet())
 512     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 513   if (isFullSet() || Other.isFullSet())
 514     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 515
 516   APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
 517   APInt NewLower = getLower() + Other.getLower();
 518   APInt NewUpper = getUpper() + Other.getUpper() - 1;
 519   if (NewLower == NewUpper)
 520     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 521
 522   ConstantRange X = ConstantRange(NewLower, NewUpper);
 523   if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y))
 524     // We've wrapped, therefore, full set.
 525     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 526
 527   return X;
 528 }
 529
 530 ConstantRange
 531 ConstantRange::sub(const ConstantRange &Other) const {
 532   if (isEmptySet() || Other.isEmptySet())
 533     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 534   if (isFullSet() || Other.isFullSet())
 535     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 536
 537   APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
 538   APInt NewLower = getLower() - Other.getLower();
 539   APInt NewUpper = getUpper() - Other.getUpper() + 1;
 540   if (NewLower == NewUpper)
 541     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 542
 543   ConstantRange X = ConstantRange(NewLower, NewUpper);
 544   if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y))
 545     // We've wrapped, therefore, full set.
 546     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 547
 548   return X;
 549 }
 550
 551 ConstantRange
 552 ConstantRange::multiply(const ConstantRange &Other) const {
 553   // TODO: If either operand is a single element and the multiply is known to
 554   // be non-wrapping, round the result min and max value to the appropriate
 555   // multiple of that element. If wrapping is possible, at least adjust the
 556   // range according to the greatest power-of-two factor of the single element.
 557
 558   if (isEmptySet() || Other.isEmptySet())
 559     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 560   if (isFullSet() || Other.isFullSet())
 561     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 562
 563   APInt this_min = getUnsignedMin().zext(getBitWidth() * 2);
 564   APInt this_max = getUnsignedMax().zext(getBitWidth() * 2);
 565   APInt Other_min = Other.getUnsignedMin().zext(getBitWidth() * 2);
 566   APInt Other_max = Other.getUnsignedMax().zext(getBitWidth() * 2);
 567
 568   ConstantRange Result_zext = ConstantRange(this_min * Other_min,
 569                                             this_max * Other_max + 1);
 570   return Result_zext.truncate(getBitWidth());
 571 }
 572
 573 ConstantRange
 574 ConstantRange::smax(const ConstantRange &Other) const {
 575   // X smax Y is: range(smax(X_smin, Y_smin),
 576   //                    smax(X_smax, Y_smax))
 577   if (isEmptySet() || Other.isEmptySet())
 578     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 579   APInt NewL = APIntOps::smax(getSignedMin(), Other.getSignedMin());
 580   APInt NewU = APIntOps::smax(getSignedMax(), Other.getSignedMax()) + 1;
 581   if (NewU == NewL)
 582     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 583   return ConstantRange(NewL, NewU);
 584 }
 585
 586 ConstantRange
 587 ConstantRange::umax(const ConstantRange &Other) const {
 588   // X umax Y is: range(umax(X_umin, Y_umin),
 589   //                    umax(X_umax, Y_umax))
 590   if (isEmptySet() || Other.isEmptySet())
 591     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 592   APInt NewL = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
 593   APInt NewU = APIntOps::umax(getUnsignedMax(), Other.getUnsignedMax()) + 1;
 594   if (NewU == NewL)
 595     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 596   return ConstantRange(NewL, NewU);
 597 }
 598
 599 ConstantRange
 600 ConstantRange::udiv(const ConstantRange &RHS) const {
 601   if (isEmptySet() || RHS.isEmptySet() || RHS.getUnsignedMax() == 0)
 602     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 603   if (RHS.isFullSet())
 604     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 605
 606   APInt Lower = getUnsignedMin().udiv(RHS.getUnsignedMax());
 607
 608   APInt RHS_umin = RHS.getUnsignedMin();
 609   if (RHS_umin == 0) {
 610     // We want the lowest value in RHS excluding zero. Usually that would be 1
 611     // except for a range in the form of [X, 1) in which case it would be X.
 612     if (RHS.getUpper() == 1)
 613       RHS_umin = RHS.getLower();
 614     else
 615       RHS_umin = APInt(getBitWidth(), 1);
 616   }
 617
 618   APInt Upper = getUnsignedMax().udiv(RHS_umin) + 1;
 619
 620   // If the LHS is Full and the RHS is a wrapped interval containing 1 then
 621   // this could occur.
 622   if (Lower == Upper)
 623     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 624
 625   return ConstantRange(Lower, Upper);
 626 }
 627
 628 ConstantRange
 629 ConstantRange::binaryAnd(const ConstantRange &Other) const {
 630   if (isEmptySet() || Other.isEmptySet())
 631     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 632
 633   // TODO: replace this with something less conservative
 634
 635   APInt umin = APIntOps::umin(Other.getUnsignedMax(), getUnsignedMax());
 636   if (umin.isAllOnesValue())
 637     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 638   return ConstantRange(APInt::getNullValue(getBitWidth()), umin + 1);
 639 }
 640
 641 ConstantRange
 642 ConstantRange::binaryOr(const ConstantRange &Other) const {
 643   if (isEmptySet() || Other.isEmptySet())
 644     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 645
 646   // TODO: replace this with something less conservative
 647
 648   APInt umax = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
 649   if (umax.isMinValue())
 650     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 651   return ConstantRange(umax, APInt::getNullValue(getBitWidth()));
 652 }
 653
 654 ConstantRange
 655 ConstantRange::shl(const ConstantRange &Other) const {
 656   if (isEmptySet() || Other.isEmptySet())
 657     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 658
 659   APInt min = getUnsignedMin().shl(Other.getUnsignedMin());
 660   APInt max = getUnsignedMax().shl(Other.getUnsignedMax());
 661
 662   // there's no overflow!
 663   APInt Zeros(getBitWidth(), getUnsignedMax().countLeadingZeros());
 664   if (Zeros.ugt(Other.getUnsignedMax()))
 665     return ConstantRange(min, max + 1);
 666
 667   // FIXME: implement the other tricky cases
 668   return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 669 }
 670
 671 ConstantRange
 672 ConstantRange::lshr(const ConstantRange &Other) const {
 673   if (isEmptySet() || Other.isEmptySet())
 674     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 675
 676   APInt max = getUnsignedMax().lshr(Other.getUnsignedMin());
 677   APInt min = getUnsignedMin().lshr(Other.getUnsignedMax());
 678   if (min == max + 1)
 679     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 680
 681   return ConstantRange(min, max + 1);
 682 }
 683
 684 ConstantRange ConstantRange::inverse() const {
 685   if (isFullSet()) {
 686     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 687   } else if (isEmptySet()) {
 688     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 689   }
 690   return ConstantRange(Upper, Lower);
 691 }
 692
 693 /// print - Print out the bounds to a stream...
 694 ///
 695 void ConstantRange::print(raw_ostream &OS) const {
 696   if (isFullSet())
 697     OS << "full-set";
 698   else if (isEmptySet())
 699     OS << "empty-set";
 700   else
 701     OS << "[" << Lower << "," << Upper << ")";
 702 }
 703
 704 /// dump - Allow printing from a debugger easily...
 705 ///
 706 void ConstantRange::dump() const {
 707   print(dbgs());
 708 }