[APInt] Give the value union a name so we can remove assumptions on VAL being the larger member

[craig.topper]

Summary

Currently several places assume the VAL member is always at least the same size as pVal. In particular for a memcpy in the move assignment operator. While this is a true assumption, it isn't good practice to assume this.

This patch gives the union a name so we can write the memcpy in terms of the union itself. This also adds a similar memcpy to the move constructor where we previously just copied using VAL directly.

This patch is mostly just a mechanical addition of the U in front of VAL and pVAL everywhere. But several constructors had to be modified since we can't directly initializer a field of named union from the initializer list.

For the string constructor I pushed the VAL initialization down to where we know whether we need to use VAL or pVal. This leaves the upper bits of the union unitialized on a 32-bit target, but I'm not sure that's really a problem.

For the uint64_t constructor and the copy constructor I just removed the initialization of VAL to 0 altogether. pVal or VAL will always be assigned as needed. Again this makes the upper bits of the union garbage on 32-bit targets, but hopefully that's ok. This removal also makes the compiled binaries smaller because the compiler was unable to infer that the store is unnecessary on 64-bit target due to slow case init function being out of line.

[dblaikie]

Skimmed through most of it - looks good to me.

If you like, you could wait to see, or check with others, in case my idea that this is the Right Way to do this (having a named enum, etc) is correct/a shared opinion.

[craig.topper]

Adding a few others who have been involved or reviewed APInt patch changes recently.

[hans]

I don't know about The Right Way (tm), but this seems very reasonable to me. LGTM

[RKSimon]

Any reason you haven't committed this yet? Makes sense to me too fwiw.

llvm/trunk/include/llvm/ADT/APInt.h

public:
   static const WordType WORD_MAX = ~WordType(0);
 
 private:
   /// This union is used to store the integer value. When the
   /// integer bit-width <= 64, it uses VAL, otherwise it uses pVal.
   union {
     uint64_t VAL;   ///< Used to store the <= 64 bits integer value.
     uint64_t *pVal; ///< Used to store the >64 bits integer value.
-  };
+  } U;
 
   unsigned BitWidth; ///< The number of bits in this APInt.
 
   friend struct DenseMapAPIntKeyInfo;
 
   friend class APSInt;
 
   /// \brief Fast internal constructor
   ///
   /// This constructor is used only internally for speed of construction of
   /// temporaries. It is unsafe for general use so it is not public.
-  APInt(uint64_t *val, unsigned bits) : pVal(val), BitWidth(bits) {}
+  APInt(uint64_t *val, unsigned bits) : BitWidth(bits) {
+    U.pVal = val;
+  }
 
   /// \brief Determine if this APInt just has one word to store value.
   ///
   /// \returns true if the number of bits <= 64, false otherwise.
   bool isSingleWord() const { return BitWidth <= APINT_BITS_PER_WORD; }
 
   /// \brief Determine which word a bit is in.
   ///
private:
   /// zero'd out.
   APInt &clearUnusedBits() {
     // Compute how many bits are used in the final word
     unsigned WordBits = ((BitWidth-1) % APINT_BITS_PER_WORD) + 1;
 
     // Mask out the high bits.
     uint64_t mask = WORD_MAX >> (APINT_BITS_PER_WORD - WordBits);
     if (isSingleWord())
-      VAL &= mask;
+      U.VAL &= mask;
     else
-      pVal[getNumWords() - 1] &= mask;
+      U.pVal[getNumWords() - 1] &= mask;
     return *this;
   }
 
   /// \brief Get the word corresponding to a bit position
   /// \returns the corresponding word for the specified bit position.
   uint64_t getWord(unsigned bitPosition) const {
-    return isSingleWord() ? VAL : pVal[whichWord(bitPosition)];
+    return isSingleWord() ? U.VAL : U.pVal[whichWord(bitPosition)];
   }
 
   /// \brief Convert a char array into an APInt
   ///
   /// \param radix 2, 8, 10, 16, or 36
   /// Converts a string into a number.  The string must be non-empty
   /// and well-formed as a number of the given base. The bit-width
   /// must be sufficient to hold the result.
public:
   ///
   /// \param numBits the bit width of the constructed APInt
   /// \param val the initial value of the APInt
   /// \param isSigned how to treat signedness of val
   APInt(unsigned numBits, uint64_t val, bool isSigned = false)
       : BitWidth(numBits) {
     assert(BitWidth && "bitwidth too small");
     if (isSingleWord()) {
-      VAL = val;
+      U.VAL = val;
       clearUnusedBits();
     } else {
       initSlowCase(val, isSigned);
     }
   }
 
   /// \brief Construct an APInt of numBits width, initialized as bigVal[].
   ///
public:
   /// \param str the string to be interpreted
   /// \param radix the radix to use for the conversion
   APInt(unsigned numBits, StringRef str, uint8_t radix);
 
   /// Simply makes *this a copy of that.
   /// @brief Copy Constructor.
   APInt(const APInt &that) : BitWidth(that.BitWidth) {
     if (isSingleWord())
-      VAL = that.VAL;
+      U.VAL = that.U.VAL;
     else
       initSlowCase(that);
   }
 
   /// \brief Move Constructor.
-  APInt(APInt &&that) : VAL(that.VAL), BitWidth(that.BitWidth) {
+  APInt(APInt &&that) : BitWidth(that.BitWidth) {
+    memcpy(&U, &that.U, sizeof(U));
     that.BitWidth = 0;
   }
 
   /// \brief Destructor.
   ~APInt() {
     if (needsCleanup())
-      delete[] pVal;
+      delete[] U.pVal;
   }
 
   /// \brief Default constructor that creates an uninteresting APInt
   /// representing a 1-bit zero value.
   ///
   /// This is useful for object deserialization (pair this with the static
   ///  method Read).
-  explicit APInt() : VAL(0), BitWidth(1) {}
+  explicit APInt() : BitWidth(1) { U.VAL = 0; }
 
   /// \brief Returns whether this instance allocated memory.
   bool needsCleanup() const { return !isSingleWord(); }
 
   /// Used to insert APInt objects, or objects that contain APInt objects, into
   ///  FoldingSets.
   void Profile(FoldingSetNodeID &id) const;
 
public:
   /// \returns true if this APInt is positive.
   bool isStrictlyPositive() const { return isNonNegative() && !isNullValue(); }
 
   /// \brief Determine if all bits are set
   ///
   /// This checks to see if the value has all bits of the APInt are set or not.
   bool isAllOnesValue() const {
     if (isSingleWord())
-      return VAL == WORD_MAX >> (APINT_BITS_PER_WORD - BitWidth);
+      return U.VAL == WORD_MAX >> (APINT_BITS_PER_WORD - BitWidth);
     return countPopulationSlowCase() == BitWidth;
   }
 
   /// \brief Determine if all bits are clear
   ///
   /// This checks to see if the value has all bits of the APInt are clear or
   /// not.
   bool isNullValue() const { return !*this; }
bool isSignedIntN(unsigned N) const {
     return getMinSignedBits() <= N;
   }
 
   /// \brief Check if this APInt's value is a power of two greater than zero.
   ///
   /// \returns true if the argument APInt value is a power of two > 0.
   bool isPowerOf2() const {
     if (isSingleWord())
-      return isPowerOf2_64(VAL);
+      return isPowerOf2_64(U.VAL);
     return countPopulationSlowCase() == 1;
   }
 
   /// \brief Check if the APInt's value is returned by getSignMask.
   ///
   /// \returns true if this is the value returned by getSignMask.
   bool isSignMask() const { return isMinSignedValue(); }
 
public:
   bool isSplat(unsigned SplatSizeInBits) const;
 
   /// \returns true if this APInt value is a sequence of \param numBits ones
   /// starting at the least significant bit with the remainder zero.
   bool isMask(unsigned numBits) const {
     assert(numBits != 0 && "numBits must be non-zero");
     assert(numBits <= BitWidth && "numBits out of range");
     if (isSingleWord())
-      return VAL == (WORD_MAX >> (APINT_BITS_PER_WORD - numBits));
+      return U.VAL == (WORD_MAX >> (APINT_BITS_PER_WORD - numBits));
     unsigned Ones = countTrailingOnesSlowCase();
     return (numBits == Ones) &&
            ((Ones + countLeadingZerosSlowCase()) == BitWidth);
   }
 
   /// \returns true if this APInt is a non-empty sequence of ones starting at
   /// the least significant bit with the remainder zero.
   /// Ex. isMask(0x0000FFFFU) == true.
   bool isMask() const {
     if (isSingleWord())
-      return isMask_64(VAL);
+      return isMask_64(U.VAL);
     unsigned Ones = countTrailingOnesSlowCase();
     return (Ones > 0) && ((Ones + countLeadingZerosSlowCase()) == BitWidth);
   }
 
   /// \brief Return true if this APInt value contains a sequence of ones with
   /// the remainder zero.
   bool isShiftedMask() const {
     if (isSingleWord())
-      return isShiftedMask_64(VAL);
+      return isShiftedMask_64(U.VAL);
     unsigned Ones = countPopulationSlowCase();
     unsigned LeadZ = countLeadingZerosSlowCase();
     return (Ones + LeadZ + countTrailingZeros()) == BitWidth;
   }
 
   /// @}
   /// \name Value Generators
   /// @{
public:
   /// \brief Overload to compute a hash_code for an APInt value.
   friend hash_code hash_value(const APInt &Arg);
 
   /// This function returns a pointer to the internal storage of the APInt.
   /// This is useful for writing out the APInt in binary form without any
   /// conversions.
   const uint64_t *getRawData() const {
     if (isSingleWord())
-      return &VAL;
-    return &pVal[0];
+      return &U.VAL;
+    return &U.pVal[0];
   }
 
   /// @}
   /// \name Unary Operators
   /// @{
 
   /// \brief Postfix increment operator.
   ///
public:
 
   /// \brief Logical negation operator.
   ///
   /// Performs logical negation operation on this APInt.
   ///
   /// \returns true if *this is zero, false otherwise.
   bool operator!() const {
     if (isSingleWord())
-      return VAL == 0;
+      return U.VAL == 0;
     return countLeadingZerosSlowCase() == BitWidth;
   }
 
   /// @}
   /// \name Assignment Operators
   /// @{
 
   /// \brief Copy assignment operator.
   ///
   /// \returns *this after assignment of RHS.
   APInt &operator=(const APInt &RHS) {
     // If the bitwidths are the same, we can avoid mucking with memory
     if (isSingleWord() && RHS.isSingleWord()) {
-      VAL = RHS.VAL;
+      U.VAL = RHS.U.VAL;
       BitWidth = RHS.BitWidth;
       return clearUnusedBits();
     }
 
     AssignSlowCase(RHS);
     return *this;
   }
 
   /// @brief Move assignment operator.
   APInt &operator=(APInt &&that) {
     assert(this != &that && "Self-move not supported");
     if (!isSingleWord())
-      delete[] pVal;
+      delete[] U.pVal;
 
     // Use memcpy so that type based alias analysis sees both VAL and pVal
     // as modified.
-    memcpy(&VAL, &that.VAL, sizeof(uint64_t));
+    memcpy(&U, &that.U, sizeof(U));
 
     BitWidth = that.BitWidth;
     that.BitWidth = 0;
 
     return *this;
   }
 
   /// \brief Assignment operator.
   ///
   /// The RHS value is assigned to *this. If the significant bits in RHS exceed
   /// the bit width, the excess bits are truncated. If the bit width is larger
   /// than 64, the value is zero filled in the unspecified high order bits.
   ///
   /// \returns *this after assignment of RHS value.
   APInt &operator=(uint64_t RHS) {
     if (isSingleWord()) {
-      VAL = RHS;
+      U.VAL = RHS;
       clearUnusedBits();
     } else {
-      pVal[0] = RHS;
-      memset(pVal+1, 0, (getNumWords() - 1) * APINT_WORD_SIZE);
+      U.pVal[0] = RHS;
+      memset(U.pVal+1, 0, (getNumWords() - 1) * APINT_WORD_SIZE);
     }
     return *this;
   }
 
   /// \brief Bitwise AND assignment operator.
   ///
   /// Performs a bitwise AND operation on this APInt and RHS. The result is
   /// assigned to *this.
   ///
   /// \returns *this after ANDing with RHS.
   APInt &operator&=(const APInt &RHS) {
     assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
     if (isSingleWord())
-      VAL &= RHS.VAL;
+      U.VAL &= RHS.U.VAL;
     else
       AndAssignSlowCase(RHS);
     return *this;
   }
 
   /// \brief Bitwise AND assignment operator.
   ///
   /// Performs a bitwise AND operation on this APInt and RHS. RHS is
   /// logically zero-extended or truncated to match the bit-width of
   /// the LHS.
   APInt &operator&=(uint64_t RHS) {
     if (isSingleWord()) {
-      VAL &= RHS;
+      U.VAL &= RHS;
       return *this;
     }
-    pVal[0] &= RHS;
-    memset(pVal+1, 0, (getNumWords() - 1) * APINT_WORD_SIZE);
+    U.pVal[0] &= RHS;
+    memset(U.pVal+1, 0, (getNumWords() - 1) * APINT_WORD_SIZE);
     return *this;
   }
 
   /// \brief Bitwise OR assignment operator.
   ///
   /// Performs a bitwise OR operation on this APInt and RHS. The result is
   /// assigned *this;
   ///
   /// \returns *this after ORing with RHS.
   APInt &operator|=(const APInt &RHS) {
     assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
     if (isSingleWord())
-      VAL |= RHS.VAL;
+      U.VAL |= RHS.U.VAL;
     else
       OrAssignSlowCase(RHS);
     return *this;
   }
 
   /// \brief Bitwise OR assignment operator.
   ///
   /// Performs a bitwise OR operation on this APInt and RHS. RHS is
   /// logically zero-extended or truncated to match the bit-width of
   /// the LHS.
   APInt &operator|=(uint64_t RHS) {
     if (isSingleWord()) {
-      VAL |= RHS;
+      U.VAL |= RHS;
       clearUnusedBits();
     } else {
-      pVal[0] |= RHS;
+      U.pVal[0] |= RHS;
     }
     return *this;
   }
 
   /// \brief Bitwise XOR assignment operator.
   ///
   /// Performs a bitwise XOR operation on this APInt and RHS. The result is
   /// assigned to *this.
   ///
   /// \returns *this after XORing with RHS.
   APInt &operator^=(const APInt &RHS) {
     assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
     if (isSingleWord())
-      VAL ^= RHS.VAL;
+      U.VAL ^= RHS.U.VAL;
     else
       XorAssignSlowCase(RHS);
     return *this;
   }
 
   /// \brief Bitwise XOR assignment operator.
   ///
   /// Performs a bitwise XOR operation on this APInt and RHS. RHS is
   /// logically zero-extended or truncated to match the bit-width of
   /// the LHS.
   APInt &operator^=(uint64_t RHS) {
     if (isSingleWord()) {
-      VAL ^= RHS;
+      U.VAL ^= RHS;
       clearUnusedBits();
     } else {
-      pVal[0] ^= RHS;
+      U.pVal[0] ^= RHS;
     }
     return *this;
   }
 
   /// \brief Multiplication assignment operator.
   ///
   /// Multiplies this APInt by RHS and assigns the result to *this.
   ///
public:
   ///
   /// Shifts *this left by shiftAmt and assigns the result to *this.
   ///
   /// \returns *this after shifting left by ShiftAmt
   APInt &operator<<=(unsigned ShiftAmt) {
     assert(ShiftAmt <= BitWidth && "Invalid shift amount");
     if (isSingleWord()) {
       if (ShiftAmt == BitWidth)
-        VAL = 0;
+        U.VAL = 0;
       else
-        VAL <<= ShiftAmt;
+        U.VAL <<= ShiftAmt;
       return clearUnusedBits();
     }
     shlSlowCase(ShiftAmt);
     return *this;
   }
 
   /// \brief Left-shift assignment function.
   ///
APInt ashr(unsigned ShiftAmt) const {
     R.ashrInPlace(ShiftAmt);
     return R;
   }
 
   /// Arithmetic right-shift this APInt by ShiftAmt in place.
   void ashrInPlace(unsigned ShiftAmt) {
     assert(ShiftAmt <= BitWidth && "Invalid shift amount");
     if (isSingleWord()) {
-      int64_t SExtVAL = SignExtend64(VAL, BitWidth);
+      int64_t SExtVAL = SignExtend64(U.VAL, BitWidth);
       if (ShiftAmt == BitWidth)
-        VAL = SExtVAL >> (APINT_BITS_PER_WORD - 1); // Fill with sign bit.
+        U.VAL = SExtVAL >> (APINT_BITS_PER_WORD - 1); // Fill with sign bit.
       else
-        VAL = SExtVAL >> ShiftAmt;
+        U.VAL = SExtVAL >> ShiftAmt;
       clearUnusedBits();
       return;
     }
     ashrSlowCase(ShiftAmt);
   }
 
   /// \brief Logical right-shift function.
   ///
   /// Logical right-shift this APInt by shiftAmt.
   APInt lshr(unsigned shiftAmt) const {
     APInt R(*this);
     R.lshrInPlace(shiftAmt);
     return R;
   }
 
   /// Logical right-shift this APInt by ShiftAmt in place.
   void lshrInPlace(unsigned ShiftAmt) {
     assert(ShiftAmt <= BitWidth && "Invalid shift amount");
     if (isSingleWord()) {
       if (ShiftAmt == BitWidth)
-        VAL = 0;
+        U.VAL = 0;
       else
-        VAL >>= ShiftAmt;
+        U.VAL >>= ShiftAmt;
       return;
     }
     lshrSlowCase(ShiftAmt);
   }
 
   /// \brief Left-shift function.
   ///
   /// Left-shift this APInt by shiftAmt.
public:
   APInt ushl_ov(const APInt &Amt, bool &Overflow) const;
 
   /// \brief Array-indexing support.
   ///
   /// \returns the bit value at bitPosition
   bool operator[](unsigned bitPosition) const {
     assert(bitPosition < getBitWidth() && "Bit position out of bounds!");
     return (maskBit(bitPosition) &
-            (isSingleWord() ? VAL : pVal[whichWord(bitPosition)])) !=
+            (isSingleWord() ? U.VAL : U.pVal[whichWord(bitPosition)])) !=
            0;
   }
 
   /// @}
   /// \name Comparison Operators
   /// @{
 
   /// \brief Equality operator.
   ///
   /// Compares this APInt with RHS for the validity of the equality
   /// relationship.
   bool operator==(const APInt &RHS) const {
     assert(BitWidth == RHS.BitWidth && "Comparison requires equal bit widths");
     if (isSingleWord())
-      return VAL == RHS.VAL;
+      return U.VAL == RHS.U.VAL;
     return EqualSlowCase(RHS);
   }
 
   /// \brief Equality operator.
   ///
   /// Compares this APInt with a uint64_t for the validity of the equality
   /// relationship.
   ///

   /// \returns true if *this >= RHS when considered signed.
   bool sge(int64_t RHS) const { return !slt(RHS); }
 
   /// This operation tests if there are any pairs of corresponding bits
   /// between this APInt and RHS that are both set.
   bool intersects(const APInt &RHS) const {
     assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
     if (isSingleWord())
-      return (VAL & RHS.VAL) != 0;
+      return (U.VAL & RHS.U.VAL) != 0;
     return intersectsSlowCase(RHS);
   }
 
   /// This operation checks that all bits set in this APInt are also set in RHS.
   bool isSubsetOf(const APInt &RHS) const {
     assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
     if (isSingleWord())
-      return (VAL & ~RHS.VAL) == 0;
+      return (U.VAL & ~RHS.U.VAL) == 0;
     return isSubsetOfSlowCase(RHS);
   }
 
   /// @}
   /// \name Resizing Operators
   /// @{
 
   /// \brief Truncate to new width.

 
   /// @}
   /// \name Bit Manipulation Operators
   /// @{
 
   /// \brief Set every bit to 1.
   void setAllBits() {
     if (isSingleWord())
-      VAL = WORD_MAX;
+      U.VAL = WORD_MAX;
     else
       // Set all the bits in all the words.
-      memset(pVal, -1, getNumWords() * APINT_WORD_SIZE);
+      memset(U.pVal, -1, getNumWords() * APINT_WORD_SIZE);
     // Clear the unused ones
     clearUnusedBits();
   }
 
   /// \brief Set a given bit to 1.
   ///
   /// Set the given bit to 1 whose position is given as "bitPosition".
   void setBit(unsigned BitPosition) {
     assert(BitPosition <= BitWidth && "BitPosition out of range");
     WordType Mask = maskBit(BitPosition);
     if (isSingleWord())
-      VAL |= Mask;
+      U.VAL |= Mask;
     else
-      pVal[whichWord(BitPosition)] |= Mask;
+      U.pVal[whichWord(BitPosition)] |= Mask;
   }
 
   /// Set the sign bit to 1.
   void setSignBit() {
     setBit(BitWidth - 1);
   }
 
   /// Set the bits from loBit (inclusive) to hiBit (exclusive) to 1.
   void setBits(unsigned loBit, unsigned hiBit) {
     assert(hiBit <= BitWidth && "hiBit out of range");
     assert(loBit <= BitWidth && "loBit out of range");
     assert(loBit <= hiBit && "loBit greater than hiBit");
     if (loBit == hiBit)
       return;
     if (loBit < APINT_BITS_PER_WORD && hiBit <= APINT_BITS_PER_WORD) {
       uint64_t mask = WORD_MAX >> (APINT_BITS_PER_WORD - (hiBit - loBit));
       mask <<= loBit;
       if (isSingleWord())
-        VAL |= mask;
+        U.VAL |= mask;
       else
-        pVal[0] |= mask;
+        U.pVal[0] |= mask;
     } else {
       setBitsSlowCase(loBit, hiBit);
     }
   }
 
   /// Set the top bits starting from loBit.
   void setBitsFrom(unsigned loBit) {
     return setBits(loBit, BitWidth);
   }
 
   /// Set the bottom loBits bits.
   void setLowBits(unsigned loBits) {
     return setBits(0, loBits);
   }
 
   /// Set the top hiBits bits.
   void setHighBits(unsigned hiBits) {
     return setBits(BitWidth - hiBits, BitWidth);
   }
 
   /// \brief Set every bit to 0.
   void clearAllBits() {
     if (isSingleWord())
-      VAL = 0;
+      U.VAL = 0;
     else
-      memset(pVal, 0, getNumWords() * APINT_WORD_SIZE);
+      memset(U.pVal, 0, getNumWords() * APINT_WORD_SIZE);
   }
 
   /// \brief Set a given bit to 0.
   ///
   /// Set the given bit to 0 whose position is given as "bitPosition".
   void clearBit(unsigned BitPosition) {
     assert(BitPosition <= BitWidth && "BitPosition out of range");
     WordType Mask = ~maskBit(BitPosition);
     if (isSingleWord())
-      VAL &= Mask;
+      U.VAL &= Mask;
     else
-      pVal[whichWord(BitPosition)] &= Mask;
+      U.pVal[whichWord(BitPosition)] &= Mask;
   }
 
   /// Set the sign bit to 0.
   void clearSignBit() {
     clearBit(BitWidth - 1);
   }
 
   /// \brief Toggle every bit to its opposite value.
   void flipAllBits() {
     if (isSingleWord()) {
-      VAL ^= WORD_MAX;
+      U.VAL ^= WORD_MAX;
       clearUnusedBits();
     } else {
       flipAllBitsSlowCase();
     }
   }
 
   /// \brief Toggles a given bit to its opposite value.
   ///

 
   /// \brief Get zero extended value
   ///
   /// This method attempts to return the value of this APInt as a zero extended
   /// uint64_t. The bitwidth must be <= 64 or the value must fit within a
   /// uint64_t. Otherwise an assertion will result.
   uint64_t getZExtValue() const {
     if (isSingleWord())
-      return VAL;
+      return U.VAL;
     assert(getActiveBits() <= 64 && "Too many bits for uint64_t");
-    return pVal[0];
+    return U.pVal[0];
   }
 
   /// \brief Get sign extended value
   ///
   /// This method attempts to return the value of this APInt as a sign extended
   /// int64_t. The bit width must be <= 64 or the value must fit within an
   /// int64_t. Otherwise an assertion will result.
   int64_t getSExtValue() const {
     if (isSingleWord())
-      return SignExtend64(VAL, BitWidth);
+      return SignExtend64(U.VAL, BitWidth);
     assert(getMinSignedBits() <= 64 && "Too many bits for int64_t");
-    return int64_t(pVal[0]);
+    return int64_t(U.pVal[0]);
   }
 
   /// \brief Get bits required for string value.
   ///
   /// This method determines how many bits are required to hold the APInt
   /// equivalent of the string given by \p str.
   static unsigned getBitsNeeded(StringRef str, uint8_t radix);
 
   /// \brief The APInt version of the countLeadingZeros functions in
   ///   MathExtras.h.
   ///
   /// It counts the number of zeros from the most significant bit to the first
   /// one bit.
   ///
   /// \returns BitWidth if the value is zero, otherwise returns the number of
   ///   zeros from the most significant bit to the first one bits.
   unsigned countLeadingZeros() const {
     if (isSingleWord()) {
       unsigned unusedBits = APINT_BITS_PER_WORD - BitWidth;
-      return llvm::countLeadingZeros(VAL) - unusedBits;
+      return llvm::countLeadingZeros(U.VAL) - unusedBits;
     }
     return countLeadingZerosSlowCase();
   }
 
   /// \brief Count the number of leading one bits.
   ///
   /// This function is an APInt version of the countLeadingOnes
   /// functions in MathExtras.h. It counts the number of ones from the most

   /// This function is an APInt version of the countTrailingOnes
   /// functions in MathExtras.h. It counts the number of ones from the least
   /// significant bit to the first zero bit.
   ///
   /// \returns BitWidth if the value is all ones, otherwise returns the number
   /// of ones from the least significant bit to the first zero bit.
   unsigned countTrailingOnes() const {
     if (isSingleWord())
-      return llvm::countTrailingOnes(VAL);
+      return llvm::countTrailingOnes(U.VAL);
     return countTrailingOnesSlowCase();
   }
 
   /// \brief Count the number of bits set.
   ///
   /// This function is an APInt version of the countPopulation functions
   /// in MathExtras.h. It counts the number of 1 bits in the APInt value.
   ///
   /// \returns 0 if the value is zero, otherwise returns the number of set bits.
   unsigned countPopulation() const {
     if (isSingleWord())
-      return llvm::countPopulation(VAL);
+      return llvm::countPopulation(U.VAL);
     return countPopulationSlowCase();
   }
 
   /// @}
   /// \name Conversion Functions
   /// @{
   void print(raw_ostream &OS, bool isSigned) const;
 

   /// The conversion does not do a translation from integer to double, it just
   /// re-interprets the bits as a double. Note that it is valid to do this on
   /// any bit width. Exactly 64 bits will be translated.
   double bitsToDouble() const {
     union {
       uint64_t I;
       double D;
     } T;
-    T.I = (isSingleWord() ? VAL : pVal[0]);
+    T.I = (isSingleWord() ? U.VAL : U.pVal[0]);
     return T.D;
   }
 
   /// \brief Converts APInt bits to a double
   ///
   /// The conversion does not do a translation from integer to float, it just
   /// re-interprets the bits as a float. Note that it is valid to do this on
   /// any bit width. Exactly 32 bits will be translated.
   float bitsToFloat() const {
     union {
       unsigned I;
       float F;
     } T;
-    T.I = unsigned((isSingleWord() ? VAL : pVal[0]));
+    T.I = unsigned((isSingleWord() ? U.VAL : U.pVal[0]));
     return T.F;
   }
 
   /// \brief Converts a double to APInt bits.
   ///
   /// The conversion does not do a translation from double to integer, it just
   /// re-interprets the bits of the double.
   static APInt doubleToBits(double V) {

   ///
   /// to get around any mathematical concerns resulting from
   /// referencing 2 in a space where 2 does no exist.
   unsigned nearestLogBase2() const {
     // Special case when we have a bitwidth of 1. If VAL is 1, then we
     // get 0. If VAL is 0, we get WORD_MAX which gets truncated to
     // UINT32_MAX.
     if (BitWidth == 1)
-      return VAL - 1;
+      return U.VAL - 1;
 
     // Handle the zero case.
     if (isNullValue())
       return UINT32_MAX;
 
     // The non-zero case is handled by computing:
     //
     //   nearestLogBase2(x) = logBase2(x) + x[logBase2(x)-1].

llvm/trunk/lib/IR/LLVMContextImpl.h

 class GCStrategy;
 class LLVMContext;
 class Type;
 class Value;
 
 struct DenseMapAPIntKeyInfo {
   static inline APInt getEmptyKey() {
     APInt V(nullptr, 0);
-    V.VAL = 0;
+    V.U.VAL = 0;
     return V;
   }
   static inline APInt getTombstoneKey() {
     APInt V(nullptr, 0);
-    V.VAL = 1;
+    V.U.VAL = 1;
     return V;
   }
   static unsigned getHashValue(const APInt &Key) {
     return static_cast<unsigned>(hash_value(Key));
   }
   static bool isEqual(const APInt &LHS, const APInt &RHS) {
     return LHS.getBitWidth() == RHS.getBitWidth() && LHS == RHS;
   }

llvm/trunk/lib/Support/APInt.cpp

inline static unsigned getDigit(char cdigit, uint8_t radix) {
   if (r < radix)
     return r;
 
   return -1U;
 }
 
 
 void APInt::initSlowCase(uint64_t val, bool isSigned) {
-  VAL = 0;
-  pVal = getClearedMemory(getNumWords());
-  pVal[0] = val;
+  U.pVal = getClearedMemory(getNumWords());
+  U.pVal[0] = val;
   if (isSigned && int64_t(val) < 0)
     for (unsigned i = 1; i < getNumWords(); ++i)
-      pVal[i] = WORD_MAX;
+      U.pVal[i] = WORD_MAX;
   clearUnusedBits();
 }
 
 void APInt::initSlowCase(const APInt& that) {
-  VAL = 0;
-  pVal = getMemory(getNumWords());
-  memcpy(pVal, that.pVal, getNumWords() * APINT_WORD_SIZE);
+  U.pVal = getMemory(getNumWords());
+  memcpy(U.pVal, that.U.pVal, getNumWords() * APINT_WORD_SIZE);
 }
 
 void APInt::initFromArray(ArrayRef<uint64_t> bigVal) {
   assert(BitWidth && "Bitwidth too small");
   assert(bigVal.data() && "Null pointer detected!");
   if (isSingleWord())
-    VAL = bigVal[0];
+    U.VAL = bigVal[0];
   else {
     // Get memory, cleared to 0
-    VAL = 0;
-    pVal = getClearedMemory(getNumWords());
+    U.pVal = getClearedMemory(getNumWords());
     // Calculate the number of words to copy
     unsigned words = std::min<unsigned>(bigVal.size(), getNumWords());
     // Copy the words from bigVal to pVal
-    memcpy(pVal, bigVal.data(), words * APINT_WORD_SIZE);
+    memcpy(U.pVal, bigVal.data(), words * APINT_WORD_SIZE);
   }
   // Make sure unused high bits are cleared
   clearUnusedBits();
 }
 
 APInt::APInt(unsigned numBits, ArrayRef<uint64_t> bigVal)
   : BitWidth(numBits) {
   initFromArray(bigVal);
 }
 
 APInt::APInt(unsigned numBits, unsigned numWords, const uint64_t bigVal[])
   : BitWidth(numBits) {
   initFromArray(makeArrayRef(bigVal, numWords));
 }
 
 APInt::APInt(unsigned numbits, StringRef Str, uint8_t radix)
-  : VAL(0), BitWidth(numbits) {
+  : BitWidth(numbits) {
   assert(BitWidth && "Bitwidth too small");
   fromString(numbits, Str, radix);
 }
 
 void APInt::AssignSlowCase(const APInt& RHS) {
   // Don't do anything for X = X
   if (this == &RHS)
     return;
 
   if (BitWidth == RHS.getBitWidth()) {
     // assume same bit-width single-word case is already handled
     assert(!isSingleWord());
-    memcpy(pVal, RHS.pVal, getNumWords() * APINT_WORD_SIZE);
+    memcpy(U.pVal, RHS.U.pVal, getNumWords() * APINT_WORD_SIZE);
     return;
   }
 
   if (isSingleWord()) {
     // assume case where both are single words is already handled
     assert(!RHS.isSingleWord());
-    VAL = 0;
-    pVal = getMemory(RHS.getNumWords());
-    memcpy(pVal, RHS.pVal, RHS.getNumWords() * APINT_WORD_SIZE);
+    U.pVal = getMemory(RHS.getNumWords());
+    memcpy(U.pVal, RHS.U.pVal, RHS.getNumWords() * APINT_WORD_SIZE);
   } else if (getNumWords() == RHS.getNumWords())
-    memcpy(pVal, RHS.pVal, RHS.getNumWords() * APINT_WORD_SIZE);
+    memcpy(U.pVal, RHS.U.pVal, RHS.getNumWords() * APINT_WORD_SIZE);
   else if (RHS.isSingleWord()) {
-    delete [] pVal;
-    VAL = RHS.VAL;
+    delete [] U.pVal;
+    U.VAL = RHS.U.VAL;
   } else {
-    delete [] pVal;
-    pVal = getMemory(RHS.getNumWords());
-    memcpy(pVal, RHS.pVal, RHS.getNumWords() * APINT_WORD_SIZE);
+    delete [] U.pVal;
+    U.pVal = getMemory(RHS.getNumWords());
+    memcpy(U.pVal, RHS.U.pVal, RHS.getNumWords() * APINT_WORD_SIZE);
   }
   BitWidth = RHS.BitWidth;
   clearUnusedBits();
 }
 
 /// This method 'profiles' an APInt for use with FoldingSet.
 void APInt::Profile(FoldingSetNodeID& ID) const {
   ID.AddInteger(BitWidth);
 
   if (isSingleWord()) {
-    ID.AddInteger(VAL);
+    ID.AddInteger(U.VAL);
     return;
   }
 
   unsigned NumWords = getNumWords();
   for (unsigned i = 0; i < NumWords; ++i)
-    ID.AddInteger(pVal[i]);
+    ID.AddInteger(U.pVal[i]);
 }
 
 /// @brief Prefix increment operator. Increments the APInt by one.
 APInt& APInt::operator++() {
   if (isSingleWord())
-    ++VAL;
+    ++U.VAL;
   else
-    tcIncrement(pVal, getNumWords());
+    tcIncrement(U.pVal, getNumWords());
   return clearUnusedBits();
 }
 
 /// @brief Prefix decrement operator. Decrements the APInt by one.
 APInt& APInt::operator--() {
   if (isSingleWord())
-    --VAL;
+    --U.VAL;
   else
-    tcDecrement(pVal, getNumWords());
+    tcDecrement(U.pVal, getNumWords());
   return clearUnusedBits();
 }
 
 /// Adds the RHS APint to this APInt.
 /// @returns this, after addition of RHS.
 /// @brief Addition assignment operator.
 APInt& APInt::operator+=(const APInt& RHS) {
   assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
   if (isSingleWord())
-    VAL += RHS.VAL;
+    U.VAL += RHS.U.VAL;
   else
-    tcAdd(pVal, RHS.pVal, 0, getNumWords());
+    tcAdd(U.pVal, RHS.U.pVal, 0, getNumWords());
   return clearUnusedBits();
 }
 
 APInt& APInt::operator+=(uint64_t RHS) {
   if (isSingleWord())
-    VAL += RHS;
+    U.VAL += RHS;
   else
-    tcAddPart(pVal, RHS, getNumWords());
+    tcAddPart(U.pVal, RHS, getNumWords());
   return clearUnusedBits();
 }
 
 /// Subtracts the RHS APInt from this APInt
 /// @returns this, after subtraction
 /// @brief Subtraction assignment operator.
 APInt& APInt::operator-=(const APInt& RHS) {
   assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
   if (isSingleWord())
-    VAL -= RHS.VAL;
+    U.VAL -= RHS.U.VAL;
   else
-    tcSubtract(pVal, RHS.pVal, 0, getNumWords());
+    tcSubtract(U.pVal, RHS.U.pVal, 0, getNumWords());
   return clearUnusedBits();
 }
 
 APInt& APInt::operator-=(uint64_t RHS) {
   if (isSingleWord())
-    VAL -= RHS;
+    U.VAL -= RHS;
   else
-    tcSubtractPart(pVal, RHS, getNumWords());
+    tcSubtractPart(U.pVal, RHS, getNumWords());
   return clearUnusedBits();
 }
 
 /// Multiplies an integer array, x, by a uint64_t integer and places the result
 /// into dest.
 /// @returns the carry out of the multiplication.
 /// @brief Multiply a multi-digit APInt by a single digit (64-bit) integer.
 static uint64_t mul_1(uint64_t dest[], uint64_t x[], unsigned len, uint64_t y) {
for (unsigned i = 1; i < ylen; ++i) {
     }
     dest[i+xlen] = carry;
   }
 }
 
 APInt& APInt::operator*=(const APInt& RHS) {
   assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
   if (isSingleWord()) {
-    VAL *= RHS.VAL;
+    U.VAL *= RHS.U.VAL;
     clearUnusedBits();
     return *this;
   }
 
   // Get some bit facts about LHS and check for zero
   unsigned lhsBits = getActiveBits();
   unsigned lhsWords = !lhsBits ? 0 : whichWord(lhsBits - 1) + 1;
   if (!lhsWords)
if (!rhsWords) {
     return *this;
   }
 
   // Allocate space for the result
   unsigned destWords = rhsWords + lhsWords;
   uint64_t *dest = getMemory(destWords);
 
   // Perform the long multiply
-  mul(dest, pVal, lhsWords, RHS.pVal, rhsWords);
+  mul(dest, U.pVal, lhsWords, RHS.U.pVal, rhsWords);
 
   // Copy result back into *this
   clearAllBits();
   unsigned wordsToCopy = destWords >= getNumWords() ? getNumWords() : destWords;
-  memcpy(pVal, dest, wordsToCopy * APINT_WORD_SIZE);
+  memcpy(U.pVal, dest, wordsToCopy * APINT_WORD_SIZE);
   clearUnusedBits();
 
   // delete dest array and return
   delete[] dest;
   return *this;
 }
 
 void APInt::AndAssignSlowCase(const APInt& RHS) {
-  tcAnd(pVal, RHS.pVal, getNumWords());
+  tcAnd(U.pVal, RHS.U.pVal, getNumWords());
 }
 
 void APInt::OrAssignSlowCase(const APInt& RHS) {
-  tcOr(pVal, RHS.pVal, getNumWords());
+  tcOr(U.pVal, RHS.U.pVal, getNumWords());
 }
 
 void APInt::XorAssignSlowCase(const APInt& RHS) {
-  tcXor(pVal, RHS.pVal, getNumWords());
+  tcXor(U.pVal, RHS.U.pVal, getNumWords());
 }
 
 APInt APInt::operator*(const APInt& RHS) const {
   assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
   if (isSingleWord())
-    return APInt(BitWidth, VAL * RHS.VAL);
+    return APInt(BitWidth, U.VAL * RHS.U.VAL);
   APInt Result(*this);
   Result *= RHS;
   return Result;
 }
 
 bool APInt::EqualSlowCase(const APInt& RHS) const {
-  return std::equal(pVal, pVal + getNumWords(), RHS.pVal);
+  return std::equal(U.pVal, U.pVal + getNumWords(), RHS.U.pVal);
 }
 
 int APInt::compare(const APInt& RHS) const {
   assert(BitWidth == RHS.BitWidth && "Bit widths must be same for comparison");
   if (isSingleWord())
-    return VAL < RHS.VAL ? -1 : VAL > RHS.VAL;
+    return U.VAL < RHS.U.VAL ? -1 : U.VAL > RHS.U.VAL;
 
-  return tcCompare(pVal, RHS.pVal, getNumWords());
+  return tcCompare(U.pVal, RHS.U.pVal, getNumWords());
 }
 
 int APInt::compareSigned(const APInt& RHS) const {
   assert(BitWidth == RHS.BitWidth && "Bit widths must be same for comparison");
   if (isSingleWord()) {
-    int64_t lhsSext = SignExtend64(VAL, BitWidth);
-    int64_t rhsSext = SignExtend64(RHS.VAL, BitWidth);
+    int64_t lhsSext = SignExtend64(U.VAL, BitWidth);
+    int64_t rhsSext = SignExtend64(RHS.U.VAL, BitWidth);
     return lhsSext < rhsSext ? -1 : lhsSext > rhsSext;
   }
 
   bool lhsNeg = isNegative();
   bool rhsNeg = RHS.isNegative();
 
   // If the sign bits don't match, then (LHS < RHS) if LHS is negative
   if (lhsNeg != rhsNeg)
     return lhsNeg ? -1 : 1;
 
   // Otherwise we can just use an unsigned comparison, because even negative
   // numbers compare correctly this way if both have the same signed-ness.
-  return tcCompare(pVal, RHS.pVal, getNumWords());
+  return tcCompare(U.pVal, RHS.U.pVal, getNumWords());
 }
 
 void APInt::setBitsSlowCase(unsigned loBit, unsigned hiBit) {
   unsigned loWord = whichWord(loBit);
   unsigned hiWord = whichWord(hiBit);
 
   // Create an initial mask for the low word with zeros below loBit.
   uint64_t loMask = WORD_MAX << whichBit(loBit);
 
   // If hiBit is not aligned, we need a high mask.
   unsigned hiShiftAmt = whichBit(hiBit);
   if (hiShiftAmt != 0) {
     // Create a high mask with zeros above hiBit.
     uint64_t hiMask = WORD_MAX >> (APINT_BITS_PER_WORD - hiShiftAmt);
     // If loWord and hiWord are equal, then we combine the masks. Otherwise,
     // set the bits in hiWord.
     if (hiWord == loWord)
       loMask &= hiMask;
     else
-      pVal[hiWord] |= hiMask;
+      U.pVal[hiWord] |= hiMask;
   }
   // Apply the mask to the low word.
-  pVal[loWord] |= loMask;
+  U.pVal[loWord] |= loMask;
 
   // Fill any words between loWord and hiWord with all ones.
   for (unsigned word = loWord + 1; word < hiWord; ++word)
-    pVal[word] = WORD_MAX;
+    U.pVal[word] = WORD_MAX;
 }
 
 /// @brief Toggle every bit to its opposite value.
 void APInt::flipAllBitsSlowCase() {
-  tcComplement(pVal, getNumWords());
+  tcComplement(U.pVal, getNumWords());
   clearUnusedBits();
 }
 
 /// Toggle a given bit to its opposite value whose position is given
 /// as "bitPosition".
 /// @brief Toggles a given bit to its opposite value.
 void APInt::flipBit(unsigned bitPosition) {
   assert(bitPosition < BitWidth && "Out of the bit-width range!");
void APInt::insertBits(const APInt &subBits, unsigned bitPosition) {
   if (subBitWidth == BitWidth) {
     *this = subBits;
     return;
   }
 
   // Single word result can be done as a direct bitmask.
   if (isSingleWord()) {
     uint64_t mask = WORD_MAX >> (APINT_BITS_PER_WORD - subBitWidth);
-    VAL &= ~(mask << bitPosition);
-    VAL |= (subBits.VAL << bitPosition);
+    U.VAL &= ~(mask << bitPosition);
+    U.VAL |= (subBits.U.VAL << bitPosition);
     return;
   }
 
   unsigned loBit = whichBit(bitPosition);
   unsigned loWord = whichWord(bitPosition);
   unsigned hi1Word = whichWord(bitPosition + subBitWidth - 1);
 
   // Insertion within a single word can be done as a direct bitmask.
   if (loWord == hi1Word) {
     uint64_t mask = WORD_MAX >> (APINT_BITS_PER_WORD - subBitWidth);
-    pVal[loWord] &= ~(mask << loBit);
-    pVal[loWord] |= (subBits.VAL << loBit);
+    U.pVal[loWord] &= ~(mask << loBit);
+    U.pVal[loWord] |= (subBits.U.VAL << loBit);
     return;
   }
 
   // Insert on word boundaries.
   if (loBit == 0) {
     // Direct copy whole words.
     unsigned numWholeSubWords = subBitWidth / APINT_BITS_PER_WORD;
-    memcpy(pVal + loWord, subBits.getRawData(),
+    memcpy(U.pVal + loWord, subBits.getRawData(),
            numWholeSubWords * APINT_WORD_SIZE);
 
     // Mask+insert remaining bits.
     unsigned remainingBits = subBitWidth % APINT_BITS_PER_WORD;
     if (remainingBits != 0) {
       uint64_t mask = WORD_MAX >> (APINT_BITS_PER_WORD - remainingBits);
-      pVal[hi1Word] &= ~mask;
-      pVal[hi1Word] |= subBits.getWord(subBitWidth - 1);
+      U.pVal[hi1Word] &= ~mask;
+      U.pVal[hi1Word] |= subBits.getWord(subBitWidth - 1);
     }
     return;
   }
 
   // General case - set/clear individual bits in dst based on src.
   // TODO - there is scope for optimization here, but at the moment this code
   // path is barely used so prefer readability over performance.
   for (unsigned i = 0; i != subBitWidth; ++i) {
     if (subBits[i])
       setBit(bitPosition + i);
     else
       clearBit(bitPosition + i);
   }
 }
 
 APInt APInt::extractBits(unsigned numBits, unsigned bitPosition) const {
   assert(numBits > 0 && "Can't extract zero bits");
   assert(bitPosition < BitWidth && (numBits + bitPosition) <= BitWidth &&
          "Illegal bit extraction");
 
   if (isSingleWord())
-    return APInt(numBits, VAL >> bitPosition);
+    return APInt(numBits, U.VAL >> bitPosition);
 
   unsigned loBit = whichBit(bitPosition);
   unsigned loWord = whichWord(bitPosition);
   unsigned hiWord = whichWord(bitPosition + numBits - 1);
 
   // Single word result extracting bits from a single word source.
   if (loWord == hiWord)
-    return APInt(numBits, pVal[loWord] >> loBit);
+    return APInt(numBits, U.pVal[loWord] >> loBit);
 
   // Extracting bits that start on a source word boundary can be done
   // as a fast memory copy.
   if (loBit == 0)
-    return APInt(numBits, makeArrayRef(pVal + loWord, 1 + hiWord - loWord));
+    return APInt(numBits, makeArrayRef(U.pVal + loWord, 1 + hiWord - loWord));
 
   // General case - shift + copy source words directly into place.
   APInt Result(numBits, 0);
   unsigned NumSrcWords = getNumWords();
   unsigned NumDstWords = Result.getNumWords();
 
   for (unsigned word = 0; word < NumDstWords; ++word) {
-    uint64_t w0 = pVal[loWord + word];
+    uint64_t w0 = U.pVal[loWord + word];
     uint64_t w1 =
-        (loWord + word + 1) < NumSrcWords ? pVal[loWord + word + 1] : 0;
-    Result.pVal[word] = (w0 >> loBit) | (w1 << (APINT_BITS_PER_WORD - loBit));
+        (loWord + word + 1) < NumSrcWords ? U.pVal[loWord + word + 1] : 0;
+    Result.U.pVal[word] = (w0 >> loBit) | (w1 << (APINT_BITS_PER_WORD - loBit));
   }
 
   return Result.clearUnusedBits();
 }
 
 unsigned APInt::getBitsNeeded(StringRef str, uint8_t radix) {
   assert(!str.empty() && "Invalid string length");
   assert((radix == 10 || radix == 8 || radix == 16 || radix == 2 ||
if (log == (unsigned)-1) {
     return isNegative + 1;
   } else {
     return isNegative + log + 1;
   }
 }
 
 hash_code llvm::hash_value(const APInt &Arg) {
   if (Arg.isSingleWord())
-    return hash_combine(Arg.VAL);
+    return hash_combine(Arg.U.VAL);
 
-  return hash_combine_range(Arg.pVal, Arg.pVal + Arg.getNumWords());
+  return hash_combine_range(Arg.U.pVal, Arg.U.pVal + Arg.getNumWords());
 }
 
 bool APInt::isSplat(unsigned SplatSizeInBits) const {
   assert(getBitWidth() % SplatSizeInBits == 0 &&
          "SplatSizeInBits must divide width!");
   // We can check that all parts of an integer are equal by making use of a
   // little trick: rotate and check if it's still the same value.
   return *this == rotl(SplatSizeInBits);
for (unsigned I = V.getBitWidth(); I < NewLen; I <<= 1)
     Val |= Val << I;
 
   return Val;
 }
 
 unsigned APInt::countLeadingZerosSlowCase() const {
   unsigned Count = 0;
   for (int i = getNumWords()-1; i >= 0; --i) {
-    uint64_t V = pVal[i];
+    uint64_t V = U.pVal[i];
     if (V == 0)
       Count += APINT_BITS_PER_WORD;
     else {
       Count += llvm::countLeadingZeros(V);
       break;
     }
   }
   // Adjust for unused bits in the most significant word (they are zero).
   unsigned Mod = BitWidth % APINT_BITS_PER_WORD;
   Count -= Mod > 0 ? APINT_BITS_PER_WORD - Mod : 0;
   return Count;
 }
 
 unsigned APInt::countLeadingOnes() const {
   if (isSingleWord())
-    return llvm::countLeadingOnes(VAL << (APINT_BITS_PER_WORD - BitWidth));
+    return llvm::countLeadingOnes(U.VAL << (APINT_BITS_PER_WORD - BitWidth));
 
   unsigned highWordBits = BitWidth % APINT_BITS_PER_WORD;
   unsigned shift;
   if (!highWordBits) {
     highWordBits = APINT_BITS_PER_WORD;
     shift = 0;
   } else {
     shift = APINT_BITS_PER_WORD - highWordBits;
   }
   int i = getNumWords() - 1;
-  unsigned Count = llvm::countLeadingOnes(pVal[i] << shift);
+  unsigned Count = llvm::countLeadingOnes(U.pVal[i] << shift);
   if (Count == highWordBits) {
     for (i--; i >= 0; --i) {
-      if (pVal[i] == WORD_MAX)
+      if (U.pVal[i] == WORD_MAX)
         Count += APINT_BITS_PER_WORD;
       else {
-        Count += llvm::countLeadingOnes(pVal[i]);
+        Count += llvm::countLeadingOnes(U.pVal[i]);
         break;
       }
     }
   }
   return Count;
 }
 
 unsigned APInt::countTrailingZeros() const {
   if (isSingleWord())
-    return std::min(unsigned(llvm::countTrailingZeros(VAL)), BitWidth);
+    return std::min(unsigned(llvm::countTrailingZeros(U.VAL)), BitWidth);
   unsigned Count = 0;
   unsigned i = 0;
-  for (; i < getNumWords() && pVal[i] == 0; ++i)
+  for (; i < getNumWords() && U.pVal[i] == 0; ++i)
     Count += APINT_BITS_PER_WORD;
   if (i < getNumWords())
-    Count += llvm::countTrailingZeros(pVal[i]);
+    Count += llvm::countTrailingZeros(U.pVal[i]);
   return std::min(Count, BitWidth);
 }
 
 unsigned APInt::countTrailingOnesSlowCase() const {
   unsigned Count = 0;
   unsigned i = 0;
-  for (; i < getNumWords() && pVal[i] == WORD_MAX; ++i)
+  for (; i < getNumWords() && U.pVal[i] == WORD_MAX; ++i)
     Count += APINT_BITS_PER_WORD;
   if (i < getNumWords())
-    Count += llvm::countTrailingOnes(pVal[i]);
+    Count += llvm::countTrailingOnes(U.pVal[i]);
   assert(Count <= BitWidth);
   return Count;
 }
 
 unsigned APInt::countPopulationSlowCase() const {
   unsigned Count = 0;
   for (unsigned i = 0; i < getNumWords(); ++i)
-    Count += llvm::countPopulation(pVal[i]);
+    Count += llvm::countPopulation(U.pVal[i]);
   return Count;
 }
 
 bool APInt::intersectsSlowCase(const APInt &RHS) const {
   for (unsigned i = 0, e = getNumWords(); i != e; ++i)
-    if ((pVal[i] & RHS.pVal[i]) != 0)
+    if ((U.pVal[i] & RHS.U.pVal[i]) != 0)
       return true;
 
   return false;
 }
 
 bool APInt::isSubsetOfSlowCase(const APInt &RHS) const {
   for (unsigned i = 0, e = getNumWords(); i != e; ++i)
-    if ((pVal[i] & ~RHS.pVal[i]) != 0)
+    if ((U.pVal[i] & ~RHS.U.pVal[i]) != 0)
       return false;
 
   return true;
 }
 
 APInt APInt::byteSwap() const {
   assert(BitWidth >= 16 && BitWidth % 16 == 0 && "Cannot byteswap!");
   if (BitWidth == 16)
-    return APInt(BitWidth, ByteSwap_16(uint16_t(VAL)));
+    return APInt(BitWidth, ByteSwap_16(uint16_t(U.VAL)));
   if (BitWidth == 32)
-    return APInt(BitWidth, ByteSwap_32(unsigned(VAL)));
+    return APInt(BitWidth, ByteSwap_32(unsigned(U.VAL)));
   if (BitWidth == 48) {
-    unsigned Tmp1 = unsigned(VAL >> 16);
+    unsigned Tmp1 = unsigned(U.VAL >> 16);
     Tmp1 = ByteSwap_32(Tmp1);
-    uint16_t Tmp2 = uint16_t(VAL);
+    uint16_t Tmp2 = uint16_t(U.VAL);
     Tmp2 = ByteSwap_16(Tmp2);
     return APInt(BitWidth, (uint64_t(Tmp2) << 32) | Tmp1);
   }
   if (BitWidth == 64)
-    return APInt(BitWidth, ByteSwap_64(VAL));
+    return APInt(BitWidth, ByteSwap_64(U.VAL));
 
   APInt Result(getNumWords() * APINT_BITS_PER_WORD, 0);
   for (unsigned I = 0, N = getNumWords(); I != N; ++I)
-    Result.pVal[I] = ByteSwap_64(pVal[N - I - 1]);
+    Result.U.pVal[I] = ByteSwap_64(U.pVal[N - I - 1]);
   if (Result.BitWidth != BitWidth) {
     Result.lshrInPlace(Result.BitWidth - BitWidth);
     Result.BitWidth = BitWidth;
   }
   return Result;
 }
 
 APInt APInt::reverseBits() const {
   switch (BitWidth) {
   case 64:
-    return APInt(BitWidth, llvm::reverseBits<uint64_t>(VAL));
+    return APInt(BitWidth, llvm::reverseBits<uint64_t>(U.VAL));
   case 32:
-    return APInt(BitWidth, llvm::reverseBits<uint32_t>(VAL));
+    return APInt(BitWidth, llvm::reverseBits<uint32_t>(U.VAL));
   case 16:
-    return APInt(BitWidth, llvm::reverseBits<uint16_t>(VAL));
+    return APInt(BitWidth, llvm::reverseBits<uint16_t>(U.VAL));
   case 8:
-    return APInt(BitWidth, llvm::reverseBits<uint8_t>(VAL));
+    return APInt(BitWidth, llvm::reverseBits<uint8_t>(U.VAL));
   default:
     break;
   }
 
   APInt Val(*this);
   APInt Reversed(BitWidth, 0);
   unsigned S = BitWidth;
 
double APInt::roundToDouble(bool isSigned) const {
   }
   exp += 1023; // Increment for 1023 bias
 
   // Number of bits in mantissa is 52. To obtain the mantissa value, we must
   // extract the high 52 bits from the correct words in pVal.
   uint64_t mantissa;
   unsigned hiWord = whichWord(n-1);
   if (hiWord == 0) {
-    mantissa = Tmp.pVal[0];
+    mantissa = Tmp.U.pVal[0];
     if (n > 52)
       mantissa >>= n - 52; // shift down, we want the top 52 bits.
   } else {
     assert(hiWord > 0 && "huh?");
-    uint64_t hibits = Tmp.pVal[hiWord] << (52 - n % APINT_BITS_PER_WORD);
-    uint64_t lobits = Tmp.pVal[hiWord-1] >> (11 + n % APINT_BITS_PER_WORD);
+    uint64_t hibits = Tmp.U.pVal[hiWord] << (52 - n % APINT_BITS_PER_WORD);
+    uint64_t lobits = Tmp.U.pVal[hiWord-1] >> (11 + n % APINT_BITS_PER_WORD);
     mantissa = hibits | lobits;
   }
 
   // The leading bit of mantissa is implicit, so get rid of it.
   uint64_t sign = isNeg ? (1ULL << (APINT_BITS_PER_WORD - 1)) : 0;
   union {
     double D;
     uint64_t I;
APInt APInt::trunc(unsigned width) const {
   if (width <= APINT_BITS_PER_WORD)
     return APInt(width, getRawData()[0]);
 
   APInt Result(getMemory(getNumWords(width)), width);
 
   // Copy full words.
   unsigned i;
   for (i = 0; i != width / APINT_BITS_PER_WORD; i++)
-    Result.pVal[i] = pVal[i];
+    Result.U.pVal[i] = U.pVal[i];
 
   // Truncate and copy any partial word.
   unsigned bits = (0 - width) % APINT_BITS_PER_WORD;
   if (bits != 0)
-    Result.pVal[i] = pVal[i] << bits >> bits;
+    Result.U.pVal[i] = U.pVal[i] << bits >> bits;
 
   return Result;
 }
 
 // Sign extend to a new width.
 APInt APInt::sext(unsigned Width) const {
   assert(Width > BitWidth && "Invalid APInt SignExtend request");
 
   if (Width <= APINT_BITS_PER_WORD)
-    return APInt(Width, SignExtend64(VAL, BitWidth));
+    return APInt(Width, SignExtend64(U.VAL, BitWidth));
 
   APInt Result(getMemory(getNumWords(Width)), Width);
 
   // Copy words.
-  std::memcpy(Result.pVal, getRawData(), getNumWords() * APINT_WORD_SIZE);
+  std::memcpy(Result.U.pVal, getRawData(), getNumWords() * APINT_WORD_SIZE);
 
   // Sign extend the last word since there may be unused bits in the input.
-  Result.pVal[getNumWords() - 1] =
-      SignExtend64(Result.pVal[getNumWords() - 1],
+  Result.U.pVal[getNumWords() - 1] =
+      SignExtend64(Result.U.pVal[getNumWords() - 1],
                    ((BitWidth - 1) % APINT_BITS_PER_WORD) + 1);
 
   // Fill with sign bits.
-  std::memset(Result.pVal + getNumWords(), isNegative() ? -1 : 0,
+  std::memset(Result.U.pVal + getNumWords(), isNegative() ? -1 : 0,
               (Result.getNumWords() - getNumWords()) * APINT_WORD_SIZE);
   Result.clearUnusedBits();
   return Result;
 }
 
 //  Zero extend to a new width.
 APInt APInt::zext(unsigned width) const {
   assert(width > BitWidth && "Invalid APInt ZeroExtend request");
 
   if (width <= APINT_BITS_PER_WORD)
-    return APInt(width, VAL);
+    return APInt(width, U.VAL);
 
   APInt Result(getMemory(getNumWords(width)), width);
 
   // Copy words.
-  std::memcpy(Result.pVal, getRawData(), getNumWords() * APINT_WORD_SIZE);
+  std::memcpy(Result.U.pVal, getRawData(), getNumWords() * APINT_WORD_SIZE);
 
   // Zero remaining words.
-  std::memset(Result.pVal + getNumWords(), 0,
+  std::memset(Result.U.pVal + getNumWords(), 0,
               (Result.getNumWords() - getNumWords()) * APINT_WORD_SIZE);
 
   return Result;
 }
 
 APInt APInt::zextOrTrunc(unsigned width) const {
   if (BitWidth < width)
     return zext(width);
void APInt::ashrSlowCase(unsigned ShiftAmt) {
 
   // WordShift is the inter-part shift; BitShift is is intra-part shift.
   unsigned WordShift = ShiftAmt / APINT_BITS_PER_WORD;
   unsigned BitShift = ShiftAmt % APINT_BITS_PER_WORD;
 
   unsigned WordsToMove = getNumWords() - WordShift;
   if (WordsToMove != 0) {
     // Sign extend the last word to fill in the unused bits.
-    pVal[getNumWords() - 1] = SignExtend64(
-        pVal[getNumWords() - 1], ((BitWidth - 1) % APINT_BITS_PER_WORD) + 1);
+    U.pVal[getNumWords() - 1] = SignExtend64(
+        U.pVal[getNumWords() - 1], ((BitWidth - 1) % APINT_BITS_PER_WORD) + 1);
 
     // Fastpath for moving by whole words.
     if (BitShift == 0) {
-      std::memmove(pVal, pVal + WordShift, WordsToMove * APINT_WORD_SIZE);
+      std::memmove(U.pVal, U.pVal + WordShift, WordsToMove * APINT_WORD_SIZE);
     } else {
       // Move the words containing significant bits.
       for (unsigned i = 0; i != WordsToMove - 1; ++i)
-        pVal[i] = (pVal[i + WordShift] >> BitShift) |
-                  (pVal[i + WordShift + 1] << (APINT_BITS_PER_WORD - BitShift));
+        U.pVal[i] = (U.pVal[i + WordShift] >> BitShift) |
+                    (U.pVal[i + WordShift + 1] << (APINT_BITS_PER_WORD - BitShift));
 
       // Handle the last word which has no high bits to copy.
-      pVal[WordsToMove - 1] = pVal[WordShift + WordsToMove - 1] >> BitShift;
+      U.pVal[WordsToMove - 1] = U.pVal[WordShift + WordsToMove - 1] >> BitShift;
       // Sign extend one more time.
-      pVal[WordsToMove - 1] =
-          SignExtend64(pVal[WordsToMove - 1], APINT_BITS_PER_WORD - BitShift);
+      U.pVal[WordsToMove - 1] =
+          SignExtend64(U.pVal[WordsToMove - 1], APINT_BITS_PER_WORD - BitShift);
     }
   }
 
   // Fill in the remainder based on the original sign.
-  std::memset(pVal + WordsToMove, Negative ? -1 : 0,
+  std::memset(U.pVal + WordsToMove, Negative ? -1 : 0,
               WordShift * APINT_WORD_SIZE);
   clearUnusedBits();
 }
 
 /// Logical right-shift this APInt by shiftAmt.
 /// @brief Logical right-shift function.
 void APInt::lshrInPlace(const APInt &shiftAmt) {
   lshrInPlace((unsigned)shiftAmt.getLimitedValue(BitWidth));
 }
 
 /// Logical right-shift this APInt by shiftAmt.
 /// @brief Logical right-shift function.
 void APInt::lshrSlowCase(unsigned ShiftAmt) {
-  tcShiftRight(pVal, getNumWords(), ShiftAmt);
+  tcShiftRight(U.pVal, getNumWords(), ShiftAmt);
 }
 
 /// Left-shift this APInt by shiftAmt.
 /// @brief Left-shift function.
 APInt &APInt::operator<<=(const APInt &shiftAmt) {
   // It's undefined behavior in C to shift by BitWidth or greater.
   *this <<= (unsigned)shiftAmt.getLimitedValue(BitWidth);
   return *this;
 }
 
 void APInt::shlSlowCase(unsigned ShiftAmt) {
-  tcShiftLeft(pVal, getNumWords(), ShiftAmt);
+  tcShiftLeft(U.pVal, getNumWords(), ShiftAmt);
   clearUnusedBits();
 }
 
 // Calculate the rotate amount modulo the bit width.
 static unsigned rotateModulo(unsigned BitWidth, const APInt &rotateAmt) {
   unsigned rotBitWidth = rotateAmt.getBitWidth();
   APInt rot = rotateAmt;
   if (rotBitWidth < BitWidth) {
static const uint8_t results[32] = {
       /*     0 */ 0,
       /*  1- 2 */ 1, 1,
       /*  3- 6 */ 2, 2, 2, 2,
       /*  7-12 */ 3, 3, 3, 3, 3, 3,
       /* 13-20 */ 4, 4, 4, 4, 4, 4, 4, 4,
       /* 21-30 */ 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
       /*    31 */ 6
     };
-    return APInt(BitWidth, results[ (isSingleWord() ? VAL : pVal[0]) ]);
+    return APInt(BitWidth, results[ (isSingleWord() ? U.VAL : U.pVal[0]) ]);
   }
 
   // If the magnitude of the value fits in less than 52 bits (the precision of
   // an IEEE double precision floating point value), then we can use the
   // libc sqrt function which will probably use a hardware sqrt computation.
   // This should be faster than the algorithm below.
   if (magnitude < 52) {
     return APInt(BitWidth,
-                 uint64_t(::round(::sqrt(double(isSingleWord()?VAL:pVal[0])))));
+                 uint64_t(::round(::sqrt(double(isSingleWord() ? U.VAL
+                                                               : U.pVal[0])))));
   }
 
   // Okay, all the short cuts are exhausted. We must compute it. The following
   // is a classical Babylonian method for computing the square root. This code
   // was adapted to APInt from a wikipedia article on such computations.
   // See http://www.wikipedia.org/ and go to the page named
   // Calculate_an_integer_square_root.
   unsigned nbits = BitWidth, i = 4;
if ((Remainder?4:3)*n+2*m+1 <= 128) {
     Q = new unsigned[m+n];
     if (Remainder)
       R = new unsigned[n];
   }
 
   // Initialize the dividend
   memset(U, 0, (m+n+1)*sizeof(unsigned));
   for (unsigned i = 0; i < lhsWords; ++i) {
-    uint64_t tmp = (LHS.getNumWords() == 1 ? LHS.VAL : LHS.pVal[i]);
+    uint64_t tmp = (LHS.getNumWords() == 1 ? LHS.U.VAL : LHS.U.pVal[i]);
     U[i * 2] = (unsigned)(tmp & mask);
     U[i * 2 + 1] = (unsigned)(tmp >> (sizeof(unsigned)*CHAR_BIT));
   }
   U[m+n] = 0; // this extra word is for "spill" in the Knuth algorithm.
 
   // Initialize the divisor
   memset(V, 0, (n)*sizeof(unsigned));
   for (unsigned i = 0; i < rhsWords; ++i) {
-    uint64_t tmp = (RHS.getNumWords() == 1 ? RHS.VAL : RHS.pVal[i]);
+    uint64_t tmp = (RHS.getNumWords() == 1 ? RHS.U.VAL : RHS.U.pVal[i]);
     V[i * 2] = (unsigned)(tmp & mask);
     V[i * 2 + 1] = (unsigned)(tmp >> (sizeof(unsigned)*CHAR_BIT));
   }
 
   // initialize the quotient and remainder
   memset(Q, 0, (m+n) * sizeof(unsigned));
   if (Remainder)
     memset(R, 0, n * sizeof(unsigned));
if (n == 1) {
     KnuthDiv(U, V, Q, R, m, n);
   }
 
   // If the caller wants the quotient
   if (Quotient) {
     // Set up the Quotient value's memory.
     if (Quotient->BitWidth != LHS.BitWidth) {
       if (Quotient->isSingleWord())
-        Quotient->VAL = 0;
+        Quotient->U.VAL = 0;
       else
-        delete [] Quotient->pVal;
+        delete [] Quotient->U.pVal;
       Quotient->BitWidth = LHS.BitWidth;
       if (!Quotient->isSingleWord())
-        Quotient->pVal = getClearedMemory(Quotient->getNumWords());
+        Quotient->U.pVal = getClearedMemory(Quotient->getNumWords());
     } else
       Quotient->clearAllBits();
 
     // The quotient is in Q. Reconstitute the quotient into Quotient's low
     // order words.
     // This case is currently dead as all users of divide() handle trivial cases
     // earlier.
     if (lhsWords == 1) {
       uint64_t tmp =
         uint64_t(Q[0]) | (uint64_t(Q[1]) << (APINT_BITS_PER_WORD / 2));
       if (Quotient->isSingleWord())
-        Quotient->VAL = tmp;
+        Quotient->U.VAL = tmp;
       else
-        Quotient->pVal[0] = tmp;
+        Quotient->U.pVal[0] = tmp;
     } else {
       assert(!Quotient->isSingleWord() && "Quotient APInt not large enough");
       for (unsigned i = 0; i < lhsWords; ++i)
-        Quotient->pVal[i] =
+        Quotient->U.pVal[i] =
           uint64_t(Q[i*2]) | (uint64_t(Q[i*2+1]) << (APINT_BITS_PER_WORD / 2));
     }
   }
 
   // If the caller wants the remainder
   if (Remainder) {
     // Set up the Remainder value's memory.
     if (Remainder->BitWidth != RHS.BitWidth) {
       if (Remainder->isSingleWord())
-        Remainder->VAL = 0;
+        Remainder->U.VAL = 0;
       else
-        delete [] Remainder->pVal;
+        delete [] Remainder->U.pVal;
       Remainder->BitWidth = RHS.BitWidth;
       if (!Remainder->isSingleWord())
-        Remainder->pVal = getClearedMemory(Remainder->getNumWords());
+        Remainder->U.pVal = getClearedMemory(Remainder->getNumWords());
     } else
       Remainder->clearAllBits();
 
     // The remainder is in R. Reconstitute the remainder into Remainder's low
     // order words.
     if (rhsWords == 1) {
       uint64_t tmp =
         uint64_t(R[0]) | (uint64_t(R[1]) << (APINT_BITS_PER_WORD / 2));
       if (Remainder->isSingleWord())
-        Remainder->VAL = tmp;
+        Remainder->U.VAL = tmp;
       else
-        Remainder->pVal[0] = tmp;
+        Remainder->U.pVal[0] = tmp;
     } else {
       assert(!Remainder->isSingleWord() && "Remainder APInt not large enough");
       for (unsigned i = 0; i < rhsWords; ++i)
-        Remainder->pVal[i] =
+        Remainder->U.pVal[i] =
           uint64_t(R[i*2]) | (uint64_t(R[i*2+1]) << (APINT_BITS_PER_WORD / 2));
     }
   }
 
   // Clean up the memory we allocated.
   if (U != &SPACE[0]) {
     delete [] U;
     delete [] V;
     delete [] Q;
     delete [] R;
   }
 }
 
 APInt APInt::udiv(const APInt& RHS) const {
   assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
 
   // First, deal with the easy case
   if (isSingleWord()) {
-    assert(RHS.VAL != 0 && "Divide by zero?");
-    return APInt(BitWidth, VAL / RHS.VAL);
+    assert(RHS.U.VAL != 0 && "Divide by zero?");
+    return APInt(BitWidth, U.VAL / RHS.U.VAL);
   }
 
   // Get some facts about the LHS and RHS number of bits and words
   unsigned rhsBits = RHS.getActiveBits();
   unsigned rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1);
   assert(rhsWords && "Divided by zero???");
   unsigned lhsBits = this->getActiveBits();
   unsigned lhsWords = !lhsBits ? 0 : (APInt::whichWord(lhsBits - 1) + 1);
 
   // Deal with some degenerate cases
   if (!lhsWords)
     // 0 / X ===> 0
     return APInt(BitWidth, 0);
   else if (lhsWords < rhsWords || this->ult(RHS)) {
     // X / Y ===> 0, iff X < Y
     return APInt(BitWidth, 0);
   } else if (*this == RHS) {
     // X / X ===> 1
     return APInt(BitWidth, 1);
   } else if (lhsWords == 1 && rhsWords == 1) {
     // All high words are zero, just use native divide
-    return APInt(BitWidth, this->pVal[0] / RHS.pVal[0]);
+    return APInt(BitWidth, this->U.pVal[0] / RHS.U.pVal[0]);
   }
 
   // We have to compute it the hard way. Invoke the Knuth divide algorithm.
   APInt Quotient(1,0); // to hold result.
   divide(*this, lhsWords, RHS, rhsWords, &Quotient, nullptr);
   return Quotient;
 }
 
 APInt APInt::sdiv(const APInt &RHS) const {
   if (isNegative()) {
     if (RHS.isNegative())
       return (-(*this)).udiv(-RHS);
     return -((-(*this)).udiv(RHS));
   }
   if (RHS.isNegative())
     return -(this->udiv(-RHS));
   return this->udiv(RHS);
 }
 
 APInt APInt::urem(const APInt& RHS) const {
   assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
   if (isSingleWord()) {
-    assert(RHS.VAL != 0 && "Remainder by zero?");
-    return APInt(BitWidth, VAL % RHS.VAL);
+    assert(RHS.U.VAL != 0 && "Remainder by zero?");
+    return APInt(BitWidth, U.VAL % RHS.U.VAL);
   }
 
   // Get some facts about the LHS
   unsigned lhsBits = getActiveBits();
   unsigned lhsWords = !lhsBits ? 0 : (whichWord(lhsBits - 1) + 1);
 
   // Get some facts about the RHS
   unsigned rhsBits = RHS.getActiveBits();
   unsigned rhsWords = !rhsBits ? 0 : (APInt::whichWord(rhsBits - 1) + 1);
   assert(rhsWords && "Performing remainder operation by zero ???");
 
   // Check the degenerate cases
   if (lhsWords == 0) {
     // 0 % Y ===> 0
     return APInt(BitWidth, 0);
   } else if (lhsWords < rhsWords || this->ult(RHS)) {
     // X % Y ===> X, iff X < Y
     return *this;
   } else if (*this == RHS) {
     // X % X == 0;
     return APInt(BitWidth, 0);
   } else if (lhsWords == 1) {
     // All high words are zero, just use native remainder
-    return APInt(BitWidth, pVal[0] % RHS.pVal[0]);
+    return APInt(BitWidth, U.pVal[0] % RHS.U.pVal[0]);
   }
 
   // We have to compute it the hard way. Invoke the Knuth divide algorithm.
   APInt Remainder(1,0);
   divide(*this, lhsWords, RHS, rhsWords, nullptr, &Remainder);
   return Remainder;
 }
 

 }
 
 void APInt::udivrem(const APInt &LHS, const APInt &RHS,
                     APInt &Quotient, APInt &Remainder) {
   assert(LHS.BitWidth == RHS.BitWidth && "Bit widths must be the same");
 
   // First, deal with the easy case
   if (LHS.isSingleWord()) {
-    assert(RHS.VAL != 0 && "Divide by zero?");
-    uint64_t QuotVal = LHS.VAL / RHS.VAL;
-    uint64_t RemVal = LHS.VAL % RHS.VAL;
+    assert(RHS.U.VAL != 0 && "Divide by zero?");
+    uint64_t QuotVal = LHS.U.VAL / RHS.U.VAL;
+    uint64_t RemVal = LHS.U.VAL % RHS.U.VAL;
     Quotient = APInt(LHS.BitWidth, QuotVal);
     Remainder = APInt(LHS.BitWidth, RemVal);
     return;
   }
 
   // Get some size facts about the dividend and divisor
   unsigned lhsBits  = LHS.getActiveBits();
   unsigned lhsWords = !lhsBits ? 0 : (APInt::whichWord(lhsBits - 1) + 1);
void APInt::udivrem(const APInt &LHS, const APInt &RHS,
   if (LHS == RHS) {
     Quotient  = 1;              // X / X ===> 1
     Remainder = 0;              // X % X ===> 0;
     return;
   }
 
   if (lhsWords == 1 && rhsWords == 1) {
     // There is only one word to consider so use the native versions.
-    uint64_t lhsValue = LHS.isSingleWord() ? LHS.VAL : LHS.pVal[0];
-    uint64_t rhsValue = RHS.isSingleWord() ? RHS.VAL : RHS.pVal[0];
+    uint64_t lhsValue = LHS.isSingleWord() ? LHS.U.VAL : LHS.U.pVal[0];
+    uint64_t rhsValue = RHS.isSingleWord() ? RHS.U.VAL : RHS.U.pVal[0];
     Quotient = APInt(LHS.getBitWidth(), lhsValue / rhsValue);
     Remainder = APInt(LHS.getBitWidth(), lhsValue % rhsValue);
     return;
   }
 
   // Okay, lets do it the long way
   divide(LHS, lhsWords, RHS, rhsWords, &Quotient, &Remainder);
 }
if (*p == '-' || *p == '+') {
     assert(slen && "String is only a sign, needs a value.");
   }
   assert((slen <= numbits || radix != 2) && "Insufficient bit width");
   assert(((slen-1)*3 <= numbits || radix != 8) && "Insufficient bit width");
   assert(((slen-1)*4 <= numbits || radix != 16) && "Insufficient bit width");
   assert((((slen-1)*64)/22 <= numbits || radix != 10) &&
          "Insufficient bit width");
 
-  // Allocate memory
-  if (!isSingleWord())
-    pVal = getClearedMemory(getNumWords());
+  // Allocate memory if needed
+  if (isSingleWord())
+    U.VAL = 0;
+  else
+    U.pVal = getClearedMemory(getNumWords());
 
   // Figure out if we can shift instead of multiply
   unsigned shift = (radix == 16 ? 4 : radix == 8 ? 3 : radix == 2 ? 1 : 0);
 
   // Set up an APInt for the radix multiplier outside the loop so we don't
   // constantly construct/destruct it.
   APInt apradix(getBitWidth(), radix);