Merge commit '10251753b6897adcd22cc981c0cc42f348c109de' into merge-20130807

Conflicts:
	lib/Archive/ArchiveReader.cpp
	lib/Support/Unix/PathV2.inc

Change-Id: I29d8c1e321a4a380b6013f00bac6a8e4b593cc4e

1 files changed, 234 insertions, 176 deletions

diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 2ad66c5..34bc6b6 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -25,7 +25,13 @@
 
 using namespace llvm;
 
-#define convolve(lhs, rhs) ((lhs) * 4 + (rhs))
+/// A macro used to combine two fcCategory enums into one key which can be used
+/// in a switch statement to classify how the interaction of two APFloat's
+/// categories affects an operation.
+///
+/// TODO: If clang source code is ever allowed to use constexpr in its own
+/// codebase, change this into a static inline function.
+#define PackCategoriesIntoKey(_lhs, _rhs) ((_lhs) * 4 + (_rhs))
 
 /* Assumed in hexadecimal significand parsing, and conversion to
    hexadecimal strings.  */
@@ -38,11 +44,11 @@ namespace llvm {
   struct fltSemantics {
     /* The largest E such that 2^E is representable; this matches the
        definition of IEEE 754.  */
-    exponent_t maxExponent;
+    APFloat::ExponentType maxExponent;
 
     /* The smallest E such that 2^E is a normalized number; this
        matches the definition of IEEE 754.  */
-    exponent_t minExponent;
+    APFloat::ExponentType minExponent;
 
     /* Number of bits in the significand.  This includes the integer
        bit.  */
@@ -288,9 +294,9 @@ interpretDecimal(StringRef::iterator begin, StringRef::iterator end,
     }
 
     /* Adjust the exponents for any decimal point.  */
-    D->exponent += static_cast<exponent_t>((dot - p) - (dot > p));
+    D->exponent += static_cast<APFloat::ExponentType>((dot - p) - (dot > p));
     D->normalizedExponent = (D->exponent +
-              static_cast<exponent_t>((p - D->firstSigDigit)
+              static_cast<APFloat::ExponentType>((p - D->firstSigDigit)
                                       - (dot > D->firstSigDigit && dot < p)));
   }
 
@@ -313,8 +319,8 @@ trailingHexadecimalFraction(StringRef::iterator p, StringRef::iterator end,
   else if (digitValue < 8 && digitValue > 0)
     return lfLessThanHalf;
 
-  /* Otherwise we need to find the first non-zero digit.  */
-  while (*p == '0')
+  // Otherwise we need to find the first non-zero digit.
+  while (p != end && (*p == '0' || *p == '.'))
     p++;
 
   assert(p != end && "Invalid trailing hexadecimal fraction!");
@@ -592,14 +598,14 @@ APFloat::assign(const APFloat &rhs)
   sign = rhs.sign;
   category = rhs.category;
   exponent = rhs.exponent;
-  if (category == fcNormal || category == fcNaN)
+  if (isFiniteNonZero() || category == fcNaN)
     copySignificand(rhs);
 }
 
 void
 APFloat::copySignificand(const APFloat &rhs)
 {
-  assert(category == fcNormal || category == fcNaN);
+  assert(isFiniteNonZero() || category == fcNaN);
   assert(rhs.partCount() >= partCount());
 
   APInt::tcAssign(significandParts(), rhs.significandParts(),
@@ -679,7 +685,7 @@ APFloat::operator=(const APFloat &rhs)
 
 bool
 APFloat::isDenormal() const {
-  return isNormal() && (exponent == semantics->minExponent) &&
+  return isFiniteNonZero() && (exponent == semantics->minExponent) &&
          (APInt::tcExtractBit(significandParts(), 
                               semantics->precision - 1) == 0);
 }
@@ -687,9 +693,9 @@ APFloat::isDenormal() const {
 bool
 APFloat::isSmallest() const {
   // The smallest number by magnitude in our format will be the smallest
-  // denormal, i.e. the floating point normal with exponent being minimum
+  // denormal, i.e. the floating point number with exponent being minimum
   // exponent and significand bitwise equal to 1 (i.e. with MSB equal to 0).
-  return isNormal() && exponent == semantics->minExponent &&
+  return isFiniteNonZero() && exponent == semantics->minExponent &&
     significandMSB() == 0;
 }
 
@@ -741,7 +747,7 @@ bool
 APFloat::isLargest() const {
   // The largest number by magnitude in our format will be the floating point
   // number with maximum exponent and with significand that is all ones.
-  return isNormal() && exponent == semantics->maxExponent
+  return isFiniteNonZero() && exponent == semantics->maxExponent
     && isSignificandAllOnes();
 }
 
@@ -755,7 +761,7 @@ APFloat::bitwiseIsEqual(const APFloat &rhs) const {
     return false;
   if (category==fcZero || category==fcInfinity)
     return true;
-  else if (category==fcNormal && exponent!=rhs.exponent)
+  else if (isFiniteNonZero() && exponent!=rhs.exponent)
     return false;
   else {
     int i= partCount();
@@ -772,6 +778,7 @@ APFloat::bitwiseIsEqual(const APFloat &rhs) const {
 APFloat::APFloat(const fltSemantics &ourSemantics, integerPart value) {
   initialize(&ourSemantics);
   sign = 0;
+  category = fcNormal;
   zeroSignificand();
   exponent = ourSemantics.precision - 1;
   significandParts()[0] = value;
@@ -789,17 +796,6 @@ APFloat::APFloat(const fltSemantics &ourSemantics, uninitializedTag tag) {
   initialize(&ourSemantics);
 }
 
-APFloat::APFloat(const fltSemantics &ourSemantics,
-                 fltCategory ourCategory, bool negative) {
-  initialize(&ourSemantics);
-  category = ourCategory;
-  sign = negative;
-  if (category == fcNormal)
-    category = fcZero;
-  else if (ourCategory == fcNaN)
-    makeNaN();
-}
-
 APFloat::APFloat(const fltSemantics &ourSemantics, StringRef text) {
   initialize(&ourSemantics);
   convertFromString(text, rmNearestTiesToEven);
@@ -841,8 +837,6 @@ APFloat::significandParts() const
 integerPart *
 APFloat::significandParts()
 {
-  assert(category == fcNormal || category == fcNaN);
-
   if (partCount() > 1)
     return significand.parts;
   else
@@ -852,7 +846,6 @@ APFloat::significandParts()
 void
 APFloat::zeroSignificand()
 {
-  category = fcNormal;
   APInt::tcSet(significandParts(), 0, partCount());
 }
 
@@ -1121,7 +1114,7 @@ lostFraction
 APFloat::shiftSignificandRight(unsigned int bits)
 {
   /* Our exponent should not overflow.  */
-  assert((exponent_t) (exponent + bits) >= exponent);
+  assert((ExponentType) (exponent + bits) >= exponent);
 
   exponent += bits;
 
@@ -1150,8 +1143,8 @@ APFloat::compareAbsoluteValue(const APFloat &rhs) const
   int compare;
 
   assert(semantics == rhs.semantics);
-  assert(category == fcNormal);
-  assert(rhs.category == fcNormal);
+  assert(isFiniteNonZero());
+  assert(rhs.isFiniteNonZero());
 
   compare = exponent - rhs.exponent;
 
@@ -1203,7 +1196,7 @@ APFloat::roundAwayFromZero(roundingMode rounding_mode,
                            unsigned int bit) const
 {
   /* NaNs and infinities should not have lost fractions.  */
-  assert(category == fcNormal || category == fcZero);
+  assert(isFiniteNonZero() || category == fcZero);
 
   /* Current callers never pass this so we don't handle it.  */
   assert(lost_fraction != lfExactlyZero);
@@ -1241,7 +1234,7 @@ APFloat::normalize(roundingMode rounding_mode,
   unsigned int omsb;                /* One, not zero, based MSB.  */
   int exponentChange;
 
-  if (category != fcNormal)
+  if (!isFiniteNonZero())
     return opOK;
 
   /* Before rounding normalize the exponent of fcNormal numbers.  */
@@ -1345,42 +1338,43 @@ APFloat::normalize(roundingMode rounding_mode,
 APFloat::opStatus
 APFloat::addOrSubtractSpecials(const APFloat &rhs, bool subtract)
 {
-  switch (convolve(category, rhs.category)) {
+  switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
     llvm_unreachable(0);
 
-  case convolve(fcNaN, fcZero):
-  case convolve(fcNaN, fcNormal):
-  case convolve(fcNaN, fcInfinity):
-  case convolve(fcNaN, fcNaN):
-  case convolve(fcNormal, fcZero):
-  case convolve(fcInfinity, fcNormal):
-  case convolve(fcInfinity, fcZero):
+  case PackCategoriesIntoKey(fcNaN, fcZero):
+  case PackCategoriesIntoKey(fcNaN, fcNormal):
+  case PackCategoriesIntoKey(fcNaN, fcInfinity):
+  case PackCategoriesIntoKey(fcNaN, fcNaN):
+  case PackCategoriesIntoKey(fcNormal, fcZero):
+  case PackCategoriesIntoKey(fcInfinity, fcNormal):
+  case PackCategoriesIntoKey(fcInfinity, fcZero):
     return opOK;
 
-  case convolve(fcZero, fcNaN):
-  case convolve(fcNormal, fcNaN):
-  case convolve(fcInfinity, fcNaN):
+  case PackCategoriesIntoKey(fcZero, fcNaN):
+  case PackCategoriesIntoKey(fcNormal, fcNaN):
+  case PackCategoriesIntoKey(fcInfinity, fcNaN):
+    sign = false;
     category = fcNaN;
     copySignificand(rhs);
     return opOK;
 
-  case convolve(fcNormal, fcInfinity):
-  case convolve(fcZero, fcInfinity):
+  case PackCategoriesIntoKey(fcNormal, fcInfinity):
+  case PackCategoriesIntoKey(fcZero, fcInfinity):
     category = fcInfinity;
     sign = rhs.sign ^ subtract;
     return opOK;
 
-  case convolve(fcZero, fcNormal):
+  case PackCategoriesIntoKey(fcZero, fcNormal):
     assign(rhs);
     sign = rhs.sign ^ subtract;
     return opOK;
 
-  case convolve(fcZero, fcZero):
+  case PackCategoriesIntoKey(fcZero, fcZero):
     /* Sign depends on rounding mode; handled by caller.  */
     return opOK;
 
-  case convolve(fcInfinity, fcInfinity):
+  case PackCategoriesIntoKey(fcInfinity, fcInfinity):
     /* Differently signed infinities can only be validly
        subtracted.  */
     if (((sign ^ rhs.sign)!=0) != subtract) {
@@ -1390,7 +1384,7 @@ APFloat::addOrSubtractSpecials(const APFloat &rhs, bool subtract)
 
     return opOK;
 
-  case convolve(fcNormal, fcNormal):
+  case PackCategoriesIntoKey(fcNormal, fcNormal):
     return opDivByZero;
   }
 }
@@ -1471,41 +1465,43 @@ APFloat::addOrSubtractSignificand(const APFloat &rhs, bool subtract)
 APFloat::opStatus
 APFloat::multiplySpecials(const APFloat &rhs)
 {
-  switch (convolve(category, rhs.category)) {
+  switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
     llvm_unreachable(0);
 
-  case convolve(fcNaN, fcZero):
-  case convolve(fcNaN, fcNormal):
-  case convolve(fcNaN, fcInfinity):
-  case convolve(fcNaN, fcNaN):
+  case PackCategoriesIntoKey(fcNaN, fcZero):
+  case PackCategoriesIntoKey(fcNaN, fcNormal):
+  case PackCategoriesIntoKey(fcNaN, fcInfinity):
+  case PackCategoriesIntoKey(fcNaN, fcNaN):
+    sign = false;
     return opOK;
 
-  case convolve(fcZero, fcNaN):
-  case convolve(fcNormal, fcNaN):
-  case convolve(fcInfinity, fcNaN):
+  case PackCategoriesIntoKey(fcZero, fcNaN):
+  case PackCategoriesIntoKey(fcNormal, fcNaN):
+  case PackCategoriesIntoKey(fcInfinity, fcNaN):
+    sign = false;
     category = fcNaN;
     copySignificand(rhs);
     return opOK;
 
-  case convolve(fcNormal, fcInfinity):
-  case convolve(fcInfinity, fcNormal):
-  case convolve(fcInfinity, fcInfinity):
+  case PackCategoriesIntoKey(fcNormal, fcInfinity):
+  case PackCategoriesIntoKey(fcInfinity, fcNormal):
+  case PackCategoriesIntoKey(fcInfinity, fcInfinity):
     category = fcInfinity;
     return opOK;
 
-  case convolve(fcZero, fcNormal):
-  case convolve(fcNormal, fcZero):
-  case convolve(fcZero, fcZero):
+  case PackCategoriesIntoKey(fcZero, fcNormal):
+  case PackCategoriesIntoKey(fcNormal, fcZero):
+  case PackCategoriesIntoKey(fcZero, fcZero):
     category = fcZero;
     return opOK;
 
-  case convolve(fcZero, fcInfinity):
-  case convolve(fcInfinity, fcZero):
+  case PackCategoriesIntoKey(fcZero, fcInfinity):
+  case PackCategoriesIntoKey(fcInfinity, fcZero):
     makeNaN();
     return opInvalidOp;
 
-  case convolve(fcNormal, fcNormal):
+  case PackCategoriesIntoKey(fcNormal, fcNormal):
     return opOK;
   }
 }
@@ -1513,41 +1509,40 @@ APFloat::multiplySpecials(const APFloat &rhs)
 APFloat::opStatus
 APFloat::divideSpecials(const APFloat &rhs)
 {
-  switch (convolve(category, rhs.category)) {
+  switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
     llvm_unreachable(0);
 
-  case convolve(fcNaN, fcZero):
-  case convolve(fcNaN, fcNormal):
-  case convolve(fcNaN, fcInfinity):
-  case convolve(fcNaN, fcNaN):
-  case convolve(fcInfinity, fcZero):
-  case convolve(fcInfinity, fcNormal):
-  case convolve(fcZero, fcInfinity):
-  case convolve(fcZero, fcNormal):
-    return opOK;
-
-  case convolve(fcZero, fcNaN):
-  case convolve(fcNormal, fcNaN):
-  case convolve(fcInfinity, fcNaN):
+  case PackCategoriesIntoKey(fcZero, fcNaN):
+  case PackCategoriesIntoKey(fcNormal, fcNaN):
+  case PackCategoriesIntoKey(fcInfinity, fcNaN):
     category = fcNaN;
     copySignificand(rhs);
+  case PackCategoriesIntoKey(fcNaN, fcZero):
+  case PackCategoriesIntoKey(fcNaN, fcNormal):
+  case PackCategoriesIntoKey(fcNaN, fcInfinity):
+  case PackCategoriesIntoKey(fcNaN, fcNaN):
+    sign = false;
+  case PackCategoriesIntoKey(fcInfinity, fcZero):
+  case PackCategoriesIntoKey(fcInfinity, fcNormal):
+  case PackCategoriesIntoKey(fcZero, fcInfinity):
+  case PackCategoriesIntoKey(fcZero, fcNormal):
     return opOK;
 
-  case convolve(fcNormal, fcInfinity):
+  case PackCategoriesIntoKey(fcNormal, fcInfinity):
     category = fcZero;
     return opOK;
 
-  case convolve(fcNormal, fcZero):
+  case PackCategoriesIntoKey(fcNormal, fcZero):
     category = fcInfinity;
     return opDivByZero;
 
-  case convolve(fcInfinity, fcInfinity):
-  case convolve(fcZero, fcZero):
+  case PackCategoriesIntoKey(fcInfinity, fcInfinity):
+  case PackCategoriesIntoKey(fcZero, fcZero):
     makeNaN();
     return opInvalidOp;
 
-  case convolve(fcNormal, fcNormal):
+  case PackCategoriesIntoKey(fcNormal, fcNormal):
     return opOK;
   }
 }
@@ -1555,35 +1550,36 @@ APFloat::divideSpecials(const APFloat &rhs)
 APFloat::opStatus
 APFloat::modSpecials(const APFloat &rhs)
 {
-  switch (convolve(category, rhs.category)) {
+  switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
     llvm_unreachable(0);
 
-  case convolve(fcNaN, fcZero):
-  case convolve(fcNaN, fcNormal):
-  case convolve(fcNaN, fcInfinity):
-  case convolve(fcNaN, fcNaN):
-  case convolve(fcZero, fcInfinity):
-  case convolve(fcZero, fcNormal):
-  case convolve(fcNormal, fcInfinity):
+  case PackCategoriesIntoKey(fcNaN, fcZero):
+  case PackCategoriesIntoKey(fcNaN, fcNormal):
+  case PackCategoriesIntoKey(fcNaN, fcInfinity):
+  case PackCategoriesIntoKey(fcNaN, fcNaN):
+  case PackCategoriesIntoKey(fcZero, fcInfinity):
+  case PackCategoriesIntoKey(fcZero, fcNormal):
+  case PackCategoriesIntoKey(fcNormal, fcInfinity):
     return opOK;
 
-  case convolve(fcZero, fcNaN):
-  case convolve(fcNormal, fcNaN):
-  case convolve(fcInfinity, fcNaN):
+  case PackCategoriesIntoKey(fcZero, fcNaN):
+  case PackCategoriesIntoKey(fcNormal, fcNaN):
+  case PackCategoriesIntoKey(fcInfinity, fcNaN):
+    sign = false;
     category = fcNaN;
     copySignificand(rhs);
     return opOK;
 
-  case convolve(fcNormal, fcZero):
-  case convolve(fcInfinity, fcZero):
-  case convolve(fcInfinity, fcNormal):
-  case convolve(fcInfinity, fcInfinity):
-  case convolve(fcZero, fcZero):
+  case PackCategoriesIntoKey(fcNormal, fcZero):
+  case PackCategoriesIntoKey(fcInfinity, fcZero):
+  case PackCategoriesIntoKey(fcInfinity, fcNormal):
+  case PackCategoriesIntoKey(fcInfinity, fcInfinity):
+  case PackCategoriesIntoKey(fcZero, fcZero):
     makeNaN();
     return opInvalidOp;
 
-  case convolve(fcNormal, fcNormal):
+  case PackCategoriesIntoKey(fcNormal, fcNormal):
     return opOK;
   }
 }
@@ -1664,7 +1660,7 @@ APFloat::multiply(const APFloat &rhs, roundingMode rounding_mode)
   sign ^= rhs.sign;
   fs = multiplySpecials(rhs);
 
-  if (category == fcNormal) {
+  if (isFiniteNonZero()) {
     lostFraction lost_fraction = multiplySignificand(rhs, 0);
     fs = normalize(rounding_mode, lost_fraction);
     if (lost_fraction != lfExactlyZero)
@@ -1683,7 +1679,7 @@ APFloat::divide(const APFloat &rhs, roundingMode rounding_mode)
   sign ^= rhs.sign;
   fs = divideSpecials(rhs);
 
-  if (category == fcNormal) {
+  if (isFiniteNonZero()) {
     lostFraction lost_fraction = divideSignificand(rhs);
     fs = normalize(rounding_mode, lost_fraction);
     if (lost_fraction != lfExactlyZero)
@@ -1737,7 +1733,7 @@ APFloat::mod(const APFloat &rhs, roundingMode rounding_mode)
   opStatus fs;
   fs = modSpecials(rhs);
 
-  if (category == fcNormal && rhs.category == fcNormal) {
+  if (isFiniteNonZero() && rhs.isFiniteNonZero()) {
     APFloat V = *this;
     unsigned int origSign = sign;
 
@@ -1783,9 +1779,9 @@ APFloat::fusedMultiplyAdd(const APFloat &multiplicand,
 
   /* If and only if all arguments are normal do we need to do an
      extended-precision calculation.  */
-  if (category == fcNormal &&
-      multiplicand.category == fcNormal &&
-      addend.category == fcNormal) {
+  if (isFiniteNonZero() &&
+      multiplicand.isFiniteNonZero() &&
+      addend.isFiniteNonZero()) {
     lostFraction lost_fraction;
 
     lost_fraction = multiplySignificand(multiplicand, &addend);
@@ -1822,7 +1818,7 @@ APFloat::opStatus APFloat::roundToIntegral(roundingMode rounding_mode) {
   // If the exponent is large enough, we know that this value is already
   // integral, and the arithmetic below would potentially cause it to saturate
   // to +/-Inf.  Bail out early instead.
-  if (category == fcNormal && exponent+1 >= (int)semanticsPrecision(*semantics))
+  if (isFiniteNonZero() && exponent+1 >= (int)semanticsPrecision(*semantics))
     return opOK;
 
   // The algorithm here is quite simple: we add 2^(p-1), where p is the
@@ -1866,36 +1862,36 @@ APFloat::compare(const APFloat &rhs) const
 
   assert(semantics == rhs.semantics);
 
-  switch (convolve(category, rhs.category)) {
+  switch (PackCategoriesIntoKey(category, rhs.category)) {
   default:
     llvm_unreachable(0);
 
-  case convolve(fcNaN, fcZero):
-  case convolve(fcNaN, fcNormal):
-  case convolve(fcNaN, fcInfinity):
-  case convolve(fcNaN, fcNaN):
-  case convolve(fcZero, fcNaN):
-  case convolve(fcNormal, fcNaN):
-  case convolve(fcInfinity, fcNaN):
+  case PackCategoriesIntoKey(fcNaN, fcZero):
+  case PackCategoriesIntoKey(fcNaN, fcNormal):
+  case PackCategoriesIntoKey(fcNaN, fcInfinity):
+  case PackCategoriesIntoKey(fcNaN, fcNaN):
+  case PackCategoriesIntoKey(fcZero, fcNaN):
+  case PackCategoriesIntoKey(fcNormal, fcNaN):
+  case PackCategoriesIntoKey(fcInfinity, fcNaN):
     return cmpUnordered;
 
-  case convolve(fcInfinity, fcNormal):
-  case convolve(fcInfinity, fcZero):
-  case convolve(fcNormal, fcZero):
+  case PackCategoriesIntoKey(fcInfinity, fcNormal):
+  case PackCategoriesIntoKey(fcInfinity, fcZero):
+  case PackCategoriesIntoKey(fcNormal, fcZero):
     if (sign)
       return cmpLessThan;
     else
       return cmpGreaterThan;
 
-  case convolve(fcNormal, fcInfinity):
-  case convolve(fcZero, fcInfinity):
-  case convolve(fcZero, fcNormal):
+  case PackCategoriesIntoKey(fcNormal, fcInfinity):
+  case PackCategoriesIntoKey(fcZero, fcInfinity):
+  case PackCategoriesIntoKey(fcZero, fcNormal):
     if (rhs.sign)
       return cmpGreaterThan;
     else
       return cmpLessThan;
 
-  case convolve(fcInfinity, fcInfinity):
+  case PackCategoriesIntoKey(fcInfinity, fcInfinity):
     if (sign == rhs.sign)
       return cmpEqual;
     else if (sign)
@@ -1903,10 +1899,10 @@ APFloat::compare(const APFloat &rhs) const
     else
       return cmpGreaterThan;
 
-  case convolve(fcZero, fcZero):
+  case PackCategoriesIntoKey(fcZero, fcZero):
     return cmpEqual;
 
-  case convolve(fcNormal, fcNormal):
+  case PackCategoriesIntoKey(fcNormal, fcNormal):
     break;
   }
 
@@ -1963,8 +1959,25 @@ APFloat::convert(const fltSemantics &toSemantics,
     X86SpecialNan = true;
   }
 
+  // If this is a truncation of a denormal number, and the target semantics
+  // has larger exponent range than the source semantics (this can happen
+  // when truncating from PowerPC double-double to double format), the
+  // right shift could lose result mantissa bits.  Adjust exponent instead
+  // of performing excessive shift.
+  if (shift < 0 && isFiniteNonZero()) {
+    int exponentChange = significandMSB() + 1 - fromSemantics.precision;
+    if (exponent + exponentChange < toSemantics.minExponent)
+      exponentChange = toSemantics.minExponent - exponent;
+    if (exponentChange < shift)
+      exponentChange = shift;
+    if (exponentChange < 0) {
+      shift -= exponentChange;
+      exponent += exponentChange;
+    }
+  }
+
   // If this is a truncation, perform the shift before we narrow the storage.
-  if (shift < 0 && (category==fcNormal || category==fcNaN))
+  if (shift < 0 && (isFiniteNonZero() || category==fcNaN))
     lostFraction = shiftRight(significandParts(), oldPartCount, -shift);
 
   // Fix the storage so it can hold to new value.
@@ -1973,14 +1986,14 @@ APFloat::convert(const fltSemantics &toSemantics,
     integerPart *newParts;
     newParts = new integerPart[newPartCount];
     APInt::tcSet(newParts, 0, newPartCount);
-    if (category==fcNormal || category==fcNaN)
+    if (isFiniteNonZero() || category==fcNaN)
       APInt::tcAssign(newParts, significandParts(), oldPartCount);
     freeSignificand();
     significand.parts = newParts;
   } else if (newPartCount == 1 && oldPartCount != 1) {
     // Switch to built-in storage for a single part.
     integerPart newPart = 0;
-    if (category==fcNormal || category==fcNaN)
+    if (isFiniteNonZero() || category==fcNaN)
       newPart = significandParts()[0];
     freeSignificand();
     significand.part = newPart;
@@ -1991,10 +2004,10 @@ APFloat::convert(const fltSemantics &toSemantics,
 
   // If this is an extension, perform the shift now that the storage is
   // available.
-  if (shift > 0 && (category==fcNormal || category==fcNaN))
+  if (shift > 0 && (isFiniteNonZero() || category==fcNaN))
     APInt::tcShiftLeft(significandParts(), newPartCount, shift);
 
-  if (category == fcNormal) {
+  if (isFiniteNonZero()) {
     fs = normalize(rounding_mode, lostFraction);
     *losesInfo = (fs != opOK);
   } else if (category == fcNaN) {
@@ -2290,56 +2303,46 @@ APFloat::opStatus
 APFloat::convertFromHexadecimalString(StringRef s, roundingMode rounding_mode)
 {
   lostFraction lost_fraction = lfExactlyZero;
-  integerPart *significand;
-  unsigned int bitPos, partsCount;
-  StringRef::iterator dot, firstSignificantDigit;
 
+  category = fcNormal;
   zeroSignificand();
   exponent = 0;
-  category = fcNormal;
 
-  significand = significandParts();
-  partsCount = partCount();
-  bitPos = partsCount * integerPartWidth;
+  integerPart *significand = significandParts();
+  unsigned partsCount = partCount();
+  unsigned bitPos = partsCount * integerPartWidth;
+  bool computedTrailingFraction = false;
 
-  /* Skip leading zeroes and any (hexa)decimal point.  */
+  // Skip leading zeroes and any (hexa)decimal point.
   StringRef::iterator begin = s.begin();
   StringRef::iterator end = s.end();
+  StringRef::iterator dot;
   StringRef::iterator p = skipLeadingZeroesAndAnyDot(begin, end, &dot);
-  firstSignificantDigit = p;
+  StringRef::iterator firstSignificantDigit = p;
 
-  for (; p != end;) {
+  while (p != end) {
     integerPart hex_value;
 
     if (*p == '.') {
       assert(dot == end && "String contains multiple dots");
       dot = p++;
-      if (p == end) {
-        break;
-      }
+      continue;
     }
 
     hex_value = hexDigitValue(*p);
-    if (hex_value == -1U) {
+    if (hex_value == -1U)
       break;
-    }
 
     p++;
 
-    if (p == end) {
-      break;
-    } else {
-      /* Store the number whilst 4-bit nibbles remain.  */
-      if (bitPos) {
-        bitPos -= 4;
-        hex_value <<= bitPos % integerPartWidth;
-        significand[bitPos / integerPartWidth] |= hex_value;
-      } else {
-        lost_fraction = trailingHexadecimalFraction(p, end, hex_value);
-        while (p != end && hexDigitValue(*p) != -1U)
-          p++;
-        break;
-      }
+    // Store the number while we have space.
+    if (bitPos) {
+      bitPos -= 4;
+      hex_value <<= bitPos % integerPartWidth;
+      significand[bitPos / integerPartWidth] |= hex_value;
+    } else if (!computedTrailingFraction) {
+      lost_fraction = trailingHexadecimalFraction(p, end, hex_value);
+      computedTrailingFraction = true;
     }
   }
 
@@ -2402,8 +2405,8 @@ APFloat::roundSignificandWithExponent(const integerPart *decSigParts,
     excessPrecision = calcSemantics.precision - semantics->precision;
     truncatedBits = excessPrecision;
 
-    APFloat decSig(calcSemantics, fcZero, sign);
-    APFloat pow5(calcSemantics, fcZero, false);
+    APFloat decSig = APFloat::getZero(calcSemantics, sign);
+    APFloat pow5(calcSemantics);
 
     sigStatus = decSig.convertFromUnsignedParts(decSigParts, sigPartCount,
                                                 rmNearestTiesToEven);
@@ -2488,7 +2491,14 @@ APFloat::convertFromDecimalString(StringRef str, roundingMode rounding_mode)
            42039/12655 < L < 28738/8651  [ numerator <= 65536 ]
   */
 
-  if (decDigitValue(*D.firstSigDigit) >= 10U) {
+  // Test if we have a zero number allowing for strings with no null terminators
+  // and zero decimals with non-zero exponents.
+  // 
+  // We computed firstSigDigit by ignoring all zeros and dots. Thus if
+  // D->firstSigDigit equals str.end(), every digit must be a zero and there can
+  // be at most one dot. On the other hand, if we have a zero with a non-zero
+  // exponent, then we know that D.firstSigDigit will be non-numeric.
+  if (D.firstSigDigit == str.end() || decDigitValue(*D.firstSigDigit) >= 10U) {
     category = fcZero;
     fs = opOK;
 
@@ -2505,6 +2515,7 @@ APFloat::convertFromDecimalString(StringRef str, roundingMode rounding_mode)
              (D.normalizedExponent + 1) * 28738 <=
                8651 * (semantics->minExponent - (int) semantics->precision)) {
     /* Underflow to zero and round.  */
+    category = fcNormal;
     zeroSignificand();
     fs = normalize(rounding_mode, lfLessThanHalf);
 
@@ -2571,11 +2582,40 @@ APFloat::convertFromDecimalString(StringRef str, roundingMode rounding_mode)
   return fs;
 }
 
+bool
+APFloat::convertFromStringSpecials(StringRef str) {
+  if (str.equals("inf") || str.equals("INFINITY")) {
+    makeInf(false);
+    return true;
+  }
+
+  if (str.equals("-inf") || str.equals("-INFINITY")) {
+    makeInf(true);
+    return true;
+  }
+
+  if (str.equals("nan") || str.equals("NaN")) {
+    makeNaN(false, false);
+    return true;
+  }
+
+  if (str.equals("-nan") || str.equals("-NaN")) {
+    makeNaN(false, true);
+    return true;
+  }
+
+  return false;
+}
+
 APFloat::opStatus
 APFloat::convertFromString(StringRef str, roundingMode rounding_mode)
 {
   assert(!str.empty() && "Invalid string length");
 
+  // Handle special cases.
+  if (convertFromStringSpecials(str))
+    return opOK;
+
   /* Handle a leading minus sign.  */
   StringRef::iterator p = str.begin();
   size_t slen = str.size();
@@ -2772,7 +2812,7 @@ APFloat::convertNormalToHexString(char *dst, unsigned int hexDigits,
 }
 
 hash_code llvm::hash_value(const APFloat &Arg) {
-  if (Arg.category != APFloat::fcNormal)
+  if (!Arg.isFiniteNonZero())
     return hash_combine((uint8_t)Arg.category,
                         // NaN has no sign, fix it at zero.
                         Arg.isNaN() ? (uint8_t)0 : (uint8_t)Arg.sign,
@@ -2803,7 +2843,7 @@ APFloat::convertF80LongDoubleAPFloatToAPInt() const
 
   uint64_t myexponent, mysignificand;
 
-  if (category==fcNormal) {
+  if (isFiniteNonZero()) {
     myexponent = exponent+16383; //bias
     mysignificand = significandParts()[0];
     if (myexponent==1 && !(mysignificand & 0x8000000000000000ULL))
@@ -2860,7 +2900,7 @@ APFloat::convertPPCDoubleDoubleAPFloatToAPInt() const
   // just set the second double to zero.  Otherwise, re-convert back to
   // the extended format and compute the difference.  This now should
   // convert exactly to double.
-  if (u.category == fcNormal && losesInfo) {
+  if (u.isFiniteNonZero() && losesInfo) {
     fs = u.convert(extendedSemantics, rmNearestTiesToEven, &losesInfo);
     assert(fs == opOK && !losesInfo);
     (void)fs;
@@ -2886,7 +2926,7 @@ APFloat::convertQuadrupleAPFloatToAPInt() const
 
   uint64_t myexponent, mysignificand, mysignificand2;
 
-  if (category==fcNormal) {
+  if (isFiniteNonZero()) {
     myexponent = exponent+16383; //bias
     mysignificand = significandParts()[0];
     mysignificand2 = significandParts()[1];
@@ -2922,7 +2962,7 @@ APFloat::convertDoubleAPFloatToAPInt() const
 
   uint64_t myexponent, mysignificand;
 
-  if (category==fcNormal) {
+  if (isFiniteNonZero()) {
     myexponent = exponent+1023; //bias
     mysignificand = *significandParts();
     if (myexponent==1 && !(mysignificand & 0x10000000000000LL))
@@ -2952,7 +2992,7 @@ APFloat::convertFloatAPFloatToAPInt() const
 
   uint32_t myexponent, mysignificand;
 
-  if (category==fcNormal) {
+  if (isFiniteNonZero()) {
     myexponent = exponent+127; //bias
     mysignificand = (uint32_t)*significandParts();
     if (myexponent == 1 && !(mysignificand & 0x800000))
@@ -2981,7 +3021,7 @@ APFloat::convertHalfAPFloatToAPInt() const
 
   uint32_t myexponent, mysignificand;
 
-  if (category==fcNormal) {
+  if (isFiniteNonZero()) {
     myexponent = exponent+15; //bias
     mysignificand = (uint32_t)*significandParts();
     if (myexponent == 1 && !(mysignificand & 0x400))
@@ -3104,7 +3144,7 @@ APFloat::initFromPPCDoubleDoubleAPInt(const APInt &api)
   (void)fs;
 
   // Unless we have a special case, add in second double.
-  if (category == fcNormal) {
+  if (isFiniteNonZero()) {
     APFloat v(IEEEdouble, APInt(64, i2));
     fs = v.convert(PPCDoubleDouble, rmNearestTiesToEven, &losesInfo);
     assert(fs == opOK && !losesInfo);
@@ -3355,15 +3395,17 @@ APFloat APFloat::getSmallest(const fltSemantics &Sem, bool Negative) {
 }
 
 APFloat APFloat::getSmallestNormalized(const fltSemantics &Sem, bool Negative) {
-  APFloat Val(Sem, fcNormal, Negative);
+  APFloat Val(Sem, uninitialized);
 
   // We want (in interchange format):
   //   sign = {Negative}
   //   exponent = 0..0
   //   significand = 10..0
 
-  Val.exponent = Sem.minExponent;
+  Val.category = fcNormal;
   Val.zeroSignificand();
+  Val.sign = Negative;
+  Val.exponent = Sem.minExponent;
   Val.significandParts()[partCountForBits(Sem.precision)-1] |=
     (((integerPart) 1) << ((Sem.precision - 1) % integerPartWidth));
 
@@ -3668,7 +3710,7 @@ void APFloat::toString(SmallVectorImpl<char> &Str,
 
 bool APFloat::getExactInverse(APFloat *inv) const {
   // Special floats and denormals have no exact inverse.
-  if (category != fcNormal)
+  if (!isFiniteNonZero())
     return false;
 
   // Check that the number is a power of two by making sure that only the
@@ -3686,7 +3728,7 @@ bool APFloat::getExactInverse(APFloat *inv) const {
   if (reciprocal.isDenormal())
     return false;
 
-  assert(reciprocal.category == fcNormal &&
+  assert(reciprocal.isFiniteNonZero() &&
          reciprocal.significandLSB() == reciprocal.semantics->precision - 1);
 
   if (inv)
@@ -3823,3 +3865,19 @@ APFloat::opStatus APFloat::next(bool nextDown) {
 
   return result;
 }
+
+void
+APFloat::makeInf(bool Negative) {
+  category = fcInfinity;
+  sign = Negative;
+  exponent = semantics->maxExponent + 1;
+  APInt::tcSet(significandParts(), 0, partCount());
+}
+
+void
+APFloat::makeZero(bool Negative) {
+  category = fcZero;
+  sign = Negative;
+  exponent = semantics->minExponent-1;
+  APInt::tcSet(significandParts(), 0, partCount());  
+}