Index: include/llvm/ADT/APFloat.h
===================================================================
--- include/llvm/ADT/APFloat.h
+++ include/llvm/ADT/APFloat.h
@@ -276,6 +276,10 @@
   /// \param isIEEE   - If 128 bit number, select between PPC and IEEE
   static APFloat getAllOnesValue(unsigned BitWidth, bool isIEEE = false);
 
+  /// Returns the size of the floating point number (in bits) in the given
+  /// semantics.
+  static unsigned getSizeInBits(const fltSemantics &Sem);
+
   /// @}
 
   /// Used to insert APFloat objects, or objects that contain APFloat objects,
Index: lib/Support/APFloat.cpp
===================================================================
--- lib/Support/APFloat.cpp
+++ lib/Support/APFloat.cpp
@@ -52,14 +52,17 @@
     /* Number of bits in the significand.  This includes the integer
        bit.  */
     unsigned int precision;
+
+    /* Number of bits actually used in the semantics. */
+    unsigned int sizeInBits;
   };
 
-  const fltSemantics APFloat::IEEEhalf = { 15, -14, 11 };
-  const fltSemantics APFloat::IEEEsingle = { 127, -126, 24 };
-  const fltSemantics APFloat::IEEEdouble = { 1023, -1022, 53 };
-  const fltSemantics APFloat::IEEEquad = { 16383, -16382, 113 };
-  const fltSemantics APFloat::x87DoubleExtended = { 16383, -16382, 64 };
-  const fltSemantics APFloat::Bogus = { 0, 0, 0 };
+  const fltSemantics APFloat::IEEEhalf = { 15, -14, 11, 16 };
+  const fltSemantics APFloat::IEEEsingle = { 127, -126, 24, 32 };
+  const fltSemantics APFloat::IEEEdouble = { 1023, -1022, 53, 64 };
+  const fltSemantics APFloat::IEEEquad = { 16383, -16382, 113, 128 };
+  const fltSemantics APFloat::x87DoubleExtended = { 16383, -16382, 64, 80 };
+  const fltSemantics APFloat::Bogus = { 0, 0, 0, 0 };
 
   /* The PowerPC format consists of two doubles.  It does not map cleanly
      onto the usual format above.  It is approximated using twice the
@@ -72,7 +75,7 @@
      to represent all possible values held by a PPC double-double number,
      for example: (long double) 1.0 + (long double) 0x1p-106
      Should this be replaced by a full emulation of PPC double-double?  */
-  const fltSemantics APFloat::PPCDoubleDouble = { 1023, -1022 + 53, 53 + 53 };
+  const fltSemantics APFloat::PPCDoubleDouble = { 1023, -1022 + 53, 53 + 53, 128 };
 
   /* A tight upper bound on number of parts required to hold the value
      pow(5, power) is
@@ -2416,7 +2419,7 @@
                                       roundingMode rounding_mode)
 {
   unsigned int parts, pow5PartCount;
-  fltSemantics calcSemantics = { 32767, -32767, 0 };
+  fltSemantics calcSemantics = { 32767, -32767, 0, 0 };
   integerPart pow5Parts[maxPowerOfFiveParts];
   bool isNearest;
 
@@ -3368,6 +3371,11 @@
   }
 }
 
+unsigned APFloat::getSizeInBits(const fltSemantics &Sem)
+{
+  return Sem.sizeInBits;
+}
+
 /// Make this number the largest magnitude normal number in the given
 /// semantics.
 void APFloat::makeLargest(bool Negative) {