Index: cfe/trunk/lib/Headers/__wmmintrin_pclmul.h
===================================================================
--- cfe/trunk/lib/Headers/__wmmintrin_pclmul.h
+++ cfe/trunk/lib/Headers/__wmmintrin_pclmul.h
@@ -23,6 +23,34 @@
 #ifndef _WMMINTRIN_PCLMUL_H
 #define _WMMINTRIN_PCLMUL_H
 
+/// \brief Multiplies two 64-bit integer values, which are selected from source
+///    operands using the immediate-value operand. The multiplication is a 
+///    carry-less multiplication, and the 128-bit integer product is stored in
+///    the destination.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code 
+/// __m128i _mm_clmulepi64_si128(__m128i __X, __m128i __Y, const int __I);
+/// \endcode 
+///
+/// This intrinsic corresponds to the \c VPCLMULQDQ instruction.
+///
+/// \param __X
+///    A 128-bit vector of [2 x i64] containing one of the source operands.
+/// \param __Y
+///    A 128-bit vector of [2 x i64] containing one of the source operands.
+/// \param __I
+///    An immediate value specifying which 64-bit values to select from the
+///    operands.
+///    Bit 0 is used to select a value from operand __X,
+///    and bit 4 is used to select a value from operand __Y:
+///    Bit[0]=0 indicates that bits[63:0] of operand __X are used.
+///    Bit[0]=1 indicates that bits[127:64] of operand __X are used.
+///    Bit[4]=0 indicates that bits[63:0] of operand __Y are used.
+///    Bit[4]=1 indicates that bits[127:64] of operand __Y are used.
+/// \returns The 128-bit integer vector containing the result of the carry-less
+///    multiplication of the selected 64-bit values.
 #define _mm_clmulepi64_si128(__X, __Y, __I) \
   ((__m128i)__builtin_ia32_pclmulqdq128((__v2di)(__m128i)(__X), \
                                         (__v2di)(__m128i)(__Y), (char)(__I)))