diff --git a/config.h b/config.h
index cfa3a9b6..f2d0651d 100644
--- a/config.h
+++ b/config.h
@@ -209,12 +209,6 @@ typedef unsigned int word32;
 typedef word64 lword;
 const lword LWORD_MAX = W64LIT(0xffffffffffffffff);
 
-// Clang pretends to be VC++, too.
-//   See http://github.com/weidai11/cryptopp/issues/147
-#if defined(_MSC_VER) && defined(__clang__)
-# error: "Unsupported configuration"
-#endif
-
 #ifdef __GNUC__
 	#define CRYPTOPP_GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
 #endif
@@ -327,7 +321,7 @@ NAMESPACE_END
 	#define CRYPTOPP_FASTCALL
 #endif
 
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && !defined(__clang__)
 #define CRYPTOPP_NO_VTABLE __declspec(novtable)
 #else
 #define CRYPTOPP_NO_VTABLE
diff --git a/integer.cpp b/integer.cpp
index 700e8902..ceb06ed5 100644
--- a/integer.cpp
+++ b/integer.cpp
@@ -195,7 +195,7 @@ static word AtomicInverseModPower2(word A)
 	#define HighWord(a)					a##1
 	#ifdef _MSC_VER
 		#define MultiplyWordsLoHi(p0, p1, a, b)		p0 = _umul128(a, b, &p1);
-		#ifndef __INTEL_COMPILER
+		#if !defined(__INTEL_COMPILER) && !defined(__clang__)
 			#define Double3Words(c, d)		d##1 = __shiftleft128(d##0, d##1, 1); d##0 = __shiftleft128(c, d##0, 1); c *= 2;
 		#endif
 	#elif defined(__DECCXX)
diff --git a/rdrand.cpp b/rdrand.cpp
index 75889f1d..ed6b56bc 100644
--- a/rdrand.cpp
+++ b/rdrand.cpp
@@ -152,6 +152,14 @@ inline void RDRAND32(void* output)
         : "=a" (*reinterpret_cast<word32*>(output))
         : : "cc"
     );
+#elif defined(CRYPTOPP_MSC_VERSION) && defined(CRYPTOPP_LLVM_CLANG_VERSION)
+    __asm__ __volatile__
+    (
+        ".byte 0x0f, 0xc7, 0xf0;\n"
+        ".byte 0x73, 0xfb;\n"
+        : "=a" (*reinterpret_cast<word32*>(output))
+        : : "cc"
+    );
 #elif defined(ALL_RDRAND_INTRIN_AVAILABLE)
     while(!_rdrand32_step(reinterpret_cast<word32*>(output))) {}
 #else
@@ -191,6 +199,14 @@ inline void RDRAND64(void* output)
         : "=a" (*reinterpret_cast<word64*>(output))
         : : "cc"
     );
+#elif defined(CRYPTOPP_MSC_VERSION) && defined(CRYPTOPP_LLVM_CLANG_VERSION)
+    __asm__ __volatile__
+    (
+        ".byte 0x48, 0x0f, 0xc7, 0xf0;\n"
+        ".byte 0x73, 0xfa;\n"
+        : "=a" (*reinterpret_cast<word64*>(output))
+        : : "cc"
+    );
 #elif defined(ALL_RDRAND_INTRIN_AVAILABLE)
     while(!_rdrand64_step(reinterpret_cast<unsigned long long*>(output))) {}
 #else
@@ -296,6 +312,14 @@ inline void RDSEED32(void* output)
         : "=a" (*reinterpret_cast<word32*>(output))
         : : "cc"
     );
+#elif defined(CRYPTOPP_MSC_VERSION) && defined(CRYPTOPP_LLVM_CLANG_VERSION)
+    __asm__ __volatile__
+    (
+        ".byte 0x0f, 0xc7, 0xf8;\n"
+        ".byte 0x73, 0xfb;\n"
+        : "=a" (*reinterpret_cast<word32*>(output))
+        : : "cc"
+    );
 #elif defined(ALL_RDSEED_INTRIN_AVAILABLE)
     while(!_rdseed32_step(reinterpret_cast<word32*>(output))) {}
 #else
@@ -335,6 +359,14 @@ inline void RDSEED64(void* output)
         : "=a" (*reinterpret_cast<word64*>(output))
         : : "cc"
     );
+#elif defined(CRYPTOPP_MSC_VERSION) && defined(CRYPTOPP_LLVM_CLANG_VERSION)
+    __asm__ __volatile__
+    (
+        ".byte 0x48, 0x0f, 0xc7, 0xf8;\n"
+        ".byte 0x73, 0xfa;\n"
+        : "=a" (*reinterpret_cast<word64*>(output))
+        : : "cc"
+    );
 #elif defined(ALL_RDSEED_INTRIN_AVAILABLE)
     while(!_rdseed64_step(reinterpret_cast<unsigned long long*>(output))) {}
 #else