diff --git a/include/clang/Basic/BuiltinsX86.def b/include/clang/Basic/BuiltinsX86.def
index c9f7b05..d536821 100644
--- a/include/clang/Basic/BuiltinsX86.def
+++ b/include/clang/Basic/BuiltinsX86.def
@@ -624,6 +624,11 @@
 BUILTIN(__builtin_ia32_rdrand32_step, "UiUi*", "")
 BUILTIN(__builtin_ia32_rdrand64_step, "UiULLi*", "")
 
+// RDSEED
+BUILTIN(__builtin_ia32_rdseed16_step, "UiUs*", "")
+BUILTIN(__builtin_ia32_rdseed32_step, "UiUi*", "")
+BUILTIN(__builtin_ia32_rdseed64_step, "UiULLi*", "")
+
 // BMI
 BUILTIN(__builtin_ia32_bextr_u32, "UiUiUi", "")
 BUILTIN(__builtin_ia32_bextr_u64, "ULLiULLiULLi", "")
diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 92d8698..a8e9d59 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -902,6 +902,7 @@
 def mno_f16c : Flag<["-"], "mno-f16c">, Group<m_x86_Features_Group>;
 def mno_rtm : Flag<["-"], "mno-rtm">, Group<m_x86_Features_Group>;
 def mno_prfchw : Flag<["-"], "mno-prfchw">, Group<m_x86_Features_Group>;
+def mno_rdseed : Flag<["-"], "mno-rdseed">, Group<m_x86_Features_Group>;
 
 def mno_thumb : Flag<["-"], "mno-thumb">, Group<m_Group>;
 def marm : Flag<["-"], "marm">, Alias<mno_thumb>;
@@ -946,6 +947,7 @@
 def mf16c : Flag<["-"], "mf16c">, Group<m_x86_Features_Group>;
 def mrtm : Flag<["-"], "mrtm">, Group<m_x86_Features_Group>;
 def mprfchw : Flag<["-"], "mprfchw">, Group<m_x86_Features_Group>;
+def mrdseed : Flag<["-"], "mrdseed">, Group<m_x86_Features_Group>;
 def mips16 : Flag<["-"], "mips16">, Group<m_Group>;
 def mno_mips16 : Flag<["-"], "mno-mips16">, Group<m_Group>;
 def mxgot : Flag<["-"], "mxgot">, Group<m_Group>;
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 4ca8fbf..bd3f76d 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -1703,6 +1703,7 @@
   bool HasPOPCNT;
   bool HasRTM;
   bool HasPRFCHW;
+  bool HasRDSEED;
   bool HasSSE4a;
   bool HasFMA4;
   bool HasFMA;
@@ -1854,7 +1855,7 @@
     : TargetInfo(triple), SSELevel(NoSSE), MMX3DNowLevel(NoMMX3DNow),
       HasAES(false), HasPCLMUL(false), HasLZCNT(false), HasRDRND(false),
       HasBMI(false), HasBMI2(false), HasPOPCNT(false), HasRTM(false),
-      HasPRFCHW(false), HasSSE4a(false), HasFMA4(false),
+      HasPRFCHW(false), HasRDSEED(false), HasSSE4a(false), HasFMA4(false),
       HasFMA(false), HasXOP(false), HasF16C(false), CPU(CK_Generic) {
     BigEndian = false;
     LongDoubleFormat = &llvm::APFloat::x87DoubleExtended;
@@ -2062,6 +2063,7 @@
   Features["popcnt"] = false;
   Features["rtm"] = false;
   Features["prfchw"] = false;
+  Features["rdseed"] = false;
   Features["fma4"] = false;
   Features["fma"] = false;
   Features["xop"] = false;
@@ -2286,6 +2288,8 @@
       Features["rtm"] = true;
     else if (Name == "prfchw")
       Features["prfchw"] = true;
+    else if (Name == "rdseed")
+      Features["rdseed"] = true;
   } else {
     if (Name == "mmx")
       Features["mmx"] = Features["3dnow"] = Features["3dnowa"] = false;
@@ -2352,6 +2356,8 @@
       Features["rtm"] = false;
     else if (Name == "prfchw")
       Features["prfchw"] = false;
+    else if (Name == "rdseed")
+      Features["rdseed"] = false;
   }
 
   return true;
@@ -2413,6 +2419,11 @@
       continue;
     }
 
+    if (Feature == "rdseed") {
+      HasRDSEED = true;
+      continue;
+    }
+
     if (Feature == "sse4a") {
       HasSSE4a = true;
       continue;
@@ -2640,6 +2651,9 @@
   if (HasPRFCHW)
     Builder.defineMacro("__PRFCHW__");
 
+  if (HasRDSEED)
+    Builder.defineMacro("__RDSEED__");
+
   if (HasSSE4a)
     Builder.defineMacro("__SSE4A__");
 
@@ -2729,6 +2743,7 @@
       .Case("popcnt", HasPOPCNT)
       .Case("rtm", HasRTM)
       .Case("prfchw", HasPRFCHW)
+      .Case("rdseed", HasRDSEED)
       .Case("sse", SSELevel >= SSE1)
       .Case("sse2", SSELevel >= SSE2)
       .Case("sse3", SSELevel >= SSE3)
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 8a69e8a..3c89652 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -2709,7 +2709,10 @@
   }
   case X86::BI__builtin_ia32_rdrand16_step:
   case X86::BI__builtin_ia32_rdrand32_step:
-  case X86::BI__builtin_ia32_rdrand64_step: {
+  case X86::BI__builtin_ia32_rdrand64_step:
+  case X86::BI__builtin_ia32_rdseed16_step:
+  case X86::BI__builtin_ia32_rdseed32_step:
+  case X86::BI__builtin_ia32_rdseed64_step: {
     Intrinsic::ID ID;
     switch (BuiltinID) {
     default: llvm_unreachable("Unsupported intrinsic!");
@@ -2722,6 +2725,15 @@
     case X86::BI__builtin_ia32_rdrand64_step:
       ID = Intrinsic::x86_rdrand_64;
       break;
+    case X86::BI__builtin_ia32_rdseed16_step:
+      ID = Intrinsic::x86_rdseed_16;
+      break;
+    case X86::BI__builtin_ia32_rdseed32_step:
+      ID = Intrinsic::x86_rdseed_32;
+      break;
+    case X86::BI__builtin_ia32_rdseed64_step:
+      ID = Intrinsic::x86_rdseed_64;
+      break;
     }
 
     Value *Call = Builder.CreateCall(CGM.getIntrinsic(ID));
diff --git a/lib/Headers/CMakeLists.txt b/lib/Headers/CMakeLists.txt
index 96a6cf3..ebc92e7 100644
--- a/lib/Headers/CMakeLists.txt
+++ b/lib/Headers/CMakeLists.txt
@@ -21,6 +21,7 @@
   pmmintrin.h
   popcntintrin.h
   prfchwintrin.h
+  rdseedintrin.h
   rtmintrin.h
   smmintrin.h
   stdalign.h
diff --git a/lib/Headers/rdseedintrin.h b/lib/Headers/rdseedintrin.h
new file mode 100644
index 0000000..54aabd1
--- /dev/null
+++ b/lib/Headers/rdseedintrin.h
@@ -0,0 +1,48 @@
+/*===---- rdseedintrin.h - RDSEED intrinsics -------------------------------===
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __X86INTRIN_H
+#error "Never use <rdseedintrin.h> directly; include <x86intrin.h> instead."
+#endif
+
+#ifdef __RDSEED__
+static __inline__ int __attribute__((__always_inline__, __nodebug__))
+_rdseed16_step(unsigned short *__p)
+{
+  return __builtin_ia32_rdseed16_step(__p);
+}
+
+static __inline__ int __attribute__((__always_inline__, __nodebug__))
+_rdseed32_step(unsigned int *__p)
+{
+  return __builtin_ia32_rdseed32_step(__p);
+}
+
+#ifdef __x86_64__
+static __inline__ int __attribute__((__always_inline__, __nodebug__))
+_rdseed64_step(unsigned long long *__p)
+{
+  return __builtin_ia32_rdseed64_step(__p);
+}
+#endif
+#endif /* __RDSEED__ */
diff --git a/lib/Headers/x86intrin.h b/lib/Headers/x86intrin.h
index 441b38a..94fbe2f 100644
--- a/lib/Headers/x86intrin.h
+++ b/lib/Headers/x86intrin.h
@@ -46,6 +46,10 @@
 #include <popcntintrin.h>
 #endif
 
+#ifdef __RDSEED__
+#include <rdseedintrin.h>
+#endif
+
 #ifdef __PRFCHW__
 #include <prfchwintrin.h>
 #endif
diff --git a/test/CodeGen/rdrand-builtins.c b/test/CodeGen/rdrand-builtins.c
index b7970f4..15414a3 100644
--- a/test/CodeGen/rdrand-builtins.c
+++ b/test/CodeGen/rdrand-builtins.c
@@ -1,9 +1,9 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-feature +rdrnd -emit-llvm -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-feature +rdrnd -target-feature +rdseed -emit-llvm -o - %s | FileCheck %s
 
 // Don't include mm_malloc.h, it's system specific.
 #define __MM_MALLOC_H
 
-#include <immintrin.h>
+#include <x86intrin.h>
 
 int rdrand16(unsigned short *p) {
   return _rdrand16_step(p);
@@ -25,3 +25,24 @@
 // CHECK: call { i64, i32 } @llvm.x86.rdrand.64
 // CHECK: store i64
 }
+
+int rdseed16(unsigned short *p) {
+  return _rdseed16_step(p);
+// CHECK: @rdseed16
+// CHECK: call { i16, i32 } @llvm.x86.rdseed.16
+// CHECK: store i16
+}
+
+int rdseed32(unsigned *p) {
+  return _rdseed32_step(p);
+// CHECK: @rdseed32
+// CHECK: call { i32, i32 } @llvm.x86.rdseed.32
+// CHECK: store i32
+}
+
+int rdseed64(unsigned long long *p) {
+  return _rdseed64_step(p);
+// CHECK: @rdseed64
+// CHECK: call { i64, i32 } @llvm.x86.rdseed.64
+// CHECK: store i64
+}