Index: include/clang/Basic/BuiltinsX86.def
===================================================================
--- include/clang/Basic/BuiltinsX86.def
+++ include/clang/Basic/BuiltinsX86.def
@@ -35,6 +35,10 @@
 BUILTIN(__builtin_ms_va_end, "vc*&", "n")
 BUILTIN(__builtin_ms_va_copy, "vc*&c*&", "n")
 
+// Bit scan
+BUILTIN(__builtin_bit_scan_forward, "ii", "")
+BUILTIN(__builtin_bit_scan_reverse, "ii", "")
+
 // Undefined Values
 //
 TARGET_BUILTIN(__builtin_ia32_undef128, "V2d", "nc", "")
Index: lib/Headers/avxintrin.h
===================================================================
--- lib/Headers/avxintrin.h
+++ lib/Headers/avxintrin.h
@@ -537,6 +537,25 @@
   return (__m256i)__builtin_ia32_cvttps2dq256((__v8sf) __a);
 }
 
+static __inline double __DEFAULT_FN_ATTRS
+_mm256_cvtsd_f64(__m256d __a)
+{
+	return __a[0];
+}
+
+static __inline int __DEFAULT_FN_ATTRS
+_mm256_cvtsi256_si32(__m256i __a)
+{
+	__v8si __b = (__v8si)__a;
+	return __b[0];
+}
+
+static __inline float __DEFAULT_FN_ATTRS
+_mm256_cvtss_f32(__m256 __a)
+{
+	return __a[0];
+}
+
 /* Vector replicate */
 static __inline __m256 __DEFAULT_FN_ATTRS
 _mm256_movehdup_ps(__m256 __a)
Index: lib/Headers/ia32intrin.h
===================================================================
--- lib/Headers/ia32intrin.h
+++ lib/Headers/ia32intrin.h
@@ -74,4 +74,6 @@
 
 #define _rdtsc() __rdtsc()
 
+#define _rdpmc(A) __rdpmc(A)
+
 #endif /* __IA32INTRIN_H */
Index: lib/Headers/immintrin.h
===================================================================
--- lib/Headers/immintrin.h
+++ lib/Headers/immintrin.h
@@ -157,6 +157,19 @@
 {
   return __builtin_ia32_wrgsbase64(__V);
 }
+
+/* __bit_scan_forward */
+static __inline__ int __attribute__((__always_inline__, __nodebug__))
+_bit_scan_forward(int __A) {
+  return __builtin_bit_scan_forward(__A);
+}
+
+/* __bit_scan_reverse */
+static __inline__ int __attribute__((__always_inline__, __nodebug__))
+_bit_scan_reverse(int __A) {
+  return __builtin_bit_scan_reverse(__A);
+}
+
 #endif
 
 #include <rtmintrin.h>
Index: test/CodeGen/avx-builtins.c
===================================================================
--- test/CodeGen/avx-builtins.c
+++ test/CodeGen/avx-builtins.c
@@ -168,3 +168,24 @@
   // CHECK: ret <4 x i64> undef
   return _mm256_undefined_si256();
 }
+
+double test_mm256_cvtsd_f64(__m256d __a)
+{
+	// CHECK-LABEL: @test_mm256_cvtsd_f64
+	// CHECK: extractelement <4 x double> %{{.*}}, i32 0
+	return _mm256_cvtsd_f64(__a);
+}
+
+int test_mm256_cvtsi256_si32(__m256i __a)
+{
+	// CHECK-LABEL: @test_mm256_cvtsi256_si32
+	// CHECK: extractelement <8 x i32> %{{.*}}, i32 0
+	return _mm256_cvtsi256_si32(__a);
+}
+
+float test_mm256_cvtss_f32(__m256 __a)
+{
+	// CHECK-LABEL: @test_mm256_cvtss_f32
+	// CHECK: extractelement <8 x float> %{{.*}}, i32 0
+	return _mm256_cvtss_f32(__a);
+}
\ No newline at end of file
Index: test/CodeGen/bitscan-builtins.c
===================================================================
--- test/CodeGen/bitscan-builtins.c
+++ test/CodeGen/bitscan-builtins.c
@@ -0,0 +1,17 @@
+// 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>
+
+int test_bit_scan_forward(int a) {
+  return _bit_scan_forward(a);
+// CHECK: @test_bit_scan_forward
+// CHECK: call i32 @llvm.x86.bit.scan.forward
+}
+
+int test_bit_scan_reverse(int a) {
+  return _bit_scan_reverse(a);
+// CHECK: @test_bit_scan_reverse
+// CHECK: call i32 @llvm.x86.bit.scan.reverse
+}
\ No newline at end of file
Index: test/CodeGen/rd-builtins.c
===================================================================
--- test/CodeGen/rd-builtins.c
+++ test/CodeGen/rd-builtins.c
@@ -0,0 +1,18 @@
+// 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 <x86intrin.h>
+
+unsigned long long test_rdpmc(int a) {
+  return _rdpmc(a);
+// CHECK: @test_rdpmc
+// CHECK: call i64 @llvm.x86.rdpmc
+}
+
+int test_rdtsc() {
+  return _rdtsc();
+// CHECK: @test_rdtsc
+// CHECK: call i64 @llvm.x86.rdtsc
+}
\ No newline at end of file