--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/lib/Headers/popcntintrin.h	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,52 @@
+/*===---- popcntintrin.h - POPCNT intrinsics -------------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __POPCNTINTRIN_H
+#define __POPCNTINTRIN_H
+
+/* Define the default attributes for the functions in this file. */
+#define __DEFAULT_FN_ATTRS __attribute__((__always_inline__, __nodebug__, __target__("popcnt")))
+
+/// Counts the number of bits in the source operand having a value of 1.
+///
+/// \headerfile <x86intrin.h>
+///
+/// This intrinsic corresponds to the <c> POPCNT </c> instruction.
+///
+/// \param __A
+///    An unsigned 32-bit integer operand.
+/// \returns A 32-bit integer containing the number of bits with value 1 in the
+///    source operand.
+static __inline__ int __DEFAULT_FN_ATTRS
+_mm_popcnt_u32(unsigned int __A)
+{
+  return __builtin_popcount(__A);
+}
+
+#ifdef __x86_64__
+/// Counts the number of bits in the source operand having a value of 1.
+///
+/// \headerfile <x86intrin.h>
+///
+/// This intrinsic corresponds to the <c> POPCNT </c> instruction.
+///
+/// \param __A
+///    An unsigned 64-bit integer operand.
+/// \returns A 64-bit integer containing the number of bits with value 1 in the
+///    source operand.
+static __inline__ long long __DEFAULT_FN_ATTRS
+_mm_popcnt_u64(unsigned long long __A)
+{
+  return __builtin_popcountll(__A);
+}
+#endif /* __x86_64__ */
+
+#undef __DEFAULT_FN_ATTRS
+
+#endif /* __POPCNTINTRIN_H */