diff --git a/src/include/port/simd.h b/src/include/port/simd.h
new file mode 100644
index 0000000000..a571e79f57
--- /dev/null
+++ b/src/include/port/simd.h
@@ -0,0 +1,30 @@
+/*-------------------------------------------------------------------------
+ *
+ * simd.h
+ *	  Support for platform-specific vector operations.
+ *
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/port/simd.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef SIMD_H
+#define SIMD_H
+
+/*
+ * SSE2 instructions are part of the spec for the 64-bit x86 ISA. We assume
+ * that compilers targeting this architecture understand SSE2 intrinsics.
+ *
+ * We use emmintrin.h rather than the comprehensive header immintrin.h in
+ * order to exclude extensions beyond SSE2. This is because MSVC, at least,
+ * will allow the use of intrinsics that haven't been enabled at compile
+ * time.
+ */
+#if (defined(__x86_64__) || defined(_M_AMD64))
+#include <emmintrin.h>
+#define USE_SSE2
+#endif
+
+#endif							/* SIMD_H */