diff --git a/r5dev/mathlib/ssemath.h b/r5dev/mathlib/ssemath.h
index 62c295cd..98091686 100644
--- a/r5dev/mathlib/ssemath.h
+++ b/r5dev/mathlib/ssemath.h
@@ -5942,7 +5942,7 @@ inline const fltx4 Normalized3SIMD(const fltx4 vec)
 // Some convenience operator overloads, which are just aliasing the functions above.
 // Unnecessary on 360, as you already have them from xboxmath.h
 // Component wise add
-#ifndef COMPILER_GCC
+#if !defined (COMPILER_GCC) && !defined (COMPILER_CLANG)
 
 FORCEINLINE fltx4 operator+=(fltx4& a, FLTX4 b)
 {
diff --git a/r5dev/tier0/platform.h b/r5dev/tier0/platform.h
index f3b90c9c..ca778c8b 100644
--- a/r5dev/tier0/platform.h
+++ b/r5dev/tier0/platform.h
@@ -5,9 +5,15 @@
 #pragma intrinsic(__rdtsc)
 #endif
 
-
 #define TIER0_DLL_EXPORT
-#define COMPILER_MSVC
+
+#ifdef _MSC_VER
+#define COMPILER_MSVC 1 // !TODO: Set in CMake!
+#endif // _MSC_VER
+
+#ifdef __clang__
+#define COMPILER_CLANG 1 // !TODO: Set in CMake!
+#endif // __clang__
 
 //-----------------------------------------------------------------------------
 // Set up platform defines.
@@ -133,6 +139,11 @@
 #define GNUC 1
 #endif
 
+#ifdef COMPILER_CLANG
+#define CLANG 1
+#define POSIX_MATH 1
+#endif
+
 #if defined( _WIN32 )
 #define _WINDOWS 1
 #endif