diff --git a/glm/detail/setup.hpp b/glm/detail/setup.hpp
index 8df19a8e..51b8c680 100644
--- a/glm/detail/setup.hpp
+++ b/glm/detail/setup.hpp
@@ -428,17 +428,17 @@
 #endif
 
 // N2235 Generalized Constant Expressions http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2235.pdf
-#if GLM_COMPILER & GLM_COMPILER_CLANG
+#if (GLM_COMPILER & GLM_COMPILER_CLANG) && (GLM_ARCH == GLM_ARCH_PURE)
 #	define GLM_HAS_CONSTEXPR_CXX11 __has_feature(cxx_constexpr)
-#elif GLM_LANG & GLM_LANG_CXX11_FLAG
+#elif (GLM_LANG & GLM_LANG_CXX11_FLAG) && (GLM_ARCH == GLM_ARCH_PURE)
 #	define GLM_HAS_CONSTEXPR_CXX11 1
 #else
 	// GCC 4.6 support constexpr but there is a compiler bug causing a crash
 	// Visual C++ has a bug #594 https://github.com/g-truc/glm/issues/594
-#	define GLM_HAS_CONSTEXPR_CXX11 ((GLM_LANG & GLM_LANG_CXX0X_FLAG) && (\
-		((GLM_COMPILER & GLM_COMPILER_GCC) && (GLM_COMPILER >= GLM_COMPILER_GCC48) && (GLM_ARCH == GLM_ARCH_PURE)) || \
+#	define GLM_HAS_CONSTEXPR_CXX11 ((GLM_LANG & GLM_LANG_CXX0X_FLAG) && (GLM_ARCH == GLM_ARCH_PURE) && (\
+		((GLM_COMPILER & GLM_COMPILER_GCC) && (GLM_COMPILER >= GLM_COMPILER_GCC48)) || \
 		((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_COMPILER >= GLM_COMPILER_INTEL14)) || \
-		((GLM_COMPILER & GLM_COMPILER_VC) && (GLM_COMPILER >= GLM_COMPILER_VC14) && (GLM_ARCH == GLM_ARCH_PURE))))
+		((GLM_COMPILER & GLM_COMPILER_VC) && (GLM_COMPILER >= GLM_COMPILER_VC14))))
 #endif
 
 #if GLM_HAS_CONSTEXPR_CXX11
@@ -448,15 +448,15 @@
 #endif
 
 // N3652 Extended Constant Expressions http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3652.html
-#if GLM_COMPILER & GLM_COMPILER_CLANG
+#if (GLM_COMPILER & GLM_COMPILER_CLANG) && (GLM_ARCH == GLM_ARCH_PURE)
 #	define GLM_HAS_CONSTEXPR_CXX14 __has_feature(cxx_relaxed_constexpr)
-#elif GLM_LANG & GLM_LANG_CXX14_FLAG
+#elif (GLM_LANG & GLM_LANG_CXX14_FLAG) && (GLM_ARCH == GLM_ARCH_PURE)
 #	define GLM_HAS_CONSTEXPR_CXX14 1
 #else
-#	define GLM_HAS_CONSTEXPR_CXX14 ((GLM_LANG & GLM_LANG_CXX0X_FLAG) && (\
-		((GLM_COMPILER & GLM_COMPILER_GCC) && (GLM_COMPILER >= GLM_COMPILER_GCC50) && (GLM_ARCH == GLM_ARCH_PURE)) || \
-		((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_COMPILER >= GLM_COMPILER_INTEL17) && (GLM_ARCH == GLM_ARCH_PURE)) || \
-		((GLM_COMPILER & GLM_COMPILER_VC) && (GLM_COMPILER >= GLM_COMPILER_VC15) && (GLM_ARCH == GLM_ARCH_PURE))))
+#	define GLM_HAS_CONSTEXPR_CXX14 ((GLM_LANG & GLM_LANG_CXX0X_FLAG) && (GLM_ARCH == GLM_ARCH_PURE) && (\
+		((GLM_COMPILER & GLM_COMPILER_GCC) && (GLM_COMPILER >= GLM_COMPILER_GCC50)) || \
+		((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_COMPILER >= GLM_COMPILER_INTEL17)) || \
+		((GLM_COMPILER & GLM_COMPILER_VC) && (GLM_COMPILER >= GLM_COMPILER_VC15))))
 #endif
 
 #if GLM_HAS_CONSTEXPR_CXX14
diff --git a/readme.md b/readme.md
index 4084a869..1ed0e9dc 100644
--- a/readme.md
+++ b/readme.md
@@ -57,7 +57,7 @@ glm::mat4 camera(float Translate, glm::vec2 const& Rotate)
 
 #### Improvements:
 - Added missing vec1 based constructors
-- Redesigned constexpr support which supports both SIMD and constexpr on Clang #783
+- Redesigned constexpr support which excludes both SIMD and constexpr #783
 - Added detection of Visual C++ 2017 toolsets
 
 #### Fixes: