diff --git a/glm/detail/setup.hpp b/glm/detail/setup.hpp
index 4b39b311..d57cc557 100644
--- a/glm/detail/setup.hpp
+++ b/glm/detail/setup.hpp
@@ -274,12 +274,14 @@
 
 // N2235 Generalized Constant Expressions http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2235.pdf
 // N3652 Extended Constant Expressions http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3652.html
-#if (GLM_COMPILER & GLM_COMPILER_CLANG) && !(GLM_ARCH & GLM_ARCH_SIMD_BIT)
+#if (GLM_ARCH & GLM_ARCH_SIMD_BIT) // Compiler SIMD intrinsics don't support constexpr...
+#	define GLM_HAS_CONSTEXPR 0
+#elif (GLM_COMPILER & GLM_COMPILER_CLANG)
 #	define GLM_HAS_CONSTEXPR __has_feature(cxx_relaxed_constexpr)
-#elif (GLM_LANG & GLM_LANG_CXX14_FLAG) && !(GLM_ARCH & GLM_ARCH_SIMD_BIT)
+#elif (GLM_LANG & GLM_LANG_CXX14_FLAG)
 #	define GLM_HAS_CONSTEXPR 1
 #else
-#	define GLM_HAS_CONSTEXPR ((GLM_LANG & GLM_LANG_CXX0X_FLAG) && !(GLM_ARCH & GLM_ARCH_SIMD_BIT) && GLM_HAS_INITIALIZER_LISTS && (\
+#	define GLM_HAS_CONSTEXPR ((GLM_LANG & GLM_LANG_CXX0X_FLAG) && GLM_HAS_INITIALIZER_LISTS && (\
 		((GLM_COMPILER & GLM_COMPILER_INTEL) && (GLM_COMPILER >= GLM_COMPILER_INTEL17)) || \
 		((GLM_COMPILER & GLM_COMPILER_VC) && (GLM_COMPILER >= GLM_COMPILER_VC15))))
 #endif
diff --git a/manual.md b/manual.md
index 993e79c5..e9441e89 100644
--- a/manual.md
+++ b/manual.md
@@ -390,12 +390,14 @@ For example, if a program is compiled with Visual Studio using `/arch:AVX`, GLM
 It’s possible to avoid the instruction set detection by forcing the use of a specific instruction set with one of the fallowing define:
 `GLM_FORCE_SSE2`, `GLM_FORCE_SSE3`, `GLM_FORCE_SSSE3`, `GLM_FORCE_SSE41`, `GLM_FORCE_SSE42`, `GLM_FORCE_AVX`, `GLM_FORCE_AVX2` or `GLM_FORCE_AVX512`.
 
-The use of intrinsic functions by GLM implementation can be avoided using the define `GLM_FORCE_PURE` before any inclusion of GLM headers.
+The use of intrinsic functions by GLM implementation can be avoided using the define `GLM_FORCE_PURE` before any inclusion of GLM headers. This can be particularly useful if we want to rely on C++14 `constexpr`.
 
 ```cpp
 #define GLM_FORCE_PURE
 #include <glm/glm.hpp>
 
+static_assert(glm::vec4::length() == 4, "Using GLM C++ 14 constexpr support for compile time tests");
+
 // GLM code will be compiled using pure C++ code without any intrinsics
 ```
 
diff --git a/readme.md b/readme.md
index dfd97d82..16052c15 100644
--- a/readme.md
+++ b/readme.md
@@ -67,6 +67,7 @@ glm::mat4 camera(float Translate, glm::vec2 const& Rotate)
 - Added identity functions #765
 - Splitted headers into EXT extensions to improve compilation time #670
 - Added separated performance tests
+- Refactor manual, lists all configuration defines
 
 #### Fixes:
 - Fixed SIMD detection on Clang and GCC