diff --git a/glm/detail/setup.hpp b/glm/detail/setup.hpp
index d976d746..c1a75de1 100644
--- a/glm/detail/setup.hpp
+++ b/glm/detail/setup.hpp
@@ -294,10 +294,8 @@
 
 //
 #if GLM_HAS_CONSTEXPR
-# if (GLM_COMPILER & GLM_COMPILER_CLANG)
-#	define GLM_HAS_IF_CONSTEXPR __has_feature(cxx_if_constexpr)
-# elif (GLM_COMPILER & GLM_COMPILER_GCC) 
-#	define GLM_HAS_IF_CONSTEXPR (__cplusplus >= 201703L)
+# if (GLM_COMPILER & GLM_COMPILER_CLANG) && __has_feature(cxx_if_constexpr)
+#	define GLM_HAS_IF_CONSTEXPR 1
 # elif (GLM_LANG & GLM_LANG_CXX17_FLAG)
 # 	define GLM_HAS_IF_CONSTEXPR 1
 # else
diff --git a/readme.md b/readme.md
index 60cb1ee6..6a24b0eb 100644
--- a/readme.md
+++ b/readme.md
@@ -73,6 +73,7 @@ glm::mat4 camera(float Translate, glm::vec2 const& Rotate)
 - Fixed EXT_scalar_ulp and EXT_vector_ulp API coding style
 - Fixed quaternion componant order: w, {x, y, z} #916
 - Fixed GLM_HAS_CXX11_STL broken on Clang with Linux #926
+- Fixed Clang or GCC build due to wrong GLM_HAS_IF_CONSTEXPR definition #907
 
 ### [GLM 0.9.9.5](https://github.com/g-truc/glm/releases/tag/0.9.9.5) - 2019-04-01
 #### Fixes: