diff --git a/src/SFML/Graphics/RenderQueue.cpp b/src/SFML/Graphics/RenderQueue.cpp
index 5161c9458..1d0a747fd 100644
--- a/src/SFML/Graphics/RenderQueue.cpp
+++ b/src/SFML/Graphics/RenderQueue.cpp
@@ -38,13 +38,22 @@ namespace
 {
     // Fast float to int conversion
     inline sf::Int32 Round(double value)
-    {
-        value += 6755399441055744.0;
+    {
+        // Use a union rather than reinterpret_cast, because it doesn't break strict-aliasing
+        // rules and results in a correct behaviour when compiling in optimized mode
+        union DoubleToInt
+        {
+            double d; 
+            sf::Int32 i[2];
+        };
+
+        DoubleToInt u;
+        u.d = value + 6755399441055744.0;
 
         #if defined(SFML_ENDIAN_LITTLE)
-            return (reinterpret_cast<sf::Int32*>(&value))[0];
+            return u.i[0];
         #else
-            return (reinterpret_cast<sf::Int32*>(&value))[1];
+            return u.i[1];
         #endif
     } 
 }
diff --git a/src/SFML/Window/Linux/ContextGLX.cpp b/src/SFML/Window/Linux/ContextGLX.cpp
index 08156bd16..d9f308b7b 100644
--- a/src/SFML/Window/Linux/ContextGLX.cpp
+++ b/src/SFML/Window/Linux/ContextGLX.cpp
@@ -275,7 +275,7 @@ void ContextGLX::CreateContext(ContextGLX* shared, unsigned int bitsPerPixel, co
     GLXContext toShare = shared ? shared->myContext : NULL;
 
     // Create the context -- first try an OpenGL 3.0 context if it is supported
-    const GLubyte* name = reinterpret_cast<const GLubyte*>("glXCreateContextAttribsARB");
+    /*const GLubyte* name = reinterpret_cast<const GLubyte*>("glXCreateContextAttribsARB");
     PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB = reinterpret_cast<PFNGLXCREATECONTEXTATTRIBSARBPROC>(glXGetProcAddress(name));
     if (glXCreateContextAttribsARB)
     {
@@ -295,7 +295,7 @@ void ContextGLX::CreateContext(ContextGLX* shared, unsigned int bitsPerPixel, co
             0, 0
         };
         myContext = glXCreateContextAttribsARB(myDisplay, configs[0], toShare, true, attributes);
-    }
+    }*/
 
     // If the OpenGL 3.0 context failed, create a regular OpenGL 1.x context
     if (!myContext)