Add a CXX11-conditional test for exp2 precision with larger exponents

test/core/core_func_exponential.cpp

@@ -113,6 +113,12 @@ static int test_exp2()
 	glm::vec4 E = glm::exp2(glm::vec4(4.f, 3.f, 2.f, 1.f));
 	Error += glm::all(glm::epsilonEqual(E, glm::vec4(16.f, 8.f, 4.f, 2.f), 0.01f)) ? 0 : 1;
 
+#   if GLM_HAS_CXX11_STL
+    //large exponent
+    float F = glm::exp2(23.f);
+    Error += glm::epsilonEqual(F, 8388608.f, 0.01f) ? 0 : 1;
+#   endif
+    
 	return Error;
 }