diff --git a/math/KahanSum.h b/math/KahanSum.h
index e2622a0..cb0edb9 100644
--- a/math/KahanSum.h
+++ b/math/KahanSum.h
@@ -49,10 +49,15 @@ public:
 
 private:
 
-#define NO_OPT	__attribute__((optimize("-O0")))
+#ifdef _MSC_VER 
+  #pragma optimize( "", off )
+#else
+  #pragma GCC push_options
+  #pragma GCC optimize ("O0")
+#endif
 
 	/** adjust the sum */
-	void add(const T val) NO_OPT {
+	void add(const T val) {
 		const T y = val - comp;
 		const T t = sum + y;
 		comp = (t-sum) - y;				// very important line
@@ -60,13 +65,19 @@ private:
 	}
 
 	/** adjust the sum */
-	void sub(const T val) NO_OPT {
+	void sub(const T val) {
 		const T y = val - comp;
 		const T t = sum - y;
 		comp = (t-sum) + y;				// very important line
 		sum = t;
 	}
 
+#ifdef _MSC_VER
+  #pragma optimize( "", on ) 
+#else
+  #pragma GCC pop_options
+#endif
+
 public:
 
 	static T get(const std::vector<T>& values, const T zero = T()) {