diff --git a/plugins/GSdx/stdafx.h b/plugins/GSdx/stdafx.h
index be7096a88a..a1e0312e28 100644
--- a/plugins/GSdx/stdafx.h
+++ b/plugins/GSdx/stdafx.h
@@ -391,11 +391,17 @@ using namespace stdext;
 
 	// http://svn.reactos.org/svn/reactos/trunk/reactos/include/crt/mingw32/intrin_x86.h?view=markup
 
-	__forceinline unsigned char _BitScanForward(unsigned long* const Index, const unsigned long Mask)
+	__forceinline int _BitScanForward(unsigned long* const Index, const unsigned long Mask)
 	{
-		__asm__("bsfl %k[Mask], %k[Index]" : [Index] "=r" (*Index) : [Mask] "mr" (Mask));
-		
+#if defined(__GCC_ASM_FLAG_OUTPUTS__) && 0
+		// Need GCC6 to test the code validity
+		int flag;
+		__asm__("bsfl %k[Mask], %k[Index]" : [Index] "=r" (*Index), "=@ccz" (flag) : [Mask] "mr" (Mask));
+		return flag;
+#else
+		__asm__("bsfl %k[Mask], %k[Index]" : [Index] "=r" (*Index) : [Mask] "mr" (Mask) : "cc");
 		return Mask ? 1 : 0;
+#endif
 	}
 
 	#ifdef __GNUC__