diff --git a/CMakeLists.txt b/CMakeLists.txt
index 55e79e9..bf17cbe 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,8 +24,8 @@ set(EXECUTABLE_OUTPUT_PATH "${CMAKE_BINARY_DIR}")
 find_package(OpenMP)
 
 # set compiler flags, see http://stackoverflow.com/questions/7724569/debug-vs-release-in-cmake
-set(CMAKE_CXX_FLAGS "-march=native -Ofast -fno-signed-zeros -fno-trapping-math -Wall -Wno-format-extra-args -Wextra -Wformat-nonliteral -Wformat-security -Wformat=2 -Wextra -Wno-implicit-fallthrough -Wno-narrowing -pedantic")
-set(CMAKE_C_FLAGS "-march=native -Ofast -fno-signed-zeros -fno-trapping-math -Wall -Wno-format-extra-args -Wextra -Wformat-nonliteral -Wformat-security -Wformat=2 -Wextra -Wno-implicit-fallthrough -Wno-narrowing -pedantic")
+set(CMAKE_CXX_FLAGS "-march=native -O3 -Wall -Wno-format-extra-args -Wextra -Wformat-nonliteral -Wformat-security -Wformat=2 -Wextra -Wno-implicit-fallthrough -Wno-narrowing -pedantic")
+set(CMAKE_C_FLAGS "-march=native -O3 -Wall -Wno-format-extra-args -Wextra -Wformat-nonliteral -Wformat-security -Wformat=2 -Wextra -Wno-implicit-fallthrough -Wno-narrowing -pedantic")
 
 if (OPENMP_FOUND)
 	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
diff --git a/src/util b/src/util
index af5dfda..608bcfd 160000
--- a/src/util
+++ b/src/util
@@ -1 +1 @@
-Subproject commit af5dfda8b99049207e8e2fcce172d250d61ad2ac
+Subproject commit 608bcfd4a0aa3e7ea1aa8ab2a34ce557bbbaf74c