diff --git a/gdtoa/CMakeLists.txt b/gdtoa/CMakeLists.txt
index 4dff4c30db..a0b76e0c33 100644
--- a/gdtoa/CMakeLists.txt
+++ b/gdtoa/CMakeLists.txt
@@ -12,9 +12,6 @@ if( ZD_CMAKE_COMPILER_IS_GNUC_COMPATIBLE )
 	set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra" )
 endif()
 
-# Enable fast flag for gdtoa
-set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${ZD_FASTMATH_FLAG}" )
-
 include_directories( ${CMAKE_CURRENT_BINARY_DIR} )
 add_definitions( -DINFNAN_CHECK -DMULTIPLE_THREADS )