diff --git a/glslang/OGLCompilersDLL/CMakeLists.txt b/glslang/OGLCompilersDLL/CMakeLists.txt
index 08d8cefd6..db97e565f 100644
--- a/glslang/OGLCompilersDLL/CMakeLists.txt
+++ b/glslang/OGLCompilersDLL/CMakeLists.txt
@@ -1,5 +1,8 @@
 cmake_minimum_required(VERSION 2.8.12)
 
+make_release_only()
+set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${ZD_FASTMATH_FLAG}" )
+
 # Request C++11
 if(${CMAKE_VERSION} VERSION_LESS 3.1)
     # CMake versions before 3.1 do not understand CMAKE_CXX_STANDARD
diff --git a/glslang/glslang/CMakeLists.txt b/glslang/glslang/CMakeLists.txt
index f3fba3be5..4ac7159b3 100644
--- a/glslang/glslang/CMakeLists.txt
+++ b/glslang/glslang/CMakeLists.txt
@@ -1,5 +1,8 @@
 cmake_minimum_required(VERSION 2.8.12)
 
+make_release_only()
+set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${ZD_FASTMATH_FLAG}" )
+
 if(WIN32)
     add_subdirectory(OSDependent/Windows)
 elseif(UNIX)
diff --git a/glslang/spirv/CMakeLists.txt b/glslang/spirv/CMakeLists.txt
index 95439bf5b..c7fc8f983 100644
--- a/glslang/spirv/CMakeLists.txt
+++ b/glslang/spirv/CMakeLists.txt
@@ -1,5 +1,8 @@
 cmake_minimum_required(VERSION 2.8.12)
 
+make_release_only()
+set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${ZD_FASTMATH_FLAG}" )
+
 # Request C++11
 if(${CMAKE_VERSION} VERSION_LESS 3.1)
     # CMake versions before 3.1 do not understand CMAKE_CXX_STANDARD