diff --git a/CMakeLists.txt b/CMakeLists.txt
index d53c48aa1..4c987bd7a 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -105,7 +105,7 @@ ENDIF()
 
 IF(NOT CMAKE_SYSTEM_NAME)
   MESSAGE(FATAL_ERROR "CMAKE_SYSTEM_NAME not defined")
-ELSEIF(NOT CMAKE_SYSTEM_NAME MATCHES "^(Darwin|Linux|Android|Windows|CYGWIN|MSYS)$")
+ELSEIF(NOT CMAKE_SYSTEM_NAME MATCHES "^(Darwin|Linux|Android|Windows|CYGWIN|MSYS|Emscripten|iOS)$")
   MESSAGE(FATAL_ERROR "Unrecognized CMAKE_SYSTEM_NAME = ${CMAKE_SYSTEM_NAME}")
 ENDIF()
 
@@ -7108,6 +7108,10 @@ IF(MSVC)
   SET_PROPERTY(SOURCE ${ALL_MICROKERNEL_SRCS} APPEND_STRING PROPERTY COMPILE_FLAGS "$<$<NOT:$<CONFIG:Debug>>: /O2 >")
   SET_PROPERTY(SOURCE ${HOT_SRCS} APPEND_STRING PROPERTY COMPILE_FLAGS "$<$<NOT:$<CONFIG:Debug>>: /O2 >")
   SET_PROPERTY(SOURCE ${COLD_SRCS} APPEND_STRING PROPERTY COMPILE_FLAGS "$<$<NOT:$<CONFIG:Debug>>: /O1 >")
+ELSEIF(CMAKE_GENERATOR STREQUAL Xcode)
+  TARGET_COMPILE_OPTIONS(all_microkernels PRIVATE $<$<NOT:$<CONFIG:Debug>>: -O2 >)
+  TARGET_COMPILE_OPTIONS(XNNPACK PRIVATE $<$<NOT:$<CONFIG:Debug>>: -O2 >)
+  TARGET_COMPILE_OPTIONS(XNNPACK PRIVATE $<$<NOT:$<CONFIG:Debug>>: -Os >)
 ELSE()
   SET_PROPERTY(SOURCE ${ALL_MICROKERNEL_SRCS} APPEND_STRING PROPERTY COMPILE_FLAGS "$<$<NOT:$<CONFIG:Debug>>: -O2 >")
   SET_PROPERTY(SOURCE ${HOT_SRCS} APPEND_STRING PROPERTY COMPILE_FLAGS "$<$<NOT:$<CONFIG:Debug>>: -O2 >")