Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -274,16 +274,24 @@
     execute_process(
       COMMAND xcodebuild -version -sdk ${sdk_name}.internal Path
       OUTPUT_VARIABLE ${var}
+      RESULT_VARIABLE result_xcodebuild
       OUTPUT_STRIP_TRAILING_WHITESPACE
       ERROR_FILE /dev/null
     )
+    if(result_xcodebuild)
+      set(${var})
+    endif()
     if(${var} STREQUAL "")
       execute_process(
         COMMAND xcodebuild -version -sdk ${sdk_name} Path
         OUTPUT_VARIABLE ${var}
+        RESULT_VARIABLE result_xcodebuild
         OUTPUT_STRIP_TRAILING_WHITESPACE
         ERROR_FILE /dev/null
       )
+      if(result_xcodebuild)
+        set(${var})
+      endif()
     endif()
   endmacro()
 
Index: cmake/config-ix.cmake
===================================================================
--- cmake/config-ix.cmake
+++ cmake/config-ix.cmake
@@ -160,22 +160,37 @@
 else()
   if("${LLVM_NATIVE_ARCH}" STREQUAL "X86")
     if(NOT MSVC)
+      if(APPLE)
+        set(CMAKE_TRY_COMPILE_OSX_ARCHITECTURES x86_64)
+      endif()
       test_target_arch(x86_64 "" "-m64")
       # FIXME: We build runtimes for both i686 and i386, as "clang -m32" may
       # target different variant than "$CMAKE_C_COMPILER -m32". This part should
       # be gone after we resolve PR14109.
+      if(APPLE)
+        set(CMAKE_TRY_COMPILE_OSX_ARCHITECTURES i386)
+      endif()
       test_target_arch(i686 __i686__ "-m32")
       test_target_arch(i386 __i386__ "-m32")
+      if(APPLE)
+        set(CMAKE_TRY_COMPILE_OSX_ARCHITECTURES)
+      endif()
     else()
       test_target_arch(i386 "" "")
     endif()
   elseif("${LLVM_NATIVE_ARCH}" STREQUAL "PowerPC")
     TEST_BIG_ENDIAN(HOST_IS_BIG_ENDIAN)
+    if(APPLE)
+      set(CMAKE_TRY_COMPILE_OSX_ARCHITECTURES ppc64)
+    endif()
     if(HOST_IS_BIG_ENDIAN)
       test_target_arch(powerpc64 "" "-m64")
     else()
       test_target_arch(powerpc64le "" "-m64")
     endif()
+    if(APPLE)
+      set(CMAKE_TRY_COMPILE_OSX_ARCHITECTURES)
+    endif()
   elseif("${LLVM_NATIVE_ARCH}" STREQUAL "Mips")
     if("${COMPILER_RT_TEST_TARGET_ARCH}" MATCHES "mipsel|mips64el")
       # regex for mipsel, mips64el
@@ -186,11 +201,23 @@
       test_target_arch(mips64 "" "-m64")
     endif()
   elseif("${COMPILER_RT_TEST_TARGET_ARCH}" MATCHES "arm")
+    if(APPLE)
+      set(CMAKE_TRY_COMPILE_OSX_ARCHITECTURES armv7)
+    endif()
     test_target_arch(arm "" "-march=armv7-a")
+    if(APPLE)
+      set(CMAKE_TRY_COMPILE_OSX_ARCHITECTURES)
+    endif()
   elseif("${COMPILER_RT_TEST_TARGET_ARCH}" MATCHES "aarch32")
     test_target_arch(aarch32 "" "-march=armv8-a")
   elseif("${COMPILER_RT_TEST_TARGET_ARCH}" MATCHES "aarch64")
+    if(APPLE)
+      set(CMAKE_TRY_COMPILE_OSX_ARCHITECTURES arm64)
+    endif()
     test_target_arch(aarch64 "" "-march=armv8-a")
+    if(APPLE)
+      set(CMAKE_TRY_COMPILE_OSX_ARCHITECTURES)
+    endif()
   endif()
   set(COMPILER_RT_OS_SUFFIX "")
 endif()