Index: compiler-rt/cmake/base-config-ix.cmake
===================================================================
--- compiler-rt/cmake/base-config-ix.cmake
+++ compiler-rt/cmake/base-config-ix.cmake
@@ -58,10 +58,14 @@
   else()
     set(_host_executable_suffix ${CMAKE_EXECUTABLE_SUFFIX})
   endif()
-  set(COMPILER_RT_TEST_COMPILER
-    ${LLVM_RUNTIME_OUTPUT_INTDIR}/clang${_host_executable_suffix})
-  set(COMPILER_RT_TEST_CXX_COMPILER
-    ${LLVM_RUNTIME_OUTPUT_INTDIR}/clang++${_host_executable_suffix})
+  if (NOT COMPILER_RT_TEST_COMPILER)
+    set(COMPILER_RT_TEST_COMPILER
+      ${LLVM_RUNTIME_OUTPUT_INTDIR}/clang${_host_executable_suffix})
+  endif()
+  if (NOT COMPILER_RT_TEST_CXX_COMPILER)
+    set(COMPILER_RT_TEST_CXX_COMPILER
+      ${LLVM_RUNTIME_OUTPUT_INTDIR}/clang++${_host_executable_suffix})
+  endif()
 else()
     # Take output dir and install path from the user.
   set(COMPILER_RT_OUTPUT_DIR ${CMAKE_CURRENT_BINARY_DIR} CACHE PATH