Index: llvm/trunk/cmake/modules/AddLLVM.cmake
===================================================================
--- llvm/trunk/cmake/modules/AddLLVM.cmake
+++ llvm/trunk/cmake/modules/AddLLVM.cmake
@@ -1095,10 +1095,16 @@
   if (NOT CMAKE_CFG_INTDIR STREQUAL ".")
     list(APPEND LIT_ARGS --param build_mode=${CMAKE_CFG_INTDIR})
   endif ()
-  if (LLVM_MAIN_SRC_DIR)
-    set (LIT_COMMAND ${PYTHON_EXECUTABLE} ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
+  if (EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
+    # reset cache after erraneous r283029
+    # TODO: remove this once all buildbots run
+    if (LIT_COMMAND STREQUAL "${PYTHON_EXECUTABLE} ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py")
+      unset(LIT_COMMAND CACHE)
+    endif()
+    set (LIT_COMMAND "${PYTHON_EXECUTABLE};${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py"
+         CACHE STRING "Command used to spawn llvm-lit")
   else()
-    find_program(LIT_COMMAND llvm-lit)
+    find_program(LIT_COMMAND NAMES llvm-lit lit.py lit)
   endif ()
   list(APPEND LIT_COMMAND ${LIT_ARGS})
   foreach(param ${ARG_PARAMS})