fix PR13550: add a cmake WITH_POLLY option

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203486 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Sebastian Pop

CMakeLists.txt

@@ -565,3 +565,9 @@ if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
     )
 endif()
 
+option(WITH_POLLY "Build LLVM with Polly" ON)
+if(WITH_POLLY)
+  if(NOT EXISTS ${LLVM_MAIN_SRC_DIR}/tools/polly/CMakeLists.txt)
+    set(WITH_POLLY OFF)
+  endif()
+endif(WITH_POLLY)

tools/CMakeLists.txt

@@ -66,7 +66,12 @@ add_llvm_external_project(clang)
 if( NOT LLVM_INCLUDE_TOOLS STREQUAL "bootstrap-only" )
   add_llvm_external_project(lld)
   add_llvm_external_project(lldb)
-  add_llvm_external_project(polly)
+
+  if(WITH_POLLY)
+    add_llvm_external_project(polly)
+  else(WITH_POLLY)
+    list(APPEND LLVM_IMPLICIT_PROJECT_IGNORE "${CMAKE_CURRENT_SOURCE_DIR}/polly")
+  endif(WITH_POLLY)
 
   # Automatically add remaining sub-directories containing a 'CMakeLists.txt'
   # file as external projects.