PR4591: Make sure to initialize the pass manager before using it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76422 91177308-0d34-0410-b5e6-96231b3b80d8

examples/Kaleidoscope/toy.cpp

@@ -1125,6 +1125,8 @@ int main() {
     // Simplify the control flow graph (deleting unreachable blocks, etc).
     OurFPM.add(createCFGSimplificationPass());
 
+    OurFPM.doInitialization();
+
     // Set the global so the code gen can use this.
     TheFPM = &OurFPM;