Fix entrypoint lookup.

Author: maleadt

src/driver.jl

@@ -372,9 +372,6 @@ const __llvm_initialized = Ref(false)
                         end
                     end
                 end
-
-                # optimization may have replaced functions, so look the entry point up again
-                entry = functions(ir)[entry_fn]
             end
 
             if job.config.cleanup
@@ -390,6 +387,9 @@ const __llvm_initialized = Ref(false)
                 end
             end
 
+            # optimization may have replaced functions, so look the entry point up again
+            entry = functions(ir)[entry_fn]
+
             # finish the module
             #
             # we want to finish the module after optimization, so we cannot do so