MakeClass Analysis hangs with TChain


I’m using a simple MakeClass loop a few simple ntuples. I have replaced the TTree with a TChain to add multiple files. It runs fine with one in the tree, but not two. I ran a profiler on the hanging process and it makes a lot of calls to:

operator new(unsigned long)
                _spin_lock$VARIANT$mp (libsystem_c.dylib)

Any ideas?

Looks like it was due to some optimisations. I removed -O3 from my build script and now it finishes.