SSA Trees and Lockless Implementation

Greetings, It seems possible after looking at the SSA dominator trees briefly to make them lockless at least partly for insertion/deletion/removal of both standard SSA nodes and PHI nodes. Am I right in assuming this or our there some subtle details that I'm missing when looking at and understandi

Question about pass_fix_loops or other loop fixing classes

Greetings, I was wondering why the execute function in the file tree-ssa-loop.c does not for all the pass fixing classes run it on a separate thread. Seems a good idea to call execute for these classes on another thread and then join up with the main thread into order to avoid shared state or waiti