> I can't see how this triggers on the IL above, the loop should have > ignored both the return and the clobber and when recursing to > the predecessor stop before the above check when runnig into the > call?
Yes, I tracked that down later. The problem was that there were multiple successors to the BB due to exception handling, which makes the find_tail_calls walker give up. Putting the new pass after ehcleanup fixed that, but there are still cases when ehcleanup cannot get rid of them and then it gives up. musttail checking at expand time still works, but can only give a vague error message. > > > In a optimized build this passes, but with -O0 it always fails > > when the pass is placed before pass_optimizations_g. I assume > > it's some problem with mem ssa form. > > > > Any ideas how to fix that? Otherwise I can restrict musttail to non > > structs. > > I wonder how this works when optimizing? It just doesn't. You need optimization to do tail calls with structs. The only alternative would be to detect the situation and pull in some extra passes. Also even with optimization it only works for structs that fit into registers. This could be maybe fixed, but is out of scope for this patch kit. -Andi
