Do you know if llvm got good at garbage collection support recently? My understanding was always that their optimisations would mangle your stack/registers so much that a decent incremental exact GC becomes super hard. And that something like keeping one/two pointers to the tip of the heap in dedicated registers is super hard/annoying too.

I don't have anything new. I might have to re-write a GC for Clasp. Then I know :)

A better questions would be whether anybody has a moving, precise GC running on LLVM. Clasp with MPS runs, but that might be coincidence/luck.