[Bug middle-end/124552] [16 Regression] fn->copyid_alloc is never released

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124552

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I'll note this is the most heavy polluter of valgrind --leak-check=full given
the backtrace is quite random as we allocate this on demand.  So the overall
impact of the leak is likely worse.  It also seems to not exactly be a space
optimized representation :/  (but there's no switch to turn it off, so it's
difficult to make a 1:1 comparison here)

A trivially correct point to delete would be free_after_compilation, but I
hope it might be possible earlier?