https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100844
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Oh, and at -O0 garbage collection recursion overflows the stack following
SSA_NAME_DEF_STMT. We can almost make that GTY((skip(""))) but for the fact
that we have GIMPLE_NOP for default-defs and those are not in the IL ...
(OTOH it presents the opportunity to have a single global GIMPLE_NOP as
GTY root since GIMPLE_NOP does not have a SSA def). Or simply have NULL
as SSA def of default defs.
Btw, we're entering the SSA def chain via REG_DECL, we might want to consider
NULLing all SSA_NAME_DEF_STMT after expanding to RTL as well.
