https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102579
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Ah, so the idea is that we want to avoid re-ordering volatile accesses even if
they do not alias. Note the global var case is handled because we're going the
mark_all_reaching_defs_necessary way here but the
mark_all_reaching_defs_necessary_1 worker has the special-case
/* We want to skip statments that do not constitute stores but have
a virtual definition. */
if (gcall *call = dyn_cast <gcall *> (def_stmt))
{
...
if (callee != NULL_TREE
&& (DECL_IS_REPLACEABLE_OPERATOR_NEW_P (callee)
|| DECL_IS_OPERATOR_DELETE_P (callee))
&& gimple_call_from_new_or_delete (call))
return false;
which the mark_aliased_reaching_defs_necessary_1 worker has not.
