bother checking if a region is safe to use. In
cases where regions need to be synthesized rather
than properly allocated, the memory reads required
to determine whether the area is used are
- insufficient, because intermediate locations
could be in use, and
- unsafe, because on some platforms reading from
memory can trigger events.
All this only makes a difference on platforms
where memory allocation in the target is impossible.
Behavior on platforms where it is possible should
stay the same.
<rdar://problem/14023970>
llvm-svn: 185046