Emiting invariant.group.barrier for ctors bugfix
Ensure that the vptr store in the most-derived constructor is not behind
an invariant group barrier. Previously, the base-most vptr store would
be the one behind no barrier, and that could result in the creator of
the object thinking it had the base-most vtable.
This bug caused clang call pure virtual functions when called from
constructor body.
http://reviews.llvm.org/D13373
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@249197
91177308-0d34-0410-b5e6-
96231b3b80d8