r177329 - This code works around what appears to be a bug in another part of clang.

[Rafael Espíndola]

> So, about the testcase. It is the one in llvm.org/pr15538 that needs
> reducing, right? If that is so I am more than happy to help you reduce
> it and create a testcase we can add to clang.

It reduces to:

struct B {
  B();
};
B::B() {
}

The problem is that you are being passed an alias because of
-mconstructor-aliases. Since aliases don't have attributes, the
correct fix is probably to not call SetTargetAttributes since there is
nothing for it to set attributes on.

Cheers,
Rafael