Prevent Clang from crashing on template code.

Fixes PR20110, where Clang hits an assertion failure when it expects that the
sub-expression of a bit cast to pointer to also be a pointer, but gets a value
instead.

Differential Revision: http://reviews.llvm.org/D4280


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212160 91177308-0d34-0410-b5e6-96231b3b80d8