In this instance, a way to write a text representation of an internal data structure that represents code, run a single optimization pass over that data structure, dump the result, compare the result with serialized text representation of "expected value"?
Will they add the other parts, to extract an llvm-like core out of gcc and implement the C and C++ compilers and link time optimizer as users of that core?
Not as far as I can tell.
> In this instance, a way to write a text representation of an internal data structure that represents code, run a single optimization pass over that data structure, dump the result, compare the result with serialized text representation of "expected value"?
That's already existed for ages. See the -fdump-tree-* family of functions. It also doesn't do anything llvm-like.
Also, tons of things reused tons of bits for different purposes :)
Way the heck back when (pre-c++), i started splitting up just the decl hierarchy in trees to try to get things to stop reusing bits, and to expose what would be required to make it independent of the frontendy bits.