[bschmitt]

> Optimizations may be completely turned off with the directive PRAGMA PRESERVE_BLOCK [0]

This turn off compilation itself. If you read the documentation you referred me to, you will notice that code inside the directive won't be guaranteed to be legal QPU code after compilation.

> Many of the links you’ve listed are either “compilation frameworks” (like scaffcc, akin to LLVM), unitary factorizers (like qubiter, though I’m less familiar), and so on.

I don't know what you mean by "compilation framework" nor where you are drawing the line of what is a compiler, but ScaffCC is a compiler. It is built using llvm (so it is akin to Clang, not llvm) and compiles Scaffold to QASM.