[LLVMdev] interesting LLVM code optimization issue regarding timer registers

[Tim Northover]

> THe dsp instruction has no side effects and does not access memory.
>
> It's a valid thing to do.

At's a sympathetic desire, but doesn't fit entirely well with what the
compiler's doing. Associated with tha DSP instruction are likely to be
argument marshalling COPYs, and it's not entirely clear what semantics
they should have w.r.t. moving past the timer (even in an ideal
world).

Regardless, I don't think LLVM has that level of "keep your hands off" hints.

> Should be some way to do this I would think.

If I really wanted that degree of control I'd put the whole lot into
an inline assembly block.

Sorry I couldn't suggest anything neater.

Tim.