[LLVMdev] About the information about live variable analysis

[Andrew Clinton]

> This information is only available during register allocation in the code generator. Look at LiveInterval::overlaps().
>
> That is quite late in the compilation process, and it is not easy to translate back to variables in the original program.
>
> /jakob
>

I'm noticing too that some useful analysis/transforms are only available 
in the code generator, after the IR has been transformed to another 
format.  At least for my application, I'm finding it would be useful to 
have some of these analysis (eg. register allocation) available in the 
optimizer as well, though I'm sure there is a good reason 
architecturally that LLVM is using a separate representation for codegen.

Andrew