Re: Graph colouring and local register allocation

> Many other global allocators are also able to solve local allocation.
> After all, local allocation is an easier problem. I expect the reason
> some people use a separate local allocator is that they have a bright
> idea about how to do a better job on the simpler problem, so they try
> it out.


One bright spot is how you approach register allocation on a stack
architecture(e.g. x87). That architecture allows you to think only in
local allocation terms. A useful idea to exploit in local register
allocation is placement of spill code. If you build a trace(like the
one that is created by an instruction scheduler) then you can try
moving code across basic block boundaries(either up or down) to bring
live ranges "closer"(i.e. make them shorter). The more closer a live
range becomes, the less likely will it approach k.


Sincerely.

Return to the comp.compilers page.
Search the comp.compilers archives again.