[LLVMdev] Regalloc Refactoring
greened at obbligato.org
Wed Apr 18 09:10:43 PDT 2007
Evan Cheng wrote:
> the given infrastructure? Perhaps. But not without pain. The current
> data structure is lacking detailed def-use info to properly determine
> the correct split point. The register allocator even treat
> "fixed" (i.e. physical register) intervals separately from other
> active ones.
> The point is, the current code needs a lot of massaging. If you are
> interested (after your first rounds of refactoring), please consider
> a replacement for LiveInterval that keeps more accurate info that can
> be plugged into the same existing allocator. The next step is to do
> away with the r2rmap and rep().
This gets back to my questions about what LiveIntervals lacks.
- What "data structure" are you referring to above?
- What specific def-use info is needed that we don't have access
- A couple of weeks ago I asked about the comment in
LiveIntervalAnalysis referring to "conservative" computation.
What's conservative about it? What information does it lack that
a traditional live variable/live range analysis provides?
The answers I got back said essentially that it's not conservative
at all and can't be improved upon. I'm getting a different sense
from you so I'd like to understand this better.
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