[llvm-commits] [llvm] r117174 - in /llvm/trunk: include/llvm/CodeGen/LinkAllCodegenComponents.h include/llvm/CodeGen/Passes.h lib/CodeGen/CMakeLists.txt lib/CodeGen/LiveIntervalUnion.cpp lib/CodeGen/LiveIntervalUnion.h lib/CodeGen/RegAllocBase.h lib/CodeGen/RegAllocBasic.cpp lib/CodeGen/SplitKit.h

[Jakob Stoklund Olesen]

On Oct 26, 2010, at 5:22 PM, Evan Cheng wrote:

> 
> On Oct 26, 2010, at 3:59 PM, Jakob Stoklund Olesen wrote:
>>> No particular reason. LiveStacks is a bit of a hack, I just think we should work towards removing the hack. Not having the allocator updating it is a good start.
>> 
>> What do you have in mind? It seems like an OK design to me.
> 
> 1) LiveStacks is only used to track live time of spill slots. We would want to track non-spill ones as well.

Good point. But we probably need to have llvm.lifetime.{start,end} up and running before that is going anywhere.

> 2) It's using LiveIntervals. Doesn't it seem a bit heavy weight?

Yes, that is true. Currently, all VNInfo's are coalesced into one, but we are still storing a bunch of pointers to that one.