llvm dev - Mar 2011 - [LLVMdev] How to get register liveness information for each MachineBasicBlock

Hi all,

I try to print the live-in and live-out registers for each basic block in a
backend for my own target.
And I can get a list of live-in registers directly in MachineBasicBlock.

Is there a quick way to also get the list of live-out registers without
redoing the analysis. I think
this information is computed and stored somewhere.

-- 

Regards,

Dongrui
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On Mar 21, 2011, at 3:46 AM, Dongrui She wrote:
> Hi all,
> 
> I try to print the live-in and live-out registers for each basic block in a
backend for my own target.
> And I can get a list of live-in registers directly in MachineBasicBlock.
> 
> Is there a quick way to also get the list of live-out registers without
redoing the analysis. I think
> this information is computed and stored somewhere.
This information is not available. You can compute the live-out set as the union
of the live-in sets of all successor blocks.

Note that the live-in lists only contain physical registers. Register allocation
computes liveness information for virtual registers in the LiveIntervals
analysis.

/jakob