[llvm-dev] Liveness Analysis

[Matthias Braun via llvm-dev]

Assuming you talk about the machine representation:
- The register allocators use the LiveIntervals analysis (there is also LiveVariables but that is deprecated, please don't use it).
- When register allocation is done we keep the block live-in lists around and you can use LivePhysReg or LiveRegUnits to recompute the liveness information in the middle of a basic block when necessary.
- The RDF framework in lib/Target/Hexagon performs a dataflow analysis post-regalloc to determine values in physical registers.

- Matthias

> On Sep 20, 2018, at 11:31 AM, Jason Ott via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> Where is the liveness analysis pass?  I have been looking for days but cannot find anything.
> 
> I just want to know transfer variables in and out of basic blocks, that are calculated using simple data flow equations. 
> 
> Thanks!
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