how to disable live variable analyst with optimization option in codegen ?

Hello llvmer:
I am develop new registerb allocation for my study . my register allocation
do not depend on live variable . I add an option which will be cheked
whether the pass should be add or not in "addOptimizeRegalloc ,".

But live variable analysis still appeare

After debug,I'm sure that live variable is not add during addPass stage .
FYI ,I disable the phiEliminate,live interval , and other analysis depend on
live variable .