These LiveRangeCalc methods are to be used when computing a live range
from scratch.

llvm-svn: 158027

Remove the same pointers from all the other LiveRangeCalc functions,
simplifying the interface.

llvm-svn: 157941

llvm-svn: 139581

SplitKit will soon need two copies of these data structures, and the
algorithms will also be useful when LiveIntervalAnalysis becomes
independent of LiveVariables.

llvm-svn: 139572