Also compute interference intervals for blocks with no uses.

When the live range is live through a block that doesn't use the register, but
that has interference, region splitting wants to split at the top and bottom of
the basic block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124839 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed