Unfortunately the fix for the previous bug introduced the previous

Unfortunately the fix for the previous bug introduced the previous
exponential behavior (bork!).  This patch processes stuff with an
explicit SCC finder, allowing the algorithm to be more clear,
efficient, and also (as a bonus) correct!  This gets us back to taking
0.6s to disassemble my horrible .bc file that previously took something
> 30 mins.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16811 91177308-0d34-0410-b5e6-96231b3b80d8