Add CFG Simplification pass after Loop Unswitching.
Loop unswitching produces conditional branches with constant condition,
and it's beneficial for later passes to clean this up with simplify-cfg.
We do this after the second invocation of loop-unswitch, but not after
the first one. Not doing so might cause problem for passes like
LoopUnroll, whose estimate of loop body size would be less accurate.
Reviewers: hfinkel
Differential Revision: http://reviews.llvm.org/D13064
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248460
91177308-0d34-0410-b5e6-
96231b3b80d8