[Loop Peeling] Enable peeling of multiple exits by default

[skatkov]

Summary

Enable loop peeling with multiple exits where all non-latch exits
ends up with deopt by default.

llvm/trunk/lib/Transforms/Utils/LoopUnrollPeel.cpp

static cl::opt<unsigned> UnrollPeelMaxCount(
     "unroll-peel-max-count", cl::init(7), cl::Hidden,
     cl::desc("Max average trip count which will cause loop peeling."));
 
 static cl::opt<unsigned> UnrollForcePeelCount(
     "unroll-force-peel-count", cl::init(0), cl::Hidden,
     cl::desc("Force a peel count regardless of profiling information."));
 
 static cl::opt<bool> UnrollPeelMultiDeoptExit(
-    "unroll-peel-multi-deopt-exit", cl::init(false), cl::Hidden,
+    "unroll-peel-multi-deopt-exit", cl::init(true), cl::Hidden,
     cl::desc("Allow peeling of loops with multiple deopt exits."));
 
 // Designates that a Phi is estimated to become invariant after an "infinite"
 // number of loop iterations (i.e. only may become an invariant if the loop is
 // fully unrolled).
 static const unsigned InfiniteIterationsToInvariance =
     std::numeric_limits<unsigned>::max();