[LoopUnroll] Enable PGO-based loop peeling by default.

This enables peeling of loops with low dynamic iteration count by default,
when profile information is available.

Differential Revision: https://reviews.llvm.org/D27734

llvm-svn: 295796

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index 934bb3b6f1e..95daf3bc72c 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -110,7 +110,7 @@ static cl::opt<unsigned> FlatLoopTripCountThreshold(
              "aggressively unrolled."));
 
 static cl::opt<bool>
-    UnrollAllowPeeling("unroll-allow-peeling", cl::Hidden,
+    UnrollAllowPeeling("unroll-allow-peeling", cl::init(true), cl::Hidden,
                        cl::desc("Allows loops to be peeled when the dynamic "
                                 "trip count is known to be low."));
 
@@ -155,7 +155,7 @@ static TargetTransformInfo::UnrollingPreferences gatherUnrollingPreferences(
   UP.AllowExpensiveTripCount = false;
   UP.Force = false;
   UP.UpperBound = false;
-  UP.AllowPeeling = false;
+  UP.AllowPeeling = true;
 
   // Override with any target specific settings
   TTI.getUnrollingPreferences(L, UP);