diff --git a/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
index 2058dd06b21..24cb129b0b7 100644
--- a/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -104,7 +104,7 @@ public:
     return 64;
   }
 
-  unsigned getMaximumUnrollFactor() const override { return 2; }
+  unsigned getMaximumUnrollFactor() const override;
 
   unsigned getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src) const
       override;
@@ -513,3 +513,9 @@ unsigned AArch64TTI::getCostOfKeepingLiveOverCall(ArrayRef<Type*> Tys) const {
   }
   return Cost;
 }
+
+unsigned AArch64TTI::getMaximumUnrollFactor() const {
+  if (ST->isCortexA57() || ST->isCyclone())
+    return 4;
+  return 2;
+}