diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index f528143a8ba..10256e7ded3 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -363,6 +363,9 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   }
 
   computeRegisterProperties();
+
+  // Perferred loop alignment is 16.
+  setPrefLoopAlignment(16);
 }
 
 /// getByValTypeAlignment - Return the desired alignment for ByVal aggregate