Enable aligned NEON spilling by default.

Experiments show this to be a small speedup for modern ARM cores.

llvm-svn: 147689
diff --git a/llvm/lib/Target/ARM/ARMFrameLowering.cpp b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
index deac545..5f54d49 100644
--- a/llvm/lib/Target/ARM/ARMFrameLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
@@ -28,7 +28,7 @@
 using namespace llvm;
 
 cl::opt<bool>
-SpillAlignedNEONRegs("align-neon-spills", cl::Hidden,
+SpillAlignedNEONRegs("align-neon-spills", cl::Hidden, cl::init(true),
                      cl::desc("Align ARM NEON spills in prolog and epilog"));
 
 static MachineBasicBlock::iterator