Silence a bogus compile time warning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58297 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PreAllocSplitting.cpp b/lib/CodeGen/PreAllocSplitting.cpp
index 0969440..f3a3ac3 100644
--- a/lib/CodeGen/PreAllocSplitting.cpp
+++ b/lib/CodeGen/PreAllocSplitting.cpp
@@ -543,9 +543,9 @@
   // Add a spill either before the barrier or after the definition.
   MachineBasicBlock *DefMBB = DefMI ? DefMI->getParent() : NULL;
   const TargetRegisterClass *RC = MRI->getRegClass(CurrLI->reg);
-  int SS;
   unsigned SpillIndex = 0;
   MachineInstr *SpillMI = NULL;
+  int SS = -1;
   bool PrevSpilled = isAlreadySplit(CurrLI->reg, ValNo->id, SS);
   if (ValNo->def == ~0U) {
     // If it's defined by a phi, we must split just before the barrier.