Frame index can be negative.

llvm-svn: 102577
diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
index ec946d4..ae1fbd8 100644
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -647,7 +647,7 @@
 
 MachineInstr*
 PPCInstrInfo::emitFrameIndexDebugValue(MachineFunction &MF,
-                                       unsigned FrameIx, uint64_t Offset,
+                                       int FrameIx, uint64_t Offset,
                                        const MDNode *MDPtr,
                                        DebugLoc DL) const {
   MachineInstrBuilder MIB = BuildMI(MF, DL, get(PPC::DBG_VALUE));