Rename DBG_LABEL PROLOG_LABEL, because it's only used during prolog emission and
thus is a much more meaningful name.

llvm-svn: 108563
diff --git a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
index 49c16f3..7d19666 100644
--- a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -501,7 +501,7 @@
       llvm_unreachable("Unknown or unset size field for instr!");
     case TargetOpcode::IMPLICIT_DEF:
     case TargetOpcode::KILL:
-    case TargetOpcode::DBG_LABEL:
+    case TargetOpcode::PROLOG_LABEL:
     case TargetOpcode::EH_LABEL:
     case TargetOpcode::DBG_VALUE:
       return 0;