Hoist boundary condition out of loop header.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181248 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/DebugInfo/DWARFContext.cpp b/lib/DebugInfo/DWARFContext.cpp
index a47fe56..9f52133 100644
--- a/lib/DebugInfo/DWARFContext.cpp
+++ b/lib/DebugInfo/DWARFContext.cpp
@@ -141,7 +141,8 @@
       OS << "\n.debug_str_offsets.dwo contents:\n";
       DataExtractor strOffsetExt(getStringOffsetDWOSection(), isLittleEndian(), 0);
       offset = 0;
-      while (offset < getStringOffsetDWOSection().size()) {
+      uint64_t size = getStringOffsetDWOSection().size();
+      while (offset < size) {
         OS << format("0x%8.8x: ", offset);
         OS << format("%8.8x\n", strOffsetExt.getU32(&offset));
       }