Whitespace and comment changes. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63660 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/GCStrategy.cpp b/lib/CodeGen/GCStrategy.cpp
index b851c07..3ec368f 100644
--- a/lib/CodeGen/GCStrategy.cpp
+++ b/lib/CodeGen/GCStrategy.cpp
@@ -329,6 +329,7 @@
 unsigned MachineCodeAnalysis::InsertLabel(MachineBasicBlock &MBB, 
                                      MachineBasicBlock::iterator MI) const {
   unsigned Label = MMI->NextLabelID();
+  // N.B. we assume that MI is *not* equal to the "end()" iterator.
   BuildMI(MBB, MI, MI->getDebugLoc(),
           TII->get(TargetInstrInfo::GC_LABEL)).addImm(Label);
   return Label;