update comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49010 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 2 deletions

diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h
index 48e8e55b29..fee1ef44e8 100644
--- a/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -21,8 +21,9 @@
 
 namespace llvm {
   
-/// MachineRegisterInfo - Keep track of information for each virtual register,
-/// including its register class.
+/// MachineRegisterInfo - Keep track of information for virtual and physical
+/// registers, including vreg register classes, use/def chains for registers,
+/// etc.
 class MachineRegisterInfo {
   /// VRegInfo - Information we keep for each virtual register.  The entries in
   /// this vector are actually converted to vreg numbers by adding the