update comment.

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

diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h
index 48e8e55b296e118ff3a4057aea01897ce00a4772..fee1ef44e833b49fd76936d7036277e5e1a4750e 100644 (file)
--- 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