diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h
index eb997cddf23..5913d67b904 100644
--- a/include/llvm/Target/TargetRegisterInfo.h
+++ b/include/llvm/Target/TargetRegisterInfo.h
@@ -320,7 +320,8 @@ public:
     getPhysicalRegisterRegClass(unsigned Reg, EVT VT = MVT::Other) const;
 
   /// getMinimalPhysRegClass - Returns the Register Class of a physical
-  /// register of the given type.
+  /// register of the given type, picking the most sub register class of
+  /// the right type that contains this physreg.
   const TargetRegisterClass *
     getMinimalPhysRegClass(unsigned Reg, EVT VT = MVT::Other) const;
 
diff --git a/lib/Target/TargetRegisterInfo.cpp b/lib/Target/TargetRegisterInfo.cpp
index 48374d93d88..65898243d0a 100644
--- a/lib/Target/TargetRegisterInfo.cpp
+++ b/lib/Target/TargetRegisterInfo.cpp
@@ -61,7 +61,8 @@ TargetRegisterInfo::getPhysicalRegisterRegClass(unsigned reg, EVT VT) const {
 }
 
 /// getMinimalPhysRegClass - Returns the Register Class of a physical
-/// register of the given type.
+/// register of the given type, picking the most sub register class of
+/// the right type that contains this physreg.
 const TargetRegisterClass *
 TargetRegisterInfo::getMinimalPhysRegClass(unsigned reg, EVT VT) const {
   assert(isPhysicalRegister(reg) && "reg must be a physical register");