Changed the liveness tracking in the RegisterScavenger

[oota-llvm.git] / include / llvm / CodeGen / MachineRegisterInfo.h

diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h
index 8a93e0a4b8442988b2d8050f5363622bbcec7652..0b9f8d150cfd9d0e030860aba80cc409cd7061c8 100644 (file)
--- a/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -516,8 +516,12 @@ public:
   ///
   /// That function will return NULL if the virtual registers have incompatible
   /// constraints.
+  ///
+  /// Note that if ToReg is a physical register the function will replace and
+  /// apply sub registers to ToReg in order to obtain a final/proper physical
+  /// register.
   void replaceRegWith(unsigned FromReg, unsigned ToReg);
-
+  
   /// getVRegDef - Return the machine instr that defines the specified virtual
   /// register or null if none is found.  This assumes that the code is in SSA
   /// form, so there should only be one definition.