Clarify meaning of copyRegToReg's return value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57449 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 1 deletions

diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index fcd0016ca0..510da1adfa 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -220,7 +220,9 @@ public:
     return 0;
   }
   
-  /// copyRegToReg - Add a copy between a pair of registers
+  /// copyRegToReg - Emit instructions to copy between a pair of registers. It
+  /// returns false if the target does not how to copy between the specified
+  /// registers.
   virtual bool copyRegToReg(MachineBasicBlock &MBB,
                             MachineBasicBlock::iterator MI,
                             unsigned DestReg, unsigned SrcReg,