refactor some code to avoid overloading the name 'usesLR' in 
different places to mean different things.  Document what the
one in PPCFunctionInfo means and when it is valid.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44699 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCMachineFunctionInfo.h b/lib/Target/PowerPC/PPCMachineFunctionInfo.h
index e227456..bf1fea2 100644
--- a/lib/Target/PowerPC/PPCMachineFunctionInfo.h
+++ b/lib/Target/PowerPC/PPCMachineFunctionInfo.h
@@ -39,8 +39,12 @@
   int getFramePointerSaveIndex() const { return FramePointerSaveIndex; }
   void setFramePointerSaveIndex(int Idx) { FramePointerSaveIndex = Idx; }
   
+  /// UsesLR - This is set when the prolog/epilog inserter does its initial scan
+  /// of the function, it is true if the LR/LR8 register is ever explicitly
+  /// accessed/clobbered in the machine function (e.g. by calls and movpctolr,
+  /// which is used in PIC generation).
   void setUsesLR(bool U) { UsesLR = U; }
-  bool usesLR()          { return UsesLR; }
+  bool usesLR() const    { return UsesLR; }
 
 };