Update some comments, and expose LCSSAID in preparation for having other passes

require LCSSA.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28734 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Transforms/Scalar.h

@@ -306,6 +306,7 @@ FunctionPass *createBlockPlacementPass();
 // This pass inserts phi nodes at loop boundaries to simplify other loop 
 // optimizations.
 FunctionPass *createLCSSAPass();
+extern const PassInfo *LCSSAID;
 
 } // End llvm namespace