Add some comments, and tidy up some whitespace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70510 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/ScalarEvolution.h

@@ -449,7 +449,8 @@ namespace llvm {
     SCEVHandle getSCEVAtScope(Value *V, const Loop *L);
 
     /// isLoopGuardedByCond - Test whether entry to the loop is protected by
-    /// a conditional between LHS and RHS.
+    /// a conditional between LHS and RHS.  This is used to help avoid max
+    /// expressions in loop trip counts.
     bool isLoopGuardedByCond(const Loop *L, ICmpInst::Predicate Pred,
                              SCEV *LHS, SCEV *RHS);