Fix typos in comments, NFC

Summary: Just fixing comments, no functional change.

Test Plan: N/A

Reviewers: jfb

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D5130

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216784 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/ScalarEvolutionNormalization.cpp

@@ -126,7 +126,7 @@ TransformImpl(const SCEV *S, Instruction *User, Value *OperandValToReplace) {
       // Normalized form:   {-2,+,1,+,2}
       // Denormalized form: {1,+,3,+,2}
       //
-      // However, denormalization would use the a different step expression than
+      // However, denormalization would use a different step expression than
       // normalization (see getPostIncExpr), generating the wrong final
       // expression: {-2,+,1,+,2} + {1,+,2} => {-1,+,3,+,2}
       if (AR->isAffine() &&