Fix typo.

Author: tianleliu

llvm/lib/Analysis/ValueTracking.cpp

@@ -8907,7 +8907,7 @@ static Value *lookThroughCast(CmpInst *CmpI, Value *V1, Value *V2,
       // We can always move trunc after select operation:
       //   %y_ext = sext iK %y to iN
       //   %cond = cmp iN %x, %y_ext
-      //   %widesel = select i1 %cond, iN %x, iN%y_ext
+      //   %widesel = select i1 %cond, iN %x, iN %y_ext
       //   %tr = trunc iN %widesel to iK
       assert(V2->getType() == Cast1->getType() &&
              "V2 and Cast1 should be the same type.");