Fix a merge conflict.

Author: dcci

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -6457,7 +6457,6 @@ InstructionCost BoUpSLP::getEntryCost(const TreeEntry *E,
             if (Mask[I] != UndefMaskElem)
               Mask[I] = I + VecSz;
           for (unsigned I = OffsetEnd + 1 - Offset; I < VecSz; ++I)
-            Mask[I] = InMask.test(I) ? UndefMaskElem : I;
             Mask[I] =
                 ((I >= InMask.size()) || InMask.test(I)) ? UndefMaskElem : I;
           Cost += TTI->getShuffleCost(TTI::SK_PermuteTwoSrc, InsertVecTy, Mask);