Revert "[SLP]Fix a crash when insert subvector is out of range."

This reverts commit f1ee273.

Revert due to the revert of a dependent commit `[SLP]Improve shuffles cost estimation where possible.`

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -6168,16 +6168,6 @@ InstructionCost BoUpSLP::getEntryCost(const TreeEntry *E,
           PowerOf2Ceil(OffsetEnd - OffsetBeg + 1),
           ((OffsetEnd - OffsetBeg + VecScalarsSz) / VecScalarsSz) *
               VecScalarsSz);
-      bool IsWholeSubvector =
-          OffsetBeg == Offset && ((OffsetEnd + 1) % VecScalarsSz == 0);
-      // Check if we can safely insert a subvector. If it is not possible, just
-      // generate a whole-sized vector and shuffle the source vector and the new
-      // subvector.
-      if (OffsetBeg + InsertVecSz > VecSz) {
-        // Align OffsetBeg to generate correct mask.
-        OffsetBeg = alignDown(OffsetBeg, VecSz, Offset);
-        InsertVecSz = VecSz;
-      }
 
       APInt DemandedElts = APInt::getZero(NumElts);
       // TODO: Add support for Instruction::InsertValue.
@@ -6221,7 +6211,7 @@ InstructionCost BoUpSLP::getEntryCost(const TreeEntry *E,
       // TODO: Implement the analysis of the FirstInsert->getOperand(0)
       // subvector of ActualVecTy.
       if (!isUndefVector(FirstInsert->getOperand(0)) && NumScalars != NumElts &&
-          !IsWholeSubvector) {
+          (Offset != OffsetBeg || (OffsetEnd + 1) % VecScalarsSz != 0)) {
         if (InsertVecSz != VecSz) {
           auto *ActualVecTy =
               FixedVectorType::get(SrcVecTy->getElementType(), VecSz);