Revert "[SLP]Check for the whole vector vectorization in unique scalars analysis"

This reverts commit b74e09c after
post-commit review. The number of parts is calculated incorrectly.

Author: alexey-bataev

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -408,7 +408,7 @@ static bool isVectorLikeInstWithConstOps(Value *V) {
 /// total number of elements \p Size and number of registers (parts) \p
 /// NumParts.
 static unsigned getPartNumElems(unsigned Size, unsigned NumParts) {
-  return std::min<unsigned>(Size, PowerOf2Ceil(divideCeil(Size, NumParts)));
+  return PowerOf2Ceil(divideCeil(Size, NumParts));
 }
 
 /// Returns correct remaining number of elements, considering total amount \p
@@ -7021,11 +7021,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
         UniqueValues.emplace_back(V);
     }
     size_t NumUniqueScalarValues = UniqueValues.size();
-    bool IsFullVectors =
-        hasFullVectorsOnly(*TTI, UniqueValues.front()->getType(),
-                           NumUniqueScalarValues);
-    if (NumUniqueScalarValues == VL.size() &&
-        (VectorizeNonPowerOf2 || IsFullVectors)) {
+    if (NumUniqueScalarValues == VL.size()) {
       ReuseShuffleIndices.clear();
     } else {
       // FIXME: Reshuffing scalars is not supported yet for non-power-of-2 ops.
@@ -7036,10 +7032,14 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
         return false;
       }
       LLVM_DEBUG(dbgs() << "SLP: Shuffle for reused scalars.\n");
-      if (NumUniqueScalarValues <= 1 || !IsFullVectors ||
-          (UniquePositions.size() == 1 && all_of(UniqueValues, [](Value *V) {
-             return isa<UndefValue>(V) || !isConstant(V);
-           }))) {
+      if (NumUniqueScalarValues <= 1 ||
+          (UniquePositions.size() == 1 && all_of(UniqueValues,
+                                                 [](Value *V) {
+                                                   return isa<UndefValue>(V) ||
+                                                          !isConstant(V);
+                                                 })) ||
+          !hasFullVectorsOnly(*TTI, UniqueValues.front()->getType(),
+                              NumUniqueScalarValues)) {
         if (DoNotFail && UniquePositions.size() > 1 &&
             NumUniqueScalarValues > 1 && S.MainOp->isSafeToRemove() &&
             all_of(UniqueValues, [=](Value *V) {
@@ -9143,6 +9143,9 @@ class BoUpSLP::ShuffleCostEstimator : public BaseShuffleAnalysis {
       return nullptr;
     Value *VecBase = nullptr;
     ArrayRef<Value *> VL = E->Scalars;
+    // If the resulting type is scalarized, do not adjust the cost.
+    if (NumParts == VL.size())
+      return nullptr;
     // Check if it can be considered reused if same extractelements were
     // vectorized already.
     bool PrevNodeFound = any_of(
@@ -9795,7 +9798,7 @@ BoUpSLP::getEntryCost(const TreeEntry *E, ArrayRef<Value *> VectorizedVals,
       InsertMask[Idx] = I + 1;
     }
     unsigned VecScalarsSz = PowerOf2Ceil(NumElts);
-    if (NumOfParts > 0 && NumOfParts < NumElts)
+    if (NumOfParts > 0)
       VecScalarsSz = PowerOf2Ceil((NumElts + NumOfParts - 1) / NumOfParts);
     unsigned VecSz = (1 + OffsetEnd / VecScalarsSz - OffsetBeg / VecScalarsSz) *
                      VecScalarsSz;