Revert "[RISCV][TTI] Recognize CONCAT_VECTORS if a shufflevector mask is multiple insert subvector. (llvm#110457)"

This reverts commit 554eaec.  Change was not approved when landed.

Author: preames

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

@@ -343,49 +343,6 @@ RISCVTTIImpl::getConstantPoolLoadCost(Type *Ty,  TTI::TargetCostKind CostKind) {
                              /*AddressSpace=*/0, CostKind);
 }
 
-InstructionCost
-RISCVTTIImpl::isMultipleInsertSubvector(VectorType *Tp, ArrayRef<int> Mask,
-                                        TTI::TargetCostKind CostKind) {
-  if (!isa<FixedVectorType>(Tp))
-    return InstructionCost::getInvalid();
-  std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Tp);
-  if (LT.second.getScalarSizeInBits() == 1)
-    return InstructionCost::getInvalid();
-  // Try to guess SubTp.
-  for (unsigned SubVecSize = 1, E = Mask.size(); SubVecSize < E;
-       SubVecSize <<= 1) {
-    if (E % SubVecSize != 0)
-      continue;
-    SmallVector<int> RepeatedPattern(createSequentialMask(0, SubVecSize, 0));
-    bool Skip = false;
-    for (unsigned I = 0; I != E; I += SubVecSize)
-      if (!Mask.slice(I, SubVecSize).equals(RepeatedPattern)) {
-        Skip = true;
-        break;
-      }
-    if (Skip)
-      continue;
-    InstructionCost Cost = 0;
-    unsigned NumSlides = Log2_32(E / SubVecSize);
-    // The cost of extraction from a subvector is 0 if the index is 0.
-    for (unsigned I = 0; I != NumSlides; ++I) {
-      unsigned InsertIndex = SubVecSize * (1 << I);
-      FixedVectorType *SubTp = FixedVectorType::get(
-          cast<FixedVectorType>(Tp)->getElementType(), InsertIndex);
-      FixedVectorType *DesTp =
-          FixedVectorType::getDoubleElementsVectorType(SubTp);
-      std::pair<InstructionCost, MVT> DesLT = getTypeLegalizationCost(DesTp);
-      // Add the cost of whole vector register move because the destination
-      // vector register group for vslideup cannot overlap the source.
-      Cost += DesLT.first * TLI->getLMULCost(DesLT.second);
-      Cost += getShuffleCost(TTI::SK_InsertSubvector, DesTp, {}, CostKind,
-                             InsertIndex, SubTp);
-    }
-    return Cost;
-  }
-  return InstructionCost::getInvalid();
-}
-
 static VectorType *getVRGatherIndexType(MVT DataVT, const RISCVSubtarget &ST,
                                         LLVMContext &C) {
   assert((DataVT.getScalarSizeInBits() != 8 ||
@@ -437,10 +394,6 @@ InstructionCost RISCVTTIImpl::getShuffleCost(TTI::ShuffleKind Kind,
                                                         LT.second, CostKind);
           }
         }
-        if (InstructionCost Cost =
-                isMultipleInsertSubvector(Tp, Mask, CostKind);
-            Cost.isValid())
-          return Cost;
       }
       // vrgather + cost of generating the mask constant.
       // We model this for an unknown mask with a single vrgather.

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h

@@ -55,12 +55,6 @@ class RISCVTTIImpl : public BasicTTIImplBase<RISCVTTIImpl> {
   /// type.
   InstructionCost getConstantPoolLoadCost(Type *Ty,
                                           TTI::TargetCostKind CostKind);
-
-  /// Return the cost if a shufflevector can be consist of multiple vslideup.
-  /// Otherwise, return InstructionCost::getInvalid().
-  InstructionCost isMultipleInsertSubvector(VectorType *Tp, ArrayRef<int> Mask,
-                                            TTI::TargetCostKind CostKind);
-
 public:
   explicit RISCVTTIImpl(const RISCVTargetMachine *TM, const Function &F)
       : BaseT(TM, F.getDataLayout()), ST(TM->getSubtargetImpl(F)),

llvm/test/Analysis/CostModel/RISCV/fixed-vector-insert-subvector.ll

@@ -8,7 +8,7 @@
 ; YAML-NEXT:  Function:        test
 ; YAML-NEXT:  Args:
 ; YAML-NEXT:  - String:          'Stores SLP vectorized with cost '
-; YAML-NEXT:  - Cost:            '0'
+; YAML-NEXT:  - Cost:            '2'
 ; YAML-NEXT:  - String:          ' and with tree size '
 ; YAML-NEXT:  - TreeSize:        '7'
 

llvm/test/Transforms/SLPVectorizer/RISCV/remarks-insert-into-small-vector.ll

@@ -8,7 +8,7 @@
 ; YAML: Function:        test1
 ; YAML: Args:
 ; YAML:   - String:          'Stores SLP vectorized with cost '
-; YAML:   - Cost:            '4'
+; YAML:   - Cost:            '6'
 ; YAML:   - String:          ' and with tree size '
 ; YAML:   - TreeSize:        '5'
 
@@ -47,7 +47,7 @@ declare <4 x float> @llvm.fmuladd.v4f32(<4 x float>, <4 x float>, <4 x float>)
 ; YAML: Function:        test2
 ; YAML: Args:
 ; YAML:   - String:          'Stores SLP vectorized with cost '
-; YAML:   - Cost:            '12'
+; YAML:   - Cost:            '16'
 ; YAML:   - String:          ' and with tree size '
 ; YAML:   - TreeSize:        '5'