[RISCV][TTI] Use vtype for getRISCVInstructionCost

Author: arcbbb

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

@@ -1301,13 +1301,16 @@ InstructionCost RISCVTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
                                             : RISCV::VFNCVT_F_F_W;
     InstructionCost Cost = 0;
     for (; SrcEltSize != DstEltSize;) {
-      MVT ElementMVT = (ISD == ISD::TRUNCATE)
-                           ? MVT::getIntegerVT(DstEltSize)
+      MVT ElementMVT = (ISD == ISD::TRUNCATE) ? MVT::getIntegerVT(DstEltSize)
+                       : (ISD == ISD::FP_EXTEND)
+                           ? MVT::getFloatingPointVT(SrcEltSize)
                            : MVT::getFloatingPointVT(DstEltSize);
-      MVT DstMVT = DstLT.second.changeVectorElementType(ElementMVT);
-      DstEltSize =
-          (DstEltSize > SrcEltSize) ? DstEltSize >> 1 : DstEltSize << 1;
-      Cost += getRISCVInstructionCost(Op, DstMVT, CostKind);
+      MVT VTypeMVT = DstLT.second.changeVectorElementType(ElementMVT);
+      Cost += getRISCVInstructionCost(Op, VTypeMVT, CostKind);
+      if (DstEltSize > SrcEltSize)
+        SrcEltSize = SrcEltSize << 1;
+      else
+        DstEltSize = DstEltSize << 1;
     }
     return Cost;
   }

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h

@@ -48,6 +48,11 @@ class RISCVTTIImpl : public BasicTTIImplBase<RISCVTTIImpl> {
   /// actual target hardware.
   unsigned getEstimatedVLFor(VectorType *Ty);
 
+  /// This function calculates the costs for one or more RVV opcodes based
+  /// on the vtype and the cost kind.
+  /// \param Opcodes A list of opcodes of the RVV instruction to evaluate.
+  /// \param VT The MVT of vtype associated with the RVV instructions.
+  /// \param CostKind The type of cost to compute.
   InstructionCost getRISCVInstructionCost(ArrayRef<unsigned> OpCodes, MVT VT,
                                           TTI::TargetCostKind CostKind);