[RISCV] Return an invalid cost for memory ops with unsupported types

[liaolucy]

Maybe we can not return invalid costs. Just reference D123799.

[Miss_Grape]

ping

[jrtc27]

With no knowledge of how this side of things works, you at least need tests

[reames]

This patch does not meet basic standards.

• It has no explanation of intent.
• It has no tests.
• The code change itself seems nonsensical.

Phabricator doesn't give a way to hard reject, so marking as Request Changes and removing myself as reviewer.

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

 InstructionCost
 RISCVTTIImpl::getMaskedMemoryOpCost(unsigned Opcode, Type *Src, Align Alignment,
                                     unsigned AddressSpace,
                                     TTI::TargetCostKind CostKind) {
   if (!isa<ScalableVectorType>(Src))
     return BaseT::getMaskedMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
                                         CostKind);
 
-  return getMemoryOpCost(Opcode, Src, Alignment, AddressSpace, CostKind);
+  auto LT = TLI->getTypeLegalizationCost(DL, Src);
+  if (!LT.first.isValid())
+    return InstructionCost::getInvalid();
+
+  return LT.first;
 }
 
 InstructionCost RISCVTTIImpl::getGatherScatterOpCost(
     unsigned Opcode, Type *DataTy, const Value *Ptr, bool VariableMask,
     Align Alignment, TTI::TargetCostKind CostKind, const Instruction *I) {
   if (CostKind != TTI::TCK_RecipThroughput)
     return BaseT::getGatherScatterOpCost(Opcode, DataTy, Ptr, VariableMask,
                                          Alignment, CostKind, I);