//  [IfRegionA(4)],
//  [IfRegionA(5), IfRegionA(6)]]
using RegionVec2D = llvm::SmallVector<llvm::SmallVector<TF::IfRegionOp, 8>, 8>;
using OperationVec2D = llvm::SmallVector<llvm::SmallVector<Operation*, 8>, 8>;
using MapToRegionVec2D = llvm::SmallDenseMap<Value, RegionVec2D>;
using MapToOperationVec2D = llvm::SmallDenseMap<Value, OperationVec2D>;
using IfOpIterConst =
    llvm::SmallVectorTemplateCommon<mlir::TF::IfRegionOp>::const_iterator;