ElaborationPass.cpp

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//===- ElaborationPass.cpp - RTG ElaborationPass implementation -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This pass elaborates the random parts of the RTG dialect.
// It performs randomization top-down, i.e., random constructs in a sequence
// that is invoked multiple times can yield different randomization results
// for each invokation.
//
//===----------------------------------------------------------------------===//
 
#include "circt/Dialect/RTG/IR/RTGAttributes.h"
#include "circt/Dialect/RTG/IR/RTGOps.h"
#include "circt/Dialect/RTG/IR/RTGVisitors.h"
#include "circt/Dialect/RTG/Transforms/RTGPasses.h"
#include "circt/Support/Namespace.h"
#include "mlir/Dialect/Arith/IR/Arith.h"
#include "mlir/Dialect/Index/IR/IndexDialect.h"
#include "mlir/Dialect/Index/IR/IndexOps.h"
#include "mlir/Dialect/SCF/IR/SCF.h"
#include "mlir/IR/IRMapping.h"
#include "mlir/IR/PatternMatch.h"
#include "llvm/ADT/DenseMapInfoVariant.h"
#include "llvm/Support/Debug.h"
#include <queue>
#include <random>
 
namespace circt {
namespace rtg {
#define GEN_PASS_DEF_ELABORATIONPASS
#include "circt/Dialect/RTG/Transforms/RTGPasses.h.inc"
} // namespace rtg
} // namespace circt
 
using namespace mlir;
using namespace circt;
using namespace circt::rtg;
using llvm::MapVector;
 
#define DEBUG_TYPE "rtg-elaboration"
 
//===----------------------------------------------------------------------===//
// Uniform Distribution Helper
//
// Simplified version of
// https://github.com/llvm/llvm-project/blob/main/libcxx/include/__random/uniform_int_distribution.h
// We use our custom version here to get the same results when compiled with
// different compiler versions and standard libraries.
//===----------------------------------------------------------------------===//
 
static uint32_t computeMask(size_t w) {
  size_t n = w / 32 + (w % 32 != 0);
  size_t w0 = w / n;
  return w0 > 0 ? uint32_t(~0) >> (32 - w0) : 0;
}
 
/// Get a number uniformly at random in the in specified range.
static uint32_t getUniformlyInRange(std::mt19937 &rng, uint32_t a, uint32_t b) {
  const uint32_t diff = b - a + 1;
  if (diff == 1)
    return a;
 
  const uint32_t digits = std::numeric_limits<uint32_t>::digits;
  if (diff == 0)
    return rng();
 
  uint32_t width = digits - llvm::countl_zero(diff) - 1;
  if ((diff & (std::numeric_limits<uint32_t>::max() >> (digits - width))) != 0)
    ++width;
 
  uint32_t mask = computeMask(diff);
  uint32_t u;
  do {
    u = rng() & mask;
  } while (u >= diff);
 
  return u + a;
}
 
//===----------------------------------------------------------------------===//
// Elaborator Value
//===----------------------------------------------------------------------===//
 
namespace {
struct ArrayStorage;
struct BagStorage;
struct SequenceStorage;
struct RandomizedSequenceStorage;
struct InterleavedSequenceStorage;
struct SetStorage;
struct VirtualRegisterStorage;
struct UniqueLabelStorage;
struct TupleStorage;
struct MemoryStorage;
struct MemoryBlockStorage;
struct ValidationValue;
struct ValidationMuxedValue;
struct ImmediateConcatStorage;
struct ImmediateSliceStorage;
 
/// Simple wrapper around a 'StringAttr' such that we know to materialize it as
/// a label declaration instead of calling the builtin dialect constant
/// materializer.
struct LabelValue {
  LabelValue(StringAttr name) : name(name) {}
 
  bool operator==(const LabelValue &other) const { return name == other.name; }
 
  /// The label name.
  StringAttr name;
};
 
/// The abstract base class for elaborated values.
using ElaboratorValue = std::variant<
    TypedAttr, BagStorage *, bool, size_t, SequenceStorage *,
    RandomizedSequenceStorage *, InterleavedSequenceStorage *, SetStorage *,
    VirtualRegisterStorage *, UniqueLabelStorage *, LabelValue, ArrayStorage *,
    TupleStorage *, MemoryStorage *, MemoryBlockStorage *, ValidationValue *,
    ValidationMuxedValue *, ImmediateConcatStorage *, ImmediateSliceStorage *>;
 
// NOLINTNEXTLINE(readability-identifier-naming)
llvm::hash_code hash_value(const LabelValue &val) {
  return llvm::hash_value(val.name);
}
 
// NOLINTNEXTLINE(readability-identifier-naming)
llvm::hash_code hash_value(const ElaboratorValue &val) {
  return std::visit(
      [&val](const auto &alternative) {
        // Include index in hash to make sure same value as different
        // alternatives don't collide.
        return llvm::hash_combine(val.index(), alternative);
      },
      val);
}
 
} // namespace
 
namespace llvm {
 
template <>
struct DenseMapInfo<bool> {
  static inline unsigned getEmptyKey() { return false; }
  static inline unsigned getTombstoneKey() { return true; }
  static unsigned getHashValue(const bool &val) { return val * 37U; }
 
  static bool isEqual(const bool &lhs, const bool &rhs) { return lhs == rhs; }
};
template <>
struct DenseMapInfo<LabelValue> {
  static inline LabelValue getEmptyKey() {
    return DenseMapInfo<StringAttr>::getEmptyKey();
  }
  static inline LabelValue getTombstoneKey() {
    return DenseMapInfo<StringAttr>::getTombstoneKey();
  }
  static unsigned getHashValue(const LabelValue &val) {
    return hash_value(val);
  }
 
  static bool isEqual(const LabelValue &lhs, const LabelValue &rhs) {
    return lhs == rhs;
  }
};
 
} // namespace llvm
 
//===----------------------------------------------------------------------===//
// Elaborator Value Storages and Internalization
//===----------------------------------------------------------------------===//
 
namespace {
 
/// Lightweight object to be used as the key for internalization sets. It caches
/// the hashcode of the internalized object and a pointer to it. This allows a
/// delayed allocation and construction of the actual object and thus only has
/// to happen if the object is not already in the set.
template <typename StorageTy>
struct HashedStorage {
  HashedStorage(unsigned hashcode = 0, StorageTy *storage = nullptr)
      : hashcode(hashcode), storage(storage) {}
 
  unsigned hashcode;
  StorageTy *storage;
};
 
/// A DenseMapInfo implementation to support 'insert_as' for the internalization
/// sets. When comparing two 'HashedStorage's we can just compare the already
/// internalized storage pointers, otherwise we have to call the costly
/// 'isEqual' method.
template <typename StorageTy>
struct StorageKeyInfo {
  static inline HashedStorage<StorageTy> getEmptyKey() {
    return HashedStorage<StorageTy>(0,
                                    DenseMapInfo<StorageTy *>::getEmptyKey());
  }
  static inline HashedStorage<StorageTy> getTombstoneKey() {
    return HashedStorage<StorageTy>(
        0, DenseMapInfo<StorageTy *>::getTombstoneKey());
  }
 
  static inline unsigned getHashValue(const HashedStorage<StorageTy> &key) {
    return key.hashcode;
  }
  static inline unsigned getHashValue(const StorageTy &key) {
    return key.hashcode;
  }
 
  static inline bool isEqual(const HashedStorage<StorageTy> &lhs,
                             const HashedStorage<StorageTy> &rhs) {
    return lhs.storage == rhs.storage;
  }
  static inline bool isEqual(const StorageTy &lhs,
                             const HashedStorage<StorageTy> &rhs) {
    if (isEqual(rhs, getEmptyKey()) || isEqual(rhs, getTombstoneKey()))
      return false;
 
    return lhs.isEqual(rhs.storage);
  }
};
 
// Values with structural equivalence intended to be internalized.
//===----------------------------------------------------------------------===//
 
/// Storage object for an '!rtg.set<T>'.
struct SetStorage {
  static unsigned computeHash(const SetVector<ElaboratorValue> &set,
                              Type type) {
    llvm::hash_code setHash = 0;
    for (auto el : set) {
      // Just XOR all hashes because it's a commutative operation and
      // `llvm::hash_combine_range` is not commutative.
      // We don't want the order in which elements were added to influence the
      // hash and thus the equivalence of sets.
      setHash = setHash ^ llvm::hash_combine(el);
    }
    return llvm::hash_combine(type, setHash);
  }
 
  SetStorage(SetVector<ElaboratorValue> &&set, Type type)
      : hashcode(computeHash(set, type)), set(std::move(set)), type(type) {}
 
  bool isEqual(const SetStorage *other) const {
    // Note: we are not using the `==` operator of `SetVector` because it
    // takes the order in which elements were added into account (since it's a
    // vector after all). We just use it as a convenient way to keep track of a
    // deterministic order for re-materialization.
    bool allContained = true;
    for (auto el : set)
      allContained &= other->set.contains(el);
 
    return hashcode == other->hashcode && set.size() == other->set.size() &&
           allContained && type == other->type;
  }
 
  // The cached hashcode to avoid repeated computations.
  const unsigned hashcode;
 
  // Stores the elaborated values contained in the set.
  const SetVector<ElaboratorValue> set;
 
  // Store the set type such that we can materialize this evaluated value
  // also in the case where the set is empty.
  const Type type;
};
 
/// Storage object for an '!rtg.bag<T>'.
struct BagStorage {
  BagStorage(MapVector<ElaboratorValue, uint64_t> &&bag, Type type)
      : hashcode(llvm::hash_combine(
            type, llvm::hash_combine_range(bag.begin(), bag.end()))),
        bag(std::move(bag)), type(type) {}
 
  bool isEqual(const BagStorage *other) const {
    return hashcode == other->hashcode && llvm::equal(bag, other->bag) &&
           type == other->type;
  }
 
  // The cached hashcode to avoid repeated computations.
  const unsigned hashcode;
 
  // Stores the elaborated values contained in the bag with their number of
  // occurences.
  const MapVector<ElaboratorValue, uint64_t> bag;
 
  // Store the bag type such that we can materialize this evaluated value
  // also in the case where the bag is empty.
  const Type type;
};
 
/// Storage object for an '!rtg.sequence'.
struct SequenceStorage {
  SequenceStorage(StringAttr familyName, SmallVector<ElaboratorValue> &&args)
      : hashcode(llvm::hash_combine(
            familyName, llvm::hash_combine_range(args.begin(), args.end()))),
        familyName(familyName), args(std::move(args)) {}
 
  bool isEqual(const SequenceStorage *other) const {
    return hashcode == other->hashcode && familyName == other->familyName &&
           args == other->args;
  }
 
  // The cached hashcode to avoid repeated computations.
  const unsigned hashcode;
 
  // The name of the sequence family this sequence is derived from.
  const StringAttr familyName;
 
  // The elaborator values used during substitution of the sequence family.
  const SmallVector<ElaboratorValue> args;
};
 
/// Storage object for interleaved '!rtg.randomized_sequence'es.
struct InterleavedSequenceStorage {
  InterleavedSequenceStorage(SmallVector<ElaboratorValue> &&sequences,
                             uint32_t batchSize)
      : sequences(std::move(sequences)), batchSize(batchSize),
        hashcode(llvm::hash_combine(
            llvm::hash_combine_range(sequences.begin(), sequences.end()),
            batchSize)) {}
 
  explicit InterleavedSequenceStorage(RandomizedSequenceStorage *sequence)
      : sequences(SmallVector<ElaboratorValue>(1, sequence)), batchSize(1),
        hashcode(llvm::hash_combine(
            llvm::hash_combine_range(sequences.begin(), sequences.end()),
            batchSize)) {}
 
  bool isEqual(const InterleavedSequenceStorage *other) const {
    return hashcode == other->hashcode && sequences == other->sequences &&
           batchSize == other->batchSize;
  }
 
  const SmallVector<ElaboratorValue> sequences;
 
  const uint32_t batchSize;
 
  // The cached hashcode to avoid repeated computations.
  const unsigned hashcode;
};
 
/// Storage object for '!rtg.array`-typed values.
struct ArrayStorage {
  ArrayStorage(Type type, SmallVector<ElaboratorValue> &&array)
      : hashcode(llvm::hash_combine(
            type, llvm::hash_combine_range(array.begin(), array.end()))),
        type(type), array(array) {}
 
  bool isEqual(const ArrayStorage *other) const {
    return hashcode == other->hashcode && type == other->type &&
           array == other->array;
  }
 
  // The cached hashcode to avoid repeated computations.
  const unsigned hashcode;
 
  /// The type of the array. This is necessary because an array of size 0
  /// cannot be reconstructed without knowing the original element type.
  const Type type;
 
  /// The label name. For unique labels, this is just the prefix.
  const SmallVector<ElaboratorValue> array;
};
 
/// Storage object for 'tuple`-typed values.
struct TupleStorage {
  TupleStorage(SmallVector<ElaboratorValue> &&values)
      : hashcode(llvm::hash_combine_range(values.begin(), values.end())),
        values(std::move(values)) {}
 
  bool isEqual(const TupleStorage *other) const {
    return hashcode == other->hashcode && values == other->values;
  }
 
  // The cached hashcode to avoid repeated computations.
  const unsigned hashcode;
 
  const SmallVector<ElaboratorValue> values;
};
 
/// Storage object for immediate concatenation operations.
/// FIXME: opaque values should be handled generically
struct ImmediateConcatStorage {
  ImmediateConcatStorage(SmallVector<ElaboratorValue> &&operands)
      : hashcode(llvm::hash_combine_range(operands.begin(), operands.end())),
        operands(std::move(operands)) {}
 
  bool isEqual(const ImmediateConcatStorage *other) const {
    return hashcode == other->hashcode && operands == other->operands;
  }
 
  const unsigned hashcode;
  const SmallVector<ElaboratorValue> operands;
};
 
/// Storage object for immediate slice operations.
/// FIXME: opaque values should be handled generically
struct ImmediateSliceStorage {
  ImmediateSliceStorage(ElaboratorValue input, unsigned lowBit, Type type)
      : hashcode(llvm::hash_combine(input, lowBit, type)), input(input),
        lowBit(lowBit), type(type) {}
 
  bool isEqual(const ImmediateSliceStorage *other) const {
    return hashcode == other->hashcode && input == other->input &&
           lowBit == other->lowBit && type == other->type;
  }
 
  const unsigned hashcode;
  const ElaboratorValue input;
  const unsigned lowBit;
  const Type type;
};
 
// Values with identity not intended to be internalized.
//===----------------------------------------------------------------------===//
 
/// Base class for storages that represent values with identity, i.e., two
/// values are not considered equivalent if they are structurally the same, but
/// each definition of such a value is unique. E.g., unique labels or virtual
/// registers. These cannot be materialized anew in each nested sequence, but
/// must be passed as arguments.
struct IdentityValue {
 
  IdentityValue(Type type) : type(type) {}
 
#ifndef NDEBUG
 
  /// In debug mode, track whether this value was already materialized to
  /// assert if it's illegally materialized multiple times.
  ///
  /// Instead of deleting operations defining these values and materializing
  /// them again, we could retain the operations. However, we still need
  /// specific storages to represent these values in some cases, e.g., to get
  /// the size of a memory allocation. Also, elaboration of nested control-flow
  /// regions (e.g. `scf.for`) relies on materialization of such values lazily
  /// instead of cloning the operations eagerly.
  bool alreadyMaterialized = false;
 
#endif
 
  const Type type;
};
 
/// Represents a unique virtual register.
struct VirtualRegisterStorage : IdentityValue {
  VirtualRegisterStorage(VirtualRegisterConfigAttr allowedRegs, Type type)
      : IdentityValue(type), allowedRegs(allowedRegs) {}
 
  // NOTE: we don't need an 'isEqual' function and 'hashcode' here because
  // VirtualRegisters are never internalized.
 
  // The list of fixed registers allowed to be selected for this virtual
  // register.
  const VirtualRegisterConfigAttr allowedRegs;
};
 
struct UniqueLabelStorage : IdentityValue {
  UniqueLabelStorage(StringAttr name)
      : IdentityValue(LabelType::get(name.getContext())), name(name) {}
 
  // NOTE: we don't need an 'isEqual' function and 'hashcode' here because
  // VirtualRegisters are never internalized.
 
  /// The label name. For unique labels, this is just the prefix.
  const StringAttr name;
};
 
/// Storage object for '!rtg.isa.memoryblock`-typed values.
struct MemoryBlockStorage : IdentityValue {
  MemoryBlockStorage(const APInt &baseAddress, const APInt &endAddress,
                     Type type)
      : IdentityValue(type), baseAddress(baseAddress), endAddress(endAddress) {}
 
  // The base address of the memory. The width of the APInt also represents the
  // address width of the memory. This is an APInt to support memories of
  // >64-bit machines.
  const APInt baseAddress;
 
  // The last address of the memory.
  const APInt endAddress;
};
 
/// Storage object for '!rtg.isa.memory`-typed values.
struct MemoryStorage : IdentityValue {
  MemoryStorage(MemoryBlockStorage *memoryBlock, size_t size, size_t alignment)
      : IdentityValue(MemoryType::get(memoryBlock->type.getContext(),
                                      memoryBlock->baseAddress.getBitWidth())),
        memoryBlock(memoryBlock), size(size), alignment(alignment) {}
 
  MemoryBlockStorage *memoryBlock;
  const size_t size;
  const size_t alignment;
};
 
/// Storage object for an '!rtg.randomized_sequence'.
struct RandomizedSequenceStorage : IdentityValue {
  RandomizedSequenceStorage(ContextResourceAttrInterface context,
                            SequenceStorage *sequence)
      : IdentityValue(
            RandomizedSequenceType::get(sequence->familyName.getContext())),
        context(context), sequence(sequence) {}
 
  // The context under which this sequence is placed.
  const ContextResourceAttrInterface context;
 
  const SequenceStorage *sequence;
};
 
/// Storage object for an '!rtg.validate' result.
struct ValidationValue : IdentityValue {
  ValidationValue(Type type, const ElaboratorValue &ref,
                  const ElaboratorValue &defaultValue, StringAttr id,
                  SmallVector<ElaboratorValue> &&defaultUsedValues,
                  SmallVector<ElaboratorValue> &&elseValues)
      : IdentityValue(type), ref(ref), defaultValue(defaultValue), id(id),
        defaultUsedValues(std::move(defaultUsedValues)),
        elseValues(std::move(elseValues)) {}
 
  const ElaboratorValue ref;
  const ElaboratorValue defaultValue;
  const StringAttr id;
  const SmallVector<ElaboratorValue> defaultUsedValues;
  const SmallVector<ElaboratorValue> elseValues;
};
 
/// Storage object for the 'values' results of 'rtg.validate'.
struct ValidationMuxedValue : IdentityValue {
  ValidationMuxedValue(Type type, const ValidationValue *value, unsigned idx)
      : IdentityValue(type), value(value), idx(idx) {}
 
  const ValidationValue *value;
  const unsigned idx;
};
 
/// An 'Internalizer' object internalizes storages and takes ownership of them.
/// When the initializer object is destroyed, all owned storages are also
/// deallocated and thus must not be accessed anymore.
class Internalizer {
public:
  /// Internalize a storage of type `StorageTy` constructed with arguments
  /// `args`. The pointers returned by this method can be used to compare
  /// objects when, e.g., computing set differences, uniquing the elements in a
  /// set, etc. Otherwise, we'd need to do a deep value comparison in those
  /// situations.
  template <typename StorageTy, typename... Args>
  StorageTy *internalize(Args &&...args) {
    static_assert(!std::is_base_of_v<IdentityValue, StorageTy> &&
                  "values with identity must not be internalized");
 
    StorageTy storage(std::forward<Args>(args)...);
 
    auto existing = getInternSet<StorageTy>().insert_as(
        HashedStorage<StorageTy>(storage.hashcode), storage);
    StorageTy *&storagePtr = existing.first->storage;
    if (existing.second)
      storagePtr =
          new (allocator.Allocate<StorageTy>()) StorageTy(std::move(storage));
 
    return storagePtr;
  }
 
  template <typename StorageTy, typename... Args>
  StorageTy *create(Args &&...args) {
    static_assert(std::is_base_of_v<IdentityValue, StorageTy> &&
                  "values with structural equivalence must be internalized");
 
    return new (allocator.Allocate<StorageTy>())
        StorageTy(std::forward<Args>(args)...);
  }
 
private:
  template <typename StorageTy>
  DenseSet<HashedStorage<StorageTy>, StorageKeyInfo<StorageTy>> &
  getInternSet() {
    if constexpr (std::is_same_v<StorageTy, ArrayStorage>)
      return internedArrays;
    else if constexpr (std::is_same_v<StorageTy, SetStorage>)
      return internedSets;
    else if constexpr (std::is_same_v<StorageTy, BagStorage>)
      return internedBags;
    else if constexpr (std::is_same_v<StorageTy, SequenceStorage>)
      return internedSequences;
    else if constexpr (std::is_same_v<StorageTy, RandomizedSequenceStorage>)
      return internedRandomizedSequences;
    else if constexpr (std::is_same_v<StorageTy, InterleavedSequenceStorage>)
      return internedInterleavedSequences;
    else if constexpr (std::is_same_v<StorageTy, TupleStorage>)
      return internedTuples;
    else if constexpr (std::is_same_v<StorageTy, ImmediateConcatStorage>)
      return internedImmediateConcatValues;
    else if constexpr (std::is_same_v<StorageTy, ImmediateSliceStorage>)
      return internedImmediateSliceValues;
    else
      static_assert(!sizeof(StorageTy),
                    "no intern set available for this storage type.");
  }
 
  // This allocator allocates on the heap. It automatically deallocates all
  // objects it allocated once the allocator itself is destroyed.
  llvm::BumpPtrAllocator allocator;
 
  // The sets holding the internalized objects. We use one set per storage type
  // such that we can have a simpler equality checking function (no need to
  // compare some sort of TypeIDs).
  DenseSet<HashedStorage<ArrayStorage>, StorageKeyInfo<ArrayStorage>>
      internedArrays;
  DenseSet<HashedStorage<SetStorage>, StorageKeyInfo<SetStorage>> internedSets;
  DenseSet<HashedStorage<BagStorage>, StorageKeyInfo<BagStorage>> internedBags;
  DenseSet<HashedStorage<SequenceStorage>, StorageKeyInfo<SequenceStorage>>
      internedSequences;
  DenseSet<HashedStorage<RandomizedSequenceStorage>,
           StorageKeyInfo<RandomizedSequenceStorage>>
      internedRandomizedSequences;
  DenseSet<HashedStorage<InterleavedSequenceStorage>,
           StorageKeyInfo<InterleavedSequenceStorage>>
      internedInterleavedSequences;
  DenseSet<HashedStorage<TupleStorage>, StorageKeyInfo<TupleStorage>>
      internedTuples;
  DenseSet<HashedStorage<ImmediateConcatStorage>,
           StorageKeyInfo<ImmediateConcatStorage>>
      internedImmediateConcatValues;
  DenseSet<HashedStorage<ImmediateSliceStorage>,
           StorageKeyInfo<ImmediateSliceStorage>>
      internedImmediateSliceValues;
};
 
} // namespace
 
#ifndef NDEBUG
 
static llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
                                     const ElaboratorValue &value);
 
static void print(TypedAttr val, llvm::raw_ostream &os) {
  os << "<attr " << val << ">";
}
 
static void print(BagStorage *val, llvm::raw_ostream &os) {
  os << "<bag {";
  llvm::interleaveComma(val->bag, os,
                        [&](const std::pair<ElaboratorValue, uint64_t> &el) {
                          os << el.first << " -> " << el.second;
                        });
  os << "} at " << val << ">";
}
 
static void print(bool val, llvm::raw_ostream &os) {
  os << "<bool " << (val ? "true" : "false") << ">";
}
 
static void print(size_t val, llvm::raw_ostream &os) {
  os << "<index " << val << ">";
}
 
static void print(SequenceStorage *val, llvm::raw_ostream &os) {
  os << "<sequence @" << val->familyName.getValue() << "(";
  llvm::interleaveComma(val->args, os,
                        [&](const ElaboratorValue &val) { os << val; });
  os << ") at " << val << ">";
}
 
static void print(RandomizedSequenceStorage *val, llvm::raw_ostream &os) {
  os << "<randomized-sequence derived from @"
     << val->sequence->familyName.getValue() << " under context "
     << val->context << "(";
  llvm::interleaveComma(val->sequence->args, os,
                        [&](const ElaboratorValue &val) { os << val; });
  os << ") at " << val << ">";
}
 
static void print(InterleavedSequenceStorage *val, llvm::raw_ostream &os) {
  os << "<interleaved-sequence [";
  llvm::interleaveComma(val->sequences, os,
                        [&](const ElaboratorValue &val) { os << val; });
  os << "] batch-size " << val->batchSize << " at " << val << ">";
}
 
static void print(ArrayStorage *val, llvm::raw_ostream &os) {
  os << "<array [";
  llvm::interleaveComma(val->array, os,
                        [&](const ElaboratorValue &val) { os << val; });
  os << "] at " << val << ">";
}
 
static void print(SetStorage *val, llvm::raw_ostream &os) {
  os << "<set {";
  llvm::interleaveComma(val->set, os,
                        [&](const ElaboratorValue &val) { os << val; });
  os << "} at " << val << ">";
}
 
static void print(const VirtualRegisterStorage *val, llvm::raw_ostream &os) {
  os << "<virtual-register " << val << " " << val->allowedRegs << ">";
}
 
static void print(const UniqueLabelStorage *val, llvm::raw_ostream &os) {
  os << "<unique-label " << val << " " << val->name << ">";
}
 
static void print(const LabelValue &val, llvm::raw_ostream &os) {
  os << "<label " << val.name << ">";
}
 
static void print(const TupleStorage *val, llvm::raw_ostream &os) {
  os << "<tuple (";
  llvm::interleaveComma(val->values, os,
                        [&](const ElaboratorValue &val) { os << val; });
  os << ")>";
}
 
static void print(const MemoryStorage *val, llvm::raw_ostream &os) {
  os << "<memory {" << ElaboratorValue(val->memoryBlock)
     << ", size=" << val->size << ", alignment=" << val->alignment << "}>";
}
 
static void print(const MemoryBlockStorage *val, llvm::raw_ostream &os) {
  os << "<memory-block {"
     << ", address-width=" << val->baseAddress.getBitWidth()
     << ", base-address=" << val->baseAddress
     << ", end-address=" << val->endAddress << "}>";
}
 
static void print(const ValidationValue *val, llvm::raw_ostream &os) {
  os << "<validation-value {type=" << val->type << ", ref=" << val->ref
     << ", defaultValue=" << val->defaultValue << "}>";
}
 
static void print(const ValidationMuxedValue *val, llvm::raw_ostream &os) {
  os << "<validation-muxed-value (" << val->value << ") at " << val->idx << ">";
}
 
static void print(const ImmediateConcatStorage *val, llvm::raw_ostream &os) {
  os << "<immediate-concat [";
  llvm::interleaveComma(val->operands, os,
                        [&](const ElaboratorValue &val) { os << val; });
  os << "]>";
}
 
static void print(const ImmediateSliceStorage *val, llvm::raw_ostream &os) {
  os << "<immediate-slice " << val->input << " from " << val->lowBit << ">";
}
 
static llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
                                     const ElaboratorValue &value) {
  std::visit([&](auto val) { print(val, os); }, value);
 
  return os;
}
 
#endif
 
//===----------------------------------------------------------------------===//
// Elaborator Value Materialization
//===----------------------------------------------------------------------===//
 
namespace {
 
/// State that should be shared by all elaborator and materializer instances.
struct SharedState {
  SharedState(SymbolTable &table, unsigned seed) : table(table), rng(seed) {}
 
  SymbolTable &table;
  std::mt19937 rng;
  Namespace names;
  Internalizer internalizer;
};
 
/// A collection of state per RTG test.
struct TestState {
  /// The name of the test.
  StringAttr name;
 
  /// The context switches registered for this test.
  MapVector<
      std::pair<ContextResourceAttrInterface, ContextResourceAttrInterface>,
      SequenceStorage *>
      contextSwitches;
};
 
/// Construct an SSA value from a given elaborated value.
class Materializer {
public:
  Materializer(OpBuilder builder, TestState &testState,
               SharedState &sharedState,
               SmallVector<ElaboratorValue> &blockArgs)
      : builder(builder), testState(testState), sharedState(sharedState),
        blockArgs(blockArgs) {}
 
  /// Materialize IR representing the provided `ElaboratorValue` and return the
  /// `Value` or a null value on failure.
  Value materialize(ElaboratorValue val, Location loc,
                    function_ref<InFlightDiagnostic()> emitError) {
    auto iter = materializedValues.find(val);
    if (iter != materializedValues.end())
      return iter->second;
 
    LLVM_DEBUG(llvm::dbgs() << "Materializing " << val);
 
    // In debug mode, track whether values with identity were already
    // materialized before and assert in such a situation.
    Value res = std::visit(
        [&](auto value) {
          if constexpr (std::is_base_of_v<IdentityValue,
                                          std::remove_pointer_t<
                                              std::decay_t<decltype(value)>>>) {
            if (identityValueRoot.contains(value)) {
#ifndef NDEBUG
              bool &materialized =
                  static_cast<IdentityValue *>(value)->alreadyMaterialized;
              assert(!materialized && "must not already be materialized");
              materialized = true;
#endif
 
              return visit(value, loc, emitError);
            }
 
            Value arg = builder.getBlock()->addArgument(value->type, loc);
            blockArgs.push_back(val);
            blockArgTypes.push_back(arg.getType());
            materializedValues[val] = arg;
            return arg;
          }
 
          return visit(value, loc, emitError);
        },
        val);
 
    LLVM_DEBUG(llvm::dbgs() << " to\n" << res << "\n\n");
 
    return res;
  }
 
  /// If `op` is not in the same region as the materializer insertion point, a
  /// clone is created at the materializer's insertion point by also
  /// materializing the `ElaboratorValue`s for each operand just before it.
  /// Otherwise, all operations after the materializer's insertion point are
  /// deleted until `op` is reached. An error is returned if the operation is
  /// before the insertion point.
  LogicalResult materialize(Operation *op,
                            DenseMap<Value, ElaboratorValue> &state) {
    if (op->getNumRegions() > 0)
      return op->emitOpError("ops with nested regions must be elaborated away");
 
    // We don't support opaque values. If there is an SSA value that has a
    // use-site it needs an equivalent ElaborationValue representation.
    // NOTE: We could support cases where there is initially a use-site but that
    // op is guaranteed to be deleted during elaboration. Or the use-sites are
    // replaced with freshly materialized values from the ElaborationValue. But
    // then, why can't we delete the value defining op?
    for (auto res : op->getResults())
      if (!res.use_empty() && !isa<ValidateOp>(op))
        return op->emitOpError(
            "ops with results that have uses are not supported");
 
    if (op->getParentRegion() == builder.getBlock()->getParent()) {
      // We are doing in-place materialization, so mark all ops deleted until we
      // reach the one to be materialized and modify it in-place.
      deleteOpsUntil([&](auto iter) { return &*iter == op; });
 
      if (builder.getInsertionPoint() == builder.getBlock()->end())
        return op->emitError("operation did not occur after the current "
                             "materializer insertion point");
 
      LLVM_DEBUG(llvm::dbgs() << "Modifying in-place: " << *op << "\n\n");
    } else {
      LLVM_DEBUG(llvm::dbgs() << "Materializing a clone of " << *op << "\n\n");
      op = builder.clone(*op);
      builder.setInsertionPoint(op);
    }
 
    for (auto &operand : op->getOpOperands()) {
      auto emitError = [&]() {
        auto diag = op->emitError();
        diag.attachNote(op->getLoc())
            << "while materializing value for operand#"
            << operand.getOperandNumber();
        return diag;
      };
 
      auto elabVal = state.at(operand.get());
      Value val = materialize(elabVal, op->getLoc(), emitError);
      if (!val)
        return failure();
 
      state[val] = elabVal;
      operand.set(val);
    }
 
    builder.setInsertionPointAfter(op);
    return success();
  }
 
  /// Should be called once the `Region` is successfully materialized. No calls
  /// to `materialize` should happen after this anymore.
  void finalize() {
    deleteOpsUntil([](auto iter) { return false; });
 
    for (auto *op : llvm::reverse(toDelete))
      op->erase();
  }
 
  /// Tell this materializer that it is responsible for materializing the given
  /// identity value at the earliest position it is needed, and should't
  /// request the value via block argument.
  void registerIdentityValue(IdentityValue *val) {
    identityValueRoot.insert(val);
  }
 
  ArrayRef<Type> getBlockArgTypes() const { return blockArgTypes; }
 
  void map(ElaboratorValue eval, Value val) { materializedValues[eval] = val; }
 
  template <typename OpTy, typename... Args>
  OpTy create(Location location, Args &&...args) {
    return OpTy::create(builder, location, std::forward<Args>(args)...);
  }
 
private:
  SequenceOp elaborateSequence(const RandomizedSequenceStorage *seq,
                               SmallVector<ElaboratorValue> &elabArgs);
 
  void deleteOpsUntil(function_ref<bool(Block::iterator)> stop) {
    auto ip = builder.getInsertionPoint();
    while (ip != builder.getBlock()->end() && !stop(ip)) {
      LLVM_DEBUG(llvm::dbgs() << "Marking to be deleted: " << *ip << "\n\n");
      toDelete.push_back(&*ip);
 
      builder.setInsertionPointAfter(&*ip);
      ip = builder.getInsertionPoint();
    }
  }
 
  Value visit(TypedAttr val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    // For index attributes (and arithmetic operations on them) we use the
    // index dialect.
    if (auto intAttr = dyn_cast<IntegerAttr>(val);
        intAttr && isa<IndexType>(val.getType())) {
      Value res = index::ConstantOp::create(builder, loc, intAttr);
      materializedValues[val] = res;
      return res;
    }
 
    // For any other attribute, we just call the materializer of the dialect
    // defining that attribute.
    auto *op =
        val.getDialect().materializeConstant(builder, val, val.getType(), loc);
    if (!op) {
      emitError() << "materializer of dialect '"
                  << val.getDialect().getNamespace()
                  << "' unable to materialize value for attribute '" << val
                  << "'";
      return Value();
    }
 
    Value res = op->getResult(0);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(size_t val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    Value res = index::ConstantOp::create(builder, loc, val);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(bool val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    Value res = index::BoolConstantOp::create(builder, loc, val);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(ArrayStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    SmallVector<Value> elements;
    elements.reserve(val->array.size());
    for (auto el : val->array) {
      auto materialized = materialize(el, loc, emitError);
      if (!materialized)
        return Value();
 
      elements.push_back(materialized);
    }
 
    Value res = ArrayCreateOp::create(builder, loc, val->type, elements);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(SetStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    SmallVector<Value> elements;
    elements.reserve(val->set.size());
    for (auto el : val->set) {
      auto materialized = materialize(el, loc, emitError);
      if (!materialized)
        return Value();
 
      elements.push_back(materialized);
    }
 
    auto res = SetCreateOp::create(builder, loc, val->type, elements);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(BagStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    SmallVector<Value> values, weights;
    values.reserve(val->bag.size());
    weights.reserve(val->bag.size());
    for (auto [val, weight] : val->bag) {
      auto materializedVal = materialize(val, loc, emitError);
      auto materializedWeight = materialize(weight, loc, emitError);
      if (!materializedVal || !materializedWeight)
        return Value();
 
      values.push_back(materializedVal);
      weights.push_back(materializedWeight);
    }
 
    auto res = BagCreateOp::create(builder, loc, val->type, values, weights);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(MemoryBlockStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    auto intType = builder.getIntegerType(val->baseAddress.getBitWidth());
    Value res = MemoryBlockDeclareOp::create(
        builder, loc, val->type, IntegerAttr::get(intType, val->baseAddress),
        IntegerAttr::get(intType, val->endAddress));
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(MemoryStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    auto memBlock = materialize(val->memoryBlock, loc, emitError);
    auto memSize = materialize(val->size, loc, emitError);
    auto memAlign = materialize(val->alignment, loc, emitError);
    if (!(memBlock && memSize && memAlign))
      return {};
 
    Value res =
        MemoryAllocOp::create(builder, loc, memBlock, memSize, memAlign);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(SequenceStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    emitError() << "materializing a non-randomized sequence not supported yet";
    return Value();
  }
 
  Value visit(RandomizedSequenceStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    // To know which values we have to pass by argument (and not just pass all
    // that migth be used eagerly), we have to elaborate the sequence family if
    // not already done so.
    // We need to get back the sequence to reference, and the list of elaborated
    // values to pass as arguments.
    SmallVector<ElaboratorValue> elabArgs;
    SequenceOp seqOp = elaborateSequence(val, elabArgs);
    if (!seqOp)
      return {};
 
    // Materialize all the values we need to pass as arguments and collect their
    // types.
    SmallVector<Value> args;
    SmallVector<Type> argTypes;
    for (auto arg : elabArgs) {
      Value materialized = materialize(arg, loc, emitError);
      if (!materialized)
        return {};
 
      args.push_back(materialized);
      argTypes.push_back(materialized.getType());
    }
 
    Value res = GetSequenceOp::create(
        builder, loc, SequenceType::get(builder.getContext(), argTypes),
        seqOp.getSymName());
 
    // Only materialize a substitute_sequence op when we have arguments to
    // substitute since this op does not support 0 arguments.
    if (!args.empty())
      res = SubstituteSequenceOp::create(builder, loc, res, args);
 
    res = RandomizeSequenceOp::create(builder, loc, res);
 
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(InterleavedSequenceStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    SmallVector<Value> sequences;
    for (auto seqVal : val->sequences) {
      Value materialized = materialize(seqVal, loc, emitError);
      if (!materialized)
        return {};
 
      sequences.push_back(materialized);
    }
 
    if (sequences.size() == 1)
      return sequences[0];
 
    Value res =
        InterleaveSequencesOp::create(builder, loc, sequences, val->batchSize);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(VirtualRegisterStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    Value res = VirtualRegisterOp::create(builder, loc, val->allowedRegs);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(UniqueLabelStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    Value res =
        LabelUniqueDeclOp::create(builder, loc, val->name, ValueRange());
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(const LabelValue &val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    Value res = LabelDeclOp::create(builder, loc, val.name, ValueRange());
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(TupleStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    SmallVector<Value> materialized;
    materialized.reserve(val->values.size());
    for (auto v : val->values)
      materialized.push_back(materialize(v, loc, emitError));
    Value res = TupleCreateOp::create(builder, loc, materialized);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(ValidationValue *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    SmallVector<Value> usedDefaultValues, elseValues;
    for (auto [dfltVal, elseVal] :
         llvm::zip(val->defaultUsedValues, val->elseValues)) {
      auto dfltMat = materialize(dfltVal, loc, emitError);
      auto elseMat = materialize(elseVal, loc, emitError);
      if (!dfltMat || !elseMat)
        return {};
 
      usedDefaultValues.push_back(dfltMat);
      usedDefaultValues.push_back(elseMat);
    }
 
    auto validateOp = ValidateOp::create(
        builder, loc, val->type, materialize(val->ref, loc, emitError),
        materialize(val->defaultValue, loc, emitError), val->id,
        usedDefaultValues, elseValues);
    materializedValues[val] = validateOp.getValue();
    return validateOp.getValue();
  }
 
  Value visit(ValidationMuxedValue *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    Value validateValue =
        materialize(const_cast<ValidationValue *>(val->value), loc, emitError);
    if (!validateValue)
      return {};
    auto validateOp = validateValue.getDefiningOp<ValidateOp>();
    if (!validateOp) {
      auto *defOp = validateValue.getDefiningOp();
      emitError()
          << "expected validate op for validation muxed value, but found "
          << (defOp ? defOp->getName().getStringRef() : "block argument");
      return {};
    }
    materializedValues[val] = validateOp.getValues()[val->idx];
    return validateOp.getValues()[val->idx];
  }
 
  Value visit(ImmediateConcatStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    SmallVector<Value> operands;
    for (auto operand : val->operands) {
      auto materialized = materialize(operand, loc, emitError);
      if (!materialized)
        return {};
 
      operands.push_back(materialized);
    }
 
    Value res = ConcatImmediateOp::create(builder, loc, operands);
    materializedValues[val] = res;
    return res;
  }
 
  Value visit(ImmediateSliceStorage *val, Location loc,
              function_ref<InFlightDiagnostic()> emitError) {
    Value input = materialize(val->input, loc, emitError);
    if (!input)
      return {};
 
    Value res =
        SliceImmediateOp::create(builder, loc, val->type, input, val->lowBit);
    materializedValues[val] = res;
    return res;
  }
 
private:
  /// Cache values we have already materialized to reuse them later. We start
  /// with an insertion point at the start of the block and cache the (updated)
  /// insertion point such that future materializations can also reuse previous
  /// materializations without running into dominance issues (or requiring
  /// additional checks to avoid them).
  DenseMap<ElaboratorValue, Value> materializedValues;
 
  /// Cache the builder to continue insertions at their current insertion point
  /// for the reason stated above.
  OpBuilder builder;
 
  SmallVector<Operation *> toDelete;
 
  TestState &testState;
  SharedState &sharedState;
 
  /// Keep track of the block arguments we had to add to this materializer's
  /// block for identity values and also remember which elaborator values are
  /// expected to be passed as arguments from outside.
  SmallVector<ElaboratorValue> &blockArgs;
  SmallVector<Type> blockArgTypes;
 
  /// Identity values in this set are materialized by this materializer,
  /// otherwise they are added as block arguments and the block that wants to
  /// embed this sequence is expected to provide a value for it.
  DenseSet<IdentityValue *> identityValueRoot;
};
 
//===----------------------------------------------------------------------===//
// Elaboration Visitor
//===----------------------------------------------------------------------===//
 
/// Used to signal to the elaboration driver whether the operation should be
/// removed.
enum class DeletionKind { Keep, Delete };
 
/// Interprets the IR to perform and lower the represented randomizations.
class Elaborator : public RTGOpVisitor<Elaborator, FailureOr<DeletionKind>> {
public:
  using RTGBase = RTGOpVisitor<Elaborator, FailureOr<DeletionKind>>;
  using RTGBase::visitOp;
 
  Elaborator(SharedState &sharedState, TestState &testState,
             Materializer &materializer,
             ContextResourceAttrInterface currentContext = {})
      : sharedState(sharedState), testState(testState),
        materializer(materializer), currentContext(currentContext) {}
 
  template <typename ValueTy>
  inline ValueTy get(Value val) const {
    return std::get<ValueTy>(state.at(val));
  }
 
  FailureOr<DeletionKind> visitPureOp(Operation *op) {
    SmallVector<Attribute> operands;
    for (auto operand : op->getOperands()) {
      auto evalValue = state[operand];
      if (std::holds_alternative<TypedAttr>(evalValue))
        operands.push_back(std::get<TypedAttr>(evalValue));
      else
        return visitUnhandledOp(op);
    }
 
    SmallVector<OpFoldResult> results;
    if (failed(op->fold(operands, results)))
      return visitUnhandledOp(op);
 
    // We don't support in-place folders.
    if (results.size() != op->getNumResults())
      return visitUnhandledOp(op);
 
    for (auto [res, val] : llvm::zip(results, op->getResults())) {
      auto attr = llvm::dyn_cast_or_null<TypedAttr>(res.dyn_cast<Attribute>());
      if (!attr)
        return op->emitError(
            "only typed attributes supported for constant-like operations");
 
      auto intAttr = dyn_cast<IntegerAttr>(attr);
      if (intAttr && isa<IndexType>(attr.getType()))
        state[op->getResult(0)] = size_t(intAttr.getInt());
      else if (intAttr && intAttr.getType().isSignlessInteger(1))
        state[op->getResult(0)] = bool(intAttr.getInt());
      else
        state[op->getResult(0)] = attr;
    }
 
    return DeletionKind::Delete;
  }
 
  /// Print a nice error message for operations we don't support yet.
  FailureOr<DeletionKind> visitUnhandledOp(Operation *op) {
    return op->emitOpError("elaboration not supported");
  }
 
  FailureOr<DeletionKind> visitExternalOp(Operation *op) {
    auto memOp = dyn_cast<MemoryEffectOpInterface>(op);
    if (op->hasTrait<OpTrait::ConstantLike>() || (memOp && memOp.hasNoEffect()))
      return visitPureOp(op);
 
    // TODO: we only have this to be able to write tests for this pass without
    // having to add support for more operations for now, so it should be
    // removed once it is not necessary anymore for writing tests
    if (op->use_empty())
      return DeletionKind::Keep;
 
    return visitUnhandledOp(op);
  }
 
  FailureOr<DeletionKind> visitOp(ConstantOp op) { return visitPureOp(op); }
 
  FailureOr<DeletionKind> visitOp(GetSequenceOp op) {
    SmallVector<ElaboratorValue> replacements;
    state[op.getResult()] =
        sharedState.internalizer.internalize<SequenceStorage>(
            op.getSequenceAttr().getAttr(), std::move(replacements));
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(SubstituteSequenceOp op) {
    auto *seq = get<SequenceStorage *>(op.getSequence());
 
    SmallVector<ElaboratorValue> replacements(seq->args);
    for (auto replacement : op.getReplacements())
      replacements.push_back(state.at(replacement));
 
    state[op.getResult()] =
        sharedState.internalizer.internalize<SequenceStorage>(
            seq->familyName, std::move(replacements));
 
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(RandomizeSequenceOp op) {
    auto *seq = get<SequenceStorage *>(op.getSequence());
    auto *randomizedSeq =
        sharedState.internalizer.create<RandomizedSequenceStorage>(
            currentContext, seq);
    materializer.registerIdentityValue(randomizedSeq);
    state[op.getResult()] =
        sharedState.internalizer.internalize<InterleavedSequenceStorage>(
            randomizedSeq);
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(InterleaveSequencesOp op) {
    SmallVector<ElaboratorValue> sequences;
    for (auto seq : op.getSequences())
      sequences.push_back(get<InterleavedSequenceStorage *>(seq));
 
    state[op.getResult()] =
        sharedState.internalizer.internalize<InterleavedSequenceStorage>(
            std::move(sequences), op.getBatchSize());
    return DeletionKind::Delete;
  }
 
  // NOLINTNEXTLINE(misc-no-recursion)
  LogicalResult isValidContext(ElaboratorValue value, Operation *op) const {
    if (std::holds_alternative<RandomizedSequenceStorage *>(value)) {
      auto *seq = std::get<RandomizedSequenceStorage *>(value);
      if (seq->context != currentContext) {
        auto err = op->emitError("attempting to place sequence derived from ")
                   << seq->sequence->familyName.getValue() << " under context "
                   << currentContext
                   << ", but it was previously randomized for context ";
        if (seq->context)
          err << seq->context;
        else
          err << "'default'";
        return err;
      }
      return success();
    }
 
    auto *interVal = std::get<InterleavedSequenceStorage *>(value);
    for (auto val : interVal->sequences)
      if (failed(isValidContext(val, op)))
        return failure();
    return success();
  }
 
  FailureOr<DeletionKind> visitOp(EmbedSequenceOp op) {
    auto *seqVal = get<InterleavedSequenceStorage *>(op.getSequence());
    if (failed(isValidContext(seqVal, op)))
      return failure();
 
    return DeletionKind::Keep;
  }
 
  FailureOr<DeletionKind> visitOp(SetCreateOp op) {
    SetVector<ElaboratorValue> set;
    for (auto val : op.getElements())
      set.insert(state.at(val));
 
    state[op.getSet()] = sharedState.internalizer.internalize<SetStorage>(
        std::move(set), op.getSet().getType());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(SetSelectRandomOp op) {
    auto set = get<SetStorage *>(op.getSet())->set;
 
    if (set.empty())
      return op->emitError("cannot select from an empty set");
 
    size_t selected;
    if (auto intAttr =
            op->getAttrOfType<IntegerAttr>("rtg.elaboration_custom_seed")) {
      std::mt19937 customRng(intAttr.getInt());
      selected = getUniformlyInRange(customRng, 0, set.size() - 1);
    } else {
      selected = getUniformlyInRange(sharedState.rng, 0, set.size() - 1);
    }
 
    state[op.getResult()] = set[selected];
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(SetDifferenceOp op) {
    auto original = get<SetStorage *>(op.getOriginal())->set;
    auto diff = get<SetStorage *>(op.getDiff())->set;
 
    SetVector<ElaboratorValue> result(original);
    result.set_subtract(diff);
 
    state[op.getResult()] = sharedState.internalizer.internalize<SetStorage>(
        std::move(result), op.getResult().getType());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(SetUnionOp op) {
    SetVector<ElaboratorValue> result;
    for (auto set : op.getSets())
      result.set_union(get<SetStorage *>(set)->set);
 
    state[op.getResult()] = sharedState.internalizer.internalize<SetStorage>(
        std::move(result), op.getType());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(SetSizeOp op) {
    auto size = get<SetStorage *>(op.getSet())->set.size();
    state[op.getResult()] = size;
    return DeletionKind::Delete;
  }
 
  // {a0,a1} x {b0,b1} x {c0,c1} -> {(a0), (a1)} -> {(a0,b0), (a0,b1), (a1,b0),
  // (a1,b1)} -> {(a0,b0,c0), (a0,b0,c1), (a0,b1,c0), (a0,b1,c1), (a1,b0,c0),
  // (a1,b0,c1), (a1,b1,c0), (a1,b1,c1)}
  FailureOr<DeletionKind> visitOp(SetCartesianProductOp op) {
    SetVector<ElaboratorValue> result;
    SmallVector<SmallVector<ElaboratorValue>> tuples;
    tuples.push_back({});
 
    for (auto input : op.getInputs()) {
      auto &set = get<SetStorage *>(input)->set;
      if (set.empty()) {
        SetVector<ElaboratorValue> empty;
        state[op.getResult()] =
            sharedState.internalizer.internalize<SetStorage>(std::move(empty),
                                                             op.getType());
        return DeletionKind::Delete;
      }
 
      for (unsigned i = 0, e = tuples.size(); i < e; ++i) {
        for (auto setEl : set.getArrayRef().drop_back()) {
          tuples.push_back(tuples[i]);
          tuples.back().push_back(setEl);
        }
        tuples[i].push_back(set.back());
      }
    }
 
    for (auto &tup : tuples)
      result.insert(
          sharedState.internalizer.internalize<TupleStorage>(std::move(tup)));
 
    state[op.getResult()] = sharedState.internalizer.internalize<SetStorage>(
        std::move(result), op.getType());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(SetConvertToBagOp op) {
    auto set = get<SetStorage *>(op.getInput())->set;
    MapVector<ElaboratorValue, uint64_t> bag;
    for (auto val : set)
      bag.insert({val, 1});
    state[op.getResult()] = sharedState.internalizer.internalize<BagStorage>(
        std::move(bag), op.getType());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(BagCreateOp op) {
    MapVector<ElaboratorValue, uint64_t> bag;
    for (auto [val, multiple] :
         llvm::zip(op.getElements(), op.getMultiples())) {
      // If the multiple is not stored as an AttributeValue, the elaboration
      // must have already failed earlier (since we don't have
      // unevaluated/opaque values).
      bag[state.at(val)] += get<size_t>(multiple);
    }
 
    state[op.getBag()] = sharedState.internalizer.internalize<BagStorage>(
        std::move(bag), op.getType());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(BagSelectRandomOp op) {
    auto bag = get<BagStorage *>(op.getBag())->bag;
 
    if (bag.empty())
      return op->emitError("cannot select from an empty bag");
 
    SmallVector<std::pair<ElaboratorValue, uint32_t>> prefixSum;
    prefixSum.reserve(bag.size());
    uint32_t accumulator = 0;
    for (auto [val, weight] : bag) {
      accumulator += weight;
      prefixSum.push_back({val, accumulator});
    }
 
    auto customRng = sharedState.rng;
    if (auto intAttr =
            op->getAttrOfType<IntegerAttr>("rtg.elaboration_custom_seed")) {
      customRng = std::mt19937(intAttr.getInt());
    }
 
    auto idx = getUniformlyInRange(customRng, 0, accumulator - 1);
    auto *iter = llvm::upper_bound(
        prefixSum, idx,
        [](uint32_t a, const std::pair<ElaboratorValue, uint32_t> &b) {
          return a < b.second;
        });
 
    state[op.getResult()] = iter->first;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(BagDifferenceOp op) {
    auto original = get<BagStorage *>(op.getOriginal())->bag;
    auto diff = get<BagStorage *>(op.getDiff())->bag;
 
    MapVector<ElaboratorValue, uint64_t> result;
    for (const auto &el : original) {
      if (!diff.contains(el.first)) {
        result.insert(el);
        continue;
      }
 
      if (op.getInf())
        continue;
 
      auto toDiff = diff.lookup(el.first);
      if (el.second <= toDiff)
        continue;
 
      result.insert({el.first, el.second - toDiff});
    }
 
    state[op.getResult()] = sharedState.internalizer.internalize<BagStorage>(
        std::move(result), op.getType());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(BagUnionOp op) {
    MapVector<ElaboratorValue, uint64_t> result;
    for (auto bag : op.getBags()) {
      auto val = get<BagStorage *>(bag)->bag;
      for (auto [el, multiple] : val)
        result[el] += multiple;
    }
 
    state[op.getResult()] = sharedState.internalizer.internalize<BagStorage>(
        std::move(result), op.getType());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(BagUniqueSizeOp op) {
    auto size = get<BagStorage *>(op.getBag())->bag.size();
    state[op.getResult()] = size;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(BagConvertToSetOp op) {
    auto bag = get<BagStorage *>(op.getInput())->bag;
    SetVector<ElaboratorValue> set;
    for (auto [k, v] : bag)
      set.insert(k);
    state[op.getResult()] = sharedState.internalizer.internalize<SetStorage>(
        std::move(set), op.getType());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(VirtualRegisterOp op) {
    auto *val = sharedState.internalizer.create<VirtualRegisterStorage>(
        op.getAllowedRegsAttr(), op.getType());
    state[op.getResult()] = val;
    materializer.registerIdentityValue(val);
    return DeletionKind::Delete;
  }
 
  StringAttr substituteFormatString(StringAttr formatString,
                                    ValueRange substitutes) const {
    if (substitutes.empty() || formatString.empty())
      return formatString;
 
    auto original = formatString.getValue().str();
    for (auto [i, subst] : llvm::enumerate(substitutes)) {
      size_t startPos = 0;
      std::string from = "{{" + std::to_string(i) + "}}";
      while ((startPos = original.find(from, startPos)) != std::string::npos) {
        auto substString = std::to_string(get<size_t>(subst));
        original.replace(startPos, from.length(), substString);
      }
    }
 
    return StringAttr::get(formatString.getContext(), original);
  }
 
  FailureOr<DeletionKind> visitOp(ArrayCreateOp op) {
    SmallVector<ElaboratorValue> array;
    array.reserve(op.getElements().size());
    for (auto val : op.getElements())
      array.emplace_back(state.at(val));
 
    state[op.getResult()] = sharedState.internalizer.internalize<ArrayStorage>(
        op.getResult().getType(), std::move(array));
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(ArrayExtractOp op) {
    auto array = get<ArrayStorage *>(op.getArray())->array;
    size_t idx = get<size_t>(op.getIndex());
 
    if (array.size() <= idx)
      return op->emitError("invalid to access index ")
             << idx << " of an array with " << array.size() << " elements";
 
    state[op.getResult()] = array[idx];
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(ArrayInjectOp op) {
    auto array = get<ArrayStorage *>(op.getArray())->array;
    size_t idx = get<size_t>(op.getIndex());
 
    if (array.size() <= idx)
      return op->emitError("invalid to access index ")
             << idx << " of an array with " << array.size() << " elements";
 
    array[idx] = state[op.getValue()];
    state[op.getResult()] = sharedState.internalizer.internalize<ArrayStorage>(
        op.getResult().getType(), std::move(array));
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(ArraySizeOp op) {
    auto array = get<ArrayStorage *>(op.getArray())->array;
    state[op.getResult()] = array.size();
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(LabelDeclOp op) {
    auto substituted =
        substituteFormatString(op.getFormatStringAttr(), op.getArgs());
    state[op.getLabel()] = LabelValue(substituted);
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(LabelUniqueDeclOp op) {
    auto *val = sharedState.internalizer.create<UniqueLabelStorage>(
        substituteFormatString(op.getFormatStringAttr(), op.getArgs()));
    state[op.getLabel()] = val;
    materializer.registerIdentityValue(val);
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(LabelOp op) { return DeletionKind::Keep; }
 
  FailureOr<DeletionKind> visitOp(TestSuccessOp op) {
    return DeletionKind::Keep;
  }
 
  FailureOr<DeletionKind> visitOp(TestFailureOp op) {
    return DeletionKind::Keep;
  }
 
  FailureOr<DeletionKind> visitOp(RandomNumberInRangeOp op) {
    size_t lower = get<size_t>(op.getLowerBound());
    size_t upper = get<size_t>(op.getUpperBound());
    if (lower > upper)
      return op->emitError("cannot select a number from an empty range");
 
    if (auto intAttr =
            op->getAttrOfType<IntegerAttr>("rtg.elaboration_custom_seed")) {
      std::mt19937 customRng(intAttr.getInt());
      state[op.getResult()] =
          size_t(getUniformlyInRange(customRng, lower, upper));
    } else {
      state[op.getResult()] =
          size_t(getUniformlyInRange(sharedState.rng, lower, upper));
    }
 
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(IntToImmediateOp op) {
    size_t input = get<size_t>(op.getInput());
    auto width = op.getType().getWidth();
    auto emitError = [&]() { return op->emitError(); };
    if (input > APInt::getAllOnes(width).getZExtValue())
      return emitError() << "cannot represent " << input << " with " << width
                         << " bits";
 
    state[op.getResult()] =
        ImmediateAttr::get(op.getContext(), APInt(width, input));
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(OnContextOp op) {
    ContextResourceAttrInterface from = currentContext,
                                 to = cast<ContextResourceAttrInterface>(
                                     get<TypedAttr>(op.getContext()));
    if (!currentContext)
      from = DefaultContextAttr::get(op->getContext(), to.getType());
 
    auto emitError = [&]() {
      auto diag = op.emitError();
      diag.attachNote(op.getLoc())
          << "while materializing value for context switching for " << op;
      return diag;
    };
 
    if (from == to) {
      Value seqVal = materializer.materialize(
          get<SequenceStorage *>(op.getSequence()), op.getLoc(), emitError);
      if (!seqVal)
        return failure();
 
      Value randSeqVal =
          materializer.create<RandomizeSequenceOp>(op.getLoc(), seqVal);
      materializer.create<EmbedSequenceOp>(op.getLoc(), randSeqVal);
      return DeletionKind::Delete;
    }
 
    // Switch to the desired context.
    // First, check if a context switch is registered that has the concrete
    // context as source and target.
    auto *iter = testState.contextSwitches.find({from, to});
 
    // Try with 'any' context as target and the concrete context as source.
    if (iter == testState.contextSwitches.end())
      iter = testState.contextSwitches.find(
          {from, AnyContextAttr::get(op->getContext(), to.getType())});
 
    // Try with 'any' context as source and the concrete context as target.
    if (iter == testState.contextSwitches.end())
      iter = testState.contextSwitches.find(
          {AnyContextAttr::get(op->getContext(), from.getType()), to});
 
    // Try with 'any' context for both the source and the target.
    if (iter == testState.contextSwitches.end())
      iter = testState.contextSwitches.find(
          {AnyContextAttr::get(op->getContext(), from.getType()),
           AnyContextAttr::get(op->getContext(), to.getType())});
 
    // Otherwise, fail with an error because we couldn't find a user
    // specification on how to switch between the requested contexts.
    // NOTE: we could think about supporting context switching via intermediate
    // context, i.e., treat it as a transitive relation.
    if (iter == testState.contextSwitches.end())
      return op->emitError("no context transition registered to switch from ")
             << from << " to " << to;
 
    auto familyName = iter->second->familyName;
    SmallVector<ElaboratorValue> args{from, to,
                                      get<SequenceStorage *>(op.getSequence())};
    auto *seq = sharedState.internalizer.internalize<SequenceStorage>(
        familyName, std::move(args));
    auto *randSeq =
        sharedState.internalizer.create<RandomizedSequenceStorage>(to, seq);
    materializer.registerIdentityValue(randSeq);
    Value seqVal = materializer.materialize(randSeq, op.getLoc(), emitError);
    if (!seqVal)
      return failure();
 
    materializer.create<EmbedSequenceOp>(op.getLoc(), seqVal);
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(ContextSwitchOp op) {
    testState.contextSwitches[{op.getFromAttr(), op.getToAttr()}] =
        get<SequenceStorage *>(op.getSequence());
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(MemoryBlockDeclareOp op) {
    auto *val = sharedState.internalizer.create<MemoryBlockStorage>(
        op.getBaseAddress(), op.getEndAddress(), op.getType());
    state[op.getResult()] = val;
    materializer.registerIdentityValue(val);
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(MemoryAllocOp op) {
    size_t size = get<size_t>(op.getSize());
    size_t alignment = get<size_t>(op.getAlignment());
    auto *memBlock = get<MemoryBlockStorage *>(op.getMemoryBlock());
    auto *val = sharedState.internalizer.create<MemoryStorage>(memBlock, size,
                                                               alignment);
    state[op.getResult()] = val;
    materializer.registerIdentityValue(val);
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(MemorySizeOp op) {
    auto *memory = get<MemoryStorage *>(op.getMemory());
    state[op.getResult()] = memory->size;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(TupleCreateOp op) {
    SmallVector<ElaboratorValue> values;
    values.reserve(op.getElements().size());
    for (auto el : op.getElements())
      values.push_back(state[el]);
 
    state[op.getResult()] =
        sharedState.internalizer.internalize<TupleStorage>(std::move(values));
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(TupleExtractOp op) {
    auto *tuple = get<TupleStorage *>(op.getTuple());
    state[op.getResult()] = tuple->values[op.getIndex().getZExtValue()];
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(CommentOp op) { return DeletionKind::Keep; }
 
  FailureOr<DeletionKind> visitOp(rtg::YieldOp op) {
    return DeletionKind::Keep;
  }
 
  FailureOr<DeletionKind> visitOp(ValidateOp op) {
    SmallVector<ElaboratorValue> defaultUsedValues, elseValues;
    for (auto v : op.getDefaultUsedValues())
      defaultUsedValues.push_back(state.at(v));
 
    for (auto v : op.getElseValues())
      elseValues.push_back(state.at(v));
 
    auto *validationVal = sharedState.internalizer.create<ValidationValue>(
        op.getValue().getType(), state[op.getRef()],
        state[op.getDefaultValue()], op.getIdAttr(),
        std::move(defaultUsedValues), std::move(elseValues));
    state[op.getValue()] = validationVal;
    materializer.registerIdentityValue(validationVal);
    materializer.map(validationVal, op.getValue());
 
    for (auto [i, val] : llvm::enumerate(op.getValues())) {
      auto *muxVal = sharedState.internalizer.create<ValidationMuxedValue>(
          val.getType(), validationVal, i);
      state[val] = muxVal;
      materializer.registerIdentityValue(muxVal);
      materializer.map(muxVal, val);
    }
 
    return DeletionKind::Keep;
  }
 
  FailureOr<DeletionKind> visitOp(scf::IfOp op) {
    bool cond = get<bool>(op.getCondition());
    auto &toElaborate = cond ? op.getThenRegion() : op.getElseRegion();
    if (toElaborate.empty())
      return DeletionKind::Delete;
 
    // Just reuse this elaborator for the nested region because we need access
    // to the elaborated values outside the nested region (since it is not
    // isolated from above) and we want to materialize the region inline, thus
    // don't need a new materializer instance.
    SmallVector<ElaboratorValue> yieldedVals;
    if (failed(elaborate(toElaborate, {}, yieldedVals)))
      return failure();
 
    // Map the results of the 'scf.if' to the yielded values.
    for (auto [res, out] : llvm::zip(op.getResults(), yieldedVals))
      state[res] = out;
 
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(scf::ForOp op) {
    if (!(std::holds_alternative<size_t>(state.at(op.getLowerBound())) &&
          std::holds_alternative<size_t>(state.at(op.getStep())) &&
          std::holds_alternative<size_t>(state.at(op.getUpperBound()))))
      return op->emitOpError("can only elaborate index type iterator");
 
    auto lowerBound = get<size_t>(op.getLowerBound());
    auto step = get<size_t>(op.getStep());
    auto upperBound = get<size_t>(op.getUpperBound());
 
    // Prepare for first iteration by assigning the nested regions block
    // arguments. We can just reuse this elaborator because we need access to
    // values elaborated in the parent region anyway and materialize everything
    // inline (i.e., don't need a new materializer).
    state[op.getInductionVar()] = lowerBound;
    for (auto [iterArg, initArg] :
         llvm::zip(op.getRegionIterArgs(), op.getInitArgs()))
      state[iterArg] = state.at(initArg);
 
    // This loop performs the actual 'scf.for' loop iterations.
    SmallVector<ElaboratorValue> yieldedVals;
    for (size_t i = lowerBound; i < upperBound; i += step) {
      yieldedVals.clear();
      if (failed(elaborate(op.getBodyRegion(), {}, yieldedVals)))
        return failure();
 
      // Prepare for the next iteration by updating the mapping of the nested
      // regions block arguments
      state[op.getInductionVar()] = i + step;
      for (auto [iterArg, prevIterArg] :
           llvm::zip(op.getRegionIterArgs(), yieldedVals))
        state[iterArg] = prevIterArg;
    }
 
    // Transfer the previously yielded values to the for loop result values.
    for (auto [res, iterArg] :
         llvm::zip(op->getResults(), op.getRegionIterArgs()))
      state[res] = state.at(iterArg);
 
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(scf::YieldOp op) {
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(arith::AddIOp op) {
    if (!isa<IndexType>(op.getType()))
      return op->emitError("only index operands supported");
 
    size_t lhs = get<size_t>(op.getLhs());
    size_t rhs = get<size_t>(op.getRhs());
    state[op.getResult()] = lhs + rhs;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(arith::AndIOp op) {
    if (!op.getType().isSignlessInteger(1))
      return op->emitError("only 'i1' operands supported");
 
    bool lhs = get<bool>(op.getLhs());
    bool rhs = get<bool>(op.getRhs());
    state[op.getResult()] = lhs && rhs;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(arith::XOrIOp op) {
    if (!op.getType().isSignlessInteger(1))
      return op->emitError("only 'i1' operands supported");
 
    bool lhs = get<bool>(op.getLhs());
    bool rhs = get<bool>(op.getRhs());
    state[op.getResult()] = lhs != rhs;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(arith::OrIOp op) {
    if (!op.getType().isSignlessInteger(1))
      return op->emitError("only 'i1' operands supported");
 
    bool lhs = get<bool>(op.getLhs());
    bool rhs = get<bool>(op.getRhs());
    state[op.getResult()] = lhs || rhs;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(arith::SelectOp op) {
    bool cond = get<bool>(op.getCondition());
    auto trueVal = state[op.getTrueValue()];
    auto falseVal = state[op.getFalseValue()];
    state[op.getResult()] = cond ? trueVal : falseVal;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(index::AddOp op) {
    size_t lhs = get<size_t>(op.getLhs());
    size_t rhs = get<size_t>(op.getRhs());
    state[op.getResult()] = lhs + rhs;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(index::CmpOp op) {
    size_t lhs = get<size_t>(op.getLhs());
    size_t rhs = get<size_t>(op.getRhs());
    bool result;
    switch (op.getPred()) {
    case index::IndexCmpPredicate::EQ:
      result = lhs == rhs;
      break;
    case index::IndexCmpPredicate::NE:
      result = lhs != rhs;
      break;
    case index::IndexCmpPredicate::ULT:
      result = lhs < rhs;
      break;
    case index::IndexCmpPredicate::ULE:
      result = lhs <= rhs;
      break;
    case index::IndexCmpPredicate::UGT:
      result = lhs > rhs;
      break;
    case index::IndexCmpPredicate::UGE:
      result = lhs >= rhs;
      break;
    default:
      return op->emitOpError("elaboration not supported");
    }
    state[op.getResult()] = result;
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(ConcatImmediateOp op) {
    bool anyValidationValues =
        llvm::any_of(op.getOperands(), [&](auto operand) {
          return std::holds_alternative<ValidationValue *>(state[operand]);
        });
 
    // FIXME: this is a hack and this case should be handled generically for all
    // operations
    if (anyValidationValues) {
      SmallVector<ElaboratorValue> operands;
      for (auto operand : op.getOperands())
        operands.push_back(state[operand]);
      state[op.getResult()] =
          sharedState.internalizer.internalize<ImmediateConcatStorage>(
              std::move(operands));
      return DeletionKind::Delete;
    }
 
    auto result = APInt::getZeroWidth();
    for (auto operand : op.getOperands())
      result = result.concat(
          cast<ImmediateAttr>(get<TypedAttr>(operand)).getValue());
 
    state[op.getResult()] = ImmediateAttr::get(op.getContext(), result);
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> visitOp(SliceImmediateOp op) {
    // FIXME: this is a hack and this case should be handled generically for all
    // operations
    if (std::holds_alternative<ValidationValue *>(state[op.getInput()])) {
      state[op.getResult()] =
          sharedState.internalizer.internalize<ImmediateSliceStorage>(
              state[op.getInput()], op.getLowBit(), op.getResult().getType());
      return DeletionKind::Delete;
    }
 
    auto inputValue =
        cast<ImmediateAttr>(get<TypedAttr>(op.getInput())).getValue();
    auto sliced = inputValue.extractBits(op.getResult().getType().getWidth(),
                                         op.getLowBit());
    state[op.getResult()] = ImmediateAttr::get(op.getContext(), sliced);
    return DeletionKind::Delete;
  }
 
  FailureOr<DeletionKind> dispatchOpVisitor(Operation *op) {
    return TypeSwitch<Operation *, FailureOr<DeletionKind>>(op)
        .Case<
            // Arith ops
            arith::AddIOp, arith::XOrIOp, arith::AndIOp, arith::OrIOp,
            arith::SelectOp,
            // Index ops
            index::AddOp, index::CmpOp,
            // SCF ops
            scf::IfOp, scf::ForOp, scf::YieldOp>(
            [&](auto op) { return visitOp(op); })
        .Default([&](Operation *op) { return RTGBase::dispatchOpVisitor(op); });
  }
 
  // NOLINTNEXTLINE(misc-no-recursion)
  LogicalResult elaborate(Region &region,
                          ArrayRef<ElaboratorValue> regionArguments,
                          SmallVector<ElaboratorValue> &terminatorOperands) {
    if (region.getBlocks().size() > 1)
      return region.getParentOp()->emitOpError(
          "regions with more than one block are not supported");
 
    for (auto [arg, elabArg] :
         llvm::zip(region.getArguments(), regionArguments))
      state[arg] = elabArg;
 
    Block *block = &region.front();
    for (auto &op : *block) {
      auto result = dispatchOpVisitor(&op);
      if (failed(result))
        return failure();
 
      if (*result == DeletionKind::Keep)
        if (failed(materializer.materialize(&op, state)))
          return failure();
 
      LLVM_DEBUG({
        llvm::dbgs() << "Elaborated " << op << " to\n[";
 
        llvm::interleaveComma(op.getResults(), llvm::dbgs(), [&](auto res) {
          if (state.contains(res))
            llvm::dbgs() << state.at(res);
          else
            llvm::dbgs() << "unknown";
        });
 
        llvm::dbgs() << "]\n\n";
      });
    }
 
    if (region.front().mightHaveTerminator())
      for (auto val : region.front().getTerminator()->getOperands())
        terminatorOperands.push_back(state.at(val));
 
    return success();
  }
 
private:
  // State to be shared between all elaborator instances.
  SharedState &sharedState;
 
  // State to a specific RTG test and the sequences placed within it.
  TestState &testState;
 
  // Allows us to materialize ElaboratorValues to the IR operations necessary to
  // obtain an SSA value representing that elaborated value.
  Materializer &materializer;
 
  // A map from SSA values to a pointer of an interned elaborator value.
  DenseMap<Value, ElaboratorValue> state;
 
  // The current context we are elaborating under.
  ContextResourceAttrInterface currentContext;
};
} // namespace
 
SequenceOp
Materializer::elaborateSequence(const RandomizedSequenceStorage *seq,
                                SmallVector<ElaboratorValue> &elabArgs) {
  auto familyOp =
      sharedState.table.lookup<SequenceOp>(seq->sequence->familyName);
  // TODO: don't clone if this is the only remaining reference to this
  // sequence
  OpBuilder builder(familyOp);
  auto seqOp = builder.cloneWithoutRegions(familyOp);
  auto name = sharedState.names.newName(seq->sequence->familyName.getValue());
  seqOp.setSymName(name);
  seqOp.getBodyRegion().emplaceBlock();
  sharedState.table.insert(seqOp);
  assert(seqOp.getSymName() == name && "should not have been renamed");
 
  LLVM_DEBUG(llvm::dbgs() << "\n=== Elaborating sequence family @"
                          << familyOp.getSymName() << " into @"
                          << seqOp.getSymName() << " under context "
                          << seq->context << "\n\n");
 
  Materializer materializer(OpBuilder::atBlockBegin(seqOp.getBody()), testState,
                            sharedState, elabArgs);
  Elaborator elaborator(sharedState, testState, materializer, seq->context);
  SmallVector<ElaboratorValue> yieldedVals;
  if (failed(elaborator.elaborate(familyOp.getBodyRegion(), seq->sequence->args,
                                  yieldedVals)))
    return {};
 
  seqOp.setSequenceType(
      SequenceType::get(builder.getContext(), materializer.getBlockArgTypes()));
  materializer.finalize();
 
  return seqOp;
}
 
//===----------------------------------------------------------------------===//
// Elaborator Pass
//===----------------------------------------------------------------------===//
 
namespace {
struct ElaborationPass
    : public rtg::impl::ElaborationPassBase<ElaborationPass> {
  using Base::Base;
 
  void runOnOperation() override;
  void matchTestsAgainstTargets(SymbolTable &table);
  LogicalResult elaborateModule(ModuleOp moduleOp, SymbolTable &table);
};
} // namespace
 
void ElaborationPass::runOnOperation() {
  auto moduleOp = getOperation();
  SymbolTable table(moduleOp);
 
  matchTestsAgainstTargets(table);
 
  if (failed(elaborateModule(moduleOp, table)))
    return signalPassFailure();
}
 
void ElaborationPass::matchTestsAgainstTargets(SymbolTable &table) {
  auto moduleOp = getOperation();
 
  for (auto test : llvm::make_early_inc_range(moduleOp.getOps<TestOp>())) {
    if (test.getTargetAttr())
      continue;
 
    bool matched = false;
 
    for (auto target : moduleOp.getOps<TargetOp>()) {
      // Check if the target type is a subtype of the test's target type
      // This means that for each entry in the test's target type, there must be
      // a corresponding entry with the same name and type in the target's type
      bool isSubtype = true;
      auto testEntries = test.getTargetType().getEntries();
      auto targetEntries = target.getTarget().getEntries();
 
      // Check if target is a subtype of test requirements
      // Since entries are sorted by name, we can do this in a single pass
      size_t targetIdx = 0;
      for (auto testEntry : testEntries) {
        // Find the matching entry in target entries.
        while (targetIdx < targetEntries.size() &&
               targetEntries[targetIdx].name.getValue() <
                   testEntry.name.getValue())
          targetIdx++;
 
        // Check if we found a matching entry with the same name and type
        if (targetIdx >= targetEntries.size() ||
            targetEntries[targetIdx].name != testEntry.name ||
            targetEntries[targetIdx].type != testEntry.type) {
          isSubtype = false;
          break;
        }
      }
 
      if (!isSubtype)
        continue;
 
      IRRewriter rewriter(test);
      // Create a new test for the matched target
      auto newTest = cast<TestOp>(test->clone());
      newTest.setSymName(test.getSymName().str() + "_" +
                         target.getSymName().str());
 
      // Set the target symbol specifying that this test is only suitable for
      // that target.
      newTest.setTargetAttr(target.getSymNameAttr());
 
      table.insert(newTest, rewriter.getInsertionPoint());
      matched = true;
    }
 
    if (matched || deleteUnmatchedTests)
      test->erase();
  }
}
 
static bool onlyLegalToMaterializeInTarget(Type type) {
  return isa<MemoryBlockType, ContextResourceTypeInterface>(type);
}
 
LogicalResult ElaborationPass::elaborateModule(ModuleOp moduleOp,
                                               SymbolTable &table) {
  SharedState state(table, seed);
 
  // Update the name cache
  state.names.add(moduleOp);
 
  struct TargetElabResult {
    DictType targetType;
    SmallVector<ElaboratorValue> yields;
    TestState testState;
  };
 
  // Map to store elaborated targets
  DenseMap<StringAttr, TargetElabResult> targetMap;
  for (auto targetOp : moduleOp.getOps<TargetOp>()) {
    LLVM_DEBUG(llvm::dbgs() << "=== Elaborating target @"
                            << targetOp.getSymName() << "\n\n");
 
    auto &result = targetMap[targetOp.getSymNameAttr()];
    result.targetType = targetOp.getTarget();
 
    SmallVector<ElaboratorValue> blockArgs;
    Materializer targetMaterializer(OpBuilder::atBlockBegin(targetOp.getBody()),
                                    result.testState, state, blockArgs);
    Elaborator targetElaborator(state, result.testState, targetMaterializer);
 
    // Elaborate the target
    if (failed(targetElaborator.elaborate(targetOp.getBodyRegion(), {},
                                          result.yields)))
      return failure();
  }
 
  // Initialize the worklist with the test ops since they cannot be placed by
  // other ops.
  for (auto testOp : moduleOp.getOps<TestOp>()) {
    // Skip tests without a target attribute - these couldn't be matched
    // against any target but can be useful to keep around for reporting
    // purposes.
    if (!testOp.getTargetAttr())
      continue;
 
    LLVM_DEBUG(llvm::dbgs()
               << "\n=== Elaborating test @" << testOp.getTemplateName()
               << " for target @" << *testOp.getTarget() << "\n\n");
 
    // Get the target for this test
    auto targetResult = targetMap[testOp.getTargetAttr()];
    TestState testState = targetResult.testState;
    testState.name = testOp.getSymNameAttr();
 
    SmallVector<ElaboratorValue> filteredYields;
    unsigned i = 0;
    for (auto [entry, yield] :
         llvm::zip(targetResult.targetType.getEntries(), targetResult.yields)) {
      if (i >= testOp.getTargetType().getEntries().size())
        break;
 
      if (entry.name == testOp.getTargetType().getEntries()[i].name) {
        filteredYields.push_back(yield);
        ++i;
      }
    }
 
    // Now elaborate the test with the same state, passing the target yield
    // values as arguments
    SmallVector<ElaboratorValue> blockArgs;
    Materializer materializer(OpBuilder::atBlockBegin(testOp.getBody()),
                              testState, state, blockArgs);
 
    for (auto [arg, val] :
         llvm::zip(testOp.getBody()->getArguments(), filteredYields))
      if (onlyLegalToMaterializeInTarget(arg.getType()))
        materializer.map(val, arg);
 
    Elaborator elaborator(state, testState, materializer);
    SmallVector<ElaboratorValue> ignore;
    if (failed(elaborator.elaborate(testOp.getBodyRegion(), filteredYields,
                                    ignore)))
      return failure();
 
    materializer.finalize();
  }
 
  return success();
}