// Extracts and returns the signed integer constant in a 0-rank integer tensor
// or 1-element 1-rank integer tensor if 'value' is a constant.
static std::optional<int64_t> ExtractConstantIntFromTensor(Value value) {
  ElementsAttr attr;
  if (!matchPattern(value, m_Constant(&attr))) return {};
  if (attr.getNumElements() != 1) return {};
  IntegerAttr int_attr = *attr.getValues<IntegerAttr>().begin();