Function BitCastScalarOrVector

source/opt/folding_rules.cpp:2859–2886

}

FoldingRule BitCastScalarOrVector() {
  return [](IRContext* context, Instruction* inst,
            const std::vector<const analysis::Constant*>& constants) {
    assert(inst->opcode() == spv::Op::OpBitcast && constants.size() == 1);
    if (constants[0] == nullptr) return false;

    const analysis::Type* type =
        context->get_type_mgr()->GetType(inst->type_id());
    if (HasFloatingPoint(type) && !inst->IsFloatingPointFoldingAllowed())
      return false;

    analysis::ConstantManager* const_mgr = context->get_constant_mgr();
    std::vector<uint32_t> words =
        GetWordsFromNumericScalarOrVectorConstant(const_mgr, constants[0]);
    if (words.size() == 0) return false;

    const analysis::Constant* bitcasted_constant =
        ConvertWordsToNumericScalarOrVectorConstant(const_mgr, words, type);
    if (!bitcasted_constant) return false;

    auto new_feeder_id =
        const_mgr->GetDefiningInstruction(bitcasted_constant, inst->type_id())
            ->result_id();
    inst->SetOpcode(spv::Op::OpCopyObject);
    inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {new_feeder_id}}});
    return true;
  };
}

// Remove indirect bitcasts which have no effect.
//   uint32 x;  asuint32(x)            => x