Method UpgradeExtInst

source/opt/upgrade_memory_model.cpp:779–817

}

void UpgradeMemoryModel::UpgradeExtInst(Instruction* ext_inst) {
  const bool is_modf = ext_inst->GetSingleWordInOperand(1u) == GLSLstd450Modf;
  auto ptr_id = ext_inst->GetSingleWordInOperand(3u);
  auto ptr_type_id = get_def_use_mgr()->GetDef(ptr_id)->type_id();
  auto pointee_type_id =
      get_def_use_mgr()->GetDef(ptr_type_id)->GetSingleWordInOperand(1u);
  auto element_type_id = ext_inst->type_id();
  std::vector<const analysis::Type*> element_types(2);
  element_types[0] = context()->get_type_mgr()->GetType(element_type_id);
  element_types[1] = context()->get_type_mgr()->GetType(pointee_type_id);
  analysis::Struct struct_type(element_types);
  uint32_t struct_id =
      context()->get_type_mgr()->GetTypeInstruction(&struct_type);
  // Change the operation
  GLSLstd450 new_op = is_modf ? GLSLstd450ModfStruct : GLSLstd450FrexpStruct;
  ext_inst->SetOperand(3u, {static_cast<uint32_t>(new_op)});
  // Remove the pointer argument
  ext_inst->RemoveOperand(5u);
  // Set the type id to the new struct.
  ext_inst->SetResultType(struct_id);

  // The result is now a struct of the original result. The zero'th element is
  // old result and should replace the old result. The one'th element needs to
  // be stored via a new instruction.
  auto where = ext_inst->NextNode();
  InstructionBuilder builder(
      context(), where,
      IRContext::kAnalysisDefUse | IRContext::kAnalysisInstrToBlockMapping);
  // TODO(1841): Handle id overflow.
  auto extract_0 =
      builder.AddCompositeExtract(element_type_id, ext_inst->result_id(), {0});
  context()->ReplaceAllUsesWith(ext_inst->result_id(), extract_0->result_id());
  // The extract's input was just changed to itself, so fix that.
  extract_0->SetInOperand(0u, {ext_inst->result_id()});
  // TODO(1841): Handle id overflow.
  auto extract_1 =
      builder.AddCompositeExtract(pointee_type_id, ext_inst->result_id(), {1});
  builder.AddStore(ptr_id, extract_1->result_id());
}

uint32_t UpgradeMemoryModel::MemoryAccessNumWords(uint32_t mask) {
  uint32_t result = 1;