dynarmic/src/ir_opt/get_set_elimination_pass.cpp
2016-08-17 20:46:21 +01:00

115 lines
3.5 KiB
C++

/* This file is part of the dynarmic project.
* Copyright (c) 2016 MerryMage
* This software may be used and distributed according to the terms of the GNU
* General Public License version 2 or any later version.
*/
#include <array>
#include "common/assert.h"
#include "common/common_types.h"
#include "frontend/ir/basic_block.h"
#include "frontend/ir/value.h"
#include "ir_opt/passes.h"
namespace Dynarmic {
namespace Optimization {
void GetSetElimination(IR::Block& block) {
using Iterator = decltype(block.instructions.begin());
struct RegisterInfo {
IR::Value register_value;
bool set_instruction_present = false;
Iterator last_set_instruction;
};
std::array<RegisterInfo, 15> reg_info;
RegisterInfo n_info;
RegisterInfo z_info;
RegisterInfo c_info;
RegisterInfo v_info;
const auto do_set = [&block](RegisterInfo& info, IR::Value value, Iterator set_inst) {
if (info.set_instruction_present) {
info.last_set_instruction->Invalidate();
block.instructions.erase(info.last_set_instruction);
}
info.register_value = value;
info.set_instruction_present = true;
info.last_set_instruction = set_inst;
};
const auto do_get = [](RegisterInfo& info, Iterator get_inst) {
if (info.register_value.IsEmpty()) {
info.register_value = IR::Value(&*get_inst);
return;
}
get_inst->ReplaceUsesWith(info.register_value);
};
for (auto inst = block.instructions.begin(); inst != block.instructions.end(); ++inst) {
switch (inst->GetOpcode()) {
case IR::Opcode::SetRegister: {
Arm::Reg reg = inst->GetArg(0).GetRegRef();
if (reg == Arm::Reg::PC)
break;
size_t reg_index = static_cast<size_t>(reg);
do_set(reg_info[reg_index], inst->GetArg(1), inst);
break;
}
case IR::Opcode::GetRegister: {
Arm::Reg reg = inst->GetArg(0).GetRegRef();
ASSERT(reg != Arm::Reg::PC);
size_t reg_index = static_cast<size_t>(reg);
do_get(reg_info[reg_index], inst);
break;
}
case IR::Opcode::SetNFlag: {
do_set(n_info, inst->GetArg(0), inst);
break;
}
case IR::Opcode::GetNFlag: {
do_get(n_info, inst);
break;
}
case IR::Opcode::SetZFlag: {
do_set(z_info, inst->GetArg(0), inst);
break;
}
case IR::Opcode::GetZFlag: {
do_get(z_info, inst);
break;
}
case IR::Opcode::SetCFlag: {
do_set(c_info, inst->GetArg(0), inst);
break;
}
case IR::Opcode::GetCFlag: {
do_get(c_info, inst);
break;
}
case IR::Opcode::SetVFlag: {
do_set(v_info, inst->GetArg(0), inst);
break;
}
case IR::Opcode::GetVFlag: {
do_get(v_info, inst);
break;
}
case IR::Opcode::SetCpsr:
case IR::Opcode::GetCpsr: {
n_info = {};
z_info = {};
c_info = {};
v_info = {};
break;
}
default:
break;
}
}
}
} // namespace Optimization
} // namespace Dynarmic