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// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/compiler/move-optimizer.h"
#include "test/unittests/compiler/instruction-sequence-unittest.h"
namespace v8 {
namespace internal {
namespace compiler {
class MoveOptimizerTest : public InstructionSequenceTest {
public:
Instruction* LastInstruction() { return sequence()->instructions().back(); }
void AddMove(Instruction* instr, TestOperand from, TestOperand to,
Instruction::GapPosition pos = Instruction::START) {
auto parallel_move = instr->GetOrCreateParallelMove(pos, zone());
parallel_move->AddMove(ConvertMoveArg(from), ConvertMoveArg(to));
}
int NonRedundantSize(ParallelMove* moves) {
int i = 0;
for (auto move : *moves) {
if (move->IsRedundant()) continue;
i++;
}
return i;
}
bool Contains(ParallelMove* moves, TestOperand from_op, TestOperand to_op) {
auto from = ConvertMoveArg(from_op);
auto to = ConvertMoveArg(to_op);
for (auto move : *moves) {
if (move->IsRedundant()) continue;
if (move->source().Equals(from) && move->destination().Equals(to)) {
return true;
}
}
return false;
}
// TODO(dcarney): add a verifier.
void Optimize() {
WireBlocks();
if (FLAG_trace_turbo) {
OFStream os(stdout);
PrintableInstructionSequence printable = {config(), sequence()};
os << "----- Instruction sequence before move optimization -----\n"
<< printable;
}
MoveOptimizer move_optimizer(zone(), sequence());
move_optimizer.Run();
if (FLAG_trace_turbo) {
OFStream os(stdout);
PrintableInstructionSequence printable = {config(), sequence()};
os << "----- Instruction sequence after move optimization -----\n"
<< printable;
}
}
private:
InstructionOperand ConvertMoveArg(TestOperand op) {
CHECK_EQ(kNoValue, op.vreg_.value_);
CHECK_NE(kNoValue, op.value_);
switch (op.type_) {
case kConstant:
return ConstantOperand(op.value_);
case kFixedSlot:
return AllocatedOperand(LocationOperand::STACK_SLOT, kRepWord32,
op.value_);
case kFixedRegister:
CHECK(0 <= op.value_ && op.value_ < num_general_registers());
return AllocatedOperand(LocationOperand::REGISTER, kRepWord32,
op.value_);
case kExplicit:
CHECK(0 <= op.value_ && op.value_ < num_general_registers());
return ExplicitOperand(LocationOperand::REGISTER, kRepWord32,
op.value_);
default:
break;
}
CHECK(false);
return InstructionOperand();
}
};
TEST_F(MoveOptimizerTest, RemovesRedundant) {
StartBlock();
auto first_instr = EmitNop();
AddMove(first_instr, Reg(0), Reg(1));
auto last_instr = EmitNop();
AddMove(last_instr, Reg(1), Reg(0));
EndBlock(Last());
Optimize();
CHECK_EQ(0, NonRedundantSize(first_instr->parallel_moves()[0]));
auto move = last_instr->parallel_moves()[0];
CHECK_EQ(1, NonRedundantSize(move));
CHECK(Contains(move, Reg(0), Reg(1)));
}
TEST_F(MoveOptimizerTest, RemovesRedundantExplicit) {
int first_reg_index =
RegisterConfiguration::ArchDefault(RegisterConfiguration::TURBOFAN)
->GetAllocatableGeneralCode(0);
int second_reg_index =
RegisterConfiguration::ArchDefault(RegisterConfiguration::TURBOFAN)
->GetAllocatableGeneralCode(1);
StartBlock();
auto first_instr = EmitNop();
AddMove(first_instr, Reg(first_reg_index), ExplicitReg(second_reg_index));
auto last_instr = EmitNop();
AddMove(last_instr, Reg(second_reg_index), Reg(first_reg_index));
EndBlock(Last());
Optimize();
CHECK_EQ(0, NonRedundantSize(first_instr->parallel_moves()[0]));
auto move = last_instr->parallel_moves()[0];
CHECK_EQ(1, NonRedundantSize(move));
CHECK(Contains(move, Reg(first_reg_index), ExplicitReg(second_reg_index)));
}
TEST_F(MoveOptimizerTest, SplitsConstants) {
StartBlock();
EndBlock(Last());
auto gap = LastInstruction();
AddMove(gap, Const(1), Slot(0));
AddMove(gap, Const(1), Slot(1));
AddMove(gap, Const(1), Reg(0));
AddMove(gap, Const(1), Slot(2));
Optimize();
auto move = gap->parallel_moves()[0];
CHECK_EQ(1, NonRedundantSize(move));
CHECK(Contains(move, Const(1), Reg(0)));
move = gap->parallel_moves()[1];
CHECK_EQ(3, NonRedundantSize(move));
CHECK(Contains(move, Reg(0), Slot(0)));
CHECK(Contains(move, Reg(0), Slot(1)));
CHECK(Contains(move, Reg(0), Slot(2)));
}
TEST_F(MoveOptimizerTest, SimpleMerge) {
StartBlock();
EndBlock(Branch(Imm(), 1, 2));
StartBlock();
EndBlock(Jump(2));
AddMove(LastInstruction(), Reg(0), Reg(1));
StartBlock();
EndBlock(Jump(1));
AddMove(LastInstruction(), Reg(0), Reg(1));
StartBlock();
EndBlock(Last());
auto last = LastInstruction();
Optimize();
auto move = last->parallel_moves()[0];
CHECK_EQ(1, NonRedundantSize(move));
CHECK(Contains(move, Reg(0), Reg(1)));
}
TEST_F(MoveOptimizerTest, SimpleMergeCycle) {
StartBlock();
EndBlock(Branch(Imm(), 1, 2));
StartBlock();
EndBlock(Jump(2));
auto gap_0 = LastInstruction();
AddMove(gap_0, Reg(0), Reg(1));
AddMove(LastInstruction(), Reg(1), Reg(0));
StartBlock();
EndBlock(Jump(1));
auto gap_1 = LastInstruction();
AddMove(gap_1, Reg(0), Reg(1));
AddMove(gap_1, Reg(1), Reg(0));
StartBlock();
EndBlock(Last());
auto last = LastInstruction();
Optimize();
CHECK(gap_0->AreMovesRedundant());
CHECK(gap_1->AreMovesRedundant());
auto move = last->parallel_moves()[0];
CHECK_EQ(2, NonRedundantSize(move));
CHECK(Contains(move, Reg(0), Reg(1)));
CHECK(Contains(move, Reg(1), Reg(0)));
}
TEST_F(MoveOptimizerTest, GapsCanMoveOverInstruction) {
StartBlock();
int const_index = 1;
DefineConstant(const_index);
Instruction* ctant_def = LastInstruction();
AddMove(ctant_def, Reg(1), Reg(0));
Instruction* last = EmitNop();
AddMove(last, Const(const_index), Reg(0));
AddMove(last, Reg(0), Reg(1));
EndBlock(Last());
Optimize();
ParallelMove* inst1_start =
ctant_def->GetParallelMove(Instruction::GapPosition::START);
ParallelMove* inst1_end =
ctant_def->GetParallelMove(Instruction::GapPosition::END);
ParallelMove* last_start =
last->GetParallelMove(Instruction::GapPosition::START);
CHECK(inst1_start == nullptr || inst1_start->size() == 0);
CHECK(inst1_end == nullptr || inst1_end->size() == 0);
CHECK(last_start->size() == 2);
int redundants = 0;
int assignment = 0;
for (MoveOperands* move : *last_start) {
if (move->IsRedundant()) {
++redundants;
} else {
++assignment;
CHECK(move->destination().IsRegister());
CHECK(move->source().IsConstant());
}
}
CHECK_EQ(1, redundants);
CHECK_EQ(1, assignment);
}
} // namespace compiler
} // namespace internal
} // namespace v8
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