diff options
Diffstat (limited to 'libevmasm')
| -rw-r--r-- | libevmasm/PeepholeOptimiser.cpp | 47 | ||||
| -rw-r--r-- | libevmasm/RuleList.h | 10 |
2 files changed, 56 insertions, 1 deletions
diff --git a/libevmasm/PeepholeOptimiser.cpp b/libevmasm/PeepholeOptimiser.cpp index 168d1109..8a39de24 100644 --- a/libevmasm/PeepholeOptimiser.cpp +++ b/libevmasm/PeepholeOptimiser.cpp @@ -154,6 +154,51 @@ struct DoublePush: SimplePeepholeOptimizerMethod<DoublePush, 2> } }; +struct CommutativeSwap: SimplePeepholeOptimizerMethod<CommutativeSwap, 2> +{ + static bool applySimple(AssemblyItem const& _swap, AssemblyItem const& _op, std::back_insert_iterator<AssemblyItems> _out) + { + // Remove SWAP1 if following instruction is commutative + if ( + _swap.type() == Operation && + _swap.instruction() == Instruction::SWAP1 && + SemanticInformation::isCommutativeOperation(_op) + ) + { + *_out = _op; + return true; + } + else + return false; + } +}; + +struct SwapComparison: SimplePeepholeOptimizerMethod<SwapComparison, 2> +{ + static bool applySimple(AssemblyItem const& _swap, AssemblyItem const& _op, std::back_insert_iterator<AssemblyItems> _out) + { + map<Instruction, Instruction> swappableOps{ + { Instruction::LT, Instruction::GT }, + { Instruction::GT, Instruction::LT }, + { Instruction::SLT, Instruction::SGT }, + { Instruction::SGT, Instruction::SLT } + }; + + if ( + _swap.type() == Operation && + _swap.instruction() == Instruction::SWAP1 && + _op.type() == Operation && + swappableOps.count(_op.instruction()) + ) + { + *_out = swappableOps.at(_op.instruction()); + return true; + } + else + return false; + } +}; + struct JumpToNext: SimplePeepholeOptimizerMethod<JumpToNext, 3> { static size_t applySimple( @@ -260,7 +305,7 @@ bool PeepholeOptimiser::optimise() { OptimiserState state {m_items, 0, std::back_inserter(m_optimisedItems)}; while (state.i < m_items.size()) - applyMethods(state, PushPop(), OpPop(), DoublePush(), DoubleSwap(), JumpToNext(), UnreachableCode(), TagConjunctions(), Identity()); + applyMethods(state, PushPop(), OpPop(), DoublePush(), DoubleSwap(), CommutativeSwap(), SwapComparison(), JumpToNext(), UnreachableCode(), TagConjunctions(), Identity()); if (m_optimisedItems.size() < m_items.size() || ( m_optimisedItems.size() == m_items.size() && ( eth::bytesRequired(m_optimisedItems, 3) < eth::bytesRequired(m_items, 3) || diff --git a/libevmasm/RuleList.h b/libevmasm/RuleList.h index da522cec..abcf170c 100644 --- a/libevmasm/RuleList.h +++ b/libevmasm/RuleList.h @@ -89,6 +89,16 @@ std::vector<SimplificationRule<Pattern>> simplificationRuleList( u256 mask = (u256(1) << testBit) - 1; return u256(boost::multiprecision::bit_test(B.d(), testBit) ? B.d() | ~mask : B.d() & mask); }, false}, + {{Instruction::SHL, {A, B}}, [=]{ + if (A.d() > 255) + return u256(0); + return u256(bigint(B.d()) << unsigned(A.d())); + }, false}, + {{Instruction::SHR, {A, B}}, [=]{ + if (A.d() > 255) + return u256(0); + return B.d() >> unsigned(A.d()); + }, false}, // invariants involving known constants {{Instruction::ADD, {X, 0}}, [=]{ return X; }, false}, |