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| author | Alex Beregszaszi <alex@rtfs.hu> | 2018-04-04 21:28:15 +0800 |
|---|---|---|
| committer | Alex Beregszaszi <alex@rtfs.hu> | 2018-04-04 23:47:58 +0800 |
| commit | 02ea0e547f3faa687f9c986ca9a0201b995846c0 (patch) | |
| tree | e6ab87291d5e0738c3bb2089464a75868567bb64 /libevmasm | |
| parent | efa0ccaf9e25a257e1ee6b36c0b77b1532131077 (diff) | |
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Replace comparison operators with opposites if preceded by SWAP1
Diffstat (limited to 'libevmasm')
| -rw-r--r-- | libevmasm/PeepholeOptimiser.cpp | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/libevmasm/PeepholeOptimiser.cpp b/libevmasm/PeepholeOptimiser.cpp index 30646545..8a39de24 100644 --- a/libevmasm/PeepholeOptimiser.cpp +++ b/libevmasm/PeepholeOptimiser.cpp @@ -173,6 +173,32 @@ struct CommutativeSwap: SimplePeepholeOptimizerMethod<CommutativeSwap, 2> } }; +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( @@ -279,7 +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(), CommutativeSwap(), 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) || |