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Remove useless SWAP1 in front of commutative operations

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This commit is contained in:
Alex Beregszaszi
2018-04-03 18:57:07 +02:00
parent 0edce4b570
commit 17bcabb6cf
3 changed files with 72 additions and 1 deletions
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libevmasm/PeepholeOptimiser.cpp
+20 -1
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@@ -154,6 +154,25 @@ 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 JumpToNext: SimplePeepholeOptimizerMethod<JumpToNext, 3>
{
static size_t applySimple(
@@ -260,7 +279,7 @@ 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(), 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) ||