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Peephole optimizer for "iszero iszero <tag> jumpi".

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This commit is contained in:
chriseth
2019-03-07 15:52:02 +01:00
parent c753b6bce5
commit e0d1b2f5b3
9 changed files with 169 additions and 96 deletions
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libevmasm/PeepholeOptimiser.cpp
+40 -1
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@@ -45,6 +45,14 @@ struct ApplyRule
{
};
template <class Method>
struct ApplyRule<Method, 4>
{
static bool applyRule(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems> _out)
{
return Method::applySimple(_in[0], _in[1], _in[2], _in[3], _out);
}
};
template <class Method>
struct ApplyRule<Method, 3>
{
static bool applyRule(AssemblyItems::const_iterator _in, std::back_insert_iterator<AssemblyItems> _out)
@@ -197,6 +205,32 @@ struct SwapComparison: SimplePeepholeOptimizerMethod<SwapComparison, 2>
}
};
struct IsZeroIsZeroJumpI: SimplePeepholeOptimizerMethod<IsZeroIsZeroJumpI, 4>
{
static size_t applySimple(
AssemblyItem const& _iszero1,
AssemblyItem const& _iszero2,
AssemblyItem const& _pushTag,
AssemblyItem const& _jumpi,
std::back_insert_iterator<AssemblyItems> _out
)
{
if (
_iszero1 == Instruction::ISZERO &&
_iszero2 == Instruction::ISZERO &&
_pushTag.type() == PushTag &&
_jumpi == Instruction::JUMPI
)
{
*_out = _pushTag;
*_out = _jumpi;
return true;
}
else
return false;
}
};
struct JumpToNext: SimplePeepholeOptimizerMethod<JumpToNext, 3>
{
static size_t applySimple(
@@ -320,7 +354,12 @@ 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(), SwapComparison(), JumpToNext(), UnreachableCode(), TagConjunctions(), TruthyAnd(), Identity());
applyMethods(
state,
PushPop(), OpPop(), DoublePush(), DoubleSwap(), CommutativeSwap(), SwapComparison(),
IsZeroIsZeroJumpI(), JumpToNext(), UnreachableCode(),
TagConjunctions(), TruthyAnd(), Identity()
);
if (m_optimisedItems.size() < m_items.size() || (
m_optimisedItems.size() == m_items.size() && (
eth::bytesRequired(m_optimisedItems, 3) < eth::bytesRequired(m_items, 3) ||