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Merge pull request #1345 from ethereum/optimiser-rules

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More optimiser rules
This commit is contained in:
chriseth 2016-11-30 14:26:01 +01:00 committed by GitHub
commit e43a8ebc28
2 changed files with 36 additions and 1 deletions
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14
libevmasm/ExpressionClasses.cpp
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@ -245,22 +245,25 @@ Rules::Rules()
// invariants involving known constants
{{Instruction::ADD, {X, 0}}, [=]{ return X; }},
{{Instruction::SUB, {X, 0}}, [=]{ return X; }},
{{Instruction::MUL, {X, 1}}, [=]{ return X; }},
{{Instruction::DIV, {X, 1}}, [=]{ return X; }},
{{Instruction::SDIV, {X, 1}}, [=]{ return X; }},
{{Instruction::OR, {X, 0}}, [=]{ return X; }},
{{Instruction::XOR, {X, 0}}, [=]{ return X; }},
{{Instruction::AND, {X, ~u256(0)}}, [=]{ return X; }},
{{Instruction::AND, {X, 0}}, [=]{ return u256(0); }},
{{Instruction::MUL, {X, 0}}, [=]{ return u256(0); }},
{{Instruction::DIV, {X, 0}}, [=]{ return u256(0); }},
{{Instruction::DIV, {0, X}}, [=]{ return u256(0); }},
{{Instruction::MOD, {X, 0}}, [=]{ return u256(0); }},
{{Instruction::MOD, {0, X}}, [=]{ return u256(0); }},
{{Instruction::AND, {X, 0}}, [=]{ return u256(0); }},
{{Instruction::OR, {X, ~u256(0)}}, [=]{ return ~u256(0); }},
{{Instruction::EQ, {X, 0}}, [=]() -> Pattern { return {Instruction::ISZERO, {X}}; } },
// operations involving an expression and itself
{{Instruction::AND, {X, X}}, [=]{ return X; }},
{{Instruction::OR, {X, X}}, [=]{ return X; }},
{{Instruction::XOR, {X, X}}, [=]{ return u256(0); }},
{{Instruction::SUB, {X, X}}, [=]{ return u256(0); }},
{{Instruction::EQ, {X, X}}, [=]{ return u256(1); }},
{{Instruction::LT, {X, X}}, [=]{ return u256(0); }},
@ -270,6 +273,11 @@ Rules::Rules()
{{Instruction::MOD, {X, X}}, [=]{ return u256(0); }},
{{Instruction::NOT, {{Instruction::NOT, {X}}}}, [=]{ return X; }},
{{Instruction::XOR, {{{X}, {Instruction::XOR, {X, Y}}}}}, [=]{ return Y; }},
{{Instruction::OR, {{{X}, {Instruction::AND, {X, Y}}}}}, [=]{ return X; }},
{{Instruction::AND, {{{X}, {Instruction::OR, {X, Y}}}}}, [=]{ return X; }},
{{Instruction::AND, {{{X}, {Instruction::NOT, {X}}}}}, [=]{ return u256(0); }},
{{Instruction::OR, {{{X}, {Instruction::NOT, {X}}}}}, [=]{ return ~u256(0); }},
};
// Double negation of opcodes with binary result
for (auto const& op: vector<Instruction>{
@ -287,6 +295,10 @@ Rules::Rules()
{Instruction::ISZERO, {{Instruction::ISZERO, {{Instruction::ISZERO, {X}}}}}},
[=]() -> Pattern { return {Instruction::ISZERO, {X}}; }
});
m_rules.push_back({
{Instruction::ISZERO, {{Instruction::XOR, {X, Y}}}},
[=]() -> Pattern { return { Instruction::EQ, {X, Y} }; }
});
// Associative operations
for (auto const& opFun: vector<pair<Instruction,function<u256(u256 const&,u256 const&)>>>{
{Instruction::ADD, plus<u256>()},

23
test/libsolidity/SolidityOptimizer.cpp
View File

@ -1304,6 +1304,29 @@ BOOST_AUTO_TEST_CASE(invalid_state_at_control_flow_join)
compareVersions("test()");
}
BOOST_AUTO_TEST_CASE(cse_sub_zero)
{
checkCSE({
u256(0),
Instruction::DUP2,
Instruction::SUB
}, {
Instruction::DUP1
});
checkCSE({
Instruction::DUP1,
u256(0),
Instruction::SUB
}, {
u256(0),
Instruction::DUP2,
Instruction::SWAP1,
Instruction::SUB
});
}
BOOST_AUTO_TEST_SUITE_END()
}