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fa02667075
solidity/libevmasm/RuleList.h
chriseth fa02667075 Generalize instructions.
2019-11-07 14:33:34 +01:00

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/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @date 2018
* Templatized list of simplification rules.
*/
#pragma once
#include <libevmasm/Instruction.h>
#include <libevmasm/SimplificationRule.h>
#include <libdevcore/CommonData.h>
#include <boost/multiprecision/detail/min_max.hpp>
#include <vector>
#include <functional>
namespace dev
{
namespace eth
{
template <class S> S divWorkaround(S const& _a, S const& _b)
{
return (S)(bigint(_a) / bigint(_b));
}
template <class S> S modWorkaround(S const& _a, S const& _b)
{
return (S)(bigint(_a) % bigint(_b));
}
// This works around a bug fixed with Boost 1.64.
// https://www.boost.org/doc/libs/1_68_0/libs/multiprecision/doc/html/boost_multiprecision/map/hist.html#boost_multiprecision.map.hist.multiprecision_2_3_1_boost_1_64
inline u256 shlWorkaround(u256 const& _x, unsigned _amount)
{
return u256((bigint(_x) << _amount) & u256(-1));
}
// simplificationRuleList below was split up into parts to prevent
// stack overflows in the JavaScript optimizer for emscripten builds
// that affected certain browser versions.
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleListPart1(
Pattern A,
Pattern B,
Pattern C,
Pattern,
Pattern
)
{
return std::vector<SimplificationRule<Pattern>> {
// arithmetic on constants
{{Pattern::Builtins::ADD, {A, B}}, [=]{ return A.d() + B.d(); }, false},
{{Pattern::Builtins::MUL, {A, B}}, [=]{ return A.d() * B.d(); }, false},
{{Pattern::Builtins::SUB, {A, B}}, [=]{ return A.d() - B.d(); }, false},
{{Pattern::Builtins::DIV, {A, B}}, [=]{ return B.d() == 0 ? 0 : divWorkaround(A.d(), B.d()); }, false},
{{Pattern::Builtins::SDIV, {A, B}}, [=]{ return B.d() == 0 ? 0 : s2u(divWorkaround(u2s(A.d()), u2s(B.d()))); }, false},
{{Pattern::Builtins::MOD, {A, B}}, [=]{ return B.d() == 0 ? 0 : modWorkaround(A.d(), B.d()); }, false},
{{Pattern::Builtins::SMOD, {A, B}}, [=]{ return B.d() == 0 ? 0 : s2u(modWorkaround(u2s(A.d()), u2s(B.d()))); }, false},
{{Pattern::Builtins::EXP, {A, B}}, [=]{ return u256(boost::multiprecision::powm(bigint(A.d()), bigint(B.d()), bigint(1) << 256)); }, false},
{{Pattern::Builtins::NOT, {A}}, [=]{ return ~A.d(); }, false},
{{Pattern::Builtins::LT, {A, B}}, [=]() -> u256 { return A.d() < B.d() ? 1 : 0; }, false},
{{Pattern::Builtins::GT, {A, B}}, [=]() -> u256 { return A.d() > B.d() ? 1 : 0; }, false},
{{Pattern::Builtins::SLT, {A, B}}, [=]() -> u256 { return u2s(A.d()) < u2s(B.d()) ? 1 : 0; }, false},
{{Pattern::Builtins::SGT, {A, B}}, [=]() -> u256 { return u2s(A.d()) > u2s(B.d()) ? 1 : 0; }, false},
{{Pattern::Builtins::EQ, {A, B}}, [=]() -> u256 { return A.d() == B.d() ? 1 : 0; }, false},
{{Pattern::Builtins::ISZERO, {A}}, [=]() -> u256 { return A.d() == 0 ? 1 : 0; }, false},
{{Pattern::Builtins::AND, {A, B}}, [=]{ return A.d() & B.d(); }, false},
{{Pattern::Builtins::OR, {A, B}}, [=]{ return A.d() | B.d(); }, false},
{{Pattern::Builtins::XOR, {A, B}}, [=]{ return A.d() ^ B.d(); }, false},
{{Pattern::Builtins::BYTE, {A, B}}, [=]{ return A.d() >= 32 ? 0 : (B.d() >> unsigned(8 * (31 - A.d()))) & 0xff; }, false},
{{Pattern::Builtins::ADDMOD, {A, B, C}}, [=]{ return C.d() == 0 ? 0 : u256((bigint(A.d()) + bigint(B.d())) % C.d()); }, false},
{{Pattern::Builtins::MULMOD, {A, B, C}}, [=]{ return C.d() == 0 ? 0 : u256((bigint(A.d()) * bigint(B.d())) % C.d()); }, false},
{{Pattern::Builtins::SIGNEXTEND, {A, B}}, [=]() -> u256 {
if (A.d() >= 31)
return B.d();
unsigned testBit = unsigned(A.d()) * 8 + 7;
u256 mask = (u256(1) << testBit) - 1;
return boost::multiprecision::bit_test(B.d(), testBit) ? B.d() | ~mask : B.d() & mask;
}, false},
{{Pattern::Builtins::SHL, {A, B}}, [=]{
if (A.d() > 255)
return u256(0);
return shlWorkaround(B.d(), unsigned(A.d()));
}, false},
{{Pattern::Builtins::SHR, {A, B}}, [=]{
if (A.d() > 255)
return u256(0);
return B.d() >> unsigned(A.d());
}, false}
};
}
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleListPart2(
Pattern,
Pattern,
Pattern,
Pattern X,
Pattern Y
)
{
return std::vector<SimplificationRule<Pattern>> {
// invariants involving known constants
{{Pattern::Builtins::ADD, {X, 0}}, [=]{ return X; }, false},
{{Pattern::Builtins::ADD, {0, X}}, [=]{ return X; }, false},
{{Pattern::Builtins::SUB, {X, 0}}, [=]{ return X; }, false},
{{Pattern::Builtins::SUB, {~u256(0), X}}, [=]() -> Pattern { return {Pattern::Builtins::NOT, {X}}; }, false},
{{Pattern::Builtins::MUL, {X, 0}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::MUL, {0, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::MUL, {X, 1}}, [=]{ return X; }, false},
{{Pattern::Builtins::MUL, {1, X}}, [=]{ return X; }, false},
{{Pattern::Builtins::MUL, {X, u256(-1)}}, [=]() -> Pattern { return {Pattern::Builtins::SUB, {0, X}}; }, false},
{{Pattern::Builtins::MUL, {u256(-1), X}}, [=]() -> Pattern { return {Pattern::Builtins::SUB, {0, X}}; }, false},
{{Pattern::Builtins::DIV, {X, 0}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::DIV, {0, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::DIV, {X, 1}}, [=]{ return X; }, false},
{{Pattern::Builtins::SDIV, {X, 0}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::SDIV, {0, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::SDIV, {X, 1}}, [=]{ return X; }, false},
{{Pattern::Builtins::AND, {X, ~u256(0)}}, [=]{ return X; }, false},
{{Pattern::Builtins::AND, {~u256(0), X}}, [=]{ return X; }, false},
{{Pattern::Builtins::AND, {X, 0}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::AND, {0, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::OR, {X, 0}}, [=]{ return X; }, false},
{{Pattern::Builtins::OR, {0, X}}, [=]{ return X; }, false},
{{Pattern::Builtins::OR, {X, ~u256(0)}}, [=]{ return ~u256(0); }, true},
{{Pattern::Builtins::OR, {~u256(0), X}}, [=]{ return ~u256(0); }, true},
{{Pattern::Builtins::XOR, {X, 0}}, [=]{ return X; }, false},
{{Pattern::Builtins::XOR, {0, X}}, [=]{ return X; }, false},
{{Pattern::Builtins::MOD, {X, 0}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::MOD, {0, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::EQ, {X, 0}}, [=]() -> Pattern { return {Pattern::Builtins::ISZERO, {X}}; }, false },
{{Pattern::Builtins::EQ, {0, X}}, [=]() -> Pattern { return {Pattern::Builtins::ISZERO, {X}}; }, false },
{{Pattern::Builtins::SHL, {0, X}}, [=]{ return X; }, false},
{{Pattern::Builtins::SHR, {0, X}}, [=]{ return X; }, false},
{{Pattern::Builtins::SHL, {X, 0}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::SHR, {X, 0}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::GT, {X, 0}}, [=]() -> Pattern { return {Pattern::Builtins::ISZERO, {{Pattern::Builtins::ISZERO, {X}}}}; }, false},
{{Pattern::Builtins::LT, {0, X}}, [=]() -> Pattern { return {Pattern::Builtins::ISZERO, {{Pattern::Builtins::ISZERO, {X}}}}; }, false},
{{Pattern::Builtins::GT, {X, ~u256(0)}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::LT, {~u256(0), X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::GT, {0, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::LT, {X, 0}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::AND, {{Pattern::Builtins::BYTE, {X, Y}}, {u256(0xff)}}}, [=]() -> Pattern { return {Pattern::Builtins::BYTE, {X, Y}}; }, false},
{{Pattern::Builtins::BYTE, {31, X}}, [=]() -> Pattern { return {Pattern::Builtins::AND, {X, u256(0xff)}}; }, false}
};
}
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleListPart3(
Pattern,
Pattern,
Pattern,
Pattern X,
Pattern
)
{
return std::vector<SimplificationRule<Pattern>> {
// operations involving an expression and itself
{{Pattern::Builtins::AND, {X, X}}, [=]{ return X; }, true},
{{Pattern::Builtins::OR, {X, X}}, [=]{ return X; }, true},
{{Pattern::Builtins::XOR, {X, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::SUB, {X, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::EQ, {X, X}}, [=]{ return u256(1); }, true},
{{Pattern::Builtins::LT, {X, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::SLT, {X, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::GT, {X, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::SGT, {X, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::MOD, {X, X}}, [=]{ return u256(0); }, true}
};
}
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleListPart4(
Pattern,
Pattern,
Pattern,
Pattern X,
Pattern Y
)
{
return std::vector<SimplificationRule<Pattern>> {
// logical instruction combinations
{{Pattern::Builtins::NOT, {{Pattern::Builtins::NOT, {X}}}}, [=]{ return X; }, false},
{{Pattern::Builtins::XOR, {X, {Pattern::Builtins::XOR, {X, Y}}}}, [=]{ return Y; }, true},
{{Pattern::Builtins::XOR, {X, {Pattern::Builtins::XOR, {Y, X}}}}, [=]{ return Y; }, true},
{{Pattern::Builtins::XOR, {{Pattern::Builtins::XOR, {X, Y}}, X}}, [=]{ return Y; }, true},
{{Pattern::Builtins::XOR, {{Pattern::Builtins::XOR, {Y, X}}, X}}, [=]{ return Y; }, true},
{{Pattern::Builtins::OR, {X, {Pattern::Builtins::AND, {X, Y}}}}, [=]{ return X; }, true},
{{Pattern::Builtins::OR, {X, {Pattern::Builtins::AND, {Y, X}}}}, [=]{ return X; }, true},
{{Pattern::Builtins::OR, {{Pattern::Builtins::AND, {X, Y}}, X}}, [=]{ return X; }, true},
{{Pattern::Builtins::OR, {{Pattern::Builtins::AND, {Y, X}}, X}}, [=]{ return X; }, true},
{{Pattern::Builtins::AND, {X, {Pattern::Builtins::OR, {X, Y}}}}, [=]{ return X; }, true},
{{Pattern::Builtins::AND, {X, {Pattern::Builtins::OR, {Y, X}}}}, [=]{ return X; }, true},
{{Pattern::Builtins::AND, {{Pattern::Builtins::OR, {X, Y}}, X}}, [=]{ return X; }, true},
{{Pattern::Builtins::AND, {{Pattern::Builtins::OR, {Y, X}}, X}}, [=]{ return X; }, true},
{{Pattern::Builtins::AND, {X, {Pattern::Builtins::NOT, {X}}}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::AND, {{Pattern::Builtins::NOT, {X}}, X}}, [=]{ return u256(0); }, true},
{{Pattern::Builtins::OR, {X, {Pattern::Builtins::NOT, {X}}}}, [=]{ return ~u256(0); }, true},
{{Pattern::Builtins::OR, {{Pattern::Builtins::NOT, {X}}, X}}, [=]{ return ~u256(0); }, true},
};
}
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleListPart5(
Pattern A,
Pattern,
Pattern,
Pattern X,
Pattern
)
{
std::vector<SimplificationRule<Pattern>> rules;
// Replace MOD X, <power-of-two> with AND X, <power-of-two> - 1
for (size_t i = 0; i < 256; ++i)
{
u256 value = u256(1) << i;
rules.push_back({
{Pattern::Builtins::MOD, {X, value}},
[=]() -> Pattern { return {Pattern::Builtins::AND, {X, value - 1}}; },
false
});
}
// Replace SHL >=256, X with 0
rules.push_back({
{Pattern::Builtins::SHL, {A, X}},
[=]() -> Pattern { return u256(0); },
true,
[=]() { return A.d() >= 256; }
});
// Replace SHR >=256, X with 0
rules.push_back({
{Pattern::Builtins::SHR, {A, X}},
[=]() -> Pattern { return u256(0); },
true,
[=]() { return A.d() >= 256; }
});
// Replace BYTE(A, X), A >= 32 with 0
rules.push_back({
{Pattern::Builtins::BYTE, {A, X}},
[=]() -> Pattern { return u256(0); },
true,
[=]() { return A.d() >= 32; }
});
for (auto const& op: std::vector<Instruction>{
Pattern::Builtins::ADDRESS,
Pattern::Builtins::CALLER,
Pattern::Builtins::ORIGIN,
Pattern::Builtins::COINBASE
})
{
u256 const mask = (u256(1) << 160) - 1;
rules.push_back({
{Pattern::Builtins::AND, {{op, mask}}},
[=]() -> Pattern { return op; },
false
});
rules.push_back({
{Pattern::Builtins::AND, {{mask, op}}},
[=]() -> Pattern { return op; },
false
});
}
return rules;
}
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleListPart6(
Pattern,
Pattern,
Pattern,
Pattern X,
Pattern Y
)
{
std::vector<SimplificationRule<Pattern>> rules;
// Double negation of opcodes with boolean result
for (auto const& op: std::vector<Instruction>{
Pattern::Builtins::EQ,
Pattern::Builtins::LT,
Pattern::Builtins::SLT,
Pattern::Builtins::GT,
Pattern::Builtins::SGT
})
rules.push_back({
{Pattern::Builtins::ISZERO, {{Pattern::Builtins::ISZERO, {{op, {X, Y}}}}}},
[=]() -> Pattern { return {op, {X, Y}}; },
false
});
rules.push_back({
{Pattern::Builtins::ISZERO, {{Pattern::Builtins::ISZERO, {{Pattern::Builtins::ISZERO, {X}}}}}},
[=]() -> Pattern { return {Pattern::Builtins::ISZERO, {X}}; },
false
});
rules.push_back({
{Pattern::Builtins::ISZERO, {{Pattern::Builtins::XOR, {X, Y}}}},
[=]() -> Pattern { return { Pattern::Builtins::EQ, {X, Y} }; },
false
});
return rules;
}
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleListPart7(
Pattern A,
Pattern B,
Pattern,
Pattern X,
Pattern Y
)
{
std::vector<SimplificationRule<Pattern>> rules;
// Associative operations
for (auto const& opFun: std::vector<std::pair<Instruction,std::function<u256(u256 const&,u256 const&)>>>{
{Pattern::Builtins::ADD, std::plus<u256>()},
{Pattern::Builtins::MUL, std::multiplies<u256>()},
{Pattern::Builtins::AND, std::bit_and<u256>()},
{Pattern::Builtins::OR, std::bit_or<u256>()},
{Pattern::Builtins::XOR, std::bit_xor<u256>()}
})
{
auto op = opFun.first;
auto fun = opFun.second;
// Moving constants to the outside, order matters here - we first add rules
// for constants and then for non-constants.
// xa can be (X, A) or (A, X)
for (auto xa: {std::vector<Pattern>{X, A}, std::vector<Pattern>{A, X}})
{
rules += std::vector<SimplificationRule<Pattern>>{{
// (X+A)+B -> X+(A+B)
{op, {{op, xa}, B}},
[=]() -> Pattern { return {op, {X, fun(A.d(), B.d())}}; },
false
}, {
// (X+A)+Y -> (X+Y)+A
{op, {{op, xa}, Y}},
[=]() -> Pattern { return {op, {{op, {X, Y}}, A}}; },
false
}, {
// B+(X+A) -> X+(A+B)
{op, {B, {op, xa}}},
[=]() -> Pattern { return {op, {X, fun(A.d(), B.d())}}; },
false
}, {
// Y+(X+A) -> (Y+X)+A
{op, {Y, {op, xa}}},
[=]() -> Pattern { return {op, {{op, {Y, X}}, A}}; },
false
}};
}
}
// Combine two SHL by constant
rules.push_back({
// SHL(B, SHL(A, X)) -> SHL(min(A+B, 256), X)
{Pattern::Builtins::SHL, {{B}, {Pattern::Builtins::SHL, {{A}, {X}}}}},
[=]() -> Pattern {
bigint sum = bigint(A.d()) + B.d();
if (sum >= 256)
return {Pattern::Builtins::AND, {X, u256(0)}};
else
return {Pattern::Builtins::SHL, {u256(sum), X}};
},
false
});
// Combine two SHR by constant
rules.push_back({
// SHR(B, SHR(A, X)) -> SHR(min(A+B, 256), X)
{Pattern::Builtins::SHR, {{B}, {Pattern::Builtins::SHR, {{A}, {X}}}}},
[=]() -> Pattern {
bigint sum = bigint(A.d()) + B.d();
if (sum >= 256)
return {Pattern::Builtins::AND, {X, u256(0)}};
else
return {Pattern::Builtins::SHR, {u256(sum), X}};
},
false
});
// Combine SHL-SHR by constant
rules.push_back({
// SHR(B, SHL(A, X)) -> AND(SH[L/R]([B - A / A - B], X), Mask)
{Pattern::Builtins::SHR, {{B}, {Pattern::Builtins::SHL, {{A}, {X}}}}},
[=]() -> Pattern {
u256 mask = shlWorkaround(u256(-1), unsigned(A.d())) >> unsigned(B.d());
if (A.d() > B.d())
return {Pattern::Builtins::AND, {{Pattern::Builtins::SHL, {A.d() - B.d(), X}}, mask}};
else if (B.d() > A.d())
return {Pattern::Builtins::AND, {{Pattern::Builtins::SHR, {B.d() - A.d(), X}}, mask}};
else
return {Pattern::Builtins::AND, {X, mask}};
},
false,
[=] { return A.d() < 256 && B.d() < 256; }
});
// Combine SHR-SHL by constant
rules.push_back({
// SHL(B, SHR(A, X)) -> AND(SH[L/R]([B - A / A - B], X), Mask)
{Pattern::Builtins::SHL, {{B}, {Pattern::Builtins::SHR, {{A}, {X}}}}},
[=]() -> Pattern {
u256 mask = shlWorkaround(u256(-1) >> unsigned(A.d()), unsigned(B.d()));
if (A.d() > B.d())
return {Pattern::Builtins::AND, {{Pattern::Builtins::SHR, {A.d() - B.d(), X}}, mask}};
else if (B.d() > A.d())
return {Pattern::Builtins::AND, {{Pattern::Builtins::SHL, {B.d() - A.d(), X}}, mask}};
else
return {Pattern::Builtins::AND, {X, mask}};
},
false,
[=] { return A.d() < 256 && B.d() < 256; }
});
// Move AND with constant across SHL and SHR by constant
for (auto shiftOp: {Pattern::Builtins::SHL, Pattern::Builtins::SHR})
{
auto replacement = [=]() -> Pattern {
u256 mask =
shiftOp == Pattern::Builtins::SHL ?
shlWorkaround(A.d(), unsigned(B.d())) :
A.d() >> unsigned(B.d());
return {Pattern::Builtins::AND, {{shiftOp, {B.d(), X}}, std::move(mask)}};
};
rules.push_back({
// SH[L/R](B, AND(X, A)) -> AND(SH[L/R](B, X), [ A << B / A >> B ])
{shiftOp, {{B}, {Pattern::Builtins::AND, {{X}, {A}}}}},
replacement,
false,
[=] { return B.d() < 256; }
});
rules.push_back({
// SH[L/R](B, AND(A, X)) -> AND(SH[L/R](B, X), [ A << B / A >> B ])
{shiftOp, {{B}, {Pattern::Builtins::AND, {{A}, {X}}}}},
replacement,
false,
[=] { return B.d() < 256; }
});
}
rules.push_back({
// MUL(X, SHL(Y, 1)) -> SHL(Y, X)
{Pattern::Builtins::MUL, {X, {Pattern::Builtins::SHL, {Y, u256(1)}}}},
[=]() -> Pattern {
return {Pattern::Builtins::SHL, {Y, X}};
},
// Actually only changes the order, does not remove.
true
});
rules.push_back({
// MUL(SHL(X, 1), Y) -> SHL(X, Y)
{Pattern::Builtins::MUL, {{Pattern::Builtins::SHL, {X, u256(1)}}, Y}},
[=]() -> Pattern {
return {Pattern::Builtins::SHL, {X, Y}};
},
false
});
rules.push_back({
// DIV(X, SHL(Y, 1)) -> SHR(Y, X)
{Pattern::Builtins::DIV, {X, {Pattern::Builtins::SHL, {Y, u256(1)}}}},
[=]() -> Pattern {
return {Pattern::Builtins::SHR, {Y, X}};
},
// Actually only changes the order, does not remove.
true
});
std::function<bool()> feasibilityFunction = [=]() {
if (B.d() > 256)
return false;
unsigned bAsUint = static_cast<unsigned>(B.d());
return (A.d() & (u256(-1) >> bAsUint)) == (u256(-1) >> bAsUint);
};
rules.push_back({
// AND(A, SHR(B, X)) -> A & ((2^256-1) >> B) == ((2^256-1) >> B)
{Pattern::Builtins::AND, {A, {Pattern::Builtins::SHR, {B, X}}}},
[=]() -> Pattern { return {Pattern::Builtins::SHR, {B, X}}; },
false,
feasibilityFunction
});
rules.push_back({
// AND(SHR(B, X), A) -> ((2^256-1) >> B) & A == ((2^256-1) >> B)
{Pattern::Builtins::AND, {{Pattern::Builtins::SHR, {B, X}}, A}},
[=]() -> Pattern { return {Pattern::Builtins::SHR, {B, X}}; },
false,
feasibilityFunction
});
return rules;
}
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleListPart8(
Pattern A,
Pattern,
Pattern,
Pattern X,
Pattern Y
)
{
std::vector<SimplificationRule<Pattern>> rules;
// move constants across subtractions
rules += std::vector<SimplificationRule<Pattern>>{
{
// X - A -> X + (-A)
{Pattern::Builtins::SUB, {X, A}},
[=]() -> Pattern { return {Pattern::Builtins::ADD, {X, 0 - A.d()}}; },
false
}, {
// (X + A) - Y -> (X - Y) + A
{Pattern::Builtins::SUB, {{Pattern::Builtins::ADD, {X, A}}, Y}},
[=]() -> Pattern { return {Pattern::Builtins::ADD, {{Pattern::Builtins::SUB, {X, Y}}, A}}; },
false
}, {
// (A + X) - Y -> (X - Y) + A
{Pattern::Builtins::SUB, {{Pattern::Builtins::ADD, {A, X}}, Y}},
[=]() -> Pattern { return {Pattern::Builtins::ADD, {{Pattern::Builtins::SUB, {X, Y}}, A}}; },
false
}, {
// X - (Y + A) -> (X - Y) + (-A)
{Pattern::Builtins::SUB, {X, {Pattern::Builtins::ADD, {Y, A}}}},
[=]() -> Pattern { return {Pattern::Builtins::ADD, {{Pattern::Builtins::SUB, {X, Y}}, 0 - A.d()}}; },
false
}, {
// X - (A + Y) -> (X - Y) + (-A)
{Pattern::Builtins::SUB, {X, {Pattern::Builtins::ADD, {A, Y}}}},
[=]() -> Pattern { return {Pattern::Builtins::ADD, {{Pattern::Builtins::SUB, {X, Y}}, 0 - A.d()}}; },
false
}
};
return rules;
}
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleListPart9(
Pattern,
Pattern,
Pattern,
Pattern W,
Pattern X,
Pattern Y,
Pattern Z
)
{
std::vector<SimplificationRule<Pattern>> rules;
u256 const mask = (u256(1) << 160) - 1;
// CREATE
rules.push_back({
{Pattern::Builtins::AND, {{Pattern::Builtins::CREATE, {W, X, Y}}, mask}},
[=]() -> Pattern { return {Pattern::Builtins::CREATE, {W, X, Y}}; },
false
});
rules.push_back({
{Pattern::Builtins::AND, {{mask, {Pattern::Builtins::CREATE, {W, X, Y}}}}},
[=]() -> Pattern { return {Pattern::Builtins::CREATE, {W, X, Y}}; },
false
});
// CREATE2
rules.push_back({
{Pattern::Builtins::AND, {{Pattern::Builtins::CREATE2, {W, X, Y, Z}}, mask}},
[=]() -> Pattern { return {Pattern::Builtins::CREATE2, {W, X, Y, Z}}; },
false
});
rules.push_back({
{Pattern::Builtins::AND, {{mask, {Pattern::Builtins::CREATE2, {W, X, Y, Z}}}}},
[=]() -> Pattern { return {Pattern::Builtins::CREATE2, {W, X, Y, Z}}; },
false
});
return rules;
}
/// @returns a list of simplification rules given certain match placeholders.
/// A, B and C should represent constants, W, X, Y, and Z arbitrary expressions.
/// The simplifications should never change the order of evaluation of
/// arbitrary operations.
template <class Pattern>
std::vector<SimplificationRule<Pattern>> simplificationRuleList(
Pattern A,
Pattern B,
Pattern C,
Pattern W,
Pattern X,
Pattern Y,
Pattern Z
)
{
std::vector<SimplificationRule<Pattern>> rules;
rules += simplificationRuleListPart1(A, B, C, W, X);
rules += simplificationRuleListPart2(A, B, C, W, X);
rules += simplificationRuleListPart3(A, B, C, W, X);
rules += simplificationRuleListPart4(A, B, C, W, X);
rules += simplificationRuleListPart5(A, B, C, W, X);
rules += simplificationRuleListPart6(A, B, C, W, X);
rules += simplificationRuleListPart7(A, B, C, W, X);
rules += simplificationRuleListPart8(A, B, C, W, X);
rules += simplificationRuleListPart9(A, B, C, W, X, Y, Z);
return rules;
}
}
}
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