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| author | Alex Beregszaszi <alex@rtfs.hu> | 2017-05-10 17:46:44 +0800 |
|---|---|---|
| committer | Alex Beregszaszi <alex@rtfs.hu> | 2018-04-10 03:07:44 +0800 |
| commit | cb352edd26f55adda63dde6cb66931089aff6656 (patch) | |
| tree | 391bdc017eea84dce51a29165cc93493f0cb0fc2 /libevmasm | |
| parent | fe61435c273bf43ac1a20d8bc97b6935a54b7117 (diff) | |
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Add constant optimiser for SHR/SHL instructions
Diffstat (limited to 'libevmasm')
| -rw-r--r-- | libevmasm/RuleList.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/libevmasm/RuleList.h b/libevmasm/RuleList.h index da522cec..abcf170c 100644 --- a/libevmasm/RuleList.h +++ b/libevmasm/RuleList.h @@ -89,6 +89,16 @@ std::vector<SimplificationRule<Pattern>> simplificationRuleList( u256 mask = (u256(1) << testBit) - 1; return u256(boost::multiprecision::bit_test(B.d(), testBit) ? B.d() | ~mask : B.d() & mask); }, false}, + {{Instruction::SHL, {A, B}}, [=]{ + if (A.d() > 255) + return u256(0); + return u256(bigint(B.d()) << unsigned(A.d())); + }, false}, + {{Instruction::SHR, {A, B}}, [=]{ + if (A.d() > 255) + return u256(0); + return B.d() >> unsigned(A.d()); + }, false}, // invariants involving known constants {{Instruction::ADD, {X, 0}}, [=]{ return X; }, false}, |