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Bugfix.

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This commit is contained in:
chriseth 2022-11-10 16:04:19 +01:00
parent 6bbef64034
commit eec258c2d2
1 changed files with 19 additions and 10 deletions
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29
libyul/optimiser/KnowledgeBase.cpp
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@ -122,24 +122,33 @@ optional<KnowledgeBase::VariableOffset> KnowledgeBase::explore(Expression const&
else if (Identifier const* identifier = std::get_if<Identifier>(&_value))
return explore(identifier->name);
else if (FunctionCall const* f = get_if<FunctionCall>(&_value))
if (f->functionName.name == "add"_yulstring || f->functionName.name == "sub"_yulstring)
{
if (f->functionName.name == "add"_yulstring)
{
if (optional<VariableOffset> a = explore(f->arguments[0]))
if (optional<VariableOffset> b = explore(f->arguments[1]))
{
u256 offset =
f->functionName.name == "add"_yulstring ?
a->offset + b->offset :
a->offset - b->offset;
if (a->reference == b->reference)
// Offsets relative to the same reference variable
return VariableOffset{a->reference, offset};
else if (a->reference == YulString{})
u256 offset = a->offset + b->offset;
if (a->reference.empty())
// a is constant
return VariableOffset{b->reference, offset};
else if (b->reference == YulString{})
else if (b->reference.empty())
// b is constant
return VariableOffset{a->reference, offset};
}
}
else if (f->functionName.name == "sub"_yulstring)
if (optional<VariableOffset> a = explore(f->arguments[0]))
if (optional<VariableOffset> b = explore(f->arguments[1]))
{
u256 offset = a->offset - b->offset;
if (a->reference == b->reference)
return VariableOffset{YulString{}, offset};
else if (b->reference.empty())
// b is constant
return VariableOffset{a->reference, offset};
}
}
return {};
}