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Change std::map to std::unordered_map in SSAValueTracker::m_values #16921

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rodiazet wants to merge 2 commits into from
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Change std::map to std::unordered_map in SSAValueTracker::m_values #16921

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Change `std::map` to `std::unordered_map` in `SSAValueTracker::m_values`
rodiazet Aug 17, 2026
d3a76c3
util::unordered_flat_map
rodiazet Aug 17, 2026
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6 changes: 3 additions & 3 deletions libyul/optimiser/SSAValueTracker.h
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@clonker clonker Aug 17, 2026

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you may want to try the new boost-unordered-containers that sean recently pull-requested here

@rodiazet rodiazet Aug 17, 2026

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pushed in a separated commit. I will prepare comparison soon.

@rodiazet rodiazet Aug 18, 2026

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It took longer than expected. I had to run on 20 iterations and add MAD (Median Absolut Deviation) to filter out outliers. Results below.

Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@
#include <libyul/optimiser/ASTWalker.h>
#include <libyul/AST.h> // Needed for m_zero below.

#include <map>
#include <libsolutil/UnorderedContainers.h>
#include <set>

namespace solidity::yul
Expand All @@ -47,7 +47,7 @@ class SSAValueTracker: public ASTWalker
void operator()(VariableDeclaration const& _varDecl) override;
void operator()(Assignment const& _assignment) override;

std::map<YulName, Expression const*> const& values() const { return m_values; }
util::unordered_flat_map<YulName, Expression const*> const& values() const { return m_values; }
Expression const* value(YulName _name) const { return m_values.at(_name); }

static std::set<YulName> ssaVariables(Block const& _ast);
Expand All @@ -58,7 +58,7 @@ class SSAValueTracker: public ASTWalker
/// Special expression whose address will be used in m_values.
/// YulName does not need to be reset because SSAValueTracker is short-lived.
Expression const m_zero{Literal{{}, LiteralKind::Number, LiteralValue(u256{0})}};
std::map<YulName, Expression const*> m_values;
util::unordered_flat_map<YulName, Expression const*> m_values;
};

}