Merge pull request #11891 from ethereum/guidedRematerializer

Allow the Rematerializer to be restricted to an exact set of variables.

Author: chriseth

libyul/optimiser/Rematerialiser.cpp

@@ -32,39 +32,44 @@ using namespace std;
 using namespace solidity;
 using namespace solidity::yul;
 
-void Rematerialiser::run(Dialect const& _dialect, Block& _ast, set<YulString> _varsToAlwaysRematerialize)
+void Rematerialiser::run(Dialect const& _dialect, Block& _ast, set<YulString> _varsToAlwaysRematerialize, bool _onlySelectedVariables)
 {
-	Rematerialiser{_dialect, _ast, std::move(_varsToAlwaysRematerialize)}(_ast);
+	Rematerialiser{_dialect, _ast, std::move(_varsToAlwaysRematerialize), _onlySelectedVariables}(_ast);
 }
 
 void Rematerialiser::run(
 	Dialect const& _dialect,
 	FunctionDefinition& _function,
-	set<YulString> _varsToAlwaysRematerialize
+	set<YulString> _varsToAlwaysRematerialize,
+	bool _onlySelectedVariables
 )
 {
-	Rematerialiser{_dialect, _function, std::move(_varsToAlwaysRematerialize)}(_function);
+	Rematerialiser{_dialect, _function, std::move(_varsToAlwaysRematerialize), _onlySelectedVariables}(_function);
 }
 
 Rematerialiser::Rematerialiser(
 	Dialect const& _dialect,
 	Block& _ast,
-	set<YulString> _varsToAlwaysRematerialize
+	set<YulString> _varsToAlwaysRematerialize,
+	bool _onlySelectedVariables
 ):
 	DataFlowAnalyzer(_dialect),
 	m_referenceCounts(ReferencesCounter::countReferences(_ast)),
-	m_varsToAlwaysRematerialize(std::move(_varsToAlwaysRematerialize))
+	m_varsToAlwaysRematerialize(std::move(_varsToAlwaysRematerialize)),
+	m_onlySelectedVariables(_onlySelectedVariables)
 {
 }
 
 Rematerialiser::Rematerialiser(
 	Dialect const& _dialect,
 	FunctionDefinition& _function,
-	set<YulString> _varsToAlwaysRematerialize
+	set<YulString> _varsToAlwaysRematerialize,
+	bool _onlySelectedVariables
 ):
 	DataFlowAnalyzer(_dialect),
 	m_referenceCounts(ReferencesCounter::countReferences(_function)),
-	m_varsToAlwaysRematerialize(std::move(_varsToAlwaysRematerialize))
+	m_varsToAlwaysRematerialize(std::move(_varsToAlwaysRematerialize)),
+	m_onlySelectedVariables(_onlySelectedVariables)
 {
 }
 
@@ -81,10 +86,13 @@ void Rematerialiser::visit(Expression& _e)
 			size_t refs = m_referenceCounts[name];
 			size_t cost = CodeCost::codeCost(m_dialect, *value.value);
 			if (
-				(refs <= 1 && value.loopDepth == m_loopDepth) ||
-				cost == 0 ||
-				(refs <= 5 && cost <= 1 && m_loopDepth == 0) ||
-				m_varsToAlwaysRematerialize.count(name)
+				(
+					!m_onlySelectedVariables && (
+						(refs <= 1 && value.loopDepth == m_loopDepth) ||
+						cost == 0 ||
+						(refs <= 5 && cost <= 1 && m_loopDepth == 0)
+					)
+				) || m_varsToAlwaysRematerialize.count(name)
 			)
 			{
 				assertThrow(m_referenceCounts[name] > 0, OptimizerException, "");

libyul/optimiser/Rematerialiser.h

@@ -50,24 +50,28 @@ class Rematerialiser: public DataFlowAnalyzer
 	static void run(
 		Dialect const& _dialect,
 		Block& _ast,
-		std::set<YulString> _varsToAlwaysRematerialize = {}
+		std::set<YulString> _varsToAlwaysRematerialize = {},
+		bool _onlySelectedVariables = false
 	);
 	static void run(
 		Dialect const& _dialect,
 		FunctionDefinition& _function,
-		std::set<YulString> _varsToAlwaysRematerialize = {}
+		std::set<YulString> _varsToAlwaysRematerialize = {},
+		bool _onlySelectedVariables = false
 	);
 
 protected:
 	Rematerialiser(
 		Dialect const& _dialect,
 		Block& _ast,
-		std::set<YulString> _varsToAlwaysRematerialize = {}
+		std::set<YulString> _varsToAlwaysRematerialize = {},
+		bool _onlySelectedVariables = false
 	);
 	Rematerialiser(
 		Dialect const& _dialect,
 		FunctionDefinition& _function,
-		std::set<YulString> _varsToAlwaysRematerialize = {}
+		std::set<YulString> _varsToAlwaysRematerialize = {},
+		bool _onlySelectedVariables = false
 	);
 
 	using DataFlowAnalyzer::operator();
@@ -77,6 +81,7 @@ class Rematerialiser: public DataFlowAnalyzer
 
 	std::map<YulString, size_t> m_referenceCounts;
 	std::set<YulString> m_varsToAlwaysRematerialize;
+	bool m_onlySelectedVariables = false;
 };
 
 /**