Take yul optimizer setting into account.

libsolidity/codegen/CompilerContext.cpp

@@ -32,6 +32,7 @@
 #include <libyul/AsmAnalysisInfo.h>
 #include <libyul/backends/evm/AsmCodeGen.h>
 #include <libyul/backends/evm/EVMDialect.h>
+#include <libyul/optimiser/Suite.h>
 #include <libyul/YulString.h>
 
 #include <liblangutil/ErrorReporter.h>
@@ -328,12 +329,19 @@ void CompilerContext::resetVisitedNodes(ASTNode const* _node)
 void CompilerContext::appendInlineAssembly(
 	string const& _assembly,
 	vector<string> const& _localVariables,
-	set<string> const&,
-	bool _system
+	set<string> const& _externallyUsedFunctions,
+	bool _system,
+	bool _optimise
 )
 {
 	int startStackHeight = stackHeight();
 
+	set<yul::YulString> externallyUsedIdentifiers;
+	for (auto const& fun: _externallyUsedFunctions)
+		externallyUsedIdentifiers.insert(yul::YulString(fun));
+	for (auto const& var: _localVariables)
+		externallyUsedIdentifiers.insert(yul::YulString(var));
+
 	yul::ExternalIdentifierAccess identifierAccess;
 	identifierAccess.resolve = [&](
 		yul::Identifier const& _identifier,
@@ -380,20 +388,12 @@ void CompilerContext::appendInlineAssembly(
 #ifdef SOL_OUTPUT_ASM
 	cout << yul::AsmPrinter()(*parserResult) << endl;
 #endif
-	yul::AsmAnalysisInfo analysisInfo;
-	bool analyzerResult = false;
-	if (parserResult)
-		analyzerResult = yul::AsmAnalyzer(
-			analysisInfo,
-			errorReporter,
-			boost::none,
-			yul::EVMDialect::strictAssemblyForEVM(m_evmVersion),
-			identifierAccess.resolve
-		).analyze(*parserResult);
-	if (!parserResult || !errorReporter.errors().empty() || !analyzerResult)
+
+	auto reportError = [&](string const& _context)
 	{
 		string message =
-			"Error parsing/analyzing inline assembly block:\n"
+			"Error parsing/analyzing inline assembly block:\n" +
+			_context + "\n"
 			"------------------ Input: -----------------\n" +
 			_assembly + "\n"
 			"------------------ Errors: ----------------\n";
@@ -405,10 +405,47 @@ void CompilerContext::appendInlineAssembly(
 		message += "-------------------------------------------\n";
 
 		solAssert(false, message);
+	};
+
+	yul::AsmAnalysisInfo analysisInfo;
+	bool analyzerResult = false;
+	if (parserResult)
+		analyzerResult = yul::AsmAnalyzer(
+			analysisInfo,
+			errorReporter,
+			boost::none,
+			yul::EVMDialect::strictAssemblyForEVM(m_evmVersion),
+			identifierAccess.resolve
+		).analyze(*parserResult);
+	if (!parserResult || !errorReporter.errors().empty() || !analyzerResult)
+		reportError("Invalid assembly generated by code generator.");
+
+	// Several optimizer steps cannot handle externally supplied stack variables,
+	// so we essentially only optimize the ABI functions.
+	if (_optimise && _localVariables.empty())
+	{
+		yul::OptimiserSuite::run(
+			yul::EVMDialect::strictAssemblyForEVM(m_evmVersion),
+			*parserResult,
+			analysisInfo,
+			externallyUsedIdentifiers
+		);
+		analysisInfo = yul::AsmAnalysisInfo{};
+		if (!yul::AsmAnalyzer(
+			analysisInfo,
+			errorReporter,
+			boost::none,
+			yul::EVMDialect::strictAssemblyForEVM(m_evmVersion),
+			identifierAccess.resolve
+		).analyze(*parserResult))
+			reportError("Optimizer introduced error into inline assembly.");
 	}
 
+	if (!errorReporter.errors().empty())
+		reportError("Failed to analyze inline assembly block.");
+
 	solAssert(errorReporter.errors().empty(), "Failed to analyze inline assembly block.");
-	yul::CodeGenerator::assemble(*parserResult, analysisInfo, *m_asm, m_evmVersion, identifierAccess, _system);
+	yul::CodeGenerator::assemble(*parserResult, analysisInfo, *m_asm, m_evmVersion, identifierAccess, _system, _optimise);
 
 	// Reset the source location to the one of the node (instead of the CODEGEN source location)
 	updateSourceLocation();

libsolidity/codegen/CompilerContext.h

@@ -216,7 +216,8 @@ public:
 		std::string const& _assembly,
 		std::vector<std::string> const& _localVariables = std::vector<std::string>(),
 		std::set<std::string> const& _externallyUsedFunctions = std::set<std::string>(),
-		bool _system = false
+		bool _system = false,
+		bool _optimise = false
 	);
 
 	/// Appends arbitrary data to the end of the bytecode.

libsolidity/codegen/ContractCompiler.cpp

@@ -978,7 +978,13 @@ void ContractCompiler::appendMissingFunctions()
 	m_context.appendMissingLowLevelFunctions();
 	auto abiFunctions = m_context.abiFunctions().requestedFunctions();
 	if (!abiFunctions.first.empty())
-		m_context.appendInlineAssembly("{" + move(abiFunctions.first) + "}", {}, abiFunctions.second, true);
+		m_context.appendInlineAssembly(
+			"{" + move(abiFunctions.first) + "}",
+			{},
+			abiFunctions.second,
+			true,
+			m_optimiserSettings.runYulOptimiser
+		);
 }
 
 void ContractCompiler::appendModifierOrFunctionCode()