Merge pull request #6780 from ethereum/moveInitialization

make_vector helper for move initialization

libdevcore/CommonData.h

@@ -346,4 +346,27 @@ inline std::string findAnyOf(std::string const& _haystack, std::vector<std::stri
 			return needle;
 	return "";
 }
+
+
+namespace detail
+{
+template<typename T>
+void variadicEmplaceBack(std::vector<T>&) {}
+template<typename T, typename A, typename... Args>
+void variadicEmplaceBack(std::vector<T>& _vector, A&& _a, Args&&... _args)
+{
+	_vector.emplace_back(std::forward<A>(_a));
+	variadicEmplaceBack(_vector, std::forward<Args>(_args)...);
+}
+}
+
+template<typename T, typename... Args>
+std::vector<T> make_vector(Args&&... _args)
+{
+	std::vector<T> result;
+	result.reserve(sizeof...(_args));
+	detail::variadicEmplaceBack(result, std::forward<Args>(_args)...);
+	return result;
+}
+
 }

libyul/optimiser/ControlFlowSimplifier.cpp

@@ -72,11 +72,7 @@ OptionalStatements reduceNoCaseSwitch(Switch& _switchStmt)
 
 	auto loc = locationOf(*_switchStmt.expression);
 
-	OptionalStatements s = vector<Statement>{};
+	return make_vector<Statement>(makePopExpressionStatement(loc, std::move(*_switchStmt.expression)));
-
-	s->emplace_back(makePopExpressionStatement(loc, std::move(*_switchStmt.expression)));
-
-	return s;
 }
 
 OptionalStatements reduceSingleCaseSwitch(Switch& _switchStmt)
@@ -86,9 +82,7 @@ OptionalStatements reduceSingleCaseSwitch(Switch& _switchStmt)
 	auto& switchCase = _switchStmt.cases.front();
 	auto loc = locationOf(*_switchStmt.expression);
 	if (switchCase.value)
-	{
+		return make_vector<Statement>(If{
-		OptionalStatements s = vector<Statement>{};
-		s->emplace_back(If{
 			std::move(_switchStmt.location),
 			make_unique<Expression>(FunctionalInstruction{
 				std::move(loc),
@@ -97,15 +91,11 @@ OptionalStatements reduceSingleCaseSwitch(Switch& _switchStmt)
 			}),
 			std::move(switchCase.body)
 		});
-		return s;
-	}
 	else
-	{
+		return make_vector<Statement>(
-		OptionalStatements s = vector<Statement>{};
+			makePopExpressionStatement(loc, std::move(*_switchStmt.expression)),
-		s->emplace_back(makePopExpressionStatement(loc, std::move(*_switchStmt.expression)));
+			std::move(switchCase.body)
-		s->emplace_back(std::move(switchCase.body));
+		);
-		return s;
-	}
 }
 
 }

libyul/optimiser/SSAReverser.cpp

@@ -56,20 +56,18 @@ void SSAReverser::operator()(Block& _block)
 					identifier &&
 					identifier->name == varDecl->variables.front().name
 				)
-				{
+					return make_vector<Statement>(
-					vector<Statement> result;
+						Assignment{
-					result.emplace_back(Assignment{
 							std::move(assignment->location),
 							assignment->variableNames,
 							std::move(varDecl->value)
-					});
+						},
-					result.emplace_back(VariableDeclaration{
+						VariableDeclaration{
 							std::move(varDecl->location),
 							std::move(varDecl->variables),
 							std::make_unique<Expression>(std::move(assignment->variableNames.front()))
-					});
-					return { std::move(result) };
 						}
+					);
 			}
 			// Replaces
 			//   let a_1 := E
@@ -89,22 +87,22 @@ void SSAReverser::operator()(Block& _block)
 					)
 				)
 				{
-					vector<Statement> result;
 					auto varIdentifier2 = std::make_unique<Expression>(Identifier{
 						varDecl2->variables.front().location,
 						varDecl2->variables.front().name
 					});
-					result.emplace_back(VariableDeclaration{
+					return make_vector<Statement>(
+						VariableDeclaration{
 							std::move(varDecl2->location),
 							std::move(varDecl2->variables),
 							std::move(varDecl->value)
-					});
+						},
-					result.emplace_back(VariableDeclaration{
+						VariableDeclaration{
 							std::move(varDecl->location),
 							std::move(varDecl->variables),
 							std::move(varIdentifier2)
-					});
+						}
-					return { std::move(result) };
+					);
 				}
 			}
 

libyul/optimiser/StructuralSimplifier.cpp

@@ -51,12 +51,10 @@ OptionalStatements replaceConstArgSwitch(Switch& _switchStmt, u256 const& _const
 	if (!matchingCaseBlock && defaultCase)
 		matchingCaseBlock = &defaultCase->body;
 
-	OptionalStatements s = vector<Statement>{};
-
 	if (matchingCaseBlock)
-		s->emplace_back(std::move(*matchingCaseBlock));
+		return make_vector<Statement>(std::move(*matchingCaseBlock));
-
+	else
-	return s;
+		return {{}};
 }
 
 }