Merge pull request #8220 from ethereum/remove-var-name-cleaner-from-optimiser-suite-step-list

Remove var name cleaner from optimiser suite step list

libyul/optimiser/Suite.cpp

@@ -308,9 +308,7 @@ void OptimiserSuite::run(
 		if (ast.statements.size() > 1 && std::get<Block>(ast.statements.front()).statements.empty())
 			ast.statements.erase(ast.statements.begin());
 	}
-	suite.runSequence({
-		VarNameCleaner::name
-	}, ast);
+	VarNameCleaner::run(suite.m_context, ast);
 
 	*_object.analysisInfo = AsmAnalyzer::analyzeStrictAssertCorrect(_dialect, _object);
 }
@@ -366,9 +364,9 @@ map<string, unique_ptr<OptimiserStep>> const& OptimiserSuite::allSteps()
 			SSATransform,
 			StructuralSimplifier,
 			UnusedPruner,
-			VarDeclInitializer,
-			VarNameCleaner
+			VarDeclInitializer
 		>();
+	// Does not include VarNameCleaner because it destroys the property of unique names.
 	return instance;
 }
 

libyul/optimiser/VarNameCleaner.h

@@ -39,6 +39,10 @@ struct Dialect;
  * renumbered by their base name.
  * Function names are not modified.
  *
+ * NOTE: This step destroys the promise of the Disambiguator and thus cannot
+ * be used in the main loop of the optimizer without running the disambiguator again.
+ * Because of that, it is not included in the step list of the Optimizer Suite.
+ *
  * Prerequisites: Disambiguator, FunctionHoister, FunctionGrouper
  */
 class VarNameCleaner: public ASTModifier

test/tools/yulopti.cpp

@@ -180,6 +180,8 @@ public:
 				break;
 			case 'l':
 				VarNameCleaner::run(context, *m_ast);
+				// VarNameCleaner destroys the unique names guarantee of the disambiguator.
+				disambiguated = false;
 				break;
 			case 'x':
 				ExpressionSplitter::run(context, *m_ast);