IRGeneratorForStatements: Fix undefined order of functions when generating code for index expressions

Changelog.md

@@ -17,6 +17,7 @@ Compiler Features:
 
 
 Bugfixes:
+ * Code Generator: Fix not entirely deterministic order of functions in unoptimized Yul output. The choice of C++ compiler in some cases would result in different (but equivalent) bytecode (especially from native binaries vs emscripten binaries)
  * Commandline Interface: Fix internal error when using ``--stop-after parsing`` and requesting some of the outputs that require full analysis or compilation.
  * Commandline Interface: It is no longer possible to specify both ``--optimize-yul`` and ``--no-optimize-yul`` at the same time.
  * SMTChecker: Fix encoding of side-effects inside ``if`` and ``ternary conditional``statements in the BMC engine.

libsolidity/codegen/ir/IRGeneratorForStatements.cpp

@@ -2295,8 +2295,9 @@ void IRGeneratorForStatements::endVisit(IndexAccess const& _indexAccess)
 			}
 			case DataLocation::Memory:
 			{
+				string indexAccessFunction = m_utils.memoryArrayIndexAccessFunction(arrayType);
 				string const memAddress =
-					m_utils.memoryArrayIndexAccessFunction(arrayType) +
+					indexAccessFunction +
 					"(" +
 					IRVariable(_indexAccess.baseExpression()).part("mpos").name() +
 					", " +