no need for intermediary returnvalue var for prefix expressions

codeGeneration/src/prog8/compiler/target/cpu6502/codegen/FunctionCallAsmGen.kt

@@ -317,8 +317,7 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
                             lda  $sourceName
                             beq  +
                             sec  
-    +           pla
-    """)
++                           pla""")
                     }
                     else -> {
                         asmgen.assignExpressionToRegister(value, RegisterOrPair.A)

codeOptimizers/src/prog8/optimizer/StatementOptimizer.kt

@@ -466,21 +466,13 @@ class StatementOptimizer(private val program: Program,
             return null
         }
 
-        when(returnStmt.value) {
-            is PrefixExpression -> {
+        if(returnStmt.value is BinaryExpression) {
             val mod = returnViaIntermediaryVar(returnStmt.value!!)
             if(mod!=null)
                 return mod
         }
-            is BinaryExpression -> {
-                val mod = returnViaIntermediaryVar(returnStmt.value!!)
-                if(mod!=null)
-                    return mod
-            }
-            else -> {}
-        }
 
-        return super.after(returnStmt, parent)
+        return noModifications
     }
 
     private fun hasBreak(scope: IStatementContainer): Boolean {

docs/source/todo.rst

@@ -3,10 +3,6 @@ TODO
 
 For next compiler release (7.6)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-why does the following use a intermediate return value and not just A?
-  sub pushing_start() -> ubyte {
-    return joy_info & 16
-  }
 ...