don't use the temp-variables introducing optimizations for the vm target

codeOptimizers/src/prog8/optimizer/BinExprSplitter.kt

@@ -15,6 +15,7 @@ import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 import prog8.code.core.CompilationOptions
 import prog8.code.core.DataType
+import prog8.code.target.VMTarget
 
 
 class BinExprSplitter(private val program: Program, private val options: CompilationOptions) : AstWalker() {
@@ -91,7 +92,7 @@ X =      BinExpr                                    X   =   LeftExpr
         val typecast = assignment.value as? TypecastExpression
         if(typecast!=null) {
             val origExpr = typecast.expression as? BinaryExpression
-            if(origExpr!=null) {
+            if(origExpr!=null && options.compTarget.name!=VMTarget.NAME) {
                 // it's a typecast of a binary expression.
                 // we can see if we can unwrap the binary expression by working on a new temporary variable
                 // (that has the type of the expression), and then finally doing the typecast.

codeOptimizers/src/prog8/optimizer/StatementOptimizer.kt

@@ -6,6 +6,8 @@ import prog8.ast.statements.*
 import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 import prog8.code.core.*
+import prog8.code.target.VMTarget
+import prog8.code.target.virtual.VirtualMachineDefinition
 import kotlin.math.floor
 
 
@@ -120,6 +122,7 @@ class StatementOptimizer(private val program: Program,
                 return listOf(IAstModification.Remove(functionCallStatement, parent as IStatementContainer))
         }
 
+        if(compTarget.name!=VMTarget.NAME) {
             // see if we can optimize any complex argument expressions to be just a simple variable
             // TODO for now, only works for single-argument functions because we use just 1 temp var: R9
             if(functionCallStatement.target.nameInSource !in listOf(listOf("pop"), listOf("popw")) && functionCallStatement.args.size==1) {
@@ -134,7 +137,7 @@ class StatementOptimizer(private val program: Program,
                     )
                 }
             }
-
+        }
 
         return noModifications
     }
@@ -464,6 +467,10 @@ class StatementOptimizer(private val program: Program,
     }
 
     override fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> {
+
+        if(compTarget.name==VMTarget.NAME)
+            return noModifications
+
         fun returnViaIntermediaryVar(value: Expression): Iterable<IAstModification>? {
             val subr = returnStmt.definingSubroutine!!
             val returnDt = subr.returntypes.single()

compiler/src/prog8/compiler/astprocessing/BeforeAsmAstChanger.kt

@@ -8,6 +8,7 @@ import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 import prog8.ast.walk.IAstVisitor
 import prog8.code.core.*
+import prog8.code.target.VMTarget
 
 internal class BeforeAsmAstChanger(val program: Program,
                                    private val options: CompilationOptions,
@@ -224,6 +225,9 @@ internal class BeforeAsmAstChanger(val program: Program,
         //       the actual conditional expression in the statement should be no more than VARIABLE <COMPARISON-OPERATOR> SIMPLE-EXPRESSION
         // NOTE: do NOT move this to an earler ast transform phase (such as StatementReorderer or StatementOptimizer) - it WILL result in larger code.
 
+        if(options.compTarget.name==VMTarget.NAME)
+            return CondExprSimplificationResult(null, null, null, null)
+
         var leftAssignment: Assignment? = null
         var leftOperandReplacement: Expression? = null
         var rightAssignment: Assignment? = null
@@ -271,12 +275,13 @@ internal class BeforeAsmAstChanger(val program: Program,
             return noModifications
         }
 
-
+        if(options.compTarget.name!=VMTarget.NAME) {
             val index = arrayIndexedExpression.indexer.indexExpr
-        if(index !is NumericLiteral && index !is IdentifierReference) {
+            if (index !is NumericLiteral && index !is IdentifierReference) {
                 // replace complex indexing expression with a temp variable to hold the computed index first
                 return getAutoIndexerVarFor(arrayIndexedExpression)
             }
+        }
 
         return noModifications
     }

docs/source/todo.rst

@@ -3,8 +3,6 @@ TODO
 
 For next release
 ^^^^^^^^^^^^^^^^
-- first for virtual target: do not create tempvars for return statements (StatementOptimizer)
-   maybe other places as well?
 - in new AST: combine param assignments + GoSub, back into PtFunctionCall node.  PtGosub node should not exist.
 
 ...
@@ -70,6 +68,10 @@ Expressions:
 
 Optimizations:
 
+- various optimizers skip stuff if compTarget.name==VMTarget.NAME.  Once (if?) 6502-codegen is no longer done from
+  the old CompilerAst, those checks should probably be removed.
+  (most of them avoid the case where extra temporary variables are introduced in an attempt to simplify
+  the expression code generation)
 - VariableAllocator: can we think of a smarter strategy for allocating variables into zeropage, rather than first-come-first-served
 - translateUnaryFunctioncall() in BuiltinFunctionsAsmGen: should be able to assign parameters to a builtin function directly from register(s), this will make the use of a builtin function in a pipe expression more efficient without using a temporary variable
    compare ``aa = startvalue(1) |> sin8u() |> cos8u() |> sin8u() |> cos8u()``