reorder const for all associative operators

compiler/src/prog8/optimizer/ConstantFoldingOptimizer.kt

@@ -415,8 +415,9 @@ internal class ConstantFoldingOptimizer(private val program: Program) : AstWalke
         // todo: this implements only a small set of possible reorderings at this time
         if(expr.operator==subExpr.operator) {
             // both operators are the same.
-            // If + or *,  we can simply shuffle the const operands around to optimize.
-            if(expr.operator=="+" || expr.operator=="*") {
+
+            // If associative,  we can simply shuffle the const operands around to optimize.
+            if(expr.operator in associativeOperators) {
                 return if(leftIsConst) {
                     if(subleftIsConst)
                         ShuffleOperands(expr, null, subExpr, subExpr.right, null, null, expr.left)

examples/test.p8

@@ -7,6 +7,20 @@ main {
 
     sub start() {
 
+        ubyte ub
+        uword uw
+        word w
+        byte b
+        float f
+
+
+        ub = 4 |  ub | 2
+        ub = ub | 2 | 7
+        ub = 4 | 2 | ub
+
+        ub = 4 + ub + 2
+        ub = ub + 2 + 7
+        ub = 4 + 2 + ub
     }
 }