try to move side effects as much as possible to the left of the

expression tree, to avoid stacking. This is not good enough yet!

diff --git a/lang/cem/cemcom/ch7bin.c b/lang/cem/cemcom/ch7bin.c
index c26a89e..0225351 100644 (file)
--- a/lang/cem/cemcom/ch7bin.c
+++ b/lang/cem/cemcom/ch7bin.c
@@ -108,6 +108,9 @@ ch7bin(expp, oper, expr)
        case TIMESAB:
                arithbalance(expp, oper, &expr);
                non_commutative_binop(expp, oper, expr);
+               if (oper != '/' && oper != '%') {
+                       (*expp)->ex_flags |= EX_SIDEEFFECTS;
+               }
                break;
 
        case '&':
@@ -144,6 +147,9 @@ ch7bin(expp, oper, expr)
                        else
                                non_commutative_binop(expp, oper, expr);
                }
+               if (oper != '+') {
+                       (*expp)->ex_flags |= EX_SIDEEFFECTS;
+               }
                break;
 
        case '-':
@@ -162,6 +168,9 @@ ch7bin(expp, oper, expr)
                        arithbalance(expp, oper, &expr);
                        non_commutative_binop(expp, oper, expr);
                }
+               if (oper != '-') {
+                       (*expp)->ex_flags |= EX_SIDEEFFECTS;
+               }
                break;
 
        case LEFT:
@@ -173,6 +182,9 @@ ch7bin(expp, oper, expr)
                arithbalance(expp, oper, &expr); /* ch. 7.5 */
                ch7cast(&expr, oper, int_type); /* cvt. rightop to int */
                non_commutative_binop(expp, oper, expr);
+               if (oper != LEFT && oper != RIGHT) {
+                       (*expp)->ex_flags |= EX_SIDEEFFECTS;
+               }
                break;
 
        case '<':
@@ -182,7 +194,10 @@ ch7bin(expp, oper, expr)
        case EQUAL:
        case NOTEQUAL:
                relbalance(expp, oper, &expr);
-               non_commutative_binop(expp, oper, expr);
+               if (oper == EQUAL || oper == NOTEQUAL) {
+                       commutative_binop(expp, oper, expr);
+               }
+               else    non_commutative_binop(expp, oper, expr);
                (*expp)->ex_type = int_type;
                break;
 
@@ -311,7 +326,10 @@ mk_binop(expp, oper, expr, commutative)
        if (is_cp_cst(expr) && is_cp_cst(ex))
                cstbin(expp, oper, expr);
        else    {
-               *expp = (commutative && expr->ex_depth >= ex->ex_depth) ?
+               *expp = (commutative &&
+                         ( expr->ex_depth > ex->ex_depth ||
+                           (expr->ex_flags & EX_SIDEEFFECTS) ||
+                           is_cp_cst(ex))) ?
                                new_oper(ex->ex_type, expr, oper, ex) :
                                new_oper(ex->ex_type, ex, oper, expr);
        }