Merge pull request #595 from Guest0x0/dev

fix cpp/java benchmark program: wrong output due to logic error

Author: daanx

test/bench/cpp/deriv.cpp

@@ -96,10 +96,10 @@ static const Expr* mul( const Expr* x, const Expr* y ) {
     return new ValExpr(((ValExpr*)x)->value * ((ValExpr*)y)->value);
   }
   else if (x->kind==Val && ((ValExpr*)x)->value==0) {
-    return x;
+    return new ValExpr(0);
   }
   else if (y->kind==Val && ((ValExpr*)y)->value==0) {
-    return y;
+    return new ValExpr(0);
   }
   else if (x->kind==Val && ((ValExpr*)x)->value==1) {
     return y;

test/bench/java/deriv.java

@@ -93,10 +93,10 @@ static Expr mul( Expr x, Expr y ) {
       return new ValExpr( a.value * b.value );
     }
     else if (x instanceof ValExpr a && a.value == 0) {
-      return x;
+      return new ValExpr(0);
     }
     else if (y instanceof ValExpr b && b.value == 0) {
-      return y;
+      return new ValExpr(0);
     }
     else if (x instanceof ValExpr a && a.value == 1) {
       return y;
@@ -110,7 +110,7 @@ else if (y instanceof ValExpr b) {
     else if (x instanceof ValExpr a && y instanceof MulExpr b && b.left instanceof ValExpr bl) {
       return mul(new ValExpr(a.value * bl.value), b.right);
     }
-    else if (y instanceof MulExpr b && b.left instanceof MulExpr) {
+    else if (y instanceof MulExpr b && b.left instanceof ValExpr) {
       return mul(b.left, mul(x,b.right));
     }
     else if (x instanceof MulExpr a) {