I noticed that dmd generates implicit checks for a NULL "this" argument in overloaded struct operators.  Assuming my operator does not modify its arguments, including "this", is there a way to avoid that cost?

Putting the equivalent code in a static member function with "in" arguments avoids the cost but gives up the nice syntax.  The struct in question is a vector, so it'd be nice to provide operators.

Perhaps D2.0's invariant keyword address this?  (There doesn't seem to be a released D2.0 compiler for linux yet, so I haven't checked.)

  struct Vec3d
  {
      double x=0, y=0, z=0;

      Vec3d opAdd(Vec3d rhs) {
          // Note: implicit assert(this != NULL) inserted here.
          // Would marking this method 'invariant' help?
          return Vec3d(x+rhs.x, y+rhs.y, z+rhs.z);
      }

      static Vec3d Add(in Vec3d a, in Vec3d b) {
          // Static method avoids the assert
          return Vec3d(a.x+b.x, a.y+b.y, a.z+b.z);
      }

      static Vec3d opCall(double x, double y, double z) {
          Vec3d v;
          v.x = x;
          v.y = y;
          v.z = z;
          return v;
      }
  }

thanks,
--
Brett.

blevin wrote:
> I noticed that dmd generates implicit checks for a NULL "this" argument in overloaded struct operators.  Assuming my operator does not modify its arguments, including "this", is there a way to avoid that cost?
> 
> Putting the equivalent code in a static member function with "in" arguments avoids the cost but gives up the nice syntax.  The struct in question is a vector, so it'd be nice to provide operators.
> 
> Perhaps D2.0's invariant keyword address this?  (There doesn't seem to be a released D2.0 compiler for linux yet, so I haven't checked.)
> 
>   struct Vec3d
>   {
>       double x=0, y=0, z=0;
> 
>       Vec3d opAdd(Vec3d rhs) {

It'll run faster if you make this a "ref Vec3d rhs".
Don't know about the rest of your question, but benchmarking was done on someone's ray tracer a while back and changing the Vec's to ref Vecs definitely made a difference.

--bb

"blevin" <brett.levin@gmail.com> wrote in message news:fglb8v$2tr4$1@digitalmars.com...
>I noticed that dmd generates implicit checks for a NULL "this" argument in overloaded struct operators.  Assuming my operator does not modify its arguments, including "this", is there a way to avoid that cost?
>

This is a debug check and disappears with the -release flag.

Jarrett Billingsley wrote:
> "blevin" <brett.levin@gmail.com> wrote in message news:fglb8v$2tr4$1@digitalmars.com...
>> I noticed that dmd generates implicit checks for a NULL "this" argument in overloaded struct operators.  Assuming my operator does not modify its arguments, including "this", is there a way to avoid that cost?
> 
> This is a debug check and disappears with the -release flag. 

Aha!  Indeed it does -- thank you!

--
Brett.