Re: [PATCH 2/2] augmented rbtree: rework the RB_DECLARE_CALLBACKS macro definition

[Peter Zijlstra]

On Mon, Jul 01, 2019 at 09:46:30AM +0200, Peter Zijlstra wrote:
> On Fri, Jun 28, 2019 at 05:49:52PM -0700, Michel Lespinasse wrote:

> > The motivation for this change is that I want to introduce augmented rbtree
> > uses where the augmented data for the subtree is a struct instead of a scalar.

> Can't we have a helper macro that converts an old (scalar) style compute
> into a new style compute and avoid this unfortunate and error prone
> copy/pasta ?

Or add a RBEQUAL argument that does:

-		if (node->RBAUGMENTED == augmented)
+		if (RBEQUAL(&node->RBAUGMENTED, &augmented))

With a bit of foo you can even provide a default implementation that
does: *a == *b.

See GEN_UNARY_RMWcc() for how to do that.