Re: Dedicated functions for negative predicate tests (issue 345190043 by address@hidden)

[dak]

On 2019/02/08 09:46:17, Valentin Villenave wrote:
> FWIW, here’s what `make test-clean; time make-test’ returns:

> Without the patch:
> real    10m5.239s
> user    17m3.656s
> sys     1m2.055s

> With the patch:
> real    9m27.001s
> user    17m5.396s
> sys     1m0.880s

> (Note that I’m not saying it has any meaning.)

> V.

Frankly, I don't like it.  The relevant metric here is the user time and
it's _increased_ in your benchmark (not that it's likely significant).
The inverted predicates are _opaque_ to the Scheme compiler and thus are
no longer useful for constant expression elimination.  Stuff like (if
(not (pair? ...))) is optimized already by the compiler, and such
optimizations will actually be more prevalent (a whole lot) if we ever
make the move to Guilev2.  Throwing code in that the compiler does not
know about is not likely to be much of an advantage.

https://codereview.appspot.com/345190043/