Re: master 669aeaf: Prefer make_nil_vector to make-vector with nil

[Paul Eggert <eggert@cs.ucla.edu>]

On 8/11/20 11:31 AM, Pip Cet wrote:
> How is it faster? It calls allocate_nil_vector, which calls
> allocate_clear_vector.  make_vector also calls allocate_clear_vector.

Oh, you're right, I forgot about the runtime test in make_vector that causes it 
to do what make_nil_vector would do if the initializer is nil.

> I'd say we cut down the complication and use
> Fmake_vector almost everywhere

Although we could simplify somewhat, using Fmake_vector everywhere would go too 
far. It's useful to know one needn't worry about invalid args when calling the 
proper make-vector variant. I found this useful when checking Emacs for 
undefined behavior on integer overflow; for example, 'Fmake_vector (make_fixnum 
(n), ...)' won't do if n is out of range for fixnum. And an uninitialized 
variant is also worthwhile, to avoid initializing vectors twice.