[PATCH] malloc: Remove redundant NULL check

[Wilco Dijkstra]

Hi Cupertino,

> I wonder if in glibc there is an assert macro we could use to better
> protect this code from programmer mistakes.
> Can we add asserts in malloc code ?

assert() is used but it's broken in that those asserts are not removed in
release builds. So we need to fix that before we add asserts in hot paths.

> When revisiting this code, all I can think of is, let me set an assert
> to protect 'e' from ever being NULL.
>
> The only reason this does not seg faults is that we only call this
> function if the bin has at least one element. Well, this check is never
> verified within the function context, making it very fragile from a
> software engineering point of view.

Well if you deference 'e' unconditionally immediately after assigning it
then that is evidence that it cannot ever be NULL!

Cheers,
Wilco