Standard way to supply hints to branches

[Manu]

On Fri, 23 Aug 2024, 19:02 Iain Buclaw via Digitalmars-d, <
digitalmars-d at puremagic.com> wrote:

> On Friday, 23 August 2024 at 02:23:37 UTC, Nicholas Wilson wrote:
> >
> > GDC probably has something similar too.
>
>
> https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#index-_005f_005fbuiltin_005fexpect
>
>
> Regarding DMD, I recall it being said that its code generator
> always treats the true branch as the "likely" code path taken. So
> if you have `if (cond) cold; else hot;`, invert the condition for
> the benefit of DMD.
>

Yes, I understand, and this is part of my point here; that leads to really
ugly code and deep nested scopes. That's what I've been doing, and I don't
want my program to look like that. It's just bad software.

For instance, an extraordinarily common function pattern is to receive some
inputs, validate a few things, and then do the thing at the end with valid
inputs.
Validations are usually a series of exclusionary checks framed as
`if(fails_validity_check) return;`
That flow keeps code in a nice linear flow, it doesn't introduce any scopes
at all... but it's the opposite of what the assume(true) prediction rule
wants. This is what lead me to this; almost every if statement I write is
predicted wrong... and I definitely don't want to solve that by writing
functions with 10 level deep nested scopes.

>
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