Re: [PATCH 2/2] vec: Add array_slice::bsearch

[Richard Biener <richard.guenther@gmail.com>]

> Am 26.08.2022 um 23:45 schrieb Martin Jambor <mjambor@suse.cz>:
> 
> Hi,
> 
>> On Fri, Aug 26 2022, Richard Sandiford wrote:
>> Richard Biener <rguenther@suse.de> writes:
>>>> Am 26.08.2022 um 18:40 schrieb Martin Jambor <mjambor@suse.cz>:
>>>> 
>>>> Hi,
>>>> 
>>>> This adds a method to binary search in a sorted array_slice.
>>>> 
>>>> The implementation is direct copy of vec:bsearch.  Moreover, to only
>>>> copy it once and not twice, I used const_cast in the non-const
>>>> variants to be able to use the const variants.  I hope that is
>>>> acceptable abuse of const_cast but I'll be happy to change that if
>>>> not.
>>>> 
>>>> Bootstrapped and tested along code that actually uses it on
>>>> x86_64-linux.  OK for trunk?
>>> 
>>> Can you avoid the copying by using array slice bsearch from the vec<> bsearch?
>> 
>> IMO it would be better to transition to using <algorithm> routines
>> for this kind of thing (for new code).  In this case that would be
>> std::lower_bound.
>> 
>> Using std::lower_bound is more convenient because it avoids the void *
>> thing (you can use lambdas to capture any number of variables instead)
>> and because it works on subranges, not just whole ranges.
>> 
> 
> OK, I can use std::lower_bound with simple lambdas too.  The semantics
> of returning the first matching a criterion actually allows me to use it
> one more time.

Can you try to compare generated code?

> Martin