[PATCH] D32060: BitVector: add iterators for bits that are set

[Zachary Turner via llvm-commits]

Would it really be that unhandy? You would only need to iterate from
iter->first to iter->second to get the same effect.

Granted it wouldn't work with existing algorithms that take predicates or
functions with integer arguments, but I wonder if anyone would even notice
that limitation. And when the bits happen to be clustered together , which
is not uncommon, it will be vastly more efficient
On Thu, Apr 13, 2017 at 5:44 PM Matthias Braun <matze at braunis.de> wrote:

> While more efficient, this seems unhandy to me...
>
> Using a BitVector as a replacement for a std::set<unsigned> is a common
> pattern and in this case I would expect the iterator to return all the
> elements that I put into the set before...
>
> - Matthias
>
> On Apr 13, 2017, at 5:41 PM, Zachary Turner <zturner at google.com> wrote:
>
> Instead of having the value type be an index, how about having it be a
> range? Eg if bits,1,2,3,6,8,9 are set then have it return (1,4), (6,7), and
> (8,10) on successive iterations. This should be much more efficient. For a
> bits_unset iterator, the above would return (0,1), (4, 6), (7,8), (10,
> size())
> On Thu, Apr 13, 2017 at 5:29 PM Matthias Braun via Phabricator <
> reviews at reviews.llvm.org> wrote:
>
>> MatzeB added reviewers: dblaikie, chandlerc, mehdi_amini.
>> MatzeB added a comment.
>>
>> Adding a few reviewers who often have comments on ADT changes.
>>
>>
>> https://reviews.llvm.org/D32060
>>
>>
>>
>>
>
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