[PATCH] D15999: Adding doxygen comments to the LLVM intrinsics (part 2, _wmmintrin_pclmul.h)

[Sean Silva via cfe-commits]

On Wed, Jan 20, 2016 at 3:14 PM, Eric Christopher <echristo at gmail.com>
wrote:

>
>
> On Wed, Jan 20, 2016 at 3:12 PM Sean Silva <chisophugis at gmail.com> wrote:
>
>> silvas added a comment.
>>
>> In http://reviews.llvm.org/D15999#331601, @kromanova wrote:
>>
>> > In http://reviews.llvm.org/D15999#330794, @silvas wrote:
>> >
>> > > This may sound stupid, but: can you benchmark the time it takes to
>> build some project (that actually uses intrinsics in most translation
>> units, e.g. a game) with the headers w/ and w/o the doxygen comments to
>> check that all the extra comment skipping doesn't affect compilation time?
>> I.e. run your script to add the comments for "all" the intrinsic headers
>> (similar to what you expect the final state to be after all these patches)
>> and test the build time of a game (and compare with the unmodified headers).
>> > >
>> > > Also, can you post a patch that changes "all" the headers to have
>> doxygen comments like you intend, so that others can test and verify?
>> >
>> >
>> > Out of curiosity, do you know if the impact to the build time for
>> Eric's change of starting to use the target attributes instead of
>> conditional inclusion was measured (r239883) on a large scale application.
>> If so, what were the results? I should probably include Eric.
>>
>>
>> I don't think we did any testing at SCE, but we probably should have. I
>> don't think Google's primary codebases (nor Apple's, or anybody else pretty
>> much) include the intrinsic headers in basically every TU so the impact is
>> probably not a huge concern overall. However, games include these headers
>> in basically every TU so we at SCE should take a look.
>>
>>
> This seems to be a pretty broad brush to paint things with and an
> assumption I wouldn't be willing to make.
>

Every vendor obviously has some projects that end up pulling in intrinsics
in basically every TU. It's just that for SCE those are the rule and not
the exception, so we should be particularly concerned.

-- Sean Silva


>
>
>> Also, the target attributes stuff had some correctness issues (e.g.
>> crashes in backend) that took a while to iron out and those issues took the
>> limelight.
>>
>>
> For the record, those were "crash on invalid" rather than "crash on valid".
>
> -eric
>
>
>
>>
>> Repository:
>>   rL LLVM
>>
>> http://reviews.llvm.org/D15999
>>
>>
>>
>>
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