Re: [PATCH] Fix ICE for boolean comparison

[Richard Biener <richard dot guenther at gmail dot com>]

On Fri, Nov 13, 2015 at 11:52 AM, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
> 2015-11-13 13:38 GMT+03:00 Richard Biener <richard.guenther@gmail.com>:
>> On Thu, Nov 12, 2015 at 4:44 PM, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
>>> Hi,
>>>
>>> Currently compiler may ICE when loaded boolean is compared with vector invariant or another boolean value.  This is because we don't detect mix of bool and non-bool vectypes and incorrectly determine vectype for boolean loop invariant for comparison.  This was fixed for COND_EXP before but also needs to be fixed for comparison.  This patch was bootstrapped and tested on x86_64-unknown-linux-gnu.  OK for trunk?
>>
>> Hmm, so this disables vectorization in these cases.  Isn't this a
>> regression?  Shouldn't we simply "materialize"
>> the non-bool vector from the boolean one say, with
>>
>>  vec = boolvec ? {-1, -1 ... } : {0, 0, 0 ...}
>
> We may do this using patterns, but still should catch cases when
> patterns don't catch it. Patterns don't have vectypes computed and
> therefore may miss such cases. Thus stability fix is still valid.
>
> I don't think we have a compiler version which can vectorize
> simd-bool-comparison-2.cc, thus technically it is not a regression.
> There are also other similar cases, e.g. store of comparison result or
> use loaded boolean as a predicate. I was going to support
> vectorization for such cases later (seems I don't hit stage1 for them
> and not sure if it will be OK for stage3).

I still think those checks show that there is an issue we should fix
differently.  We're accumulating more mess into the already messy
vectorizer :(

Ok.

Thanks,
Richard.

> Ilya
>
>>
>> ?
>>
>> Thanks,
>> Richard.
>>
>>> Thanks,
>>> Ilya