Re: [PATCH 3/4 v3][PR 67328] Added bool conversion for wide_ints

[Yuri Gribov <tetra2005@gmail.com>]

On Tue, May 30, 2017 at 7:35 AM, Richard Sandiford
<richard.sandiford@linaro.org> wrote:
> Yuri Gribov <tetra2005@gmail.com> writes:
>> From 330209f721a598ec393dcb5d62de3457ee282153 Mon Sep 17 00:00:00 2001
>> From: Yury Gribov <tetra2005@gmail.com>
>> Date: Fri, 26 May 2017 07:53:10 +0100
>> Subject: [PATCH 3/4] Added bool conversion for wide_ints.
>>
>> gcc/
>> 2017-05-26  Yury Gribov  <tetra2005@gmail.com>
>>
>>       * wide-int.cc (wi::zero_p_large): New method.
>>       * wide-int.h (wi::zero_p): New method.
>
> Do you still need this bit?  It looks like it isn't used by the other
> parts of the series.
>
> The idea was that wi::eq_p (x, 0) (or just x == 0, if x is a
> wide-int-based type) is supposed to be as fast as a dedicated zero check.
> It'd be OK to have a helper function anyway, but it should probably be
> defined using wi::eq_p.
>
> The zero_p_large fallback can never return true, since a zero of
> any precision will have a length of 1.

Thanks Richard, I'll update the patch. The bool check is used in
successive patch (4/4), in
     widest_int mask = wi::to_widest (@2);
     bool mask_all_ones_p = !(mask & (mask + 1));

-Y