From: Alexander Monakov <amonakov@ispras.ru>
To: Adonis Ling <adonis0147@gmail.com>
Cc: gcc-help@gcc.gnu.org
Subject: Re: Why does different types of array subscript used to iterate affect auto vectorization
Date: Tue, 28 Jun 2022 18:38:25 +0300 (MSK) [thread overview]
Message-ID: <3b44a272-447c-28d7-678d-5968df7ec248@ispras.ru> (raw)
In-Reply-To: <CAG5qfXi-jE1wtgsKBECR88R8c6FhnWBP3Dj07eTv5d6g4fZHYQ@mail.gmail.com>
On Tue, 28 Jun 2022, Adonis Ling via Gcc-help wrote:
> > Here the main problem is '*array' and 'nread' have the same type, so they
> > might overlap. Ideally the compiler would recognize that that cannot happen
> > because it would make 'array[nread++] = i' undefined due to unsequenced
> > modifications, but GCC is not sufficiently smart (yet). The secondary issue
> > is the same as below:
> >
>
> I got your point.
>
> After that, I tried to add __restrict__ to nread as the following shows and
> GCC still doesn't optimize it.
As I said, there's a secondary issue even if you add 'restrict'.
Alexander
next prev parent reply other threads:[~2022-06-28 15:38 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-27 2:47 Adonis Ling
2022-06-28 13:06 ` Alexander Monakov
2022-06-28 15:23 ` Adonis Ling
2022-06-28 15:38 ` Alexander Monakov [this message]
2022-06-28 15:47 ` Adonis Ling
2022-06-28 15:56 ` Alexander Monakov
2022-06-28 16:00 ` Adonis Ling
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