From: Andrew Stubbs <ams@codesourcery.com>
To: Thomas Schwinge <thomas@codesourcery.com>, <gcc-patches@gcc.gnu.org>
Cc: Hafiz Abid Qadeer <abidh@codesourcery.com>
Subject: Re: [gcn] Work-around libgomp 'error: array subscript 0 is outside array bounds of ‘__lds struct gomp_thread * __lds[0]’ [-Werror=array-bounds]' (was: [PATCH libatomic/arm] avoid warning on constant addresses (PR 101379))
Date: Mon, 19 Jul 2021 12:10:59 +0100 [thread overview]
Message-ID: <e25e68f6-d3b0-bb1b-9c65-d9ad16f2d084@codesourcery.com> (raw)
In-Reply-To: <87bl6ybsic.fsf@euler.schwinge.homeip.net>
On 19/07/2021 09:46, Thomas Schwinge wrote:
>> GCN already uses address 4 for this value because address 0 caused
>> problems with null-pointer checks.
>
> Ugh. How much wasted bytes per what is that? (I haven't looked yet;
> hopefully not per GPU thread?) Because:
It's 4 bytes per gang. And that pointer is the only 8 bytes in the whole
of LDS (OpenMP mostly uses stack and heap), so it's not so bad, but still.
I did investigate the target macro that lets you control null pointer
behaviour, but it didn't just work, and it wasn't important enough for
me to spend more time on it so I let it go.
Andrew
next prev parent reply other threads:[~2021-07-19 11:11 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-09 23:11 [PATCH libatomic/arm] avoid warning on constant addresses (PR 101379) Martin Sebor
2021-07-15 8:33 ` Christophe Lyon
2021-07-16 17:42 ` Thomas Schwinge
2021-07-16 21:11 ` Martin Sebor
2021-07-19 8:49 ` Thomas Schwinge
2021-07-17 22:28 ` Andrew Stubbs
2021-07-19 8:46 ` [gcn] Work-around libgomp 'error: array subscript 0 is outside array bounds of ‘__lds struct gomp_thread * __lds[0]’ [-Werror=array-bounds]' (was: [PATCH libatomic/arm] avoid warning on constant addresses (PR 101379)) Thomas Schwinge
2021-07-19 8:56 ` Jakub Jelinek
2021-07-19 11:10 ` Andrew Stubbs [this message]
2021-07-20 7:23 ` [gcn] Work-around libgomp 'error: array subscript 0 is outside array bounds of ‘__lds struct gomp_thread * __lds[0]’ [-Werror=array-bounds]' Thomas Schwinge
2021-07-20 8:40 ` '#pragma GCC diagnostic' (mis-)use in 'statement' of 'if' (was: [gcn] Work-around libgomp 'error: array subscript 0 is outside array bounds of ‘__lds struct gomp_thread * __lds[0]’ [-Werror=array-bounds]') Thomas Schwinge
2021-07-20 19:47 ` '#pragma GCC diagnostic' (mis-)use in 'statement' of 'if' Martin Sebor
2021-07-20 20:16 ` Jakub Jelinek
2021-07-21 16:41 ` [PATCH libatomic/arm] avoid warning on constant addresses (PR 101379) Kyrylo Tkachov
2021-07-21 16:54 ` Martin Sebor
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