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Re: Revert DECL_USER_ALIGN part of r241959
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Richard Biener <richard dot guenther at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, richard dot sandiford at linaro dot org
- Date: Fri, 5 Jan 2018 11:04:03 +0100
- Subject: Re: Revert DECL_USER_ALIGN part of r241959
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- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Fri, Jan 05, 2018 at 09:49:56AM +0000, Richard Sandiford wrote:
> Is the patch OK as a compromise for GCC 8? We don't speculatively
> increase the user alignment in increase_alignment, but do still increase
> it if it helps to vectorise a particular loop access?
I'd be a little bit worried about code that puts some variables into user
sections with specific alignment, i.e.
__attribute__((section ("whatever"), aligned(N)))
where data is collected from different TUs into the user section and
any padding added there breaks this. E.g. Linux kernel and other programs
use this technique heavily.