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Re: Proposal for merging scalar-storage-order branch into mainline
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: Richard Biener <richard dot guenther at gmail dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Tue, 09 Jun 2015 13:12 +0200
- Subject: Re: Proposal for merging scalar-storage-order branch into mainline
- Authentication-results: sourceware.org; auth=none
- References: <2354857 dot 0uXrE6NL1R at polaris> <24307404 dot yEd3bIJVu1 at polaris> <CAFiYyc3UYWMKCE=qRwY=iPjtscB3o3nyQBLDBjLrnX4d5NKNvg at mail dot gmail dot com>
> Yes, but I'd expect them to be optimized away (well, hopefully).
OK, but you cannot reasonably expose everything in GENERIC/GIMPLE, for example
the mask-and-shift operations to extract bitfields in reverse SSO, only the
RTL expander has the (quite complex) logic and I doubt you want to teach the
GIMPLE optimizers about this low-level mess.
> Anwyay, and I thought use of the feature would be rare so that "every load
> and store" is still very few?
Experience has shown that, when users start to use it, they use it extensively
(too extensively if you ask me) so the implementation cannot be too dumb.
--
Eric Botcazou