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Re: [PATCH] PR63404, gcc 5 miscompiles linux block layer
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Jeff Law <law at redhat dot com>
- Cc: Richard Henderson <rth at redhat dot com>, Jiong Wang <jiong dot wang at arm dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 10 Oct 2014 19:04:08 +0200
- Subject: Re: [PATCH] PR63404, gcc 5 miscompiles linux block layer
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- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Fri, Oct 10, 2014 at 11:00:54AM -0600, Jeff Law wrote:
> But it's really a lot more like a
> >kind of PLUS. If instead we had a LOW to match HIGH it would have been
> Right. In fact, I believe at the hardware level it's typically implemented
> as addition.
Can be addition or bitwise or, as high should have some low bits zero, both
usually work the same.
Jakub