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Re: Better info for combine results in worse code generated
- From: Alan Modra <amodra at gmail dot com>
- To: David Edelsohn <dje dot gcc at gmail dot com>
- Cc: GCC Development <gcc at gcc dot gnu dot org>
- Date: Fri, 29 May 2015 00:43:49 +0930
- Subject: Re: Better info for combine results in worse code generated
- Authentication-results: sourceware.org; auth=none
- References: <20150528143941 dot GL14752 at bubble dot grove dot modra dot org> <CAGWvnyk9E7HE6SY0R9dZz-H5TQRqV3jTDWB7oGHmk+axo4L4Ew at mail dot gmail dot com>
On Thu, May 28, 2015 at 10:47:53AM -0400, David Edelsohn wrote:
> This seems like a problem with the cost model. Rc instructions are
> more expensive and should be represented as such in rtx_costs.
The record instructions do have a higher cost (8 vs. 4 for normal
insns). If the cost is increaed I don't think you'll see them
generated at all, which would fix my testcase but probably regress
others.
--
Alan Modra
Australia Development Lab, IBM