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Re: [Committed] S/390: Provide alc patterns for overflow checks
- From: Rask Ingemann Lambertsen <rask at sygehus dot dk>
- To: Andreas Krebbel <Andreas dot Krebbel at de dot ibm dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Ulrich dot Weigand at de dot ibm dot com
- Date: Thu, 30 Aug 2007 10:15:22 +0200
- Subject: Re: [Committed] S/390: Provide alc patterns for overflow checks
- References: <20070830070117.GA5050@homer.boeblingen.de.ibm.com>
On Thu, Aug 30, 2007 at 09:01:17AM +0200, Andreas Krebbel wrote:
> Hello,
>
> the S/390 back end currently does not provide patterns which make the
> condition code available for overflow checks like a + b + carry < b.
> The attached patch adds the missing patterns.
Do you have an example piece of source which triggers combine to
generate such patterns? I'm working on canonicalizing such operations in
simplify-rtx.c and I've tried with no success to make combine create
such patterns.
--
Rask Ingemann Lambertsen