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Re: [PATCH] Improve alloca alignment
- From: Rainer Orth <ro at CeBiTec dot Uni-Bielefeld dot DE>
- To: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>
- Cc: Eric Botcazou <ebotcazou at adacore dot com>, "gcc-patches\@gcc.gnu.org" <gcc-patches at gcc dot gnu dot org>, Jeff Law <law at redhat dot com>, nd <nd at arm dot com>
- Date: Sat, 09 Sep 2017 00:53:21 +0200
- Subject: Re: [PATCH] Improve alloca alignment
- Authentication-results: sourceware.org; auth=none
- References: <DB6PR0801MB2053EFC180A8360BC943BEB883B90@DB6PR0801MB2053.eurprd08.prod.outlook.com> <152e8e72-c654-846a-c383-5c935c5af6ae@redhat.com> <yddzia8w8s2.fsf@CeBiTec.Uni-Bielefeld.DE> <28942318.eoPupIDytn@polaris> <DB6PR0801MB2053CC1BB22D65B46DD2C2AB83950@DB6PR0801MB2053.eurprd08.prod.outlook.com>
Hi Wilco,
> Eric Botcazou wrote:
>
>> The stack is aligned before the allocation but it gets misaligned during the
>> allocation because the dynamic offset is not a multiple of STACK_BOUNDARY.
>
> No, the stack never gets misaligned - my patch doesn't change that at
> all. The issue is that Sparc backend doesn't correctly set STACK_BOUNDSARY
> and neither aligns the outgoing args. Run my test which proves alloca was
> broken before my patch.
I'm currently running my SPARC bootstraps with your patch backed out so
regressions don't go overboard. The test PASSes this way.
Rainer
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Rainer Orth, Center for Biotechnology, Bielefeld University