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Re: delay slot of conditionnal branch with no annuled jump strategy

From: Jeff Law <law at redhat dot com>
To: BELBACHIR Selim <selim dot belbachir at fr dot thalesgroup dot com>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
Date: Thu, 10 Oct 2013 10:33:35 -0600
Subject: Re: delay slot of conditionnal branch with no annuled jump strategy
Authentication-results: sourceware.org; auth=none
References: <12987_1381411882_5256AC2A_12987_783_1_9C88BF562A27AA41B242B2780441926E2102E03CD4 at THSONEA01CMS05P dot one dot grp>

On 10/10/13 07:31, BELBACHIR Selim wrote:


Why GCC doesn't see, in this case, that it's not safe to fill the delay slot with my compare insn (which is a parallel RTX which clobber one register used in fallthrough branch) ?
Is a processor 'annuled jump strategy' mandatory to handle delay slot of conditionnal jump instructions ?

You'd need to debug reorg. reorg has code to track resources to avoidthese kind of issues. You'd have to debug why it's not working as expected.

annulling is not required for proper functioning of the reorg pass, it'smerely an optimization.

I'd start by first verifying your delay slot descriptions do not allownullifying the delay slot.


Jeff

Follow-Ups:
- Re: delay slot of conditionnal branch with no annuled jump strategy
  - From: Alan Lehotsky

References:
- delay slot of conditionnal branch with no annuled jump strategy
  - From: BELBACHIR Selim

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