Date: Tue, 17 Feb 2009 22:51:10 -0800 From: Marcel Moolenaar <xcllnt@mac.com> To: "M. Warner Losh" <imp@bsdimp.com> Cc: mips@FreeBSD.org, tinderbox@FreeBSD.org, current@FreeBSD.org Subject: Re: [head tinderbox] failure on mips/mips Message-ID: <B23797BE-91FB-4AE1-8370-E77D66ED05B6@mac.com> In-Reply-To: <20090217.234216.1276682135.imp@bsdimp.com> References: <20090217.203647.-1518647466.imp@bsdimp.com> <20090217.222152.-109416210.imp@bsdimp.com> <4CB77F1D-4235-47D8-B654-1C4F29B6C649@mac.com> <20090217.234216.1276682135.imp@bsdimp.com>
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On Feb 17, 2009, at 10:42 PM, M. Warner Losh wrote: > : A safer approach is to mark ifi_epoch as packed or put differently, > : define time_t as a 64-bit integral with 32-bit alignment. This can > : avoid a lot of unexpected internal padding as well (e.g. struct > : timeval). > > Marking it as packed won't help. If the elements aren't properly > aligned, gcc won't access multi-word entities properly. It might > eliminate the warning, but it will break at runtime. But GCC will use a pair of 32-bit loads and/or stores to access the 64-bit integral in that case. There should be no runtime breakage. You only do this for n32 of course. -- Marcel Moolenaar xcllnt@mac.com
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