Date: Sat, 30 Aug 2003 00:36:09 +0200 From: Matthias Andree <ma@dt.e-technik.uni-dortmund.de> To: "Daniel C. Sobral" <dcs@tcoip.com.br> Cc: Current <current@freebsd.org> Subject: Re: buildworld failure Message-ID: <m3fzjkytuu.fsf@merlin.emma.line.org> In-Reply-To: <3F4F8DB2.8040701@tcoip.com.br> (Daniel C. Sobral's message of "Fri, 29 Aug 2003 14:30:26 -0300") References: <JCEIKJMCANNPGKFKGLKLCEGIDMAA.mikej@trigger.net> <3F4F8DB2.8040701@tcoip.com.br>
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"Daniel C. Sobral" <dcs@tcoip.com.br> writes: >> I've been using freebsd since the 2.x days, I have always compiled world >> and ports with -O2, and never had any instability issues due to the >> optimizations. I have switched back to -O and -march=pentium4, the >> buildworld finished ok. > > Lucky you. It does happen that these optimizations may result in code > with no apparent problem, depending on one's hardware, though I suspect > many people's "hardware problems" were nothing of the sort. Not everything that breaks with -O2 is a compiler fault or hardware running just a tad beyond the limit. Anecdote: when bogofilter got the "unified" data base a month ago, one data structure that used to be 8 bytes got extended to 12 bytes. Now, the variable declaration was still "auto uint32_t cv[2]". memcpy() copied 12 bytes into the 8 byte buffer (cv) and caused obscure test suite failures when compiled with optimization on some architectures (among them 32-bit SPARC), but was fine with lower or no optimization. (details in sourceforge cvs browser, check src/datastore_db.c 1.29->1.30) -- Matthias Andree Encrypt your mail: my GnuPG key ID is 0x052E7D95
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