On 2012-09-05 11:36, David Chisnall wrote: > On 5 Sep 2012, at 10:31, Dimitry Andric wrote: >> TThe >> -fno-strict-aliasing is not really my choice, but it was introduced >> in the past by Nathan Whitehorn, who apparently saw problems without >> it. It will hopefully disappear in the future. > Clang currently defaults to no strict aliasing on FreeBSD. Yes, but upstream has never used -fno-strict-aliasing, just plain -O2. I run regular separate builds of pristine upstream clang on FreeBSD, and I haven't seen any failures due aliasing problems in all the regression tests. That doesn't guarantee there are no problems, of course... > In my experience, most C programmers misunderstand the aliasing rules of C and even people on the C++ standards committee often get them wrong for C++, so trading a 1-10% performance increase for a significant chance of generating non-working code seems like a poor gain. If people are certain that they do understand the rules, then they can add -fstrict-aliasing to their own CFLAGS. I'm actually quite interested in the performance difference; I think I will run a few tests. :)Received on Wed Sep 05 2012 - 08:56:06 UTC
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