On 11/13/2013 03:04 AM, Anthony Liguori wrote: > On Tue, Nov 12, 2013 at 8:08 AM, Peter Maydell <peter.maydell@xxxxxxxxxx> wrote: >> On 12 November 2013 15:58, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: >>> I don't really see a reason why QEMU should give clang more weight than >>> Windows or Mac OS X. >> >> I'm not asking for more weight (and actually my main >> reason for caring about clang is exactly MacOSX). I'm >> just asking that when a bug is reported whose underlying >> cause is "we don't work on clang because we're relying on >> undocumented behaviour of gcc" with an attached patch that >> fixes this by not relying on the undocumented behaviour, >> that we apply the patch rather than saying "why do we >> care about clang"... > > QEMU has always been intimately tied to GCC. Heck, it all started as > a giant GCC hack relying on entirely undocumented behavior (dyngen's > disassembly of functions). > > There's nothing intrinsically bad about being tied to GCC. If you > were making argument that we could do it a different way and the > result would be as nice or nicer, then it wouldn't be a discussion. > > But if supporting clang means we have to remove useful things, then > it's always going to be an uphill battle. > > In this case, the whole discussion is a bit silly. Have you actually For what it's worth, I think BOTH of the patches that have been posted should be applied. That is, the patch that does (X || 1) -> (1 || X), and the patch that adds the stub. Frankly I'd have thought this was obvious and I'm a bit dismayed about how long this thread has continued. As far as GCC is concerned, we consider trivial dead code elimination like this to be a quality of implementation issue. We would never remove it, even from -O0. We can't guarantee how successful we can be, but that's what bug reports and regression tests are for. r~ -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
