On Monday 15 February 2010 12:16:21 Daniel Dunbar wrote:> No, some build release, and some build release-asserts. > > Historically, this is a typical sign of llvm being miscompiled, see > the broken-gcc list.Yep, that's it. We've been happily using gcc 4.1.2 on OpenSUSE for test builds for some time without problem (we don't use it for releases yet, and won't now!). I guess something changed to make the issue visible to us. BTW, how sure are we that all these are gcc issues and not some incorrect code somewhere that triggers undefined behavior? -Dave
Which means it could break my CentOS tests also. One missing feature that I know of for this configuration is that 4.1.2 on this platform does not support gcc atomic builtins. I need to upgrade this environment anyway. Garrison On Feb 15, 2010, at 16:22, David Greene wrote:> On Monday 15 February 2010 12:16:21 Daniel Dunbar wrote: >> No, some build release, and some build release-asserts. >> >> Historically, this is a typical sign of llvm being miscompiled, see >> the broken-gcc list. > > Yep, that's it. We've been happily using gcc 4.1.2 on OpenSUSE for test > builds for some time without problem (we don't use it for releases yet, and > won't now!). I guess something changed to make the issue visible to us. > > BTW, how sure are we that all these are gcc issues and not some incorrect > code somewhere that triggers undefined behavior? > > -Dave > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
On Mon, Feb 15, 2010 at 1:22 PM, David Greene <dag at cray.com> wrote:> On Monday 15 February 2010 12:16:21 Daniel Dunbar wrote: >> No, some build release, and some build release-asserts. >> >> Historically, this is a typical sign of llvm being miscompiled, see >> the broken-gcc list. > > Yep, that's it. We've been happily using gcc 4.1.2 on OpenSUSE for test > builds for some time without problem (we don't use it for releases yet, and > won't now!). I guess something changed to make the issue visible to us. > > BTW, how sure are we that all these are gcc issues and not some incorrect > code somewhere that triggers undefined behavior?Medium sure? :) I spent a little while hunting this particular bug, and it acted very much like a compiler bug. I never narrowed it down to a test case, though. - Daniel> -Dave > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >
On Monday 15 February 2010 20:46:52 Daniel Dunbar wrote:> > BTW, how sure are we that all these are gcc issues and not some incorrect > > code somewhere that triggers undefined behavior? > > Medium sure? :) > > I spent a little while hunting this particular bug, and it acted very > much like a compiler bug. I never narrowed it down to a test case, > though.Is there a gcc bug for this testcase? I'd like to understand better exactly what the issue is. Looking at http://llvm.org/docs/GettingStarted.html#brokengcc here's the current recommendation: We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1 successfully with them (however, see important notes below). Is this really still true? Is there a later version of gcc that's recommended? 3.4.x is ancient. Does the page need an update? What are people out there using today? -Dave