On 04/05/2018 03:06 PM, Thomas Huth wrote: > On 05.04.2018 02:54, Richard Henderson wrote: >> On 04/05/2018 10:07 AM, Richard Henderson wrote: >>> On 04/05/2018 02:49 AM, Emilio G. Cota wrote: >>>> 1. grab this binary: >>>> http://cs.columbia.edu/~cota/qemu/nbench-aarch64 >>>> 2. run it on a PowerPC host with: >>>> $ aarch64-linux-user/qemu-aarch64 nbench-aarch64 -V >>>> >>>> Note: the "-V" (or "-v") flag is important! Without it, there's no >>>> segfault. >>> >>> How quickly? I did not see one up until it exited for lack of NNET.DAT. >>> >>> I will note that I am using gcc 7.2 on gcc112 >>> (/opt/cfarm/gcc-latest/bin/gcc). >>> >>> Are you using gcc 4.8.5, and is commit 74912f6dad in your tree? >>> That commit might have made a difference... >> >> Bah. I confirm that it doesn't, and that the test still fails. >> >> Since qemu does work on the same host when built with gcc 7.2, I can only >> blame >> this failure on a compiler bug wrt gcc 4.8 on ppc64. >> >> I have not tracked down exactly what's going wrong, and probably won't unless >> someone feels that it's worthwhile. This only begs the question of whether >> we >> should blacklist this compiler entirely. Certainly it's old enough that it's >> probably not worth fixing. > > GCC 4.8 is still used in enterprise distros like RHEL7 and AFAIK also in > SLES 12 ... so blacklisting this compiler does not sound like a good > idea to me.
I have now tracked down this failure and it turns out not to be a compiler bug at all; patch to follow. r~
