From: <chr...@ma...> - 2020-05-28 16:40:28
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On 2020-05-27 17:59, Ken Moffat via Check-devel wrote: > That new build has now been booted. I then built check and ran the > tests - they all passed, so I did need to get away from the host > glibc which was sitting under chroot. > > I think a -O1 build might be a bit slower than I like, and detuning > from glibc's default of -O2 feels odd, but I guess I'm on the way > forward and with a variety of things to try over the next week or > so. > > Thanks again to you both! Good news! You're welcome! I think if you want to pursue this it's either a bug in glibc because they're relying on undefined behaviour, or a bug in GCC because an optimization is unsound. If you do want to narrow it down, and get back most of your performance, you can make a list of optimization flags enabled by -O2 that aren't enabled by -O1, and then do a binary search for the offender. This would also be more useful information for a bug report. Of course, this might require some patience... Chris |