Hi Andreas, On Mon, Dec 05, 2022 at 04:20:41PM +0100, Andreas Tille wrote: > Hi Helmut, > > Am Mon, Dec 05, 2022 at 05:25:03PM +0530 schrieb Nilesh Patra: > > > > On 5 December 2022 12:24:23 pm IST, Andreas Tille <ti...@debian.org> wrote: > > >Since git blames you about last changes on the lines with the option in > > >question could you please comment about this?
The assumption that the one who last touched this is at fault is an interesting one. Unfortunately, it is quite distant from the truth. > > I simply applied patch supplied by Helmut to make build cross-buildable. > > Please check Bug#989942 for the explanation and context. The next step is forwarding the question to the next person until someone is found who does actual research. :-/ > Bug #982384 (libdeflate: Warnings profile count data file not found) > implies that the patch you provided once is not working as expected. > Would you mind commenting on this issue? I think the matter is relatively simple. You say that the -Wmissing-profile warnings shouldn't be there and I agree. You also imply that they haven't been there forever. So we're likely talking about a regression here, right? Once we assume to have a regression, there is a dead simple way of figuring out: Just go back in the build logs and locate a version that doesn't contain these warning. I've done this for your convenience and it turns out that 1.2-1 is the last version that lacks these warnings. 1.3-1 is the first that contains them. The changelog for 1.3-1 is: | libdeflate (1.3-1) unstable; urgency=medium | | * New upstream version, now provides libdeflate-g{un,}zip in /usr/bin | * debhelper-compat 12 | * Standards-Version: 4.4.0 | * Remove trailing whitespace in debian/rules | * Set upstream metadata fields: Name. | | -- Michael R. Crusoe <michael.cru...@gmail.com> Fri, 23 Aug 2019 12:28:07 +0200 I think this would be a better start for research than blaming random patches. While we can now start blaming someone else, we should not rule out possible toolchain changes as a cause given that 1.2-1 and 1.3-1 are half a year apart and were built with gcc 8.2 and gcc 9.2 respectively. Quite simply, it could be that the profile guided optimization never worked, but only gcc 9 would start warning about it. Maybe we could check when that warning was added to gcc? https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86957 That happens to be gcc 9. Surprise! So while we don't have proof yet, it seems quite likely that profile guided optimization never worked for libdelfate. Just now, gcc tells us about that. Hope this helps Helmut