I looked at that, and eventually found a reference to the Launchpad bug in this 500KB patch[0]. It says: + * Fixes included in the 4.2.4 upstream release

I looked at that, and eventually found a reference to the Launchpad bug in this 500KB patch[0]. It says: + * Fixes included in the 4.2.4 upstream release (compared to 4.2.3-3ubuntu7): + - Fix LP: #256797, wrong-code on ia32, taken from the gcc-4_2-branch. Which makes it sound like the problem was in GCC, not the Ubuntu package. I was under the impression that the bug was caused by an Ubuntu-specific patch, from dikaiosune's comment. Am I missing something? Edit: Ah, so the fix was added in 4.2.4-1ubuntu1, not 4.2.4-1ubuntu3. Which narrows the actual source changes to something inside this other 500KB patch[1]. From here I looked at the upstream changes using GitHub compare[2] (warning, big page). I ran a one liner in the JS console to expand all the "…" buttons next to the commit messages so I could search for relevant text, which lead me to this commit[3], which seems to be the actual code changes to fix that particular bug. That finally lead me to the bug in GCC's bug tracker[4]. I don't know if I have just been very lucky with the open source projects I've collaborated with, but this journey to find where a bug was actually fixed seems completely insane to me. Is all this info passed down from maintainer to maintainer just via folklore? Crazy. Oh, I almost forgot about what I actually wanted to know. This looks like a GCC bug that wasn't caused by Ubuntu specific patches, so I don't know what dikaiosune wanted to say. [0] https://launchpadlibrarian.net/18364478/gcc-4.2_4.2.4-1ubuntu3.diff.gz https://launchpadlibrarian.net/18364478/gcc-4.2_4.2.4-1ubunt... [1] https://launchpadlibrarian.net/17472542/gcc-4.2_4.2.3-2ubuntu7_4.2.4-1ubuntu1.diff.gz https://launchpadlibrarian.net/17472542/gcc-4.2_4.2.3-2ubunt... [2] https://github.com/gcc-mirror/gcc/compare/gcc-4_2_3-release...gcc-4_2_4-release https://github.com/gcc-mirror/gcc/compare/gcc-4_2_3-release.... [3] https://github.com/gcc-mirror/gcc/commit/80cacf54c3d410d5552b2bf262bc9ac5dc6a1e05 https://github.com/gcc-mirror/gcc/commit/80cacf54c3d410d5552... [4] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=35163 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=35163