https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115767
--- Comment #9 from Ignacy Gawędzki <bugs at qult dot net> --- (In reply to Sam James from comment #8) > While we wait for Honza, Ignacy, if you could try reduce it to get rid of > the Boost dependency, it'd be appreciated. I'm struggling to get a minimal example. I found what looks like a bug in Boost Bimap along the way, but it makes the problem go away only on x86_64, not on aarch64. I tried to find strict aliasing violations in the code by disabling ipa-modref on smaller and smaller parts of the execution path (using a function attribute), while checking that the problem goes away. All I ended up with was a method so simple that I can tell for sure it doesn't violate anything, and still, removing the attribute on it makes the problem appear. I believe the appearance of the problem is sensitive to even slight changes in register allocation, which makes finding a minimal example a very difficult task. > You can cvise for runtime testcases, just add several checks with different > compilers and UBSAN and friends. I tried to run cvise on the preprocessed code with no success at all. All the resulting code I got after hours of processing was either trivially useless (as it did not reproduce the problem), or did not compile at all. I suppose my lack of experience with this tool is to blame.
