Per VognsenWeird FUD by Phoronix about LTO builds since Mesa is apparently turning off their LTO builds due to "impossible to reproduce bugs that only happen in LTO builds". I'd like to get other people's take, but I'm assuming what's actually happening is that like with -O1 vs -O3, optimizing across translation units is exposing latent UB bugs (or much less likely, latent compiler bugs not directly related to LTO), and it's not that the LTO pass itself is buggy.
Robin Burchell@pervognsen I was thinking the same, I’ve hit hard to debug crashes in release builds that turned out to be UB problems triggered by LTO, I’ve never hit a problem that boiled down to just be LTO.
@rburchell Yeah, and I've worked on projects we couldn't ship initially with the -O3 equivalent without selectively disabling optimizations. It's a completely rational expedient but usually (unless it's something definitive and categorical like -fno-strict-aliasing where it's intentional) it should make you feel extremely uncomfortable since there might be way the same root cause could trigger without LTO after making innocuous code changes or changing compiler versions.