New comment by sternenseemann on void-packages repository https://github.com/void-linux/void-packages/issues/29526#issuecomment-872803985 Comment: I can confirm that building foot with PGO can be reproducible, i. e. I can reproduce the exact hash of the binary package produced by our builders on two different local machines (at different times). This also leads me to [believe that a reproducible gcc with PGO is possible](https://github.com/NixOS/nixpkgs/pull/112928#issuecomment-809336063), but most likely very hard to get to work. The only thing necessary to achieve a reproducible foot build is generating the random inputs which are used for profiling while building using a [fixed seed](https://github.com/NixOS/nixpkgs/blob/43b257365c2c73fc31421e9b28dde1166d75506a/pkgs/applications/terminal-emulators/foot/default.nix#L62).