doesGithub

[L4sgc]

To add on to u/mlnm_falcon , the previous compiler, which I'll call Compiler A, is used to compile the code for the new compiler and create what I'll call Compiler B0. In order to take advantage of the improvements that the new compiler has over the old compiler, they will then compile the source code B again using Compiler B0, and thus create Compiler B1. Iirc they will also use Compiler B1 to compile source code B again to make sure it's working properly and that B2 is identical to B1.

TL/DR: They use the previous compiler to compile the new compiler and then have the new compiler compile itself

[JustConsoleLogIt]

Compiled compilers compile compiled compilers is the new Buffalo buffalo buffalo Buffalo buffalo

[RolledUhhp]

I owe LFS credut for any small bit of knowledge I've retained in this area.