Question: I've been browsing through the GCC source code and I've been stumped on how to extract these. Can anyone provide a list or information on how to extract these peepholes (assembly rewrite optimizations)?

GCC code: <https://github.com/gcc-mirror/gcc>

**Edit**: To clarify, a "peephole" is defined to be a find and replace pattern with some associated side conditions for the rewrite to be valid (often just some register/flags liveness information).

Answer: 
You need to authenticate with the Gmail SMTP server in order to send mail.

This means either using your Google account password (or better - a Google account password for a new account with no sensitive information in it), or an app password if you have 2FA enabled on your Google account.
The Google account password does not work anymore. For Gmail personal users, you have to use the "App password". For paid Google Workspace users, there are more options, such as "Less secure apps" or "Google SMTP relay service". See <https://www.cubebackup.com/blog/how-to-use-google-smtp-service-to-send-emails-for-free/> for more information.