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.
[Since May 2022, Google stopped providing access to less secure apps](https://support.google.com/accounts/answer/6010255?hl=en)

Steps to generate an app password to integrate programmatically
---------------------------------------------------------------

1. Go to the Google account.
2. On the left navigation panel, click Security.
3. On the "Signing in to Google" panel, click App passwords. If prompted, enter your password.

Note: If you can't get to the page, 2-Step Verification is:
Not set up for your account

4. Make sure Mail or Other (custom name) is selected in the Select app drop-down menu. If you seelcted Mail, choose a computer or device from the Select device menu. If you selected Other (custom name), type the application name (like "My Mail Program").
5. Click Generate.
Use the generated password displayed BOTH IN IMAP and SMTP section in your email account settings in Program SMTP Setting.