[PATCH] D28746: Mention ThinLTO with PGO in ReleaseNotes 4.0

[Piotr Padlewski via Phabricator via cfe-commits]

Prazek added a comment.

Maybe I should change ThinLTO for '-flto=thin' and also mention this improvement in LLVM release notes?

BTW '-flto=thin' is not documented in UsersManual


https://reviews.llvm.org/D28746