Title: GentooLTO GCC 11
Author: Shane Peelar <lookatyouhacker@gmail.com>
Content-Type: text/plain
Posted: 2021-05-01
Revision: 1
News-Item-Format: 1.0

Greetings GentooLTO community,

As you may have heard, GCC 11.1 has been released!  And we, of course, must move with it.
As of May 15th 2021, barring any unexpected issues, GentooLTO will be officially moved over to GCC 11.
There shouldn't be any major breaking changes in this release, so I expect things to go pretty smoothly.

One important point to bring up: the GCC 11 ebuild in Gentoo now supports `custom-cflags`.  If you have
this enabled system-wide, as I'm sure many do, that means that your CFLAGS won't get stripped from the GCC
build process.  This can create problems when trying to build it.  Historically, we have always honoured `strip-flags`
for GCC as we get LTO and PGO through the USE flags provided in the ebuild anyway.  If you do want to enable
`custom-cflags` for GCC, you must filter out `-flto*` manually from it with a workaround.  I'm omitting putting
a workaround in the overlay for this as I believe this should be your choice - however, personally, I recommend
disabling `custom-cflags` with your GCC to retain the original behaviour as it's much safer.

GCC 11 brings improvements on both the LTO and the PGO front, which of course are always
welcome :)  I encourage everyone to start testing out GCC 11 themselves before then -- just don't forget to `lto-rebuild`!
And of course, if you encounter any showstoppers with GCC 11, please let us know in the issue tracker.

All the best,
-Shane