Today gcc-11.1.0 released upstream and was added to ::gentoo as:
https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=cc068d96fb49e308456cbe944fb29b1f78e6ad5c
User-visible changes are nicely described in upstream porting doc:
https://gcc.gnu.org/gcc-11/porting_to.html
A few highlights I personally encountered are:
- use -std=gnu++17 instead of -std=gnu++14
- ordered pointer comparison with integer (like int *p; 'p > 0')
- dynamic exception specifications
- gcc now enforces that comparison objects be invocable as const
- header dependency changes
On top of that:
- -fipa-modref (enabled by default) might expose latent bugs in existing
programs. -fno-ipa-modref should be a quick hack to check the hypothesis.
Failures don't look widespread, thus gcc-11 should be fine to use as a
default compiler.
Check out known bugs and workarounds on gcc-11 tracker:
https://bugs.gentoo.org/show_bug.cgi?id=gcc-11
Gentoo Toolchain wiki page for common fixes (nothing there so far):
https://wiki.gentoo.org/wiki/Project:Toolchain#gcc-11
As usual if you can't figure out what is wrong with your package
pull in toolchain@ to the bug and we'll get to the bottom of it.
Good luck!
--
Sergei