These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 0.97 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/libatomic_ops-7.10.0::gentoo  531 KiB
[ebuild  N     ] dev-libs/boehm-gc-8.2.10-r1::gentoo  USE="large threads -cxx -static-libs" 1201 KiB

Total: 2 packages (2 new), Size of downloads: 1731 KiB