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

Calculating dependencies ... done!
Dependency resolution took 0.98 s (backtrack: 0/20).

[ebuild  N     ] dev-cpp/xsimd-14.2.0::gentoo  USE="-doc -test" 332 KiB

Total: 1 package (1 new), Size of downloads: 332 KiB