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-libs/jemalloc-5.4.0-r2:0/2::gentoo  USE="stats -debug -lazy-lock -prof -xmalloc" 893 KiB

Total: 1 package (1 new), Size of downloads: 893 KiB