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

Calculating dependencies ... done!
Dependency resolution took 0.99 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/jemalloc-5.3.0-r3:0/2::gentoo  USE="-debug -lazy-lock -prof -stats -xmalloc" 719 KiB

Total: 1 package (1 new), Size of downloads: 719 KiB