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

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

[ebuild  N     ] sci-mathematics/pari-2.17.4:0/9::gentoo  USE="X threads -data -doc -examples -fltk -test" 5209 KiB
[ebuild  N     ] sci-mathematics/gp2c-0.0.12::gentoo  USE="-test" 852 KiB

Total: 2 packages (2 new), Size of downloads: 6061 KiB