public protocol BAR { func foo() } public func XXXXX<T : BAR>(arg: T) { arg.foo() } public func ZZZZZ(arg: BAR) { arg.foo() }

-O -emit-ir 結果 https://gist.github.com/rintaro/8794ecd01e78e6b001fce192b07f2d7d#file-test-sil

test.sil