http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48274
--- Comment #2 from Michael Matz <matz at gcc dot gnu.org> 2011-03-24 14:51:08 UTC --- It's x86_64-linux and indeed it does define that hook. Like 19 other targets. This is quite inconvenient. The target should have a say in what instructions are generated (as in influencing the setup of RTL call, and setup of arguments in the callee, also at RTL), not on the types the middle end sees. Sigh.