[PATCH] D53919: [X86] Don't allow illegal vector types to return by direct value on x86-64.

[Eli Friedman via Phabricator via cfe-commits]

efriedma added a comment.

As far as I know, according to the ABI docs, it's impossible to return a 256-bit vector from a function if AVX is disabled.

Given that we aren't rejecting the testcase, we're effectively implementing a new "no-AVX" ABI variant.  That variant is not defined anywhere, so we might as well pick the fastest convention, returning the value in registers.  I'm not sure why you would want to return the vector in memory instead.


Repository:
  rC Clang

https://reviews.llvm.org/D53919