http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59405
--- Comment #4 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to Yukhin Kirill from comment #3) > (In reply to Uroš Bizjak from comment #1) > > There is no testcase attached, but you need to *manually* insert _mm_empty > > (== emms) to switch from MMX to x87 state. > > > > The compiler does not automatically insert emms for you. > > Well, then problem is different, test as simple as empty call. > I doubt we should emit wrong code here. You need: float foo32x2_be (float32x2_t x) { __builtin_ia32_emms(); return x[1]; } This is documented somewhere in Intel's ISA manual, so the testcase is probably invalid.