http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56118
--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> 2013-01-26 17:57:13 UTC --- Note that the case I am most interested in is actually when r is not initialized: __m128d r; gimple_assign <real_cst, BIT_FIELD_REF <r, 64, 0>, 1.0e+0, NULL, NULL> gimple_assign <real_cst, BIT_FIELD_REF <r, 64, 64>, 2.0e+0, NULL, NULL> because I've seen users fill in constant vectors this way. That could complicate things a little as I'm not sure what r should be between the 2 assignments. On the side, if SLP is extended to vectors, it might hide this issue (but for now I've only managed to get an ICE because something takes the address of a bit_field_ref).