* gcc.dg/tree-ssa/ssa-dom-thread-4.c [avr-*-*]: Expect 6 times
        "Threaded".
        * gcc.dg/tree-ssa/ssa-pre-21.c [! size32plus]: mark as xfail.
        * gcc.dg/tree-ssa/vector-4.c (SItype): New typedef.
        (v4si): Use it.
        * gcc.dg/tree-ssa/vrp87.c [avr-*-*] (dg-additional-options): New.