> 5) Complex SIMD instructions like PSHUFB or PUNPCKxx which modern compilers can't reason deeply enough about your code to use effectively. (I'd love to be proven wrong on this one!)

I ran his example on my own machine and found this:

    193110 vshufps
    179984 pshufd
    129664 vpshufd
     88279 vpshufb
     73569 shufps
     14409 pshuflw
      8931 pshufhw
      8896 vpshuflw
      5997 pshufb
      3115 vshufpd
      1730 pshufw
      1514 vpshufhw
      1281 vshufi
       620 shufpd
        42 vpshufbitqmb
         4 vshuff

    113872 vunpcklps
     89357 vpunpcklwd
     87224 vpunpcklqdq
     80218 vpunpckhwd
     69531 vunpckhps
     51203 punpcklbw
     36962 punpcklqdq
     29082 punpcklwd
     28967 vpunpckldq
     22217 vunpcklpd
     20415 vpunpcklbw
     19423 vpunpckhdq
     18669 unpcklps
     16693 punpckldq
     16620 vpunpckhbw
     14712 vpunpckhqdq
     12289 punpckhwd
     10788 vunpckhpd
      9446 punpckhbw
      8006 unpckhps
      6207 punpckhdq
      3278 punpckhqdq
       803 unpcklpd
       483 unpckhpd
         6 kunpckwd
         5 kunpckdq
         4 kunpckbw

It's probably pretty likely that some of the lower counts are a result of hand written assembly, but the compiler has to be doing the high count ones.