Nice stuff.

I think though you're wrong that Sandy Bridge supports MAC whereas Ironlake did not.
Ironlake (just like the chips before it) had accumulator support, though it was decidedly less flexible than Sandy Bridge (only global not per-instruction enable for one which probably makes this near impossible to use for ordinary shaders, SNB might also have more accum regs maybe).
The intel docs also list MAD for Ironlake already though interestingly the intel linux driver does not seem to use it (though it doesn't do so for Sandy Bridge neither) so I don't know if it actually works... It is in the "vector arithmetic" group not the "parallel arithmetic" group (which is probably the reason it isn't used just like the other vector instructions, like DP4 etc.)
Plane equation is also supported on Ironlake already (though with some restrictions more than on Sandy Bridge - in fact docs list it as CTG-B+ so should be there since some G45 version).
Likewise, LRP is listed in Ironlake manual (just like MAD it doesn't seem to be used in the linux driver for neither SNB nor IL).

btw there's a typo on the link menu says "Dedicared Hardware".