The MLton compiler for Standard ML has a very nice SSA representation where rather than having explicit φ functions, a transfer between blocks is represented as a tail-call with the arguments being the values of any variables that would be given φ functions in the target block in a standard SSA representation.
The modified code and .cm file are found here.
The .cm file assumes that the unaltered mlton source code is in a subdirectory named mlton-20040227
Hopefully the code will help other people hacking the MLton compiler to reuse functionality in their own compilers.