[thedigitalengel]

A "false" register dependency is a Write-after-read (WAR) [1].

As far as three address code making register renaming easier, I'm not sure what the author had in mind -- isn't `add $5, %rax` essentially a condensed form of `add $5, %rax, %rax` (which is a 3AC)? In fact, 3AC is _more_ general and should make register renaming harder if anything at all.

[1] http://en.wikipedia.org/wiki/Register_renaming

[Scaevolus]

A careful compiler could avoid WARs more easily in 3AC than 2AC (by spacing reuse of registers), so an architecture without renaming could still extract ILP.

It's not a general or optimal solution, though.