It was a CPS compiler, but after they drove the first creators away, a bunch of people who had no idea about compilers nor CPS started destroying it. First the destroyed the jit. The technical justification was bullshit. Then they destroyed the run loops, and finally the CPS (2007 YAPC workshop). This caused every function call to allocate 2 objects, continuation contexts were not reused anymore, but created on the fly for every call. After this desaster they gave up (their new idea was to create a 2nd LLVM, called something with m), and I came back to cleanup the mess. I readded the compiler optimizations, added proper lock-less threading (their current VM is lockful) and started fixing the CPS, the run loops, the GC and the Jit. But before that they decided to kill it off, and rewrote everything by themselves. But not as committee anymore and without the previous leadership, which was a very good decision. It's still a very naive architecture still, that's why it's even slower than python, the slowest scripting language on earth.
Realizing that this is futile, I started improving perl5 towards perl6 instead. Just without breaking backcompat. perl11 (5+6)