The DFG propagator has complete knowledge of how each node in the data flow graph is predicted. But this knowledge is lost when going to the backend. The backends try to reinfer this, but do so poorly (for example the backend has no idea how to predict a ConvertThis node, while the propagator knows exactly how to predict it).
Created attachment 109527 [details]
Comment on attachment 109527 [details]
Landed in r96562.