All that you're allowed to assume is that they're callee-saved.
Created attachment 215011 [details] the patch
Comment on attachment 215011 [details] the patch r=me. We're going to have to save these for the FTL at some point (since they're callee save).
(In reply to comment #2) > (From update of attachment 215011 [details]) > r=me. We're going to have to save these for the FTL at some point (since they're callee save). Heh. I think this small comment of yours proves that this patch is wrong.