Ian, I'd love a little guidance with this patch: Thu Oct 21 13:08:53 BST 2010 Ian Lynagh <igloo@earth.li> * Use takeUniqFromSupply in emitProcWithConvention We were using the supply's unique, and then passing the same supply to initUs_, which sounds like a bug waiting to happen. { hunk ./compiler/codeGen/StgCmmMonad.hs 607 - ; let (offset, entry) = mkEntry (mkBlockId $ uniqFromSupply us) conv args - blks = initUs_ us $ lgraphOfAGraph $ entry <*> blocks + ; let (uniq, us') = takeUniqFromSupply us + (offset, entry) = mkEntry (mkBlockId uniq) conv args + blks = initUs_ us' $ lgraphOfAGraph $ entry <*> blocks } The new codegen has this hunk instead: ; let (offset, entry) = mkCallEntry conv args blks = initUs_ us $ lgraphOfAGraph $ entry <*> blocks and it's not clear to me if this circumvents the previous bug or mkCallEntry needs to be modified to expose the new supply. Edward