+ occ_info = lookupVarEnv usage bndr `orElse` IAmDead
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Operations over OccInfo}
+%* *
+%************************************************************************
+
+\begin{code}
+oneOcc :: OccInfo
+oneOcc = OneOcc False True
+
+markMany, markInsideLam, markInsideSCC :: OccInfo -> OccInfo
+
+markMany IAmDead = IAmDead
+markMany other = NoOccInfo
+
+markInsideSCC occ = markMany occ
+
+markInsideLam (OneOcc _ one_br) = OneOcc True one_br
+markInsideLam occ = occ
+
+addOccInfo, orOccInfo :: OccInfo -> OccInfo -> OccInfo
+
+addOccInfo IAmDead info2 = info2
+addOccInfo info1 IAmDead = info1
+addOccInfo info1 info2 = NoOccInfo
+
+-- (orOccInfo orig new) is used
+-- when combining occurrence info from branches of a case
+
+orOccInfo IAmDead info2 = info2
+orOccInfo info1 IAmDead = info1
+orOccInfo (OneOcc in_lam1 one_branch1)
+ (OneOcc in_lam2 one_branch2)
+ = OneOcc (in_lam1 || in_lam2)
+ False -- False, because it occurs in both branches