diff --git a/compiler/cmm/CmmExpr.hs b/compiler/cmm/CmmExpr.hs
index 6c38c0361dc03e4a056e3974b5c10064cbc83bd1..db42564171c5328c612290fa6a273556ad70daee 100644
--- a/compiler/cmm/CmmExpr.hs
+++ b/compiler/cmm/CmmExpr.hs
@@ -387,6 +387,7 @@ instance Ord GlobalReg where
    compare CurrentTSO CurrentTSO = EQ
    compare CurrentNursery CurrentNursery = EQ
    compare HpAlloc HpAlloc = EQ
+   compare EagerBlackholeInfo EagerBlackholeInfo = EQ
    compare GCEnter1 GCEnter1 = EQ
    compare GCFun GCFun = EQ
    compare BaseReg BaseReg = EQ