diff --git a/CHANGES.md b/CHANGES.md
index ab73fa9a6..9e8ba0982 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -15,8 +15,8 @@
   were incorrectly computed.
   ([#1773](https://github.com/GaloisInc/cryptol/issues/1773))
 
-* The reference evaluator now evaluates the `toSignedInteger` primitive instead
-  of panicking.
+* The reference evaluator now evaluates the `toSignedInteger` and `deepseq`
+  primitives instead of panicking.
 
 ## New features
 
diff --git a/src/Cryptol/Eval/Reference.lhs b/src/Cryptol/Eval/Reference.lhs
index 4ce7e99fb..d6eff26c7 100644
--- a/src/Cryptol/Eval/Reference.lhs
+++ b/src/Cryptol/Eval/Reference.lhs
@@ -247,7 +247,28 @@ Operations on Values
 >   where
 >     g (Nat n) = f n
 >     g Inf     = evalPanic "vFinPoly" ["Expected finite numeric type"]
-
+>
+> -- | Reduce a value to normal form.
+> forceValue :: Value -> E ()
+> forceValue v =
+>   case v of
+>     -- Values where the field is already is normal form
+>     VBit{}       -> pure ()
+>     VInteger{}   -> pure ()
+>     VRational{}  -> pure ()
+>     VFloat{}     -> pure ()
+>     -- Values with fields containing other values to reduce to normal form
+>     VList _ xs   -> forceValues xs
+>     VTuple xs    -> forceValues xs
+>     VRecord fs   -> forceValues $ map snd fs
+>     VEnum _ xs   -> forceValues xs
+>     -- Lambdas and other abstractions are already in normal form
+>     VFun{}       -> pure ()
+>     VPoly{}      -> pure ()
+>     VNumPoly{}   -> pure ()
+>   where
+>     forceValues :: [E Value] -> E ()
+>     forceValues = mapM_ (\x -> forceValue =<< x)
 
 Environments
 ------------
@@ -948,6 +969,13 @@ by corresponding type classes:
 >                           -- executes parmap sequentially
 >                           pure $ VList n (map f' xs')
 >
+>   , "deepseq"    ~> VPoly $ \_a -> pure $
+>                     VPoly $ \_b -> pure $
+>                     VFun $ \x -> pure $
+>                     VFun $ \y ->
+>                       do forceValue =<< x
+>                          y
+>
 >   , "error"      ~> VPoly $ \_a -> pure $
 >                     VNumPoly $ \_ -> pure $
 >                     VFun $ \s ->
diff --git a/tests/issues/issue1249.icry b/tests/issues/issue1249.icry
index e89f65c3d..46d009c6d 100644
--- a/tests/issues/issue1249.icry
+++ b/tests/issues/issue1249.icry
@@ -10,3 +10,8 @@ toSignedInteger (-1 : [64])
 :eval toSignedInteger (-1 : [64])
 toSignedInteger (-(2^^63) : [64])
 :eval toSignedInteger (-(2^^63) : [64])
+
+// deepseq
+
+deepseq ((), undefined`{()}) True
+:eval deepseq ((), undefined`{()}) True
diff --git a/tests/issues/issue1249.icry.stdout b/tests/issues/issue1249.icry.stdout
index 562bc3d33..4550eea81 100644
--- a/tests/issues/issue1249.icry.stdout
+++ b/tests/issues/issue1249.icry.stdout
@@ -9,3 +9,10 @@ Loading module Cryptol
 -1
 -9223372036854775808
 -9223372036854775808
+
+Run-time error: undefined
+-- Backtrace --
+Cryptol::error called at Cryptol:1062:13--1062:18
+Cryptol::undefined called at issue1249.icry:16:14--16:23
+Cryptol::deepseq called at issue1249.icry:16:1--16:8
+Run-time error: undefined