3 files changed, 27 insertions, 0 deletions
diff --git a/testsuite/tests/lib/integer/T18813.hs b/testsuite/tests/lib/integer/T18813.hs
new file mode 100644
index 0000000000..77f598fe7b
--- /dev/null
+++ b/testsuite/tests/lib/integer/T18813.hs
@@ -0,0 +1,22 @@
+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE MagicHash    #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# OPTIONS_GHC -O0 #-}
+
+import GHC.Exts
+import GHC.Num.BigNat  (bigNatCompareWord#, bigNatFromWord#)
+import GHC.Num.Integer (integerGcd)
+
+main :: IO ()
+main = do
+   let
+      x = noinline (14205695611797621937 :: Integer)
+      y = noinline (2 :: Word)
+   print (integerGcd x (toInteger y))
+   print (toInteger (gcd (fromInteger x) y :: Word))
+
+   let
+      x@(W# x#) = 1 :: Word
+      !x'       = bigNatFromWord# x#
+   print (bigNatCompareWord# x' x#)
+   print (compare x x)
diff --git a/testsuite/tests/lib/integer/T18813.stdout b/testsuite/tests/lib/integer/T18813.stdout
new file mode 100644
index 0000000000..2434292deb
--- /dev/null
+++ b/testsuite/tests/lib/integer/T18813.stdout
@@ -0,0 +1,4 @@
+1
+1
+EQ
+EQ
diff --git a/testsuite/tests/lib/integer/all.T b/testsuite/tests/lib/integer/all.T
index fc6b77f6fa..3f45423730 100644
--- a/testsuite/tests/lib/integer/all.T
+++ b/testsuite/tests/lib/integer/all.T
@@ -11,6 +11,7 @@ test('integerPowMod', [], compile_and_run, [''])
 test('integerGcdExt', [], compile_and_run, [''])
 test('integerRecipMod', [], compile_and_run, [''])
 test('bignumMatch', [], compile, [''])
+test('T18813', [], compile_and_run, [''])
 
 # skip ghci as it doesn't support unboxed tuples
 test('integerImportExport', [omit_ways(['ghci'])], compile_and_run, [''])