subWordC test

subWordC.diff

diff --git a/testsuite/tests/numeric/should_run/T10962.hs b/testsuite/tests/numeric/should_run/T10962.hs
new file mode 100644
index 0000000..896c9e9
--- /dev/null
+++ b/testsuite/tests/numeric/should_run/T10962.hs
@@ -0,0 +1,16 @@
+{-# LANGUAGE MagicHash     #-}
+{-# LANGUAGE UnboxedTuples #-}
+
+module Main where
+
+import GHC.Base
+
+main :: IO ()
+main = do
+  -- Overflow.
+  let (# w1, i1 #) = subWordC# 1## 3##
+  print (W# w1, I# i1)
+
+  -- No overflow.
+  let (# w2, i2 #) = subWordC# 3## 1##
+  print (W# w2, I# i2)
diff --git a/testsuite/tests/numeric/should_run/T10962.stdout b/testsuite/tests/numeric/should_run/T10962.stdout
new file mode 100644
index 0000000..853bf94
--- /dev/null
+++ b/testsuite/tests/numeric/should_run/T10962.stdout
@@ -0,0 +1,2 @@
+(18446744073709551614,1)
+(2,0)
diff --git a/testsuite/tests/numeric/should_run/all.T b/testsuite/tests/numeric/should_run/all.T
index 27dccc7..58aa187 100644
--- a/testsuite/tests/numeric/should_run/all.T
+++ b/testsuite/tests/numeric/should_run/all.T
@@ -64,3 +64,4 @@ test('T8726', normal, compile_and_run, [''])
 test('CarryOverflow', omit_ways(['ghci']), compile_and_run, [''])
 test('T9810', normal, compile_and_run, [''])
 test('T10011', normal, compile_and_run, [''])
+test('T10962', normal, compile_and_run, [''])