1 files changed, 20 insertions, 0 deletions
diff --git a/testsuite/tests/perf/should_run/3586.hs b/testsuite/tests/perf/should_run/3586.hs
new file mode 100644
index 0000000000..968f2eba27
--- /dev/null
+++ b/testsuite/tests/perf/should_run/3586.hs
@@ -0,0 +1,20 @@
+{-# LANGUAGE BangPatterns #-}
+{-# OPTIONS -fvia-C -optc-O3 -fexcess-precision -optc-msse3 #-}
+
+import Control.Monad.ST
+import Data.Array.ST
+import Data.Array.Base
+
+main = print $ runST
+          (do arr <- newArray (1,2000000) 137.0 :: ST s (STUArray s Int Double)
+              go arr 2000000 0.0 )
+
+
+go :: STUArray s Int Double -> Int -> Double -> ST s Double
+go !a i !acc
+    | i < 1     = return acc
+    | otherwise = do
+         b <- unsafeRead a i
+         unsafeWrite a i (b+3.0)
+         c <- unsafeRead a i
+         go a (i-1) (c+acc)