[commit: ghc] wip/12368: DmdAnal: Testcase about splitFVs and dmdFix abortion (570120d)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/12368
Link       : http://ghc.haskell.org/trac/ghc/changeset/570120d3c99d1cf7e4e67cba39700970446fe86b/ghc

>---------------------------------------------------------------

commit 570120d3c99d1cf7e4e67cba39700970446fe86b
Author: Joachim Breitner <mail at joachim-breitner.de>
Date:   Thu Jul 21 17:44:25 2016 +0200

    DmdAnal: Testcase about splitFVs and dmdFix abortion
    
    Any variable with useful information (strict or used-once) will not be
    included in lazy_fv (according to splitFVs). If we now also remove them
    from the strictness signatures, their uses are not recorded anywhere –
    and then probably considered absent.


>---------------------------------------------------------------

570120d3c99d1cf7e4e67cba39700970446fe86b
 testsuite/tests/stranal/should_run/T12368a.hs     | 27 +++++++++++++++++++++++
 testsuite/tests/stranal/should_run/T12368a.stderr |  3 +++
 2 files changed, 30 insertions(+)

diff --git a/testsuite/tests/stranal/should_run/T12368a.hs b/testsuite/tests/stranal/should_run/T12368a.hs
new file mode 100644
index 0000000..738e8ef
--- /dev/null
+++ b/testsuite/tests/stranal/should_run/T12368a.hs
@@ -0,0 +1,27 @@
+-- Needs to be a product type
+data Stream = S Int Stream
+
+-- a is wrongly recorded abstent if the non-lazy-fv from foo are thrown away. 
+bar :: Int -> Int -> Stream -> Int
+bar a n s = foo n s
+  where
+    -- Non terminating local rec, strict in a
+    foo :: Int -> Stream -> Int
+    foo 0 (S n s) = a
+    foo i (S n s) = a `seq` n + foo (i-1) s
+{-# NOINLINE bar #-}
+
+
+baz :: Int -> Int -> Int
+baz 0 not_absent = 0
+baz 1 not_absent = baz 2 not_absent
+baz x not_absent = bar not_absent 1000 arg
+  where
+    arg = S 1 arg
+
+bamf x = baz x (error "This is good!")
+{-# NOINLINE bamf #-}
+
+
+main :: IO ()
+main = bamf 10 `seq` return ()
diff --git a/testsuite/tests/stranal/should_run/T12368a.stderr b/testsuite/tests/stranal/should_run/T12368a.stderr
new file mode 100644
index 0000000..98246d3
--- /dev/null
+++ b/testsuite/tests/stranal/should_run/T12368a.stderr
@@ -0,0 +1,3 @@
+T12368a: This is good!
+CallStack (from HasCallStack):
+  error, called at T12368a.hs:22:17 in main:Main