DmdAnal: Annotate top-level function bindings with demands (#18894)

It's useful to annotate a non-exported top-level function like `g` in

```hs
module Lib (h) where

g :: Int -> Int -> (Int,Int)
g m 1 = (m, 0)
g m n = (2 * m, 2 `div` n)
{-# NOINLINE g #-}

h :: Int -> Int
h 1 = 0
h m
  | odd m     = snd (g m 2)
  | otherwise = uncurry (+) (g 2 m)
```

with its demand `UCU(CS(P(1P(U),SP(U))`, which tells us that whenever `g` was
called, the second component of the returned pair was evaluated strictly.

Since #18903 we do so for local functions, where we can see all calls.
For top-level functions, we can assume that all *exported* functions are
demanded according to `topDmd` and thus get sound demands for
non-exported top-level functions.

The demand on `g` is crucial information for Nested CPR, which may the
go on and unbox `g` for the second pair component. That is true even if
that pair component may diverge, as is the case for the call site `g 13
0`, which throws a div-by-zero exception.

In `T18894b`, you can even see the new demand annotation enabling us to
eta-expand a function that we wouldn't be able to eta-expand without
Call Arity.

We only track bindings of function type in order not to risk huge compile-time
regressions, see `isInterestingTopLevelFn`.

There was a CoreLint check that rejected strict demand annotations on
recursive or top-level bindings, which seems completely unjustified.
All the cases I investigated were fine, so I removed it.

Fixes #18894.

5 files changed, 643 insertions, 0 deletions

diff --git a/testsuite/tests/stranal/should_compile/T18894.hs b/testsuite/tests/stranal/should_compile/T18894.hs
new file mode 100644
index 0000000000..6b91d0e3b5
--- /dev/null
+++ b/testsuite/tests/stranal/should_compile/T18894.hs
@@ -0,0 +1,28 @@
+{-# OPTIONS_GHC -O2 -fforce-recomp #-}
+
+-- | The point of this test is that @g*@ get's a demand that says
+-- "whenever @g*@ is called, the second component of the pair is evaluated strictly".
+module T18894 (h1, h2) where
+
+g1 :: Int -> (Int,Int)
+g1 1 = (15, 0)
+g1 n = (2 * n, 2 `div` n)
+{-# NOINLINE g1 #-}
+
+h1 :: Int -> Int
+h1 1 = 0
+-- Sadly, the @g1 2@ subexpression will be floated to top-level, where we
+-- don't see the specific demand placed on it by @snd@. Tracked in #19001.
+h1 2 = snd (g1 2)
+h1 m = uncurry (+) (g1 m)
+
+g2 :: Int -> Int -> (Int,Int)
+g2 m 1 = (m, 0)
+g2 m n = (2 * m, 2 `div` n)
+{-# NOINLINE g2 #-}
+
+h2 :: Int -> Int
+h2 1 = 0
+h2 m
+  | odd m     = snd (g2 m 2)
+  | otherwise = uncurry (+) (g2 2 m)
diff --git a/testsuite/tests/stranal/should_compile/T18894.stderr b/testsuite/tests/stranal/should_compile/T18894.stderr
new file mode 100644
index 0000000000..e0efbe9272
--- /dev/null
+++ b/testsuite/tests/stranal/should_compile/T18894.stderr
@@ -0,0 +1,404 @@
+
+==================== Demand analysis ====================
+Result size of Demand analysis
+  = {terms: 177, types: 97, coercions: 0, joins: 0/0}
+
+-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Prim.Addr#
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 20 0}]
+$trModule = "main"#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Types.TrName
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+$trModule = GHC.Types.TrNameS $trModule
+
+-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Prim.Addr#
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 30 0}]
+$trModule = "T18894"#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Types.TrName
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+$trModule = GHC.Types.TrNameS $trModule
+
+-- RHS size: {terms: 3, types: 0, coercions: 0, joins: 0/0}
+T18894.$trModule :: GHC.Types.Module
+[LclIdX,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+T18894.$trModule = GHC.Types.Module $trModule $trModule
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 0#
+
+-- RHS size: {terms: 36, types: 16, coercions: 0, joins: 0/0}
+g2 [InlPrag=NOINLINE, Dmd=UCU(CS(P(1P(U),SP(U))))]
+  :: Int -> Int -> (Int, Int)
+[LclId,
+ Arity=2,
+ Str=<UP(U)><SP(SU)>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [20 20] 161 20}]
+g2
+  = \ (m [Dmd=UP(U)] :: Int) (ds [Dmd=SP(SU)] :: Int) ->
+      case ds of { GHC.Types.I# ds [Dmd=SU] ->
+      case ds of ds [Dmd=1U] {
+        __DEFAULT ->
+          (case m of { GHC.Types.I# y -> GHC.Types.I# (GHC.Prim.*# 2# y) },
+           case ds of wild {
+             __DEFAULT ->
+               case GHC.Classes.divInt# 2# wild of ww4 { __DEFAULT ->
+               GHC.Types.I# ww4
+               };
+             -1# -> GHC.Types.I# -2#;
+             0# -> case GHC.Real.divZeroError of wild [Dmd=B] { }
+           });
+        1# -> (m, lvl)
+      }
+      }
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 2#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 2#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 0#
+
+-- RHS size: {terms: 36, types: 19, coercions: 0, joins: 0/0}
+h2 :: Int -> Int
+[LclIdX,
+ Arity=1,
+ Str=<SP(MU)>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [20] 162 10}]
+h2
+  = \ (ds [Dmd=SP(MU)] :: Int) ->
+      case ds of wild [Dmd=UP(U)] { GHC.Types.I# ds [Dmd=MU] ->
+      case ds of ds {
+        __DEFAULT ->
+          case GHC.Prim.remInt# ds 2# of {
+            __DEFAULT ->
+              case g2 wild lvl of { (ds1 [Dmd=A], y [Dmd=SU]) -> y };
+            0# ->
+              case g2 lvl wild of { (x [Dmd=SP(U)], ds [Dmd=SP(U)]) ->
+              case x of { GHC.Types.I# x ->
+              case ds of { GHC.Types.I# y -> GHC.Types.I# (GHC.Prim.+# x y) }
+              }
+              }
+          };
+        1# -> lvl
+      }
+      }
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 15#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 0#
+
+-- RHS size: {terms: 3, types: 2, coercions: 0, joins: 0/0}
+lvl :: (Int, Int)
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = (lvl, lvl)
+
+-- RHS size: {terms: 30, types: 11, coercions: 0, joins: 0/0}
+g1 [InlPrag=NOINLINE, Dmd=UCU(P(UP(U),UP(U)))] :: Int -> (Int, Int)
+[LclId,
+ Arity=1,
+ Str=<SP(SU)>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [20] 141 10}]
+g1
+  = \ (ds [Dmd=SP(SU)] :: Int) ->
+      case ds of { GHC.Types.I# ds [Dmd=SU] ->
+      case ds of ds {
+        __DEFAULT ->
+          (GHC.Types.I# (GHC.Prim.*# 2# ds),
+           case ds of wild {
+             __DEFAULT ->
+               case GHC.Classes.divInt# 2# wild of ww4 { __DEFAULT ->
+               GHC.Types.I# ww4
+               };
+             -1# -> GHC.Types.I# -2#;
+             0# -> case GHC.Real.divZeroError of wild [Dmd=B] { }
+           });
+        1# -> lvl
+      }
+      }
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 0#
+
+-- RHS size: {terms: 3, types: 0, coercions: 0, joins: 0/0}
+lvl :: (Int, Int)
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=False, ConLike=False,
+         WorkFree=False, Expandable=False, Guidance=IF_ARGS [] 30 0}]
+lvl = g1 (GHC.Types.I# 2#)
+
+-- RHS size: {terms: 28, types: 18, coercions: 0, joins: 0/0}
+h1 :: Int -> Int
+[LclIdX,
+ Arity=1,
+ Str=<SP(MU)>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [20] 111 10}]
+h1
+  = \ (ds [Dmd=SP(MU)] :: Int) ->
+      case ds of wild [Dmd=1P(1U)] { GHC.Types.I# ds [Dmd=MU] ->
+      case ds of {
+        __DEFAULT ->
+          case g1 wild of { (x [Dmd=SP(U)], ds [Dmd=SP(U)]) ->
+          case x of { GHC.Types.I# x ->
+          case ds of { GHC.Types.I# y -> GHC.Types.I# (GHC.Prim.+# x y) }
+          }
+          };
+        1# -> lvl;
+        2# -> case lvl of { (ds1 [Dmd=A], y [Dmd=SU]) -> y }
+      }
+      }
+
+
+
+
+==================== Demand analysis ====================
+Result size of Demand analysis
+  = {terms: 171, types: 120, coercions: 0, joins: 0/0}
+
+-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Prim.Addr#
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 20 0}]
+$trModule = "main"#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Types.TrName
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+$trModule = GHC.Types.TrNameS $trModule
+
+-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Prim.Addr#
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 30 0}]
+$trModule = "T18894"#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Types.TrName
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+$trModule = GHC.Types.TrNameS $trModule
+
+-- RHS size: {terms: 3, types: 0, coercions: 0, joins: 0/0}
+T18894.$trModule :: GHC.Types.Module
+[LclIdX,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+T18894.$trModule = GHC.Types.Module $trModule $trModule
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 0#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# -2#
+
+-- RHS size: {terms: 32, types: 18, coercions: 0, joins: 0/0}
+$wg2 [InlPrag=NOINLINE, Dmd=UCU(CS(P(1P(U),SP(U))))]
+  :: Int -> GHC.Prim.Int# -> (# Int, Int #)
+[LclId,
+ Arity=2,
+ Str=<UP(U)><SU>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [20 30] 121 20}]
+$wg2
+  = \ (w [Dmd=UP(U)] :: Int) (ww [Dmd=SU] :: GHC.Prim.Int#) ->
+      case ww of ds {
+        __DEFAULT ->
+          (# case w of { GHC.Types.I# y -> GHC.Types.I# (GHC.Prim.*# 2# y) },
+             case ds of {
+               __DEFAULT ->
+                 case GHC.Classes.divInt# 2# ds of ww4 { __DEFAULT ->
+                 GHC.Types.I# ww4
+                 };
+               -1# -> lvl;
+               0# -> case GHC.Real.divZeroError of wild [Dmd=B] { }
+             } #);
+        1# -> (# w, lvl #)
+      }
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 2#
+
+-- RHS size: {terms: 34, types: 21, coercions: 0, joins: 0/0}
+$wh2 [InlPrag=[2], Dmd=UCU(U)] :: GHC.Prim.Int# -> Int
+[LclId,
+ Arity=1,
+ Str=<SU>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [30] 162 10}]
+$wh2
+  = \ (ww [Dmd=SU] :: GHC.Prim.Int#) ->
+      case ww of ds {
+        __DEFAULT ->
+          case GHC.Prim.remInt# ds 2# of {
+            __DEFAULT ->
+              case $wg2 (GHC.Types.I# ds) 2# of
+              { (# ww [Dmd=A], ww [Dmd=SU] #) ->
+              ww
+              };
+            0# ->
+              case $wg2 lvl ds of { (# ww [Dmd=SP(U)], ww [Dmd=SP(U)] #) ->
+              case ww of { GHC.Types.I# x ->
+              case ww of { GHC.Types.I# y -> GHC.Types.I# (GHC.Prim.+# x y) }
+              }
+              }
+          };
+        1# -> lvl
+      }
+
+-- RHS size: {terms: 6, types: 3, coercions: 0, joins: 0/0}
+h2 [InlPrag=[2]] :: Int -> Int
+[LclIdX,
+ Arity=1,
+ Str=<SP(SU)>,
+ Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True,
+         Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=False)
+         Tmpl= \ (w [Occ=Once1!] :: Int) ->
+                 case w of { GHC.Types.I# ww [Occ=Once1, Dmd=MU] -> $wh2 ww }}]
+h2
+  = \ (w [Dmd=SP(SU)] :: Int) ->
+      case w of { GHC.Types.I# ww [Dmd=SU] -> $wh2 ww }
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 15#
+
+-- RHS size: {terms: 28, types: 15, coercions: 0, joins: 0/0}
+$wg1 [InlPrag=NOINLINE, Dmd=UCU(P(UP(U),UP(U)))]
+  :: GHC.Prim.Int# -> (# Int, Int #)
+[LclId,
+ Arity=1,
+ Str=<SU>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [30] 111 20}]
+$wg1
+  = \ (ww [Dmd=SU] :: GHC.Prim.Int#) ->
+      case ww of ds {
+        __DEFAULT ->
+          (# GHC.Types.I# (GHC.Prim.*# 2# ds),
+             case ds of {
+               __DEFAULT ->
+                 case GHC.Classes.divInt# 2# ds of ww4 { __DEFAULT ->
+                 GHC.Types.I# ww4
+                 };
+               -1# -> lvl;
+               0# -> case GHC.Real.divZeroError of wild [Dmd=B] { }
+             } #);
+        1# -> (# lvl, lvl #)
+      }
+
+-- RHS size: {terms: 7, types: 9, coercions: 0, joins: 0/0}
+lvl :: (Int, Int)
+[LclId,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=False, ConLike=False,
+         WorkFree=False, Expandable=False, Guidance=IF_ARGS [] 40 10}]
+lvl = case $wg1 2# of { (# ww, ww #) -> (ww, ww) }
+
+-- RHS size: {terms: 25, types: 18, coercions: 0, joins: 0/0}
+$wh1 [InlPrag=[2], Dmd=UCU(U)] :: GHC.Prim.Int# -> Int
+[LclId,
+ Arity=1,
+ Str=<SU>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True, Guidance=IF_ARGS [50] 101 10}]
+$wh1
+  = \ (ww [Dmd=SU] :: GHC.Prim.Int#) ->
+      case ww of ds [Dmd=1U] {
+        __DEFAULT ->
+          case $wg1 ds of { (# ww [Dmd=SP(U)], ww [Dmd=SP(U)] #) ->
+          case ww of { GHC.Types.I# x ->
+          case ww of { GHC.Types.I# y -> GHC.Types.I# (GHC.Prim.+# x y) }
+          }
+          };
+        1# -> lvl;
+        2# -> case lvl of { (ds1 [Dmd=A], y [Dmd=SU]) -> y }
+      }
+
+-- RHS size: {terms: 6, types: 3, coercions: 0, joins: 0/0}
+h1 [InlPrag=[2]] :: Int -> Int
+[LclIdX,
+ Arity=1,
+ Str=<SP(SU)>,
+ Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True,
+         WorkFree=True, Expandable=True,
+         Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=False)
+         Tmpl= \ (w [Occ=Once1!] :: Int) ->
+                 case w of { GHC.Types.I# ww [Occ=Once1, Dmd=MU] -> $wh1 ww }}]
+h1
+  = \ (w [Dmd=SP(SU)] :: Int) ->
+      case w of { GHC.Types.I# ww [Dmd=SU] -> $wh1 ww }
+
+
+
diff --git a/testsuite/tests/stranal/should_compile/T18894b.hs b/testsuite/tests/stranal/should_compile/T18894b.hs
new file mode 100644
index 0000000000..e90f34e3fd
--- /dev/null
+++ b/testsuite/tests/stranal/should_compile/T18894b.hs
@@ -0,0 +1,20 @@
+{-# OPTIONS_GHC -O -fno-call-arity -fforce-recomp #-}
+
+module T18894 (f) where
+
+expensive :: Int -> (Int, Int)
+expensive n = (n+1, n+2)
+{-# NOINLINE expensive #-}
+
+-- arity 1 by itself, but not exported, thus can be eta-expanded based on usage
+eta :: Int -> Int -> Int
+eta x = if fst (expensive x) == 13
+           then \y -> x + y
+           else \y -> x * y
+{-# NOINLINE eta #-}
+
+f :: Int -> Int
+f 1 = 0
+f m
+  | odd m     = eta m 2
+  | otherwise = eta 2 m
diff --git a/testsuite/tests/stranal/should_compile/T18894b.stderr b/testsuite/tests/stranal/should_compile/T18894b.stderr
new file mode 100644
index 0000000000..d9d950769b
--- /dev/null
+++ b/testsuite/tests/stranal/should_compile/T18894b.stderr
@@ -0,0 +1,187 @@
+
+==================== Demand analysis ====================
+Result size of Demand analysis = {terms: 83, types: 40, coercions: 0, joins: 0/0}
+
+-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Prim.Addr#
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 20 0}]
+$trModule = "main"#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Types.TrName
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+$trModule = GHC.Types.TrNameS $trModule
+
+-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Prim.Addr#
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 30 0}]
+$trModule = "T18894"#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Types.TrName
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+$trModule = GHC.Types.TrNameS $trModule
+
+-- RHS size: {terms: 3, types: 0, coercions: 0, joins: 0/0}
+T18894.$trModule :: GHC.Types.Module
+[LclIdX, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+T18894.$trModule = GHC.Types.Module $trModule $trModule
+
+-- RHS size: {terms: 16, types: 7, coercions: 0, joins: 0/0}
+expensive [InlPrag=NOINLINE, Dmd=UCU(P(SP(SU),A))] :: Int -> (Int, Int)
+[LclId,
+ Arity=1,
+ Str=<UP(U)>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [40] 52 10}]
+expensive
+  = \ (n [Dmd=UP(U)] :: Int) ->
+      (case n of { GHC.Types.I# x -> GHC.Types.I# (GHC.Prim.+# x 1#) }, case n of { GHC.Types.I# x -> GHC.Types.I# (GHC.Prim.+# x 2#) })
+
+-- RHS size: {terms: 20, types: 11, coercions: 0, joins: 0/0}
+eta [InlPrag=NOINLINE, Dmd=UCU(CS(U))] :: Int -> Int -> Int
+[LclId,
+ Arity=1,
+ Str=<UP(U)>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [0] 140 120}]
+eta
+  = \ (x [Dmd=UP(U)] :: Int) ->
+      case expensive x of { (x [Dmd=SP(SU)], ds1 [Dmd=A]) ->
+      case x of { GHC.Types.I# x [Dmd=SU] ->
+      case x of {
+        __DEFAULT -> \ (y [Dmd=SP(U)] :: Int) -> GHC.Num.$fNumInt_$c* x y;
+        13# -> \ (y [Dmd=SP(U)] :: Int) -> GHC.Num.$fNumInt_$c+ x y
+      }
+      }
+      }
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 2#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 2#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 0#
+
+-- RHS size: {terms: 21, types: 5, coercions: 0, joins: 0/0}
+f :: Int -> Int
+[LclIdX,
+ Arity=1,
+ Str=<SP(MU)>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [20] 111 0}]
+f = \ (ds [Dmd=SP(MU)] :: Int) ->
+      case ds of wild [Dmd=UP(U)] { GHC.Types.I# ds [Dmd=MU] ->
+      case ds of ds {
+        __DEFAULT ->
+          case GHC.Prim.remInt# ds 2# of {
+            __DEFAULT -> eta wild lvl;
+            0# -> eta lvl wild
+          };
+        1# -> lvl
+      }
+      }
+
+
+
+
+==================== Demand analysis ====================
+Result size of Demand analysis = {terms: 85, types: 47, coercions: 0, joins: 0/0}
+
+-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Prim.Addr#
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 20 0}]
+$trModule = "main"#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Types.TrName
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+$trModule = GHC.Types.TrNameS $trModule
+
+-- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Prim.Addr#
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 30 0}]
+$trModule = "T18894"#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+$trModule :: GHC.Types.TrName
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+$trModule = GHC.Types.TrNameS $trModule
+
+-- RHS size: {terms: 3, types: 0, coercions: 0, joins: 0/0}
+T18894.$trModule :: GHC.Types.Module
+[LclIdX, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+T18894.$trModule = GHC.Types.Module $trModule $trModule
+
+-- RHS size: {terms: 16, types: 9, coercions: 0, joins: 0/0}
+$wexpensive [InlPrag=NOINLINE, Dmd=UCU(P(SP(SU),A))] :: Int -> (# Int, Int #)
+[LclId,
+ Arity=1,
+ Str=<UP(U)>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [40] 42 10}]
+$wexpensive
+  = \ (w [Dmd=UP(U)] :: Int) ->
+      (# case w of { GHC.Types.I# x -> GHC.Types.I# (GHC.Prim.+# x 1#) },
+         case w of { GHC.Types.I# x -> GHC.Types.I# (GHC.Prim.+# x 2#) } #)
+
+-- RHS size: {terms: 19, types: 12, coercions: 0, joins: 0/0}
+eta [InlPrag=NOINLINE, Dmd=UCU(CS(U))] :: Int -> Int -> Int
+[LclId,
+ Arity=2,
+ Str=<MP(U)><SP(U)>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [0 0] 120 0}]
+eta
+  = \ (x [Dmd=MP(U)] :: Int) (eta [Dmd=SP(U), OS=OneShot] :: Int) ->
+      case $wexpensive x of { (# ww [Dmd=SP(SU)], ww [Dmd=A] #) ->
+      case ww of { GHC.Types.I# x [Dmd=SU] ->
+      case x of {
+        __DEFAULT -> GHC.Num.$fNumInt_$c* x eta;
+        13# -> GHC.Num.$fNumInt_$c+ x eta
+      }
+      }
+      }
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 2#
+
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+lvl :: Int
+[LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+lvl = GHC.Types.I# 0#
+
+-- RHS size: {terms: 20, types: 3, coercions: 0, joins: 0/0}
+$wf [InlPrag=[2]] :: GHC.Prim.Int# -> Int
+[LclId,
+ Arity=1,
+ Str=<SU>,
+ Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [30] 121 0}]
+$wf
+  = \ (ww [Dmd=SU] :: GHC.Prim.Int#) ->
+      case ww of ds {
+        __DEFAULT ->
+          case GHC.Prim.remInt# ds 2# of {
+            __DEFAULT -> eta (GHC.Types.I# ds) lvl;
+            0# -> eta lvl (GHC.Types.I# ds)
+          };
+        1# -> lvl
+      }
+
+-- RHS size: {terms: 6, types: 3, coercions: 0, joins: 0/0}
+f [InlPrag=[2]] :: Int -> Int
+[LclIdX,
+ Arity=1,
+ Str=<SP(SU)>,
+ Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True,
+         Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=False)
+         Tmpl= \ (w [Occ=Once1!] :: Int) -> case w of { GHC.Types.I# ww [Occ=Once1, Dmd=MU] -> $wf ww }}]
+f = \ (w [Dmd=SP(SU)] :: Int) -> case w of { GHC.Types.I# ww [Dmd=SU] -> $wf ww }
+
+
+
diff --git a/testsuite/tests/stranal/should_compile/all.T b/testsuite/tests/stranal/should_compile/all.T
index 1262ad426e..c00d61b8c2 100644
--- a/testsuite/tests/stranal/should_compile/all.T
+++ b/testsuite/tests/stranal/should_compile/all.T
@@ -58,3 +58,7 @@ test('T18122',  [ grep_errmsg(r'wfoo =') ], compile, ['-ddump-simpl'])
 
 # We care about the call demand on $wg
 test('T18903',  [ grep_errmsg(r'Dmd=\S+C\S+') ], compile, ['-ddump-simpl -dsuppress-uniques'])
+# We care about the call demand on $wg1 and $wg2
+test('T18894',  [ grep_errmsg(r'Dmd=\S+C\S+') ], compile, ['-ddump-stranal -dsuppress-uniques'])
+# We care about the Arity 2 on eta, as a result of the annotated Dmd
+test('T18894b',  [ grep_errmsg(r'Arity=2') ], compile, ['-ddump-stranal -dsuppress-uniques -fno-call-arity -dppr-cols=200'])