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-rw-r--r--compiler/basicTypes/BasicTypes.hs10
-rw-r--r--compiler/basicTypes/MkId.hs2
-rw-r--r--compiler/specialise/Rules.hs49
-rw-r--r--compiler/stranal/WorkWrap.hs4
-rw-r--r--testsuite/tests/simplCore/should_compile/T15445.hs8
-rw-r--r--testsuite/tests/simplCore/should_compile/T15445.stderr13
-rw-r--r--testsuite/tests/simplCore/should_compile/T15445a.hs10
-rw-r--r--testsuite/tests/simplCore/should_compile/all.T1
8 files changed, 87 insertions, 10 deletions
diff --git a/compiler/basicTypes/BasicTypes.hs b/compiler/basicTypes/BasicTypes.hs
index 93010b75f9..3acd5ef4db 100644
--- a/compiler/basicTypes/BasicTypes.hs
+++ b/compiler/basicTypes/BasicTypes.hs
@@ -81,6 +81,7 @@ module BasicTypes(
Activation(..), isActive, isActiveIn, competesWith,
isNeverActive, isAlwaysActive, isEarlyActive,
+ activeAfterInitial, activeDuringFinal,
RuleMatchInfo(..), isConLike, isFunLike,
InlineSpec(..), noUserInlineSpec,
@@ -1142,6 +1143,15 @@ instance Outputable CompilerPhase where
ppr (Phase n) = int n
ppr InitialPhase = text "InitialPhase"
+activeAfterInitial :: Activation
+-- Active in the first phase after the initial phase
+-- Currently we have just phases [2,1,0]
+activeAfterInitial = ActiveAfter NoSourceText 2
+
+activeDuringFinal :: Activation
+-- Active in the final simplification phase (which is repeated)
+activeDuringFinal = ActiveAfter NoSourceText 0
+
-- See note [Pragma source text]
data Activation = NeverActive
| AlwaysActive
diff --git a/compiler/basicTypes/MkId.hs b/compiler/basicTypes/MkId.hs
index 4cd20ffdc1..47fbce7458 100644
--- a/compiler/basicTypes/MkId.hs
+++ b/compiler/basicTypes/MkId.hs
@@ -594,7 +594,7 @@ mkDataConRep dflags fam_envs wrap_name mb_bangs data_con
| otherwise = topDmd
wrap_prag = alwaysInlinePragma `setInlinePragmaActivation`
- ActiveAfter NoSourceText 2
+ activeAfterInitial
-- See Note [Activation for data constructor wrappers]
-- The wrapper will usually be inlined (see wrap_unf), so its
diff --git a/compiler/specialise/Rules.hs b/compiler/specialise/Rules.hs
index 3380d02f99..850dba64cd 100644
--- a/compiler/specialise/Rules.hs
+++ b/compiler/specialise/Rules.hs
@@ -46,7 +46,8 @@ import TysWiredIn ( anyTypeOfKind )
import Coercion
import CoreTidy ( tidyRules )
import Id
-import IdInfo ( RuleInfo( RuleInfo ) )
+import IdInfo ( IdInfo( ruleInfo, inlinePragInfo )
+ , RuleInfo( RuleInfo ), setRuleInfo, setInlinePragInfo )
import Var
import VarEnv
import VarSet
@@ -55,7 +56,7 @@ import NameSet
import NameEnv
import UniqFM
import Unify ( ruleMatchTyKiX )
-import BasicTypes ( Activation, CompilerPhase, isActive, pprRuleName )
+import BasicTypes
import DynFlags ( DynFlags )
import Outputable
import FastString
@@ -290,11 +291,23 @@ addRuleInfo (RuleInfo rs1 fvs1) (RuleInfo rs2 fvs2)
= RuleInfo (rs1 ++ rs2) (fvs1 `unionDVarSet` fvs2)
addIdSpecialisations :: Id -> [CoreRule] -> Id
-addIdSpecialisations id []
- = id
+-- See Note [Adding specialisations to an Id]
addIdSpecialisations id rules
- = setIdSpecialisation id $
- extendRuleInfo (idSpecialisation id) rules
+ | null rules
+ = id
+ | otherwise
+ = modifyIdInfo (add_rules . add_activation) id
+ where
+ add_rules, add_activation :: IdInfo -> IdInfo
+ add_rules info = info `setRuleInfo` extendRuleInfo (ruleInfo info) rules
+ add_activation info
+ | AlwaysActive <- inlinePragmaActivation inl_prag
+ = info `setInlinePragInfo` inl_prag'
+ | otherwise
+ = info
+ where
+ inl_prag = inlinePragInfo info
+ inl_prag' = inl_prag `setInlinePragmaActivation` activeAfterInitial
-- | Gather all the rules for locally bound identifiers from the supplied bindings
rulesOfBinds :: [CoreBind] -> [CoreRule]
@@ -312,7 +325,29 @@ ruleIsVisible _ BuiltinRule{} = True
ruleIsVisible vis_orphs Rule { ru_orphan = orph, ru_origin = origin }
= notOrphan orph || origin `elemModuleSet` vis_orphs
-{-
+{- Note [Adding specialisations to an Id]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Suppose (Trac #15445) we have
+ f,g :: Num a => a -> a
+ f x = ...f (x-1).....
+ g y = ...g (y-1) ....
+and we make some specialisations of 'g', either automatically, or via
+a SPECIALISE pragma. Then CSE kicks in and notices that the RHSs of
+'f' and 'g' are identical, so we get
+ f x = ...f (x-1)...
+ g = f
+ {-# RULES g @Int _ = $sg #-}
+
+Now there is terrible danger that, in an importing module, we'll inline
+'g' before we have a chance to run its specialisation!
+
+This is admittedly a bit of an exotic case; but in general with RULES
+we want to delay inlining to give the rule a chance to fire. So we
+attach a NOINLINE[2] activation to it, to ensure it's not inlined
+right away. c.f. other uses of activeAfterInitial in the compiler
+e.g. Note [Wrapper activation] in WorkWrap, and
+ Note [Activation for data constructor wrappers] in MkId
+
Note [Where rules are found]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The rules for an Id come from two places:
diff --git a/compiler/stranal/WorkWrap.hs b/compiler/stranal/WorkWrap.hs
index 6289ba039a..34cfd64ecd 100644
--- a/compiler/stranal/WorkWrap.hs
+++ b/compiler/stranal/WorkWrap.hs
@@ -551,8 +551,8 @@ splitFun dflags fam_envs fn_id fn_info wrap_dmds res_info rhs
wrap_rhs = wrap_fn work_id
wrap_act = case fn_act of -- See Note [Wrapper activation]
ActiveAfter {} -> fn_act
- NeverActive -> ActiveAfter NoSourceText 0
- _ -> ActiveAfter NoSourceText 2
+ NeverActive -> activeDuringFinal
+ _ -> activeAfterInitial
wrap_prag = InlinePragma { inl_src = SourceText "{-# INLINE"
, inl_inline = NoUserInline
, inl_sat = Nothing
diff --git a/testsuite/tests/simplCore/should_compile/T15445.hs b/testsuite/tests/simplCore/should_compile/T15445.hs
new file mode 100644
index 0000000000..36bf61dbbb
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T15445.hs
@@ -0,0 +1,8 @@
+module T15445 where
+
+import T15445a
+
+
+foo :: IO ()
+foo = do { print (plusTwoRec [1..10 :: Int])
+ ; print (plusTwoRec' [1..20 :: Int]) }
diff --git a/testsuite/tests/simplCore/should_compile/T15445.stderr b/testsuite/tests/simplCore/should_compile/T15445.stderr
new file mode 100644
index 0000000000..d5deac5a59
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T15445.stderr
@@ -0,0 +1,13 @@
+Rule fired: Class op + (BUILTIN)
+Rule fired: Class op fromInteger (BUILTIN)
+Rule fired: integerToInt (BUILTIN)
+Rule fired: SPEC plusTwoRec (T15445a)
+Rule fired: SPEC $fShow[] (GHC.Show)
+Rule fired: Class op >> (BUILTIN)
+Rule fired: Class op show (BUILTIN)
+Rule fired: SPEC plusTwoRec (T15445a)
+Rule fired: Class op enumFromTo (BUILTIN)
+Rule fired: Class op show (BUILTIN)
+Rule fired: Class op enumFromTo (BUILTIN)
+Rule fired: eftIntList (GHC.Enum)
+Rule fired: eftIntList (GHC.Enum)
diff --git a/testsuite/tests/simplCore/should_compile/T15445a.hs b/testsuite/tests/simplCore/should_compile/T15445a.hs
new file mode 100644
index 0000000000..02e5baceb5
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T15445a.hs
@@ -0,0 +1,10 @@
+module T15445a where
+
+{-# SPECIALIZE plusTwoRec :: [Int] -> [Int] #-}
+plusTwoRec :: Num a => [a] -> [a]
+plusTwoRec [] = []
+plusTwoRec (x:xs) = x+2:plusTwoRec xs
+
+plusTwoRec' :: Num a => [a] -> [a]
+plusTwoRec' [] = []
+plusTwoRec' (x:xs) = x+2:plusTwoRec' xs
diff --git a/testsuite/tests/simplCore/should_compile/all.T b/testsuite/tests/simplCore/should_compile/all.T
index d4eaf196df..1275012bf4 100644
--- a/testsuite/tests/simplCore/should_compile/all.T
+++ b/testsuite/tests/simplCore/should_compile/all.T
@@ -317,3 +317,4 @@ test('T15005', normal, compile, ['-O'])
test('T15056', [extra_files(['T15056a.hs']), omit_ways(['profasm'])], multimod_compile, ['T15056', '-O -v0 -ddump-rule-firings'])
test('T15186', normal, multimod_compile, ['T15186', '-v0'])
test('T15453', normal, compile, ['-dcore-lint -O1'])
+test('T15445', normal, multimod_compile, ['T15445', '-v0 -O -ddump-rule-firings'])
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