GitLab

6c07295a
by Andreas Klebinger at 2025-10-07T14:19:03+02:00
```
Use a predicate for joinablility
```

@@ -899,9 +899,12 @@ lintCoreExpr (Tick tickish expr)
    = do { case tickish of
             Breakpoint _ _ ids -> forM_ ids $ \id -> lintIdOcc id 0
             _                  -> return ()
 -       ; markAllJoinsBadIf block_joins $ lintCoreExpr expr }
 +       ; expr_l <- lintCoreExpr expr
 +       ; r <- markAllJoinsBadIf block_joins $ pure expr_l
 +      --  ; when block_joins
 +       ; pure r}
    where
 -    block_joins = not (tickish `tickishScopesLike` SoftScope)
 +    block_joins = not (tickishCanScopeJoin tickish)
        -- TODO Consider whether this is the correct rule. It is consistent with
        -- the simplifier's behaviour - cost-centre-scoped ticks become part of
        -- the continuation, and thus they behave like part of an evaluation

@@ -2493,7 +2493,7 @@ occAnal env (Tick tickish body)
      WUD usage body' = occAnal env body
      usage'
 -      | tickish `tickishScopesLike` SoftScope || isProfTick tickish
 +      | tickishCanScopeJoin tickish
        = usage  -- For soft-scoped ticks (including SourceNotes) we don't want
                 -- to lose join-point-hood, so we don't mess with `usage` (#24078)

@@ -15,6 +15,7 @@ module GHC.Types.Tickish (
    tickishScopesLike,
    tickishFloatable,
    tickishCanSplit,
 +  tickishCanScopeJoin,
    mkNoCount,
    mkNoScope,
    tickishIsCode,
@@ -324,6 +325,14 @@ tickishCanSplit ProfNote{profNoteScope = True, profNoteCount = True}
                     = True
  tickishCanSplit _  = False
 +-- | Is @join f x in <tick> jump f x@ valid?
 +tickishCanScopeJoin :: GenTickish pass -> Bool
 +tickishCanScopeJoin tick = case tick of
 +  ProfNote{} -> True
 +  HpcTick{} -> False
 +  Breakpoint{} -> False
 +  SourceNote{} -> True
++
  mkNoCount :: GenTickish pass -> GenTickish pass
  mkNoCount n | not (tickishCounts n)   = n
              | not (tickishCanSplit n) = panic "mkNoCount: Cannot split!"