From fded7dd4300df8e1657b710f4deed16aa1d35ebe Mon Sep 17 00:00:00 2001
From: Sebastian Graf <sgraf1337@gmail.com>
Date: Thu, 19 Oct 2023 15:15:54 +0000
Subject: [PATCH] CorePrep: Allow floating dictionary applications in -O0 into
a Rec (#24102)
---
compiler/GHC/CoreToStg/Prep.hs | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/compiler/GHC/CoreToStg/Prep.hs b/compiler/GHC/CoreToStg/Prep.hs
index 02180b86c8b2..079fa081cfa6 100644
--- a/compiler/GHC/CoreToStg/Prep.hs
+++ b/compiler/GHC/CoreToStg/Prep.hs
@@ -643,13 +643,20 @@ cpeBind top_lvl env (Rec pairs)
where
(bndrs, rhss) = unzip pairs
- -- Flatten all the floats, and the current
- -- group into a single giant Rec
+ -- Flatten all the floats, and the current
+ -- group into a single giant Rec
add_float (Float bind bound _) prs2
- | bound /= CaseBound = case bind of
+ | bound /= CaseBound
+ || all (definitelyLiftedType . idType) (bindersOf bind)
+ -- The latter check is hit in -O0 (i.e., flavours quick, devel2)
+ -- for dictionary args which haven't been floated out yet, #24102.
+ -- They are preferably CaseBound, but since they are lifted we may
+ -- just as well put them in the Rec, in contrast to lifted bindings.
+ = case bind of
NonRec x e -> (x,e) : prs2
Rec prs1 -> prs1 ++ prs2
- add_float f _ = pprPanic "cpeBind" (ppr f)
+ add_float f _ = pprPanic "cpeBind" (ppr f)
+
---------------
cpePair :: TopLevelFlag -> RecFlag -> Demand -> Bool
--
GitLab