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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2022-07-18 12:58:57 +0100 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2022-07-22 08:18:41 -0400 |
| commit | 2c5991ccaf45cb7e68e54d59a27ee144a4499edb (patch) | |
| tree | f938ee8464dad207108a131fa3bfbe45d3e94763 /compiler/GHC/Core/Subst.hs | |
| parent | 9a3e1f316598f7d5072ed4f94437f759352580a5 (diff) | |
| download | haskell-2c5991ccaf45cb7e68e54d59a27ee144a4499edb.tar.gz | |
Make the specialiser deal better with specialised methods
This patch fixes #21848, by being more careful to update unfoldings
in the type-class specialiser.
See the new Note [Update unfolding after specialisation]
Now that we are being so much more careful about unfoldings,
it turned out that I could dispense with se_interesting, and
all its tricky corners. Hooray. This fixes #21368.
Diffstat (limited to 'compiler/GHC/Core/Subst.hs')
| -rw-r--r-- | compiler/GHC/Core/Subst.hs | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/compiler/GHC/Core/Subst.hs b/compiler/GHC/Core/Subst.hs index 9f4f20591e..12a3e79559 100644 --- a/compiler/GHC/Core/Subst.hs +++ b/compiler/GHC/Core/Subst.hs @@ -494,12 +494,14 @@ It also unconditionally zaps the OccInfo. -- | Very similar to 'substBndr', but it always allocates a new 'Unique' for -- each variable in its output. It substitutes the IdInfo though. +-- Discards non-Stable unfoldings cloneIdBndr :: Subst -> UniqSupply -> Id -> (Subst, Id) cloneIdBndr subst us old_id = clone_id subst subst (old_id, uniqFromSupply us) -- | Applies 'cloneIdBndr' to a number of 'Id's, accumulating a final -- substitution from left to right +-- Discards non-Stable unfoldings cloneIdBndrs :: Subst -> UniqSupply -> [Id] -> (Subst, [Id]) cloneIdBndrs subst us ids = mapAccumL (clone_id subst) subst (ids `zip` uniqsFromSupply us) @@ -525,6 +527,7 @@ cloneRecIdBndrs subst us ids -- Just like substIdBndr, except that it always makes a new unique -- It is given the unique to use +-- Discards non-Stable unfoldings clone_id :: Subst -- Substitution for the IdInfo -> Subst -> (Id, Unique) -- Substitution and Id to transform -> (Subst, Id) -- Transformed pair @@ -602,6 +605,7 @@ substIdType subst@(Subst _ _ tv_env cv_env) id ------------------ -- | Substitute into some 'IdInfo' with regard to the supplied new 'Id'. +-- Discards unfoldings, unless they are Stable substIdInfo :: Subst -> Id -> IdInfo -> Maybe IdInfo substIdInfo subst new_id info | nothing_to_do = Nothing @@ -632,7 +636,7 @@ substUnfolding subst df@(DFunUnfolding { df_bndrs = bndrs, df_args = args }) args' = map (substExpr subst') args substUnfolding subst unf@(CoreUnfolding { uf_tmpl = tmpl, uf_src = src }) - -- Retain an InlineRule! + -- Retain stable unfoldings | not (isStableSource src) -- Zap an unstable unfolding, to save substitution work = NoUnfolding | otherwise -- But keep a stable one! |