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| author | Andreas Klebinger <klebinger.andreas@gmx.at> | 2021-05-10 15:47:12 +0200 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2021-05-11 16:59:17 -0400 |
| commit | 5daf1aa9dd5c03ec782c72f06b4704e31d92ec32 (patch) | |
| tree | a72cb6eacae0d9d5fae7996440c4e5fa75b7732b | |
| parent | 099183437c9a181c93502026216ab8eea81db520 (diff) | |
| download | haskell-5daf1aa9dd5c03ec782c72f06b4704e31d92ec32.tar.gz | |
Document unfolding treatment of simplLamBndr.
Fixes #19817
| -rw-r--r-- | compiler/GHC/Core/Opt/Simplify.hs | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/compiler/GHC/Core/Opt/Simplify.hs b/compiler/GHC/Core/Opt/Simplify.hs index dfbfd30e64..3d1a8ce3aa 100644 --- a/compiler/GHC/Core/Opt/Simplify.hs +++ b/compiler/GHC/Core/Opt/Simplify.hs @@ -1554,9 +1554,11 @@ simplLamBndr :: SimplEnv -> InBndr -> SimplM (SimplEnv, OutBndr) -- Used for lambda binders. These sometimes have unfoldings added by -- the worker/wrapper pass that must be preserved, because they can't -- be reconstructed from context. For example: --- f x = case x of (a,b) -> fw a b x --- fw a b x{=(a,b)} = ... --- The "{=(a,b)}" is an unfolding we can't reconstruct otherwise. +-- f x = case x of StrictPair a b -> fw a b x +-- fw a{=OtherCon[]} b{=OtherCon[]} x{=(StrictPair a b)} = ... +-- The "{=(StrictPair a b)}" is an unfolding we can't reconstruct otherwise. +-- Since simplBinder already retains OtherCon bindings we only have to special +-- case core unfoldings like the one for `x`. simplLamBndr env bndr | isId bndr && hasCoreUnfolding old_unf -- Special case = do { (env1, bndr1) <- simplBinder env bndr |