diff options
Diffstat (limited to 'compiler/coreSyn/CorePrep.hs')
| -rw-r--r-- | compiler/coreSyn/CorePrep.hs | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/compiler/coreSyn/CorePrep.hs b/compiler/coreSyn/CorePrep.hs index 98bffd3777..6be5346ab5 100644 --- a/compiler/coreSyn/CorePrep.hs +++ b/compiler/coreSyn/CorePrep.hs @@ -71,7 +71,7 @@ import qualified Data.Set as S The goal of this pass is to prepare for code generation. -1. Saturate constructor and primop applications. +1. Saturate constructor applications. 2. Convert to A-normal form; that is, function arguments are always variables. @@ -1063,8 +1063,21 @@ because that has different strictness. Hence the use of 'allLazy'. -- Building the saturated syntax -- --------------------------------------------------------------------------- -maybeSaturate deals with saturating primops and constructors -The type is the type of the entire application +Note [Eta expansion of hasNoBinding things in CorePrep] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +maybeSaturate deals with eta expanding to saturate things that can't deal with +unsaturated applications (identified by 'hasNoBinding', currently just +foreign calls and unboxed tuple/sum constructors). + +Note that eta expansion in CorePrep is very fragile due to the "prediction" of +CAFfyness made by TidyPgm (see Note [CAFfyness inconsistencies due to eta +expansion in CorePrep] in TidyPgm for details. We previously saturated primop +applications here as well but due to this fragility (see #16846) we now deal +with this another way, as described in Note [Primop wrappers] in PrimOp. + +It's quite likely that eta expansion of constructor applications will +eventually break in a similar way to how primops did. We really should +eliminate this case as well. -} maybeSaturate :: Id -> CpeApp -> Int -> UniqSM CpeRhs |