diff options
| author | Matthew Pickering <matthewtpickering@gmail.com> | 2021-02-23 17:45:51 +0000 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2021-04-05 20:38:42 -0400 |
| commit | 89acbf356b1e1c09cb1cd123f56ab5f3ad6d0634 (patch) | |
| tree | 504d265101deef310d8f3999446baa29750ffbe4 | |
| parent | 9c9adbd0ffe6ecc37d3a565811d8e79f24383943 (diff) | |
| download | haskell-89acbf356b1e1c09cb1cd123f56ab5f3ad6d0634.tar.gz | |
Add special case to stripStgTicksTop for []
In the common case where the list of ticks is empty, building a thunk
just applies 'reverse' to '[]' which is quite wasteful.
| -rw-r--r-- | compiler/GHC/Stg/Syntax.hs | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/compiler/GHC/Stg/Syntax.hs b/compiler/GHC/Stg/Syntax.hs index 972efc5f44..abbf4131d7 100644 --- a/compiler/GHC/Stg/Syntax.hs +++ b/compiler/GHC/Stg/Syntax.hs @@ -180,6 +180,8 @@ stgArgType (StgLitArg lit) = literalType lit stripStgTicksTop :: (StgTickish -> Bool) -> GenStgExpr p -> ([StgTickish], GenStgExpr p) stripStgTicksTop p = go [] where go ts (StgTick t e) | p t = go (t:ts) e + -- This special case avoid building a thunk for "reverse ts" when there are no ticks + go [] other = ([], other) go ts other = (reverse ts, other) -- | Strip ticks of a given type from an STG expression returning only the expression. |