diff options
Diffstat (limited to 'docs/users_guide/using-optimisation.rst')
| -rw-r--r-- | docs/users_guide/using-optimisation.rst | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/docs/users_guide/using-optimisation.rst b/docs/users_guide/using-optimisation.rst index 390b179f33..ab49f08ade 100644 --- a/docs/users_guide/using-optimisation.rst +++ b/docs/users_guide/using-optimisation.rst @@ -561,8 +561,7 @@ by saying ``-fno-wombat``. them. .. ghc-flag:: -ffun-to-thunk - :shortdesc: Allow worker-wrapper to convert a function closure into a thunk - if the function does not use any of its arguments. Off by default. + :shortdesc: *(deprecated)* superseded by -ffull-laziness. :type: dynamic :reverse: -fno-fun-to-thunk :category: @@ -574,6 +573,16 @@ by saying ``-fno-wombat``. thereby perhaps creating a space leak and/or disrupting inlining. This flag allows worker/wrapper to remove *all* value lambdas. + This flag was ineffective in the presence of :ghc-flag:`-ffull-laziness`, + which would flout a thunk out of a constant worker function *even though* + :ghc-flag:`-ffun-to-thunk` was off. + + Hence use of this flag is deprecated since GHC 9.4.1 and we rather suggest + to pass ``-fno-full-laziness`` instead. That implies there's no way for + worker/wrapper to turn a function into a thunk in the presence of + ``-fno-full-laziness``. If that is inconvenient for you, please leave a + comment `on the issue tracker (#21204) <https://gitlab.haskell.org/ghc/ghc/-/issues/21204>`__. + .. ghc-flag:: -fignore-asserts :shortdesc: Ignore assertions in the source. Implied by :ghc-flag:`-O`. :type: dynamic |