diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/users_guide/8.12.1-notes.rst | 15 | ||||
| -rw-r--r-- | docs/users_guide/using-optimisation.rst | 13 |
2 files changed, 24 insertions, 4 deletions
diff --git a/docs/users_guide/8.12.1-notes.rst b/docs/users_guide/8.12.1-notes.rst index 46a729af70..9fabc47310 100644 --- a/docs/users_guide/8.12.1-notes.rst +++ b/docs/users_guide/8.12.1-notes.rst @@ -10,7 +10,14 @@ following sections. Highlights ---------- -- TODO +* NCG + + - The linear register allocator saw improvements reducing the number + of redundant move instructions. Rare edge cases can see double + digit improvements in runtime for inner loops. + + In the mean this improved runtime by about 0.8%. For details + see ticket #17823. Full details ------------ @@ -155,11 +162,11 @@ Arrow notation ``hsGroupTopLevelFixitySigs`` function, which collects all top-level fixity signatures, including those for class methods defined inside classes. -- The ``Exception`` module was boiled down acknowledging the existence of +- The ``Exception`` module was boiled down acknowledging the existence of the ``exceptions`` dependency. In particular, the ``ExceptionMonad`` class is not a proper class anymore, but a mere synonym for ``MonadThrow``, - ``MonadCatch``, ``MonadMask`` (all from ``exceptions``) and ``MonadIO``. - All of ``g*``-functions from the module (``gtry``, ``gcatch``, etc.) are + ``MonadCatch``, ``MonadMask`` (all from ``exceptions``) and ``MonadIO``. + All of ``g*``-functions from the module (``gtry``, ``gcatch``, etc.) are erased, and their ``exceptions``-alternatives are meant to be used in the GHC code instead. diff --git a/docs/users_guide/using-optimisation.rst b/docs/users_guide/using-optimisation.rst index 4ca47524a7..8ec19cb147 100644 --- a/docs/users_guide/using-optimisation.rst +++ b/docs/users_guide/using-optimisation.rst @@ -214,6 +214,19 @@ by saying ``-fno-wombat``. to their usage sites. It also inlines simple expressions like literals or registers. +.. ghc-flag:: -fcmm-static-pred + :shortdesc: Enable static control flow prediction. Implied by :ghc-flag:`-O`. + :type: dynamic + :reverse: -fno-cmm-static-pred + :category: + + :default: off but enabled with :ghc-flag:`-O`. + + This enables static control flow prediction on the final Cmm + code. If enabled GHC will apply certain heuristics to identify + loops and hot code paths. This information is then used by the + register allocation and code layout passes. + .. ghc-flag:: -fasm-shortcutting :shortdesc: Enable shortcutting on assembly. Implied by :ghc-flag:`-O2`. :type: dynamic |