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| author | Ömer Sinan Ağacan <omeragacan@gmail.com> | 2018-10-10 10:07:05 +0300 |
|---|---|---|
| committer | Ömer Sinan Ağacan <omeragacan@gmail.com> | 2018-10-10 10:07:21 +0300 |
| commit | ac977688523e5d77eb6f041f043552410b0c21da (patch) | |
| tree | d77cb46adac639d002489f7c2432852a9a506a22 /libraries/base | |
| parent | d728c3c578cc9e9205def2c1e96934487b364b7b (diff) | |
| download | haskell-ac977688523e5d77eb6f041f043552410b0c21da.tar.gz | |
Fix dataToTag# argument evaluation
See #15696 for more details. We now always enter dataToTag# argument (done in
generated Cmm, in StgCmmExpr). Any high-level optimisations on dataToTag#
applications are done by the simplifier. Looking at tag bits (instead of
reading the info table) for small types is left to another diff.
Incorrect test T14626 is removed. We no longer do this optimisation (see
comment:44, comment:45, comment:60).
Comments and notes about special cases around dataToTag# are removed. We no
longer have any special cases around it in Core.
Other changes related to evaluating primops (seq# and dataToTag#) will be
pursued in follow-up diffs.
Test Plan: Validates with three regression tests
Reviewers: simonpj, simonmar, hvr, bgamari, dfeuer
Reviewed By: simonmar
Subscribers: rwbarton, carter
GHC Trac Issues: #15696
Differential Revision: https://phabricator.haskell.org/D5201
Diffstat (limited to 'libraries/base')
| -rw-r--r-- | libraries/base/GHC/Base.hs | 11 |
1 files changed, 1 insertions, 10 deletions
diff --git a/libraries/base/GHC/Base.hs b/libraries/base/GHC/Base.hs index 1c927405ce..d1f87e1d62 100644 --- a/libraries/base/GHC/Base.hs +++ b/libraries/base/GHC/Base.hs @@ -1388,19 +1388,10 @@ unIO (IO a) = a {- | Returns the tag of a constructor application; this function is used by the deriving code for Eq, Ord and Enum. - -The primitive dataToTag# requires an evaluated constructor application -as its argument, so we provide getTag as a wrapper that performs the -evaluation before calling dataToTag#. We could have dataToTag# -evaluate its argument, but we prefer to do it this way because (a) -dataToTag# can be an inline primop if it doesn't need to do any -evaluation, and (b) we want to expose the evaluation to the -simplifier, because it might be possible to eliminate the evaluation -in the case when the argument is already known to be evaluated. -} {-# INLINE getTag #-} getTag :: a -> Int# -getTag !x = dataToTag# x +getTag x = dataToTag# x ---------------------------------------------- -- Numeric primops |