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| author | Simon Peyton Jones <simon.peytonjones@gmail.com> | 2023-01-19 08:59:18 +0000 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2023-01-23 04:53:32 -0500 |
| commit | 82884ce063180a39afed163590738f7095394583 (patch) | |
| tree | f0f78e610d9f21b1007d6ab01d5610cf646105dd /compiler/GHC/Core | |
| parent | 9a9bec5762920306656113f2a6e676adf6c65e23 (diff) | |
| download | haskell-82884ce063180a39afed163590738f7095394583.tar.gz | |
Fix #22742
runtimeRepLevity_maybe was panicing unnecessarily; and
the error printing code made use of the case when it should
return Nothing rather than panicing.
For some bizarre reason perf/compiler/T21839r shows a 10% bump in runtime
peak-megagbytes-used, on a single architecture (alpine). See !9753 for
commentary, but I'm going to accept it.
Metric Increase:
T21839r
Diffstat (limited to 'compiler/GHC/Core')
| -rw-r--r-- | compiler/GHC/Core/Type.hs | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/compiler/GHC/Core/Type.hs b/compiler/GHC/Core/Type.hs index 81b0f1e31b..9e0d95b0d9 100644 --- a/compiler/GHC/Core/Type.hs +++ b/compiler/GHC/Core/Type.hs @@ -686,8 +686,8 @@ kindBoxedRepLevity_maybe ty -- * False of type variables, type family applications, -- and of other reps such as @IntRep :: RuntimeRep@. isLiftedRuntimeRep :: RuntimeRepType -> Bool -isLiftedRuntimeRep rep = - runtimeRepLevity_maybe rep == Just Lifted +isLiftedRuntimeRep rep + = runtimeRepLevity_maybe rep == Just Lifted -- | Check whether a type of kind 'RuntimeRep' is unlifted. -- @@ -779,7 +779,8 @@ isBoxedRuntimeRep_maybe rep | otherwise = Nothing --- | Check whether a type of kind 'RuntimeRep' is lifted, unlifted, or unknown. +-- | Check whether a type (usually of kind 'RuntimeRep') is lifted, unlifted, +-- or unknown. Returns Nothing if the type isn't of kind 'RuntimeRep'. -- -- `runtimeRepLevity_maybe rr` returns: -- @@ -793,7 +794,9 @@ runtimeRepLevity_maybe rep if (rr_tc `hasKey` boxedRepDataConKey) then case args of [lev] -> levityType_maybe lev - _ -> pprPanic "runtimeRepLevity_maybe" (ppr rep) + _ -> Nothing -- Type isn't of kind RuntimeRep + -- The latter case happens via the call to isLiftedRuntimeRep + -- in GHC.Tc.Errors.Ppr.pprMisMatchMsg (#22742) else Just Unlifted -- Avoid searching all the unlifted RuntimeRep type cons -- In the RuntimeRep data type, only LiftedRep is lifted |