[Git][ghc/ghc][wip/T17775] 48 commits: Remove further dead code found by a simple Python script.
Ben Gamari
gitlab at gitlab.haskell.org
Mon May 18 21:55:28 UTC 2020
Ben Gamari pushed to branch wip/T17775 at Glasgow Haskell Compiler / GHC
Commits:
6f6d72b2 by Brian Foley at 2020-05-08T15:29:25-04:00
Remove further dead code found by a simple Python script.
Avoid removing some functions that are part of an API even
though they're not used in-tree at the moment.
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78bf8bf9 by Julien Debon at 2020-05-08T15:29:28-04:00
Add doc examples for Bifoldable
See #17929
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66f0a847 by Julien Debon at 2020-05-08T15:29:29-04:00
doc (Bitraversable): Add examples to Bitraversable
* Add examples to Data.Bitraversable
* Fix formatting for (,) in Bitraversable and Bifoldable
* Fix mistake on bimapAccumR documentation
See #17929
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9749fe12 by Baldur Blöndal at 2020-05-08T15:29:32-04:00
Specify kind variables for inferred kinds in base.
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4e9aef9e by John Ericson at 2020-05-08T15:29:36-04:00
HsSigWcTypeScoping: Pull in documentation from stray location
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f4d5c6df by John Ericson at 2020-05-08T15:29:36-04:00
Rename local `real_fvs` to `implicit_vs`
It doesn't make sense to call the "free" variables we are about to
implicitly bind the real ones.
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20570b4b by John Ericson at 2020-05-08T15:29:36-04:00
A few tiny style nits with renaming
- Use case rather than guards that repeatedly scrutenize same thing.
- No need for view pattern when `L` is fine.
- Use type synnonym to convey the intent like elsewhere.
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09ac8de5 by John Ericson at 2020-05-08T15:29:36-04:00
Add `forAllOrNothing` function with note
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bb35c0e5 by Joseph C. Sible at 2020-05-08T15:29:40-04:00
Document lawlessness of Ap's Num instance
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cdd229ff by Joseph C. Sible at 2020-05-08T15:29:40-04:00
Apply suggestion to libraries/base/Data/Monoid.hs
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926d2aab by Joseph C. Sible at 2020-05-08T15:29:40-04:00
Apply more suggestions from Simon Jakobi
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7a763cff by Adam Gundry at 2020-05-08T15:29:41-04:00
Reject all duplicate declarations involving DuplicateRecordFields (fixes #17965)
This fixes a bug that resulted in some programs being accepted that used the same
identifier as a field label and another declaration, depending on the order they
appeared in the source code.
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88e3c815 by Simon Peyton Jones at 2020-05-08T15:29:41-04:00
Fix specialisation for DFuns
When specialising a DFun we must take care to saturate the
unfolding. See Note [Specialising DFuns] in Specialise.
Fixes #18120
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86c77b36 by Greg Steuck at 2020-05-08T15:29:45-04:00
Remove unused SEGMENT_PROT_RWX
It's been unused for a year and is problematic on any OS which
requires W^X for security.
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9d97f4b5 by nineonine at 2020-05-08T15:30:03-04:00
Add test for #16167
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aa318338 by Ryan Scott at 2020-05-08T15:30:04-04:00
Bump exceptions submodule so that dist-boot is .gitignore'd
`exceptions` is a stage-0 boot library as of commit
30272412fa437ab8e7a8035db94a278e10513413, which means that building
`exceptions` in a GHC tree will generate a `dist-boot` directory.
However, this directory was not specified in `exceptions`'
`.gitignore` file, which causes it to dirty up the current `git`
working directory.
Accordingly, this bumps the `exceptions` submodule to commit
ghc/packages/exceptions at 23c0b8a50d7592af37ca09beeec16b93080df98f,
which adds `dist-boot` to the `.gitignore` file.
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ea86360f by Ömer Sinan Ağacan at 2020-05-08T15:30:30-04:00
Linker.c: initialize n_symbols of ObjectCode with other fields
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951c1fb0 by Sylvain Henry at 2020-05-09T21:46:38-04:00
Fix unboxed-sums GC ptr-slot rubbish value (#17791)
This patch allows boot libraries to use unboxed sums without implicitly
depending on `base` package because of `absentSumFieldError`.
See updated Note [aBSENT_SUM_FIELD_ERROR_ID] in GHC.Core.Make
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b352d63c by Ben Gamari at 2020-05-09T21:47:14-04:00
rts: Make non-existent linker search path merely a warning
As noted in #18105, previously this resulted in a rather intrusive error
message. This is in contrast to the general expectation that search
paths are merely places to look, not places that must exist.
Fixes #18105.
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cf4f1e2f by Ben Gamari at 2020-05-13T02:02:33-04:00
rts/CNF: Fix fixup comparison function
Previously we would implicitly convert the difference between two words
to an int, resulting in an integer overflow on 64-bit machines.
Fixes #16992
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a03da9bf by Ömer Sinan Ağacan at 2020-05-13T02:03:16-04:00
Pack some of IdInfo fields into a bit field
This reduces residency of compiler quite a bit on some programs.
Example stats when building T10370:
Before:
2,871,242,832 bytes allocated in the heap
4,693,328,008 bytes copied during GC
33,941,448 bytes maximum residency (276 sample(s))
375,976 bytes maximum slop
83 MiB total memory in use (0 MB lost due to fragmentation)
After:
2,858,897,344 bytes allocated in the heap
4,629,255,440 bytes copied during GC
32,616,624 bytes maximum residency (278 sample(s))
314,400 bytes maximum slop
80 MiB total memory in use (0 MB lost due to fragmentation)
So -3.9% residency, -1.3% bytes copied and -0.4% allocations.
Fixes #17497
Metric Decrease:
T9233
T9675
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670c3e5c by Ben Gamari at 2020-05-13T02:03:54-04:00
get-win32-tarballs: Fix base URL
Revert a change previously made for testing purposes.
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8ad8dc41 by Ben Gamari at 2020-05-13T02:03:54-04:00
get-win32-tarballs: Improve diagnostics output
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8c0740b7 by Simon Jakobi at 2020-05-13T02:04:33-04:00
docs: Add examples for Data.Semigroup.Arg{Min,Max}
Context: #17153
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cb22348f by Ben Gamari at 2020-05-13T02:05:11-04:00
Add few cleanups of the CAF logic
Give the NameSet of non-CAFfy names a proper newtype to distinguish it
from all of the other NameSets floating about.
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90e38b81 by Emeka Nkurumeh at 2020-05-13T02:05:51-04:00
fix printf warning when using with ghc with clang on mingw
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86d8ac22 by Sebastian Graf at 2020-05-13T02:06:29-04:00
CprAnal: Don't attach CPR sigs to expandable bindings (#18154)
Instead, look through expandable unfoldings in `cprTransform`.
See the new Note [CPR for expandable unfoldings]:
```
Long static data structures (whether top-level or not) like
xs = x1 : xs1
xs1 = x2 : xs2
xs2 = x3 : xs3
should not get CPR signatures, because they
* Never get WW'd, so their CPR signature should be irrelevant after analysis
(in fact the signature might even be harmful for that reason)
* Would need to be inlined/expanded to see their constructed product
* Recording CPR on them blows up interface file sizes and is redundant with
their unfolding. In case of Nested CPR, this blow-up can be quadratic!
But we can't just stop giving DataCon application bindings the CPR property,
for example
fac 0 = 1
fac n = n * fac (n-1)
fac certainly has the CPR property and should be WW'd! But FloatOut will
transform the first clause to
lvl = 1
fac 0 = lvl
If lvl doesn't have the CPR property, fac won't either. But lvl doesn't have a
CPR signature to extrapolate into a CPR transformer ('cprTransform'). So
instead we keep on cprAnal'ing through *expandable* unfoldings for these arity
0 bindings via 'cprExpandUnfolding_maybe'.
In practice, GHC generates a lot of (nested) TyCon and KindRep bindings, one
for each data declaration. It's wasteful to attach CPR signatures to each of
them (and intractable in case of Nested CPR).
```
Fixes #18154.
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e34bf656 by Ben Gamari at 2020-05-13T02:07:08-04:00
users-guide: Add discussion of shared object naming
Fixes #18074.
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5d0f2445 by Ben Gamari at 2020-05-13T02:07:47-04:00
testsuite: Print sign of performance changes
Executes the minor formatting change in the tabulated performance
changes suggested in #18135.
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9e4b981f by Ben Gamari at 2020-05-13T02:08:24-04:00
testsuite: Add testcase for #18129
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266310c3 by Ivan-Yudin at 2020-05-13T02:09:03-04:00
doc: Reformulate the opening paragraph of Ch. 4 in User's guide
Removes mentioning of Hugs
(it is not helpful for new users anymore).
Changes the wording for the rest of the paragraph.
Fixes #18132.
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55e35c0b by Baldur Blöndal at 2020-05-13T20:02:48-04:00
Predicate, Equivalence derive via `.. -> a -> All'
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d7e0b57f by Alp Mestanogullari at 2020-05-13T20:03:30-04:00
hadrian: add a --freeze2 option to freeze stage 1 and 2
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d880d6b2 by Artem Pelenitsyn at 2020-05-13T20:04:11-04:00
Don't reload environment files on every setSessionDynFlags
Makes `interpretPackageEnv` (which loads envirinment files) a part of
`parseDynamicFlags` (parsing command-line arguments, which is typically
done once) instead of `setSessionDynFlags` (which is typically called
several times). Making several (transitive) calls to `interpretPackageEnv`,
as before, caused #18125 #16318, which should be fixed now.
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102cfd67 by Ryan Scott at 2020-05-13T20:04:46-04:00
Factor out HsPatSigType for pat sigs/RULE term sigs (#16762)
This implements chunks (2) and (3) of
https://gitlab.haskell.org/ghc/ghc/issues/16762#note_270170. Namely,
it introduces a dedicated `HsPatSigType` AST type, which represents
the types that can appear in pattern signatures and term-level `RULE`
binders. Previously, these were represented with `LHsSigWcType`.
Although `LHsSigWcType` is isomorphic to `HsPatSigType`, the intended
semantics of the two types are slightly different, as evidenced by
the fact that they have different code paths in the renamer and
typechecker.
See also the new `Note [Pattern signature binders and scoping]` in
`GHC.Hs.Types`.
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b17574f7 by Hécate at 2020-05-13T20:05:28-04:00
fix(documentation): Fix the RST links to GHC.Prim
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df021fb1 by Baldur Blöndal at 2020-05-13T20:06:06-04:00
Document (->) using inferred quantification for its runtime representations.
Fixes #18142.
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1a93ea57 by Takenobu Tani at 2020-05-13T20:06:54-04:00
Tweak man page for ghc command
This commit updates the ghc command's man page as followings:
* Enable `man_show_urls` to show URL addresses in the `DESCRIPTION`
section of ghc.rst, because sphinx currently removes hyperlinks
for man pages.
* Add a `SEE ALSO` section to point to the GHC homepage
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a951e1ba by Takenobu Tani at 2020-05-13T20:07:37-04:00
GHCi: Add link to the user's guide in help message
This commit adds a link to the user's guide in ghci's
`:help` message.
Newcomers could easily reach to details of ghci.
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404581ea by Jeff Happily at 2020-05-13T20:08:15-04:00
Handle single unused import
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1c999e5d by Ben Gamari at 2020-05-13T20:09:07-04:00
Ensure that printMinimalImports closes handle
Fixes #18166.
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c9f5a8f4 by Ben Gamari at 2020-05-13T20:09:51-04:00
hadrian: Tell testsuite driver about LLVM availability
This reflects the logic present in the Make build system into Hadrian.
Fixes #18167.
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c05c0659 by Simon Jakobi at 2020-05-14T03:31:21-04:00
Improve some folds over Uniq[D]FM
* Replace some non-deterministic lazy folds with
strict folds.
* Replace some O(n log n) folds in deterministic order
with O(n) non-deterministic folds.
* Replace some folds with set-operations on the underlying
IntMaps.
This reduces max residency when compiling
`nofib/spectral/simple/Main.hs` with -O0 by about 1%.
Maximum residency when compiling Cabal also seems reduced on the
order of 3-9%.
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477f13bb by Simon Jakobi at 2020-05-14T03:31:58-04:00
Use Data.IntMap.disjoint
Data.IntMap gained a dedicated `disjoint` function in containers-0.6.2.1.
This patch applies this function where appropriate in hopes of modest
compiler performance improvements.
Closes #16806.
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e9c0110c by Ben Gamari at 2020-05-14T12:25:53-04:00
IdInfo: Add reference to bitfield-packing ticket
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9bd20e83 by Sebastian Graf at 2020-05-15T10:42:09-04:00
DmdAnal: Improve handling of precise exceptions
This patch does two things: Fix possible unsoundness in what was called
the "IO hack" and implement part 2.1 of the "fixing precise exceptions"
plan in
https://gitlab.haskell.org/ghc/ghc/wikis/fixing-precise-exceptions,
which, in combination with !2956, supersedes !3014 and !2525.
**IO hack**
The "IO hack" (which is a fallback to preserve precise exceptions
semantics and thus soundness, rather than some smart thing that
increases precision) is called `exprMayThrowPreciseException` now.
I came up with two testcases exemplifying possible unsoundness (if
twisted enough) in the old approach:
- `T13380d`: Demonstrating unsoundness of the "IO hack" when resorting
to manual state token threading and direct use of primops.
More details below.
- `T13380e`: Demonstrating unsoundness of the "IO hack" when we have
Nested CPR. Not currently relevant, as we don't have Nested
CPR yet.
- `T13380f`: Demonstrating unsoundness of the "IO hack" for safe FFI
calls.
Basically, the IO hack assumed that precise exceptions can only be
thrown from a case scrutinee of type `(# State# RealWorld, _ #)`. I
couldn't come up with a program using the `IO` abstraction that violates
this assumption. But it's easy to do so via manual state token threading
and direct use of primops, see `T13380d`. Also similar code might be
generated by Nested CPR in the (hopefully not too) distant future, see
`T13380e`. Hence, we now have a more careful test in `forcesRealWorld`
that passes `T13380{d,e}` (and will hopefully be robust to Nested CPR).
**Precise exceptions**
In #13380 and #17676 we saw that we didn't preserve precise exception
semantics in demand analysis. We fixed that with minimal changes in
!2956, but that was terribly unprincipled.
That unprincipledness resulted in a loss of precision, which is tracked
by these new test cases:
- `T13380b`: Regression in dead code elimination, because !2956 was too
syntactic about `raiseIO#`
- `T13380c`: No need to apply the "IO hack" when the IO action may not
throw a precise exception (and the existing IO hack doesn't
detect that)
Fixing both issues in !3014 turned out to be too complicated and had
the potential to regress in the future. Hence we decided to only fix
`T13380b` and augment the `Divergence` lattice with a new middle-layer
element, `ExnOrDiv`, which means either `Diverges` (, throws an
imprecise exception) or throws a *precise* exception.
See the wiki page on Step 2.1 for more implementational details:
https://gitlab.haskell.org/ghc/ghc/wikis/fixing-precise-exceptions#dead-code-elimination-for-raiseio-with-isdeadenddiv-introducing-exnordiv-step-21
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568d7279 by Ben Gamari at 2020-05-15T10:42:46-04:00
GHC.Cmm.Opt: Handle MO_XX_Conv
This MachOp was introduced by 2c959a1894311e59cd2fd469c1967491c1e488f3
but a wildcard match in cmmMachOpFoldM hid the fact that it wasn't
handled. Ideally we would eliminate the match but this appears to be a
larger task.
Fixes #18141.
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ace31631 by Simon Peyton Jones at 2020-05-18T15:18:09-04:00
Simple subsumption
This patch simplifies GHC to use simple subsumption.
Ticket #17775
Implements GHC proposal #287
https://github.com/ghc-proposals/ghc-proposals/blob/master/
proposals/0287-simplify-subsumption.rst
All the motivation is described there; I will not repeat it here.
The implementation payload:
* tcSubType and friends become noticably simpler, because it no
longer uses eta-expansion when checking subsumption.
* No deeplyInstantiate or deeplySkolemise
That in turn means that some tests fail, by design; they can all
be fixed by eta expansion. There is a list of such changes below.
Implementing the patch led me into a variety of sticky corners, so
the patch includes several othe changes, some quite significant:
* I made String wired-in, so that
"foo" :: String rather than
"foo" :: [Char]
This improves error messages, and fixes #15679
* The pattern match checker relies on knowing about in-scope equality
constraints, andd adds them to the desugarer's environment using
addTyCsDs. But the co_fn in a FunBind was missed, and for some reason
simple-subsumption ends up with dictionaries there. So I added a
call to addTyCsDs. This is really part of #18049.
* I moved the ic_telescope field out of Implication and into
ForAllSkol instead. This is a nice win; just expresses the code
much better.
* There was a bug in GHC.Tc.TyCl.Instance.tcDataFamInstHeader.
We called checkDataKindSig inside tc_kind_sig, /before/
solveEqualities and zonking. Obviously wrong, easily fixed.
* solveLocalEqualitiesX: there was a whole mess in here, around
failing fast enough. I discovered a bad latent bug where we
could successfully kind-check a type signature, and use it,
but have unsolved constraints that could fill in coercion
holes in that signature -- aargh.
It's all explained in Note [Failure in local type signatures]
in GHC.Tc.Solver. Much better now.
* I fixed a serious bug in anonymous type holes. IN
f :: Int -> (forall a. a -> _) -> Int
that "_" should be a unification variable at the /outer/
level; it cannot be instantiated to 'a'. This was plain
wrong. New fields mode_lvl and mode_holes in TcTyMode,
and auxiliary data type GHC.Tc.Gen.HsType.HoleMode.
This fixes #16292, but makes no progress towards the more
ambitious #16082
* I got sucked into an enormous refactoring of the reporting of
equality errors in GHC.Tc.Errors, especially in
mkEqErr1
mkTyVarEqErr
misMatchMsg
misMatchMsgOrCND
In particular, the very tricky mkExpectedActualMsg function
is gone.
It took me a full day. But the result is far easier to understand.
(Still not easy!) This led to various minor improvements in error
output, and an enormous number of test-case error wibbles.
One particular point: for occurs-check errors I now just say
Can't match 'a' against '[a]'
rather than using the intimidating language of "occurs check".
* Pretty-printing AbsBinds
Tests review
* Eta expansions
T11305: one eta expansion
T12082: one eta expansion (undefined)
T13585a: one eta expansion
T3102: one eta expansion
T3692: two eta expansions (tricky)
T2239: two eta expansions
T16473: one eta
determ004: two eta expansions (undefined)
annfail06: two eta (undefined)
T17923: four eta expansions (a strange program indeed!)
tcrun035: one eta expansion
* Ambiguity check at higher rank. Now that we have simple
subsumption, a type like
f :: (forall a. Eq a => Int) -> Int
is no longer ambiguous, because we could write
g :: (forall a. Eq a => Int) -> Int
g = f
and it'd typecheck just fine. But f's type is a bit
suspicious, and we might want to consider making the
ambiguity check do a check on each sub-term. Meanwhile,
these tests are accepted, whereas they were previously
rejected as ambiguous:
T7220a
T15438
T10503
T9222
* Some more interesting error message wibbles
T13381: Fine: one error (Int ~ Exp Int)
rather than two (Int ~ Exp Int, Exp Int ~ Int)
T9834: Small change in error (improvement)
T10619: Improved
T2414: Small change, due to order of unification, fine
T2534: A very simple case in which a change of unification order
means we get tow unsolved constraints instead of one
tc211: bizarre impredicative tests; just accept this for now
- - - - -
30 changed files:
- compiler/GHC.hs
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/Builtin/Types.hs
- compiler/GHC/Builtin/Types/Prim.hs
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/Cmm/Info/Build.hs
- compiler/GHC/Cmm/Opt.hs
- compiler/GHC/Cmm/Utils.hs
- compiler/GHC/CmmToAsm/PPC/Cond.hs
- compiler/GHC/CmmToAsm/Reg/Graph/SpillClean.hs
- compiler/GHC/CmmToAsm/SPARC/Cond.hs
- compiler/GHC/CmmToAsm/X86/Cond.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/Core/Arity.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Make.hs
- compiler/GHC/Core/Opt/CallArity.hs
- compiler/GHC/Core/Opt/CprAnal.hs
- compiler/GHC/Core/Opt/DmdAnal.hs
- compiler/GHC/Core/Opt/FloatIn.hs
- compiler/GHC/Core/Opt/FloatOut.hs
- compiler/GHC/Core/Opt/LiberateCase.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Opt/Specialise.hs
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/2a57ffcd2e5d98ced8743403ac3f2a6df21abed3...ace3163101eec6f8b79d1c18700abb63dbc9edc9
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/2a57ffcd2e5d98ced8743403ac3f2a6df21abed3...ace3163101eec6f8b79d1c18700abb63dbc9edc9
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