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<h3 style="margin-top: 20px; margin-bottom: 10px;">
Matthew Pickering pushed to branch wip/ghc-fat-interface
at <a href="https://gitlab.haskell.org/ghc/ghc" style="color: #1068bf;">Glasgow Haskell Compiler / GHC</a>
</h3>
<h4 style="margin-top: 10px; margin-bottom: 10px;">
Commits:
</h4>
<ul>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/aeafdba5503b8d26a62dc7bc7078caef170d4154" style="color: #1068bf;">aeafdba5</a></strong>
<div>
<span>by Sebastian Graf</span>
<i>at 2022-09-27T15:14:54+02:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Demand: Clear distinction between Call SubDmd and eval Dmd (#21717)
In #21717 we saw a reportedly unsound strictness signature due to an unsound
definition of plusSubDmd on Calls. This patch contains a description and the fix
to the unsoundness as outlined in `Note [Call SubDemand vs. evaluation Demand]`.
This fix means we also get rid of the special handling of `-fpedantic-bottoms`
in eta-reduction. Thanks to less strict and actually sound strictness results,
we will no longer eta-reduce the problematic cases in the first place, even
without `-fpedantic-bottoms`.
So fixing the unsoundness also makes our eta-reduction code simpler with less
hacks to explain. But there is another, more unfortunate side-effect:
We *unfix* #21085, but fortunately we have a new fix ready:
See `Note [mkCall and plusSubDmd]`.
There's another change:
I decided to make `Note [SubDemand denotes at least one evaluation]` a lot
simpler by using `plusSubDmd` (instead of `lubPlusSubDmd`) even if both argument
demands are lazy. That leads to less precise results, but in turn rids ourselves
from the need for 4 different `OpMode`s and the complication of
`Note [Manual specialisation of lub*Dmd/plus*Dmd]`. The result is simpler code
that is in line with the paper draft on Demand Analysis.
I left the abandoned idea in `Note [Unrealised opportunity in plusDmd]` for
posterity. The fallout in terms of regressions is negligible, as the testsuite
and NoFib shows.
```
Program Allocs Instrs
--------------------------------------------------------------------------------
hidden +0.2% -0.2%
linear -0.0% -0.7%
--------------------------------------------------------------------------------
Min -0.0% -0.7%
Max +0.2% +0.0%
Geometric Mean +0.0% -0.0%
```
Fixes #21717.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9b1595c87f0c2406bb340c5e27a4a45dfcde0e2c" style="color: #1068bf;">9b1595c8</a></strong>
<div>
<span>by Ross Paterson</span>
<i>at 2022-09-27T14:12:01-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>implement proposal 106 (Define Kinds Without Promotion) (fixes #6024)
includes corresponding changes to haddock submodule
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/c2d73cb47562a86da76dae217d15f0dbd2b05b0e" style="color: #1068bf;">c2d73cb4</a></strong>
<div>
<span>by Andreas Klebinger</span>
<i>at 2022-09-28T15:07:30-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Apply some tricks to speed up core lint.
Below are the noteworthy changes and if given their impact on compiler
allocations for a type heavy module:
* Use the oneShot trick on LintM
* Use a unboxed tuple for the result of LintM: ~6% reduction
* Avoid a thunk for the result of typeKind in lintType: ~5% reduction
* lint_app: Don't allocate the error msg in the hot code path: ~4%
reduction
* lint_app: Eagerly force the in scope set: ~4%
* nonDetCmpType: Try to short cut using reallyUnsafePtrEquality#: ~2%
* lintM: Use a unboxed maybe for the `a` result: ~12%
* lint_app: make go_app tail recursive to avoid allocating the go function
as heap closure: ~7%
* expandSynTyCon_maybe: Use a specialized data type
For a less type heavy module like nofib/spectral/simple compiled with
-O -dcore-lint allocations went down by ~24% and compile time by ~9%.
-------------------------
Metric Decrease:
T1969
-------------------------
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b74b6191d7c442dffdfc9a9e2a6d476d7b3a28f2" style="color: #1068bf;">b74b6191</a></strong>
<div>
<span>by sheaf</span>
<i>at 2022-09-28T15:08:10-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>matchLocalInst: do domination analysis
When multiple Given quantified constraints match a Wanted, and there is
a quantified constraint that dominates all others, we now pick it
to solve the Wanted.
See Note [Use only the best matching quantified constraint].
For example:
[G] d1: forall a b. ( Eq a, Num b, C a b ) => D a b
[G] d2: forall a . C a Int => D a Int
[W] {w}: D a Int
When solving the Wanted, we find that both Givens match, but we pick
the second, because it has a weaker precondition, C a Int, compared
to (Eq a, Num Int, C a Int). We thus say that d2 dominates d1;
see Note [When does a quantified instance dominate another?].
This domination test is done purely in terms of superclass expansion,
in the function GHC.Tc.Solver.Interact.impliedBySCs. We don't attempt
to do a full round of constraint solving; this simple check suffices
for now.
Fixes #22216 and #22223
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2a53ac1877bbd29de432c0aca442904e9da96c4e" style="color: #1068bf;">2a53ac18</a></strong>
<div>
<span>by Simon Peyton Jones</span>
<i>at 2022-09-28T17:49:09-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Improve aggressive specialisation
This patch fixes #21286, by not unboxing dictionaries in
worker/wrapper (ever). The main payload is tiny:
* In `GHC.Core.Opt.DmdAnal.finaliseArgBoxities`, do not unbox
dictionaries in `get_dmd`. See Note [Do not unbox class dictionaries]
in that module
* I also found that imported wrappers were being fruitlessly
specialised, so I fixed that too, in canSpecImport.
See Note [Specialising imported functions] point (2).
In doing due diligence in the testsuite I fixed a number of
other things:
* Improve Note [Specialising unfoldings] in GHC.Core.Unfold.Make,
and Note [Inline specialisations] in GHC.Core.Opt.Specialise,
and remove duplication between the two. The new Note describes
how we specialise functions with an INLINABLE pragma.
And simplify the defn of `spec_unf` in `GHC.Core.Opt.Specialise.specCalls`.
* Improve Note [Worker/wrapper for INLINABLE functions] in
GHC.Core.Opt.WorkWrap.
And (critially) make an actual change which is to propagate the
user-written pragma from the original function to the wrapper; see
`mkStrWrapperInlinePrag`.
* Write new Note [Specialising imported functions] in
GHC.Core.Opt.Specialise
All this has a big effect on some compile times. This is
compiler/perf, showing only changes over 1%:
Metrics: compile_time/bytes allocated
-------------------------------------
LargeRecord(normal) -50.2% GOOD
ManyConstructors(normal) +1.0%
MultiLayerModulesTH_OneShot(normal) +2.6%
PmSeriesG(normal) -1.1%
T10547(normal) -1.2%
T11195(normal) -1.2%
T11276(normal) -1.0%
T11303b(normal) -1.6%
T11545(normal) -1.4%
T11822(normal) -1.3%
T12150(optasm) -1.0%
T12234(optasm) -1.2%
T13056(optasm) -9.3% GOOD
T13253(normal) -3.8% GOOD
T15164(normal) -3.6% GOOD
T16190(normal) -2.1%
T16577(normal) -2.8% GOOD
T16875(normal) -1.6%
T17836(normal) +2.2%
T17977b(normal) -1.0%
T18223(normal) -33.3% GOOD
T18282(normal) -3.4% GOOD
T18304(normal) -1.4%
T18698a(normal) -1.4% GOOD
T18698b(normal) -1.3% GOOD
T19695(normal) -2.5% GOOD
T5837(normal) -2.3%
T9630(normal) -33.0% GOOD
WWRec(normal) -9.7% GOOD
hard_hole_fits(normal) -2.1% GOOD
hie002(normal) +1.6%
geo. mean -2.2%
minimum -50.2%
maximum +2.6%
I diligently investigated some of the big drops.
* Caused by not doing w/w for dictionaries:
T13056, T15164, WWRec, T18223
* Caused by not fruitlessly specialising wrappers
LargeRecord, T9630
For runtimes, here is perf/should+_run:
Metrics: runtime/bytes allocated
--------------------------------
T12990(normal) -3.8%
T5205(normal) -1.3%
T9203(normal) -10.7% GOOD
haddock.Cabal(normal) +0.1%
haddock.base(normal) -1.1%
haddock.compiler(normal) -0.3%
lazy-bs-alloc(normal) -0.2%
------------------------------------------
geo. mean -0.3%
minimum -10.7%
maximum +0.1%
I did not investigate exactly what happens in T9203.
Nofib is a wash:
+-------------------------------++--+-----------+-----------+
| || | tsv (rel) | std. err. |
+===============================++==+===========+===========+
| real/anna || | -0.13% | 0.0% |
| real/fem || | +0.13% | 0.0% |
| real/fulsom || | -0.16% | 0.0% |
| real/lift || | -1.55% | 0.0% |
| real/reptile || | -0.11% | 0.0% |
| real/smallpt || | +0.51% | 0.0% |
| spectral/constraints || | +0.20% | 0.0% |
| spectral/dom-lt || | +1.80% | 0.0% |
| spectral/expert || | +0.33% | 0.0% |
+===============================++==+===========+===========+
| geom mean || | | |
+-------------------------------++--+-----------+-----------+
I spent quite some time investigating dom-lt, but it's pretty
complicated. See my note on !7847. Conclusion: it's just a delicate
inlining interaction, and we have plenty of those.
Metric Decrease:
LargeRecord
T13056
T13253
T15164
T16577
T18223
T18282
T18698a
T18698b
T19695
T9630
WWRec
hard_hole_fits
T9203
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/addeefc054b64286dfc231d394885bfdecfd261d" style="color: #1068bf;">addeefc0</a></strong>
<div>
<span>by Simon Peyton Jones</span>
<i>at 2022-09-28T17:49:09-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Refactor UnfoldingSource and IfaceUnfolding
I finally got tired of the way that IfaceUnfolding reflected
a previous structure of unfoldings, not the current one. This
MR refactors UnfoldingSource and IfaceUnfolding to be simpler
and more consistent.
It's largely just a refactor, but in UnfoldingSource (which moves
to GHC.Types.Basic, since it is now used in IfaceSyn too), I
distinguish between /user-specified/ and /system-generated/ stable
unfoldings.
data UnfoldingSource
= VanillaSrc
| StableUserSrc -- From a user-specified pragma
| StableSystemSrc -- From a system-generated unfolding
| CompulsorySrc
This has a minor effect in CSE (see the use of isisStableUserUnfolding
in GHC.Core.Opt.CSE), which I tripped over when working on
specialisation, but it seems like a Good Thing to know anyway.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/7be6f9a459b2fb0cdf7d1d26a373f7d4f89f7499" style="color: #1068bf;">7be6f9a4</a></strong>
<div>
<span>by Simon Peyton Jones</span>
<i>at 2022-09-28T17:49:09-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>INLINE/INLINEABLE pragmas in Foreign.Marshal.Array
Foreign.Marshal.Array contains many small functions, all of which are
overloaded, and which are critical for performance. Yet none of them
had pragmas, so it was a fluke whether or not they got inlined.
This patch makes them all either INLINE (small ones) or
INLINEABLE and hence specialisable (larger ones).
See Note [Specialising array operations] in that module.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b0c89dfaf9f8aeda9dd69a9583fd29150099aa27" style="color: #1068bf;">b0c89dfa</a></strong>
<div>
<span>by Jade Lovelace</span>
<i>at 2022-09-28T17:49:49-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Export OnOff from GHC.Driver.Session
I was working on fixing an issue where HLS was trying to pass its
DynFlags to HLint, but didn't pass any of the disabled language
extensions, which HLint would then assume are on because of their
default values.
Currently it's not possible to get any of the "No" flags because the
`DynFlags.extensions` field can't really be used since it is [OnOff
Extension] and OnOff is not exported.
So let's export it.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2f050687e75ffe6fbf140cacd15fd916d2997499" style="color: #1068bf;">2f050687</a></strong>
<div>
<span>by Bodigrim</span>
<i>at 2022-09-28T17:50:28-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Avoid Data.List.group; prefer Data.List.NonEmpty.group
This allows to avoid further partiality, e. g., map head . group is
replaced by map NE.head . NE.group, and there are less panic calls.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bc0020fa0871aff23d26b0116c1d4e43b8a3e9a9" style="color: #1068bf;">bc0020fa</a></strong>
<div>
<span>by M Farkas-Dyck</span>
<i>at 2022-09-28T22:51:59-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Clean up `findWiredInUnit`. In particular, avoid `head`.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/6a2eec98d9f5c3f5d735042f0d7bb65d0dbb3323" style="color: #1068bf;">6a2eec98</a></strong>
<div>
<span>by Bodigrim</span>
<i>at 2022-09-28T22:52:38-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Eliminate headFS, use unconsFS instead
A small step towards #22185 to avoid partial functions + safe implementation
of `startsWithUnderscore`.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5a535172d13b30c94766751d0bc21a494b8858ed" style="color: #1068bf;">5a535172</a></strong>
<div>
<span>by Sebastian Graf</span>
<i>at 2022-09-29T17:04:20+02:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Demand: Format Call SubDemands `Cn(sd)` as `C(n,sd)` (#22231)
Justification in #22231. Short form: In a demand like `1C1(C1(L))`
it was too easy to confuse which `1` belongs to which `C`. Now
that should be more obvious.
Fixes #22231
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/ea0083bf56b222579b586c8247031e04c80c15f1" style="color: #1068bf;">ea0083bf</a></strong>
<div>
<span>by Bryan Richter</span>
<i>at 2022-09-29T15:48:38-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Revert "ci: enable parallel compression for xz"
Combined wxth XZ_OPT=9, this blew the memory capacity of CI runners.
This reverts commit a5f9c35f5831ef5108e87813a96eac62803852ab.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f5e8f493b015df859833beac5a8e64a0f9b9d4f4" style="color: #1068bf;">f5e8f493</a></strong>
<div>
<span>by Sebastian Graf</span>
<i>at 2022-09-30T18:42:13+02:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Boxity: Don't update Boxity unless worker/wrapper follows (#21754)
A small refactoring in our Core Opt pipeline and some new functions for
transfering argument boxities from one signature to another to facilitate
`Note [Don't change boxity without worker/wrapper]`.
Fixes #21754.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4baf7b1ceaef2d4f49e81e5786a855e22ed864bf" style="color: #1068bf;">4baf7b1c</a></strong>
<div>
<span>by M Farkas-Dyck</span>
<i>at 2022-09-30T17:45:47-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Scrub various partiality involving empty lists.
Avoids some uses of `head` and `tail`, and some panics when an argument is null.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/95ead839fd39e0aa781dca9b1268b243c29ccaeb" style="color: #1068bf;">95ead839</a></strong>
<div>
<span>by Alexis King</span>
<i>at 2022-10-01T00:37:43-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Fix a bug in continuation capture across multiple stack chunks
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2209665273135644f1b52470ea2cb53169f2ef91" style="color: #1068bf;">22096652</a></strong>
<div>
<span>by Bodigrim</span>
<i>at 2022-10-01T00:38:22-04:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Enforce internal invariant of OrdList and fix bugs in viewCons / viewSnoc
`viewCons` used to ignore `Many` constructor completely, returning `VNothing`.
`viewSnoc` violated internal invariant of `Many` being a non-empty list.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/55bc9d048f80005b8e40601c2c14a1bc29d17574" style="color: #1068bf;">55bc9d04</a></strong>
<div>
<span>by Matthew Pickering</span>
<i>at 2022-10-01T18:15:41+01:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Tidy implicit binds
We want to put implicit binds into fat interface files, so the easiest
thing to do seems to be to treat them uniformly with other binders.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/45dbb86ed14d3c317837552b1fa1836ba2fe6cde" style="color: #1068bf;">45dbb86e</a></strong>
<div>
<span>by Matthew Pickering</span>
<i>at 2022-10-01T18:16:20+01:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Interface Files with Core Definitions
This commit adds three new flags
* -fwrite-if-simplified-core: Writes the whole core program into an interface
file
* -fbyte-code-and-object-code: Generate both byte code and object code
when compiling a file
* -fprefer-byte-code: Prefer to use byte-code if it's available when
running TH splices.
The goal for including the core bindings in an interface file is to be able to restart the compiler pipeline
at the point just after simplification and before code generation. Once compilation is
restarted then code can be created for the byte code backend.
This can significantly speed up
start-times for projects in GHCi. HLS already implements its own version of these extended interface
files for this reason.
Preferring to use byte-code means that we can avoid some potentially
expensive code generation steps (see #21700)
* Producing object code is much slower than producing bytecode, and normally you
need to compile with `-dynamic-too` to produce code in the static and dynamic way, the
dynamic way just for Template Haskell execution when using a dynamically linked compiler.
* Linking many large object files, which happens once per splice, can be quite
expensive compared to linking bytecode.
And you can get GHC to compile the necessary byte code so
`-fprefer-byte-code` has access to it by using
`-fbyte-code-and-object-code`.
Fixes #21067
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/813e95d3477e16b1537f8941d4e007b2339c4da4" style="color: #1068bf;">813e95d3</a></strong>
<div>
<span>by Matthew Pickering</span>
<i>at 2022-10-01T18:16:22+01:00</i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.8125rem; color: #303030; position: relative; font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; word-break: break-all; word-wrap: break-word; background-color: #fafafa; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dbdbdb;'>Teach -fno-code about -fprefer-byte-code
This patch teachs the code generation logic of -fno-code about
-fprefer-byte-code, so that if we need to generate code for a module
which prefers byte code, then we generate byte code rather than object
code.
We keep track separately which modules need object code and which byte
code and then enable the relevant code generation for each. Typically
the option will be enabled globally so one of these sets should be empty
and we will just turn on byte code or object code generation.
We also fix the bug where we would generate code for a module which
enables Template Haskell despite the fact it was unecessary.
Fixes #22016
</pre>
</li>
</ul>
<h4 style="margin-top: 10px; margin-bottom: 10px;">30 changed files:</h4>
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<a href="#157f7634c25bc6366cb7c9c9edb48e819dce38db" style="color: #1068bf;">
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compiler/GHC/Cmm/Node.hs
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compiler/GHC/Cmm/Switch.hs
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compiler/GHC/CmmToAsm.hs
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<a href="#b4cadffdafb6a1f441fede8639ba742ae903afca" style="color: #1068bf;">
compiler/GHC/CmmToAsm/Reg/Liveness.hs
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<a href="#76664ab267df4fc0bec2465efd78bf0afacfe3a7" style="color: #1068bf;">
compiler/GHC/CmmToC.hs
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compiler/GHC/CmmToLlvm.hs
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compiler/GHC/CmmToLlvm/Base.hs
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compiler/GHC/Core/Opt/DmdAnal.hs
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compiler/GHC/Core/Opt/OccurAnal.hs
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compiler/GHC/Core/Opt/Simplify/Iteration.hs
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compiler/GHC/Core/Opt/Specialise.hs
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compiler/GHC/Core/Opt/Stats.hs
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compiler/GHC/Core/Opt/WorkWrap.hs
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<a href="#11ffe98a94d798427bc600e4fcfe899407536346" style="color: #1068bf;">
compiler/GHC/Core/SimpleOpt.hs
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<a href="#846e2566b022c9a12a5978ac7934d5b019fbea5c" style="color: #1068bf;">
compiler/GHC/Core/Tidy.hs
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compiler/GHC/Core/TyCon.hs
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compiler/GHC/Core/Unfold.hs
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<h5 style="margin-top: 10px; margin-bottom: 10px; font-size: 0.875rem;">The diff was not included because it is too large.</h5>
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