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<h3 style="margin-top: 20px; margin-bottom: 10px;">
sheaf pushed to branch wip/amg/dcoercion at <a href="https://gitlab.haskell.org/ghc/ghc">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/aa84cff4f68e09cc33129ce3fe1bad5aff19e5d9">aa84cff4</a></strong>
<div>
<span> by Teo Camarasu </span> <i> at 2023-05-12T19:27:23-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>rts: Ensure non-moving gc is not running when pausing
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5ad776abbb7c72d65d2ae27de5b2ec48b6e72cde">5ad776ab</a></strong>
<div>
<span> by Teo Camarasu </span> <i> at 2023-05-12T19:27:23-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>rts: Teach listAllBlocks about nonmoving heap
List all blocks on the non-moving heap.
Resolves #22627
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d683b2e5b91a39a2bf16796f5800f605a0281004">d683b2e5</a></strong>
<div>
<span> by Krzysztof Gogolewski </span> <i> at 2023-05-12T19:28:00-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Fix coercion optimisation for SelCo (#23362)
setNominalRole_maybe is supposed to output a nominal coercion.
In the SelCo case, it was not updating the stored role to Nominal,
causing #23362.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/59aa4676a49b4f9d09c1cd3cc3b47c3c54b6ed80">59aa4676</a></strong>
<div>
<span> by Alexis King </span> <i> at 2023-05-12T19:28:47-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>hadrian: Fix linker script flag for MergeObjects builder
This fixes what appears to have been a typo in !9530. The `-t` flag just
enables tracing on all versions of `ld` I’ve looked at, while `-T` is
used to specify a linker script. It seems that this worked anyway for
some reason on some `ld` implementations (perhaps because they
automatically detect linker scripts), but the missing `-T` argument
causes `gold` to complain.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4bf9fa0f216bb294c1bd3644363b008a8643a653">4bf9fa0f</a></strong>
<div>
<span> by Adam Gundry </span> <i> at 2023-05-12T23:49:49-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Less coercion optimization for non-newtype axioms
See Note [Push transitivity inside newtype axioms only] for an explanation
of the change here. This change substantially improves the performance of
coercion optimization for programs involving transitive type family reductions.
-------------------------
Metric Decrease:
CoOpt_Singletons
LargeRecord
T12227
T12545
T13386
T15703
T5030
T8095
-------------------------
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/dc0c957439c2fae14547de24ff665fc4f5db56a7">dc0c9574</a></strong>
<div>
<span> by Adam Gundry </span> <i> at 2023-05-12T23:49:49-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Move checkAxInstCo to GHC.Core.Lint
A consequence of the previous change is that checkAxInstCo is no longer
called during coercion optimization, so it can be moved back where it belongs.
Also includes some edits to Note [Conflict checking with AxiomInstCo] as
suggested by @simonpj.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8b9b7dbc913b66795c283683c7fe1fb48672666d">8b9b7dbc</a></strong>
<div>
<span> by Simon Peyton Jones </span> <i> at 2023-05-12T23:50:25-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Use the eager unifier in the constraint solver
This patch continues the refactoring of the constraint solver
described in #23070.
The Big Deal in this patch is to call the regular, eager unifier from the
constraint solver, when we want to create new equalities. This
replaces the existing, unifyWanted which amounted to
yet-another-unifier, so it reduces duplication of a rather subtle
piece of technology. See
* Note [The eager unifier] in GHC.Tc.Utils.Unify
* GHC.Tc.Solver.Monad.wrapUnifierTcS
I did lots of other refactoring along the way
* I simplified the treatment of right hand sides that contain CoercionHoles.
Now, a constraint that contains a hetero-kind CoercionHole is non-canonical,
and cannot be used for rewriting or unification alike. This required me
to add the ch_hertero_kind flag to CoercionHole, with consequent knock-on
effects. See wrinkle (2) of `Note [Equalities with incompatible kinds]` in
GHC.Tc.Solver.Equality.
* I refactored the StopOrContinue type to add StartAgain, so that after a
fundep improvement (for example) we can simply start the pipeline again.
* I got rid of the unpleasant (and inefficient) rewriterSetFromType/Co functions.
With Richard I concluded that they are never needed.
* I discovered Wrinkle (W1) in Note [Wanteds rewrite Wanteds] in
GHC.Tc.Types.Constraint, and therefore now prioritise non-rewritten equalities.
Quite a few error messages change, I think always for the better.
Compiler runtime stays about the same, with one outlier: a 17% improvement in T17836
Metric Decrease:
T17836
T18223
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5cad28e73bf9a1a535fa9ed22800156c1ba2e6c8">5cad28e7</a></strong>
<div>
<span> by Bartłomiej Cieślar </span> <i> at 2023-05-12T23:51:06-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Cleanup of dynflags override in export renaming
The deprecation warnings are normally emitted whenever the name's GRE is being looked up, which calls the GHC.Rename.Env.addUsedGRE function. We do not want those warnings to be emitted when renaming export lists, so they are artificially turned off by removing all warning categories from DynFlags at the beginning of GHC.Tc.Gen.Export.rnExports. This commit removes that dependency by unifying the function used for GRE lookup in lookup_ie to lookupGreAvailRn and disabling the call to addUsedGRE in said function (the warnings are also disabled in a call to lookupSubBndrOcc_helper in lookupChildrenExport), as per #17957. This commit also changes the setting for whether to warn about deprecated names in addUsedGREs to be an explicit enum instead of a boolean.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/efc617419c9469521908772e5cbf58fa83e7fef1">efc61741</a></strong>
<div>
<span> by Adam Gundry </span> <i> at 2023-05-13T14:59:47+02:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Directed coercions
We introduce a slimmer version of coercions, directed coercions,
which store fewer types within them. This more compact representation
considerably speeds up programs which involve many type family
reductions, as the coercion size no longer grows quadratically in
the number of reduction steps.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/fbb0665a5a0cc8089832b78c4fad2869d2dbd8ab">fbb0665a</a></strong>
<div>
<span> by sheaf </span> <i> at 2023-05-13T15:58:48+02:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>WIP: remove LHS type in Reduction
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b7db69ceb32dbb4161193e9e558b8281e0873cfb">b7db69ce</a></strong>
<div>
<span> by sheaf </span> <i> at 2023-05-13T15:59:10+02:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "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: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Fix bad multiplicity role in tyConAppFunCo_maybe
The function tyConAppFunCo_maybe produces a multiplicity coercion
for the multiplicity argument of the function arrow, except that
it could be at the wrong role if asked to produce a representational
coercion. We fix this by using the 'funRole' function, which computes
the right roles for arguments to the function arrow TyCon.
Fixes #23386
</pre>
</li>
</ul>
<h4 style="margin-top: 10px; margin-bottom: 10px;">
6 changed files:
</h4>
<ul>
<li class="file-stats">
<a href="#783e5dae6e86931f06700fc088fb7d48c8a07386">
compiler/GHC/Core/Coercion.hs
</a>
</li>
<li class="file-stats">
<a href="#b0ab2032bd0c006bb9cda1e5433173de35930f53">
compiler/GHC/Core/Coercion.hs-boot
</a>
</li>
<li class="file-stats">
<a href="#975dc08a8e7942b32d621f617d5a9c1b668601dd">
compiler/GHC/Core/Coercion/Opt.hs
</a>
</li>
<li class="file-stats">
<a href="#448d7f6e0151c2014de38dead3a902f511c45b75">
compiler/GHC/Core/FVs.hs
</a>
</li>
<li class="file-stats">
<a href="#91648438362e5a35363d2bb7abb04016dedd7d7e">
compiler/GHC/Core/FamInstEnv.hs
</a>
</li>
<li class="file-stats">
<a href="#3ea3c10abbfbf3a63640759badfe5410b80a7926">
<span class="new-file">
+
compiler/GHC/Core/FamInstEnv.hs-boot
</span>
</a>
</li>
</ul>
<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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