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Simon Peyton Jones pushed to branch wip/T26989 at Glasgow Haskell Compiler / GHC

Commits:

72d6dc74

by aparker at 2026-04-20T20:15:44-04:00

NCG: Implement constant folding for vector simd ops (Issue #25030)

b9cab907

by sheaf at 2026-04-20T20:15:44-04:00

Mark some SIMD tests as broken on i386 optllvm

As seen in #25498, several SIMD tests are broken on i386 in the optllvm
way. This commit marks them as "expect_broken".

76528cc3

by Wolfgang Jeltsch at 2026-04-20T20:16:25-04:00

Move most of the `System.IO` implementation into `base`

This involves a rewrite of the `combine` helper function to avoid the
use of `last`, which would now be flagged as an error.

Metric Decrease:
    LinkableUsage01
    T3294
Metric Increase:
    T12227
    T12707
    T5642

04d143c0

by Luite Stegeman at 2026-04-21T14:05:33-04:00

rts: add a few missing i386 relocations in the rts linker

014087e7

by Luite Stegeman at 2026-04-21T14:05:34-04:00

CodeOutput: Fix finalizers on multiple platforms

 - ELF platforms: emit .fini_array section
 - wasm32/Darwin: emit initializer with __cxa_atexit call
 - Windows: use -Wl,--whole-archive to prevent dropping finalizer symbols
 - rts linker: fix crash/assertion failure unloading objects with finalizers

fixes #27072

915bba6f
by Simon Jakobi at 2026-04-21T14:06:16-04:00
```
Add regression test for #10531

Closes #10531.
```

86a646a6

by Andreas Klebinger at 2026-04-22T13:00:05-04:00

Revert use of generic instances for compiler time perf reasons.

Revert "Derive Semigroup/Monoid for instances believed could be derived in #25871"

This reverts commit 11a04cbb221cc404fe00d65d7c951558ede4caa9.

Revert "add Ghc.Data.Pair deriving"

This reverts commit 15d9ce449e1be8c01b89fd39bdf1e700ea7d1dce.

bc9ee1cf

by Wen Kokke at 2026-04-22T13:00:51-04:00

hadrian: Fix docs to remove static flavour

In 638f6548, the static flavour was turned into into the fully_static
flavour transformer. However, this commit did not update flavours.md.

cc9cc6d5

by Cheng Shao at 2026-04-23T09:40:46+00:00

configure: bump LlvmMaxVersion to 23

This patch bumps `LlvmMaxVersion` to 23 to support LLVM 22.x releases.

2ea7ef8e
by Cheng Shao at 2026-04-23T09:46:26+00:00
```
changelog: add llvm 22.x support
```

5574ee10

by Cheng Shao at 2026-04-24T08:24:30-04:00

compiler: avoid unused temporary `appendFS` operands

This patch fixes unused temporary `appendFS` operands in the codebase
that are retained in the `FastString` table after concatenation.
Rewrite rules are added so that if an operand is
`fsLit`/`mkFastString`, the `appendFS` application is rewritten to
append the `ShortByteString` operands first. The patch also fixes
`sconcat` behavior to align with `mconcat` for the same reason. Fixes #27205.

4ed78760

by mangoiv at 2026-04-24T08:25:13-04:00

contributing: adjust MR template to be less verbose

- MR template only shows text that is relevant for submissiong
- MR template was rewritten so it's readable from a user's and reviewer's
  perspective

Resolves #27165

Co-Authored-By: @sheaf

87db83e2

by Cheng Shao at 2026-04-24T14:37:21-04:00

ci: bump freebsd boot ghc to 9.10.3

This commit bumps freebsd boot ghc to 9.10.3 to align with other
platforms and prevent outdated boot libs in boot ghc to block the
freebsd job.

17e3a0b7

by Cheng Shao at 2026-04-24T14:37:21-04:00

compiler: improve Binary instance of Array

This patch improves the `Binary` instance of `Array`:

- We no longer allocate intermediate lists. When serializing an
  `Array`, we iterate over the elements directly; when deserializing
  it, we allocate the result `Array` and fill it in a loop.
- Now we only serialize the array bounds tuple; the length field is
  not needed.

Closes #27109.

2d30f7d3

by sheaf at 2026-04-24T14:38:23-04:00

Vendor mini-QuickCheck for testsuite

This commit extracts the vendored QuickCheck implementation from the
foundation testsuite to make it more broadly available in the GHC
testsuite, and makes use of it in the simd006 test (which also used
a vendored QuickCheck implementation).

On the way, we update the linear congruential generator to avoid the
shortcoming of only generating 31 bit large numbers.

Fixes #25990 and #25969.

1350271b

by sheaf at 2026-04-27T09:32:53-04:00

Ensure TcM plugins are only initialised once

This commit ensures we keep TcM plugins (typechecker plugins,
defaulting plugins and hole fit plugins) running all the way through
desugaring, instead of stopping them at the end of typechecking.

To do this, the "stop" actions of TcPlugin and DefaultingPlugin are
split into two: one for the "post-typecheck" action, and one for the
final shutdown action (after desugaring).

This allows the plugins to be invoked by the pattern match checker
(during desugaring) without having to be repeatedly re-initialised and
stopped, fixing #26839.

In the process, this commit modifies 'initTc' and 'initTcInteractive',
adding an extra argument that describes whether to start/stop the 'TcM'
plugins.

See Note [Stop TcM plugins after desugaring] for an overview.

42549222

by sheaf at 2026-04-27T09:33:50-04:00

Hadrian: add --keep-response-files

This commit adds a Hadrian flag that allows response files to be
retained. This is useful for debugging a failing Hadrian command line.

40564e8d

by sheaf at 2026-04-27T09:34:46-04:00

hadrian/build-cabal.bat: fix build on Windows

Commit 8cb99552f6 introduced a warning for a missing package index.
However, the logic was faulty on Windows: the piping was broken, and
"remote-repo-cache:" was being interpreted as a (malformed) drive letter,
leading to the error:

  The filename, directory name, or volume label syntax is incorrect.

This commit fixes that by using a temporary file instead of piping.

14bc71e4

by Sven Tennie at 2026-04-28T13:22:47-04:00

ghc: Distinguish between having an interpreter and having an internal one

Actually, these are related but different things:

- ghc can run an interpreter (either internal or external)
- ghc is compiled with an internal interpreter

Splitting the logic solves compiler warnings and expresses the intent
better.

df691563

by Vladislav Zavialov at 2026-04-28T13:23:29-04:00

Refactor HsWildCardTy to use HoleKind (#27111)

The payload of this patch is that the extension fields of HsWildCardTy
and HsHole now match:

	type instance XWildCardTy Ghc{Ps,Rn} = HoleKind
	type instance XHole       Ghc{Ps,Rn} = HoleKind

This is progress towards unification of HsExpr and HsType.
Test case: T25121_status

In addition to that, exact-printing of infix holes is fixed.
Test case: PprInfixHole

f3485446
by fendor at 2026-04-28T13:24:12-04:00
```
Expose startupHpc as an rts symbol
```

28f07d70

by fendor at 2026-04-28T13:24:12-04:00

Make HPC work with bytecode interpreter

Add support to generate .tix files from bytecode objects and the
bytecode interpreter.

Conceptually, we insert HPC ticks into the bytecode similar to how we insert
breakpoints.
HPC and breakpoints do not share the same tick array but we use a separate
tick-array for hpc/breakpoint ticks during bytecode generation.

We teach the bytecode interpreter to handle hpc ticks.
The implementation is quite trivial, simply increment the counter in the
global hpc_ticks array for the respective module.

This hpc_ticks array is generated as part of the `CStub`, so we can rely
on it existing.

A tricky bit is "registering" a bytecode object for HPC instrumentation.
In the compiled case, this is achieved via CStub and initializer/finalizers
`.init` sections which are called when the executable is run.
After the initializers have been invoked, which is before `hs_init_ghc`,
we then call `startup_hpc` in `hs_init_ghc` iff any modules were "registered"
for hpc instrumentation via `hs_hpc_module`.

Since bytecode objects are loaded after starting up GHCi, this workflow
doesn't work for supporting `hpc` and the `hpc` run-time is never
started, even if a module is added for instrumentation.

We fix this issue by employing the same technique as is for `SptEntry`s:

* We introduce a new field to `CompiledByteCode`, called `ByteCodeHpcInfo`
  which contains enough information to call `hs_hpc_module`, allowing us to
  register the module for `hpc` instrumentation`.
* After registering the module, we unconditionally call `startupHpc`, to make
  sure the .tix file is written.

Calling `startupHpc` multiple times is safe.
Calling `hs_hpc_module` multiple times for the same module is also safe.

If we didn't register the hpc module in this way, evaluating a bytecode object
instrumented with `-fhpc` without registering it in the `hpc` run-time will
simply not generate any `.tix` files for this bytecode object.

However, this shouldn't happen if everything is set up correctly.

Closes #27036

950879f0

by Vladislav Zavialov at 2026-04-28T13:24:55-04:00

Move NamespaceSpecifier from x-fields into the AST proper (#26678)

This refactoring moves NamespaceSpecifier out of extension fields and into the
AST proper, as it is part of the user-written source, and is not pass-specific.

Summary of changes:

* Move NamespaceSpecifier from GHC/Hs/Basic.hs to Language/Haskell/Syntax/ImpExp.hs
  and parameterise it by the compiler pass, creating the necessary extension points
* Move NamespaceSpecifier out of XFixitySig into FixitySig
* Move NamespaceSpecifier out of XIEThingAll (IEThingAllExt) into IEThingAll
* Move NamespaceSpecifier out of XIEWholeNamespace (IEWholeNamespaceExt) into IEWholeNamespace

This is a pure refactoring with no change in behaviour.

9797052b

by Simon Peyton Jones at 2026-04-28T13:25:37-04:00

Fix assertion check in checkResultTy

As #27210 shows, the assertion was a little bit too eager.

I refactored a bit by moving some code from GHC.Tc.Gen.App
to GHC.Tc.Utils.Unify; see the new function tcSubTypeApp,
which replaces tcSubTypeDS

d5bb0a03

by Simon Peyton Jones at 2026-04-29T13:18:08+01:00

Improve knownCon

Eliminate simplInVar

Just a refactoring to simplify the code

cbcbdca0
by Simon Peyton Jones at 2026-04-29T13:18:08+01:00
```
Wibbles [skip ci]
```
f9d74d99
by Simon Peyton Jones at 2026-04-29T13:18:08+01:00
```
Getting there [skip ci]
```
381a7f8d
by Simon Peyton Jones at 2026-04-29T13:18:08+01:00
```
Wibbles [skip ci]
```
6c8e22c7
by Simon Peyton Jones at 2026-04-29T13:18:09+01:00
```
More wibbles

This now works
```
40ff4c18
by Simon Peyton Jones at 2026-04-29T13:18:09+01:00
```
Wibble
```
6cd07658
by Simon Peyton Jones at 2026-04-29T13:18:09+01:00
```
Wibbles

Better management of casts
```
63512d20
by Simon Peyton Jones at 2026-04-29T13:18:09+01:00
```
Wibbles
```

25493b85