Simon Peyton Jones pushed to branch wip/T26746 at Glasgow Haskell Compiler / GHC

Commits:

• f25e2b12
  by Cheng Shao at 2026-01-14T11:10:39-05:00

  testsuite: remove obsolete --ci option from the testsuite driver
  
  This patch removes the obsolete `--ci` option from the testsuite
  driver: neither the CI scripts nor hadrian ever invokes the testsuite
  driver with `--ci`, and the perf notes are always fetched to the
  `refs/notes/perf` local reference anyway.
  

• 7964763b
  by Julian Ospald at 2026-01-14T11:11:31-05:00

  Fix fetch_cabal
  
  * download cabal if the existing one is of an older version
  * fix FreeBSD download url
  * fix unpacking on FreeBSD
  

• 6b0129c1
  by Julian Ospald at 2026-01-14T11:11:31-05:00

  Bump toolchain in CI
  

• 0f53ccc6
  by Julian Ospald at 2026-01-14T11:11:31-05:00

  Use libffi-clib
  
  Previously, we would build libffi via hadrian
  and bundle it manually with the GHC bindist.
  
  This now moves all that logic out of hadrian
  and allows us to have a clean Haskell package
  to build and link against and ship it without
  extra logic.
  
  This patch still retains the ability to link
  against a system libffi.
  
  The main reason of bundling libffi was that on
  some platforms (e.g. FreeBSD and Mac), system libffi
  is not visible to the C toolchain by default,
  so users would require settings in e.g. cabal
  to be able to compile anything.
  
  This adds the submodule libffi-clib to the repository.
  

• 5e1cd595
  by Peng Fan at 2026-01-14T11:12:26-05:00

  NCG/LA64: add support for la664 micro architecture
  
  Add '-mla664' flag to LA664, which has some new features:
  atomic instructions, dbar hints, etc.
  
  'LA464' is the default so that unrecognized instructions are not
  generated.
  

• 2091ee71
  by Simon Peyton Jones at 2026-01-15T14:07:36+00:00

  Improve newtype unwrapping
  
  Ticket #26746 describes several relatively-minor shortcomings of newtype
  unwrapping.  This MR addresses them, while also (arguably) simplifying
  the code a bit.
  
  See new Note [Solving newtype equalities: overview]
  and     Note [Decomposing newtype equalities]
  and     Note [Eager newtype decomposition]
  and     Note [Even more eager newtype decomposition]
  
  For some reason, on Windows only, runtime allocations decrease for test
  T5205 (from 52k to 48k).  I have not idea why. No change at all on Linux.
  I'm just going to accept the change.  (I saw this same effect in another
  MR so I think it's a fault in the baseline.)
  
  Metric Decrease:
      T5205
  

48 changed files:

• .gitlab/ci.sh
• .gitlab/generate-ci/gen_ci.hs
• .gitlab/jobs.yaml
• .gitmodules
• compiler/GHC/CmmToAsm/Config.hs
• compiler/GHC/Core/FamInstEnv.hs
• compiler/GHC/Driver/Config/CmmToAsm.hs
• compiler/GHC/Driver/DynFlags.hs
• compiler/GHC/Driver/Session.hs
• compiler/GHC/Linker/Loader.hs
• compiler/GHC/Linker/Unit.hs
• compiler/GHC/Tc/Instance/Family.hs
• compiler/GHC/Tc/Solver/Equality.hs
• compiler/GHC/Tc/Solver/Monad.hs
• compiler/GHC/Unit/State.hs
• docs/users_guide/using.rst
• hadrian/hadrian.cabal
• hadrian/src/Builder.hs
• hadrian/src/Packages.hs
• hadrian/src/Rules.hs
• hadrian/src/Rules/Documentation.hs
• hadrian/src/Rules/Generate.hs
• − hadrian/src/Rules/Libffi.hs
• hadrian/src/Rules/Register.hs
• hadrian/src/Rules/Rts.hs
• hadrian/src/Rules/SourceDist.hs
• hadrian/src/Settings/Builders/Cabal.hs
• hadrian/src/Settings/Builders/Ghc.hs
• hadrian/src/Settings/Default.hs
• hadrian/src/Settings/Packages.hs
• − libffi-tarballs
• + libraries/libffi-clib
• packages
• rts/include/rts/ghc_ffi.h
• rts/rts.buildinfo.in
• rts/rts.cabal
• testsuite/driver/perf_notes.py
• testsuite/tests/deriving/should_fail/T8984.stderr
• testsuite/tests/deriving/should_fail/deriving-via-fail.stderr
• testsuite/tests/deriving/should_fail/deriving-via-fail4.stderr
• testsuite/tests/deriving/should_fail/deriving-via-fail5.stderr
• + testsuite/tests/typecheck/should_compile/T26746.hs
• testsuite/tests/typecheck/should_compile/all.T
• testsuite/tests/typecheck/should_fail/T15801.stderr
• testsuite/tests/typecheck/should_fail/T22924b.stderr
• testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs
• testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr
• testsuite/tests/typecheck/should_fail/all.T

The diff was not included because it is too large.