Andreas Klebinger pushed to branch wip/andreask/arm-ffi at Glasgow Haskell Compiler / GHC Commits: 3ec9e2b9 by Mike Pilgrem at 2026-07-31T08:21:33-04:00 GHC Guide: Improve docs on response files - - - - - e5b2a1f7 by sheaf at 2026-07-31T08:22:23-04:00 Disable Core Lint for TcPlugin_RewritePerf This is a compiler performance test, but the test source hard-coded -dcore-lint, defeating the measurement. ------------------------- Metric Decrease: TcPlugin_RewritePerf ------------------------- - - - - - 85b10c00 by Alan Zimmerman at 2026-07-31T22:09:47+01:00 EPA: Remove LocatedP from OverlapMode We have type LocatedP = GenLocated SrcSpanAnnP type SrcSpanAnnP = EpAnn AnnPragma As the first step in removing this in favour of LocatedA which only captures location, comments and trailing annotations, we remove it from OverlapMode We do this by moving the AnnPragma into the TTG extension point instead. - - - - - c9a34a00 by Viktor Dukhovni at 2026-08-02T04:34:17-04:00 Fix note typo - - - - - 4f2a21f7 by Andreas Klebinger at 2026-08-02T22:46:46-04:00 Apply oneShot Monad trick to STG LintM - - - - - 21e4b89d by Andreas Klebinger at 2026-08-02T22:46:46-04:00 stgLint: Use a single reader env for read only arguments. - - - - - d415f38a by Alan Zimmerman at 2026-08-02T22:47:27-04:00 EPA: Remove LocatedP from CType The next step of removing use of LocatedP by moving the AnnPragma for CType into its TTG extension point instead. - - - - - 8fc6f882 by Simon Jakobi at 2026-08-05T14:53:41-04:00 testsuite: Don't crash on non-UTF-8 test output read_stdout, read_stderr_for, read_comp_stderr and read_diff decoded strictly (the first three with UTF-8, read_diff with the locale encoding), so a test emitting invalid UTF-8 (binary output, or a crash truncating a multi-byte character) raised UnicodeDecodeError and was reported as a framework failure instead of its actual result. Decode with errors='replace', like read_no_crs and safe_print. Assisted-by: Claude Fable 5 - - - - - 56534866 by Simon Jakobi at 2026-08-05T14:53:41-04:00 testsuite: Colorize the test summary, also in CI The summary headings were plain, and SUMMARY was colored unconditionally, so the escapes also ended up in the file written by --summary-file. Color is now decided per output sink via term_color.colored_if; see the comments in term_color. CI logs are not a tty, but GitLab's log viewer renders ANSI colors, so add --force-colors and pass it in .gitlab/ci.sh. Assisted-by: Claude Opus 5 - - - - - bceb541a by Simon Jakobi at 2026-08-05T14:53:42-04:00 testsuite: Repeat unexpected failure output in the summary Finding out why a test failed meant scrolling back through a possibly very long log to the point where the test ran. The summary now repeats the captured output of unexpected failures, before the statistics, so the most interesting part is at the end of the log (#16720). Output mismatches report their diff instead of the mismatching stream (see Note [Redundant output in test results]). The repeated output is bounded per stream, and skipped altogether beyond MAX_SUMMARY_OUTPUT_TESTS failure blocks. Tests failing identically in several ways share one block. Test results now report a source-relative directory, stable regardless of where the run was started from. Assisted-by: Claude Fable 5 - - - - - 2ab02c57 by Ben Gamari at 2026-08-05T14:54:24-04:00 base: Don't drop exception context in SomeException(toException) For reasons that are lost to time, the implementation of [CLC #200] that was merged inappropriately dropped `ExceptionContext` in the `toException` implementation given to `SomeException`. Fix this infelicity. [CLC #200]: https://github.com/haskell/core-libraries-committee/issues/200 - - - - - 126ce574 by Vladislav Zavialov at 2026-08-05T14:55:05-04:00 Test case for #20902 Starting with GHC 9.14.1 (the first major release to include 51e3ec83), and from point releases GHC 9.10.2 and GHC 9.12.3 (backports cc4470be68 and b30f25591e), all examples in this ticket are handled as expected. - - - - - b14d8d59 by Alan Zimmerman at 2026-08-05T14:55:46-04:00 EPA: Remove LocatedP, last use in WarningTxt The last step of removing LocatedP, by moving the AnnPragma for WarningTxt into its TTG extension point instead. This also allows us to remove LocatedP and SrcSpanAnnP - - - - - 70b58c8f by Vladislav Zavialov at 2026-08-05T14:56:27-04:00 Test cases for #18725 Starting with GHC 9.4 (the first release to include 268efcc9a4), the program in this ticket no longer panics. A standalone kind signature breaks the recursive loop, so the type constructor can be used in a kind within its own group. T18725a checks that this is accepted with the signature present, while T18725b confirms it is still rejected without it. - - - - - b18c8dd5 by Zubin Duggal at 2026-08-06T15:51:01-04:00 hie files: Dump the type table when dumping with -ddump-hie - - - - - f839d0fb by Zubin Duggal at 2026-08-06T15:51:01-04:00 hie files: Take evidence for quantified constraints into account when saving evidence terms to the hie ast Fixes #25709 - - - - - 5753ebaa by Simon Jakobi at 2026-08-06T15:51:43-04:00 testsuite: fix stale paths for the ghc-config build artifacts ghc-config.hs moved from testsuite/mk/ to testsuite/ghc-config/ in 6c7a49139c, but the .gitignore entry and the clean rule still referred to the old location. As a result the compiled ghc-config binary, which boilerplate.mk rebuilds on every make-driven test run, showed up as an untracked file and was never cleaned. Assisted-by: Claude Opus 5 - - - - - 246d4d72 by Simon Peyton Jones at 2026-08-06T15:52:25-04:00 Documentation only ...driven by my investigation of #27591 - - - - - be69e9df by Alan Zimmerman at 2026-08-06T15:53:05-04:00 EPA: Replace AnnPragma with individual types We introduced AnnPragma as a common type for all pragma usages wrapped in LocatedP / SrcSpanAnnP. Now that those are gone, and the AnnPragma moved into the TTG points for the given items, we can ensure that each carries only the annotations it needs. So we remove AnnPragma, and in its place bring in AnnCType AnnWarningTxt AnnOverlap AnnAnnDecl AnnPragSCC - - - - - 0779e12c by Simon Jakobi at 2026-08-07T12:36:11-04:00 Cmm: print unreachable blocks under -dppr-debug (#27368) Unreachable blocks linger in a CmmGraph's block map for most of the Cmm pipeline, but pprCmmGraph only ever printed the blocks reachable from the entry, so dumps looked consistent while the graph was not. Issues like #27368 were hard to debug due to this. pprCmmGraph now appends the stored-but-unreachable blocks under a "// unreachable blocks:" heading when -dppr-debug is on. See Note [unreachable blocks] in GHC.Cmm.Pipeline. Assisted-by: Claude Opus 5 - - - - - 3a0f9a51 by Simon Peyton Jones at 2026-08-07T12:36:54-04:00 Fix three bugs related to required type args and INLINE pragmas * `GHC.Core.Opt.Arity.mkEtaForAllMCo` got the visibility flags back to front, leading to a Lint error (#27557) * The arity in an InlineSaturation is the VisArity not the Arity; the two can differ when we have "required" type arguments. This made the INLINE pragma argument counting go wrong in `makeCorePair` (#27590). * When a simple binding has a type signature, we take special path in `tcPolyCheck`, leading to an outer `AbsBinds` that has no dictionaries, even when the binding is in fact overloaded. That confused the inline-arity computation in `makeCorePair` (#27589). The latter two are fixed using the new function `GHC.HsToCore.Binds.findSatArity`. That actually simplifies the API of `makeCorePair`, which is nice. The first bug is fixed by swapping the visiblity flags in `GHC.Core.Opt.Arity.mkEtaForAllMCo` Getting the INLINE behaviour right led to some perf changes: * Runtime /halved/ on T7954 due to better specialisation * Compile time increased by 6% in T21839c because a bit more inlining happened, as it always should have done. * For some reason compile-time max-bytes-used dropped by 30% on T27336, but only on one build configuration; and it increased on LinkableUsage02 by 6% on another configuration Geometric mean effect on our compile time benchmarks is +0.1%. Metric Decrease: T27336 T7954 Metric Increase: LinkableUsage02 T21839c - - - - - 4f985108 by Vladislav Zavialov at 2026-08-07T17:49:50-04:00 Discard type arguments in tcPatToExpr (#27440, #27583) The builder expression of an implicitly bidirectional pattern synonym must not mention types written in the RHS: * Invisible type arguments led to a panic (#27440) * Required type arguments failed with out-of-scope variables (#27583) Both are now discarded, following the precedent established by pattern signatures (#9867). Discarding type arguments takes some care: a type pattern cannot be told from a value pattern by syntax alone, as the `type` keyword may be omitted. Consider: data T a b c where MkT :: forall a. forall b c -> a -> T a b c pattern P :: x -> T x y z pattern P x = MkT @a (type b) c x In P's right-hand side, `@a` and `type b` are clearly type arguments, but what about `c` and `x`? We can only tell by matching the patterns against MkT's type. So tcPatToExpr now runs in TcM and matches the arguments against the constructor's TyVarBinders using zipPatsBndrs, which is made public for this purpose. The resulting builder is $bP x = MkT _ _ x. See Note [Discarding types in the builder expression]. Test cases: T27440a T27440b T27440c T27440d T27440e T27583a T27583b T27583c T27583d T27583e T27583f T27583g Metric Increase: LinkableUsage02 Metric Decrease: T27336 Assisted-by: Claude Opus 5 - - - - - eb1dcd4d by sheaf at 2026-08-07T17:50:40-04:00 mkWpFun_FRR: fix ordering of coercion composition When the subsumption machinery generates an eta-expansion, we must perform a representation polymorphism check to ensure the lambda binder it introduces has a fixed runtime representation. This is done in GHC.Tc.Utils.mkWpFun_FRR. This check involves composing quite a few coercions, arising from representation-polymorphism checks on both the actual and expected argument types. These coercions are then chained using HsWrapper composition, <.>. The ordering of composition was incorrect, leading to the Core Lint failure reported in #27639. This commit fixes that. Fixes #27639 - - - - - 3a552476 by Simon Jakobi at 2026-08-09T15:20:06-04:00 Word64Map: add compareSize compareSize m c compares the size of a map to an Int, but unlike compare (size m) c it stops traversing the map once the outcome is determined. Based on https://github.com/haskell/containers/pull/1139 Assisted-by: Claude Opus 5 - - - - - 6e2c99d8 by Simon Jakobi at 2026-08-09T15:20:06-04:00 Use a pigeonhole sort for deterministic UniqDFM iteration Deterministic UniqDFM iteration used a list mergesort, allocating O(n log n) cons cells and contributing significantly to compiler allocations (#27459). Use a pigeonhole sort where appropriate, while retaining the mergesort fallback. See Note [Sorting a UDFM] and Note [Cost of deterministic iteration]. The peak_megabytes_allocated increase for LinkableUsage02 is probably due to GC timing noise. See #27613. ------------------------- Metric Decrease: InstanceMatching InstanceMatching1 ManyAlternatives T12707 T13379 T13719 T24471 T27336 T5321FD T5321Fun T783 Metric Increase 'peak_megabytes_allocated': LinkableUsage02 ------------------------- Assisted-by: gpt-5.6-sol via Codex CLI - - - - - a938ab12 by sheaf at 2026-08-09T15:20:48-04:00 Testsuite: don't measure max residency for T27336 We really care more about total allocations for this test, so this commit removes the maximum residency measurement. - - - - - 7d94bb78 by Alan Zimmerman at 2026-08-09T15:21:29-04:00 EPA: Remove LocatedE, replace with LocatedA This gets rid of one more LocatedXXX occurrence - - - - - bc728684 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 cmm: Add machop width info with -dppr-debug for infix ops. - - - - - ce8abee4 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 Add test for #27430. - - - - - 1fc0b7a4 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 arm64 ncg: Fix subword handling of ffi calls. Our invariants require us to clear the high bits for subword results. We now do so both for unspecified bit casts (MO_CONV_XX) and when taking in results from ffi calls. I also renamed truncateReg to make it clear it changes the register. - - - - - 71d5f285 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 Fix truncateReg - - - - - 843f9321 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 CmmLint: Check for unsupported MachOp widths - - - - - 959bcbd8 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 Add tests - - - - - 685b94c7 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 arm64 ncg: Fix truncation/extension logic for genCondJump. We used to sign-extend the comparison registers in place which could clobber local variables. - - - - - 7b0176fe by Andreas Klebinger at 2026-08-10T15:53:19+00:00 Add test for #27533 In the ticket we observed a single-byte read being implemented as multi-byte read causing issues. - - - - - 9bb8c7b2 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 Added an assert for correct widths to arm64 backend - - - - - 0cfb5b82 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 arm64 ncg: Fix MO_V_Broadcast for non-literals. We now use OpReg instead of OpScalarAsVec as required since we broadcast a gp register. Also adds a test. Fixes #27533. - - - - - 16d2c078 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 cmmLint: Check address width to be equal to wordWidth. - - - - - 63723279 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 arm64 ncg: Fix subword store/load instructions. We used to read those at 32bit width even for smaller values possibly resulting in invalid memory access. Now we construct the suffix for subword variants based on the instruction format for these. - - - - - 60a08944 by Andreas Klebinger at 2026-08-10T15:53:19+00:00 cmm parser: Add comment about allowed conditionals. - - - - - 2f1e60e0 by Andreas Klebinger at 2026-08-10T15:53:20+00:00 cmm: Expand size annotations to more operators with -dppr-debug - - - - - 8f2aab66 by Andreas Klebinger at 2026-08-13T13:21:52+00:00 arm ncg: Improve bitmask immediates being too large. We used to produce invalid assembly if literls were too large, now we truncate based on the target width correctly. Note that bitmasks are still broken for non-W64 widths. This will be fixed in a future commit. - - - - - aa9a53fb by Andreas Klebinger at 2026-08-13T13:23:20+00:00 Fix testsuite/tests/codeGen/should_run/T27430_c.c - - - - - 9245b039 by Andreas Klebinger at 2026-08-13T13:23:21+00:00 arm ncg: Improve subword truncation handling: We now use a small set of helpers to truncate `Register` values rather than truncating immediate `Reg` values which greatly simplifies the code structure. This fixes a great many bugs to do with sign/zero extending subwords or the lack thereof. We now establish the invariant that subword values are zero-extended at every site at which they come into "scope" of the ncg, and rely on the invariant throughout rather than pessimistically inserting redundant extensions in a hodgepodge manner at the use sites of these values. This fixes at least the bugs described in issues #27533, #27430 #27537, #27538, #27539, and #27550. But likely more bugs yet not found. - - - - - 151 changed files: - .gitlab/ci.sh - + changelog.d/T27368-ppr-unreachable-cmm-blocks.md - + changelog.d/T27440 - + changelog.d/T27455 - + changelog.d/T27557 - + changelog.d/T27583 - + changelog.d/T27589 - + changelog.d/T27639 - + changelog.d/arm_ncg_fixes_T27430 - compiler/GHC/Builtin/Utils.hs - compiler/GHC/Cmm.hs - compiler/GHC/Cmm/Expr.hs - compiler/GHC/Cmm/Lint.hs - compiler/GHC/Cmm/MachOp.hs - compiler/GHC/Cmm/Parser.y - compiler/GHC/Cmm/Pipeline.hs - compiler/GHC/CmmToAsm/AArch64/CodeGen.hs - compiler/GHC/CmmToAsm/AArch64/Instr.hs - compiler/GHC/CmmToAsm/AArch64/Ppr.hs - compiler/GHC/Core/Class.hs - compiler/GHC/Core/Opt/Arity.hs - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Data/Word64Map/Internal.hs - compiler/GHC/Data/Word64Map/Lazy.hs - compiler/GHC/Data/Word64Map/Strict.hs - compiler/GHC/Data/Word64Map/Strict/Internal.hs - compiler/GHC/Driver/Main/Passes.hs - compiler/GHC/Hs/Decls.hs - compiler/GHC/Hs/Decls/Overlap.hs - compiler/GHC/Hs/Dump.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/Pat.hs - compiler/GHC/Hs/Utils.hs - compiler/GHC/HsToCore/Binds.hs - compiler/GHC/HsToCore/Match.hs - compiler/GHC/HsToCore/Ticks.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Iface/Ext/Types.hs - compiler/GHC/Iface/Syntax.hs - compiler/GHC/Iface/Warnings.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Annotation.hs - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Rename/HsType.hs - compiler/GHC/Rename/Pat.hs - compiler/GHC/Stg/Lint.hs - compiler/GHC/Tc/Deriv.hs - compiler/GHC/Tc/Gen/Bind.hs - compiler/GHC/Tc/Gen/Pat.hs - compiler/GHC/Tc/Gen/Sig.hs - compiler/GHC/Tc/TyCl/Instance.hs - compiler/GHC/Tc/TyCl/PatSyn.hs - compiler/GHC/Tc/Utils/Instantiate.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/ThToHs.hs - compiler/GHC/Types/Arity.hs - compiler/GHC/Types/ForeignCall.hs - compiler/GHC/Types/Id/Make.hs - compiler/GHC/Types/InlinePragma.hs - compiler/GHC/Types/Unique/DFM.hs - compiler/GHC/Types/Var.hs - compiler/GHC/Unit/Module/Warnings.hs - docs/users_guide/debugging.rst - docs/users_guide/using.rst - libraries/base/changelog.md - libraries/base/tests/perf/ElemFusionUnknownList_O1.stderr - libraries/base/tests/perf/ElemFusionUnknownList_O2.stderr - libraries/ghc-internal/src/GHC/Internal/Exception/Type.hs - libraries/ghc-internal/src/GHC/Internal/Ix.hs - testsuite/.gitignore - testsuite/Makefile - testsuite/driver/runtests.py - testsuite/driver/term_color.py - testsuite/driver/testlib.py - testsuite/tests/cmm/should_compile/Makefile - + testsuite/tests/cmm/should_compile/T27368-ppr-debug.cmm - + testsuite/tests/cmm/should_compile/T27368-ppr-debug.stdout - testsuite/tests/cmm/should_compile/all.T - + testsuite/tests/codeGen/should_run/T27430.hs - + testsuite/tests/codeGen/should_run/T27430.stdout - + testsuite/tests/codeGen/should_run/T27430_c.c - + testsuite/tests/codeGen/should_run/T27533.hs - + testsuite/tests/codeGen/should_run/T27533.stdout - + testsuite/tests/codeGen/should_run/T27533_cmm.cmm - + testsuite/tests/codeGen/should_run/T27537.hs - + testsuite/tests/codeGen/should_run/T27537.stdout - + testsuite/tests/codeGen/should_run/T27538.hs - + testsuite/tests/codeGen/should_run/T27538.stdout - testsuite/tests/codeGen/should_run/all.T - testsuite/tests/ghc-api/exactprint/T22919.stderr - testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr - testsuite/tests/ghc-e/should_fail/T18441fail7.stderr - testsuite/tests/ghc-e/should_run/ghc-e005.stderr - testsuite/tests/hiefile/should_compile/T24493.stderr - + testsuite/tests/hiefile/should_run/T25709.hs - + testsuite/tests/hiefile/should_run/T25709.stdout - testsuite/tests/hiefile/should_run/all.T - testsuite/tests/module/mod185.stderr - testsuite/tests/parser/should_compile/DumpParsedAst.stderr - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpRenamedAst.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/parser/should_compile/DumpTypecheckedAst.stderr - testsuite/tests/parser/should_compile/KindSigs.stderr - testsuite/tests/parser/should_compile/T20718.stderr - testsuite/tests/parser/should_compile/T20846.stderr - + testsuite/tests/patsyn/should_compile/T27440a.hs - + testsuite/tests/patsyn/should_compile/T27440b.hs - + testsuite/tests/patsyn/should_compile/T27440c.hs - testsuite/tests/patsyn/should_compile/all.T - + testsuite/tests/patsyn/should_fail/T27440d.hs - + testsuite/tests/patsyn/should_fail/T27440d.stderr - testsuite/tests/patsyn/should_fail/all.T - testsuite/tests/perf/compiler/all.T - testsuite/tests/printer/Test20297.stdout - testsuite/tests/printer/Test24533.stdout - + testsuite/tests/rep-poly/T27639.hs - testsuite/tests/rep-poly/all.T - + testsuite/tests/saks/should_compile/T18725a.hs - testsuite/tests/saks/should_compile/all.T - + testsuite/tests/saks/should_fail/T18725b.hs - + testsuite/tests/saks/should_fail/T18725b.stderr - testsuite/tests/saks/should_fail/all.T - + testsuite/tests/simd/should_run/T27565.hs - + testsuite/tests/simd/should_run/T27565.stdout - testsuite/tests/simd/should_run/all.T - + testsuite/tests/simplCore/should_compile/T27589.hs - + testsuite/tests/simplCore/should_compile/T27589.stderr - + testsuite/tests/simplCore/should_compile/T27590.hs - + testsuite/tests/simplCore/should_compile/T27590.stderr - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/tcplugins/TcPlugin_RewritePerf.hs - testsuite/tests/tcplugins/TcPlugin_RewritePerf.stderr - + testsuite/tests/th/T20902.hs - testsuite/tests/th/all.T - + testsuite/tests/typecheck/should_compile/T27557.hs - testsuite/tests/typecheck/should_compile/all.T - + testsuite/tests/vdq-rta/should_compile/T27583a.hs - + testsuite/tests/vdq-rta/should_compile/T27583b.hs - + testsuite/tests/vdq-rta/should_compile/T27583c.hs - + testsuite/tests/vdq-rta/should_compile/T27583d.hs - + testsuite/tests/vdq-rta/should_compile/T27583e.hs - + testsuite/tests/vdq-rta/should_compile/T27583g.hs - testsuite/tests/vdq-rta/should_compile/all.T - + testsuite/tests/vdq-rta/should_fail/T27440e.hs - + testsuite/tests/vdq-rta/should_fail/T27440e.stderr - + testsuite/tests/vdq-rta/should_fail/T27583f.hs - + testsuite/tests/vdq-rta/should_fail/T27583f.stderr - testsuite/tests/vdq-rta/should_fail/all.T - utils/check-exact/ExactPrint.hs - utils/haddock/haddock-api/src/Haddock/Types.hs The diff was not included because it is too large. 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