Zubin pushed to branch wip/9.14.2-backports at Glasgow Haskell Compiler / GHC Commits: c77b77e7 by Simon Hengel at 2026-07-15T16:39:36+05:30 Refactor GHC.Driver.Errors.printMessages (cherry picked from commit 49a44ab79d644590abdeff8699406bbd2d310715) - - - - - 704f7368 by Simon Hengel at 2026-07-15T16:40:59+05:30 Include the rendered message in -fdiagnostics-as-json output This implements #26173. (cherry picked from commit d046b5ab146167bcb86c675d101ff5e3c4eb8c8e) - - - - - 6850cb8f by fendor at 2026-07-15T16:41:10+05:30 Revert prog003 acceptance We thought the commit 286f1adff3e78d775ff325caff71d0cee25d710b fixed the test, but due to changes to ghci, modules loaded during the GHCi session, the test was actually no longer testing what it set out to do, "fixing" the broken test. As modules are added to the `interactive-session` home unit, the object code needs to be compiled with `-this-unit-id interactive-session`, otherwise the object code won't be used. Once this has been fixed in the test, the test fails as expected again. (cherry picked from commit 8f9917557a7ef290dfa8b913c3a4146289586ec6) - - - - - 41ecaadd by sheaf at 2026-07-15T16:44:19+05:30 Fix AArch64 clobbering bug for MUL2 On AArch64, the code generator could clobber one of the input operands when computing the lower bits of a MUL2 operation. This rendered invalid the subsequent computation of the high bits. This commit fixes that by using a temporary register. The register allocator can remove the redundant move in the common case when the registers do not conflict. Fixes #27046 (cherry picked from commit c9015f0953e72829e89ac768b6ad9ece34c7e187) - - - - - 985b0e36 by mangoiv at 2026-07-15T16:44:19+05:30 libraries/process: bump submodule to v1.6.30.0 - bump the submodule to the appropriate tag - suppress benign warning resulting from the change (cherry picked from commit d9ea2d76545452a7df567b162340079cb024a40c) - - - - - 16e9f578 by ARATA Mizuki at 2026-07-15T16:44:19+05:30 RISC-V NCG: Zero-extend the result of castFloatToWord32 According to the ISA manual, FMV.X.W sign-extends the result. We need to truncate the result to avoid creating an exotic Word32 value. Fixes #27300 (cherry picked from commit 291ce3aafe4ca3d2562154a28c595a858987d9f1) - - - - - c16871c9 by ARATA Mizuki at 2026-07-15T16:44:19+05:30 RISC-V NCG: Treat d28-d31 (ft8-ft11) as caller-saved According to the calling convention, the registers d28-d31 (ft8-ft11) are caller-saved. Fixes #27306 (cherry picked from commit 011be91fdaa7869dff2f30b8f2ecca3c9a713739) - - - - - d8f0999a by ARATA Mizuki at 2026-07-15T16:44:20+05:30 RISC-V NCG: Set rounding mode when emitting `truncate` If we omit the rounding mode for `fcvt`, `dyn` will be used. We do not want that for `truncate`, so we set `rtz`. In other places, we set `rne` because we do not use the dynamic rounding mode. Fixes #27303 (cherry picked from commit e8a547133031b7de8f6f9bbd70a7148eda0941ee) - - - - - bfcd8dfc by Zubin Duggal at 2026-07-15T16:44:20+05:30 rts: fix validate build with gcc 16. `__attribute__((regparm(1)))` is ignored on x86_64 and now gcc warns that it is ignored: rts/sm/Evac.h:35:1: error: error: ‘regparm’ attribute ignored [-Werror=attributes] See https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ccead81bbc39668376eb5cf47066ac... Fixes #27366 (cherry picked from commit 9438bec7117433bbc70449d4288f6ee32dbbbec4) - - - - - 275a0382 by Ian Duncan at 2026-07-15T16:44:54+05:30 AArch64: use SXTH, not SXTW, for W32 signExtendReg signExtendReg was using SXTH (sign-extend halfword, 16-bit) for W32-to-W64 sign extension. This should be SXTW (sign-extend word, 32-bit). SXTH only sign-extends the lower 16 bits, producing wrong results for 32-bit values whose bit 15 differs from bit 31. Other fixes: - At sub-W64, code gen for MO_S_Mul2 should use W32 registers for SMULL source operands as per the ARM spec (SMULL Xd, Wn, Wm), and not W64. - Ensure signExtendReg uses the source width for the source operand in SXTW/SXTH/SXTB instructions. GNU as requires sxtw Xd,Wn (not sxtw Xd,Xn), while LLVM's integrated assembler on macOS is lenient. - Fix overflow flag computation for `MO_S_Mul2`. The overflow bit was exactly inverted for sub-W64 operands. Fixes #26978 and #27047 (cherry picked from commit 636c1c7ae47495f022affa501ea0a40cb55cd4a4) - - - - - dec52356 by Luite Stegeman at 2026-07-15T16:46:04+05:30 tag inference: don't confuse functions with their return values inferTagRhs was mixing up taggedness for closures and return values for function closures. We really shouldn't assign TagTuple to a properly tagged function returning a tuple. We fix this by keeping track of functions (TagFun) separately from values (TagVal) and keeping track of their return value. TagFun is also used for join points. fixes #27005 (cherry picked from commit 7fe4f2ec3ce12ea138177c81a019dcfc148fe5d4) - - - - - a40f21b5 by Sebastian Graf at 2026-07-15T16:47:03+05:30 Desugar a `case` scrutinee only once (#27383, #20251) In `dsExpr` for `HsCase` we desugared the scrutinee /twice/: once to build the Core `case` itself, and again inside `matchWrapper`, which re-desugared the source scrutinee (via `addHsScrutTmCs`) purely to record long-distance information for the pattern-match checker. For a single `case` that is merely wasteful. But for nested cases it is catastrophic. Consider case (case (case e of ... ) of ... ) of ... Desugaring the outer scrutinee desugars the middle `case` twice, each of which desugars the inner `case` twice, and so on. The work doubles at every level, so desugaring takes O(2^n) time in the nesting depth. That is the blowup reported in #27383; it is also what makes the machine-generated program in #20251 take an age to compile. The fix is simple. `matchWrapper` is handed the scrutinee anyway, so we give it the Core expression we have /already/ desugared, and record the long-distance term constraint with `addCoreScrutTmCs` instead of re-desugaring from source. This is just what `matchSinglePatVar` already does for single-pattern matches. So: * `matchWrapper` now takes `Maybe [CoreExpr]` rather than `Maybe [LHsExpr GhcTc]`. * The `HsCase` equation of `dsExpr` passes the already-desugared `core_discrim`; the arrow desugarer passes its match variables. * `addHsScrutTmCs` had no other use, so it is gone. Desugaring is now linear in the nesting depth. (The coverage checker still runs `simpleOptExpr` over each scrutinee, which leaves the total at O(n^2); that is ample.) The long-distance information itself is unchanged: the checker sees precisely the Core that backs the generated code. Test: deSugar/should_compile/T27383 (cherry picked from commit 67d41299be96798702377e6e2b826f9c8e070821) - - - - - 46dfc982 by mangoiv at 2026-07-15T16:48:09+05:30 ExplicitLevelImports: check staging for types just like for values Previously, imported types were entirely exempted from staging checks as the implicit stage persistance assumed to be all imported types to be well staged. ExplicitLevelImports' change specification, however, does not do such an exemption. Thus we want to introduce such a check, just like we have for values. ExplicitLevelImports does not, however, talk about local names - from its perspective, we could theoretically keep treating locally introduced types specially - e.g. an ill-staged used in a quote would only emit a warning, not an error. To allow for a potential future migration away from such wrinkles as the staging check in notFound (see Note [Out of scope might be a staging error]) we consistently do the strict staging check that we also do for value if ExplicitLevelImports is on. Closes #26098 (cherry picked from commit c64cca1ef667751c02ce2eb4141349e601aac99c) - - - - - 41ff5cd7 by Simon Hengel at 2026-07-15T16:48:47+05:30 Reference correct package in error messages for reexported modules (fixes #27417) (cherry picked from commit a805b2a25021606b30d250e084d4beecbfac0d0a) - - - - - 0088aeb5 by Luite Stegeman at 2026-07-15T16:49:09+05:30 rts: handle large AP closures in compacting GC The function update_fwd_large in the compacting GC could run into an unexpected object with the following error: internal error: update_fwd_large: unknown/strange object 24 Closure type 24 is the AP closure, which was not handled in upd_fwd_large. This patch adds handling them. fixes #27434 (cherry picked from commit cca0d58963f802a8b2e43aa2dbc58592f8ad07bb) - - - - - 3bbf347b by Cheng Shao at 2026-07-15T16:49:09+05:30 compiler: fix missing handling of CmmUnsafeForeignCall node in LayoutStack This patch fixes missing handling of `CmmUnsafeForeignCall` middle node in the `LayoutStack` pass. Before proc-points splitting, this pass computes liveliness of local registers, and spills those alive across a Cmm native call onto the stack. It need to traverse all middle nodes in each block and check whether a local register is an assignee, if so then the previous mapping in `sm_regs` is invalidated and needs to be dropped. However, it didn't handle `CmmUnsafeForeignCall` node which may also assign to a local register. When proc-points splitting is enabled, this can produce an invalid basic block that doesn't properly backup the updated local register to the stack before doing a Cmm call, resulting in completely invalid runtime behavior. The patch also adds a `T27447` regression test. With no-TNTC or with LLVM backend, without the fix the test case would output a stale 0x1111111111111111 value, instead of the expected 0x2222222222222222 output. Fixes #27447. Co-authored-by: Codex <codex@openai.com> (cherry picked from commit 3f00f234d0d5b3b3b2a23a5dc70ce372eb9bbdb4) - - - - - 06fcc414 by Cheng Shao at 2026-07-15T16:49:09+05:30 ci: use treeless fetch for perf notes This patch improves the ci logic for fetching perf notes by using treeless fetch (https://github.blog/open-source/git/get-up-to-speed-with-partial-clone-and-s...), to avoid downloading all blobs of the perf notes repo at once, and only fetch the actually required blobs on-demand when needed. This makes the initial `test-metrics.sh pull` operation much faster, and also more robust, since we are seeing an increasing rate of 504 errors in CI when fetching all perf notes at once, which is a major source of CI flakiness at this point. Co-authored-by: Codex <codex@openai.com> (cherry picked from commit 3c0013778b4459c1f8e56cd0dc2600f5bb3769d2) - - - - - feaa0f47 by mangoiv at 2026-07-15T16:49:09+05:30 ci: retry fetching test metrics Retry fetching test metrics to make the CI not fail if the services is temporarily unavailable (cherry picked from commit b7e24044fde064cb3f0d44c36872a86d024cd7d4) - - - - - c19af18a by Zubin Duggal at 2026-07-15T16:49:09+05:30 Bump semaphore-compat submodule to 2.0.1 This versions includes some cruicial fixes for darwin (cherry picked from commit 4180af3f71754472dbd49b85179b25fd29bd9998) - - - - - 4e296572 by Zubin Duggal at 2026-07-15T16:49:09+05:30 CorePrep: Don't speculatively evaluate bindings that we have already discovered to be absent In #25924, we segfault because speculation forces a projection out of a RUBBISH dictionary (which we generated because it absent). Solution: Don't speculate on bindings we already know are absent. Fixes 25924 (cherry picked from commit 9b714c4c833461c621f0a050680848d7248aa57e) - - - - - 25026e53 by Zubin Duggal at 2026-07-15T16:49:55+05:30 Don't make absent fillers for terminating types In #25924 we discovered that we could speculatively evaluate an absent filler for a dictionary, and project a field (a superclass selector) out of it, resulting in segfaults. Solution: Never make an absent filler or rubbish literal for a terminating type like a dictionary. mkAbsentFiller returns Nothing for isTerminatingType, so worker/wrapper and the specialiser keep the real argument instead. Some small metric decreases because we do a little less work in the simplifier now. Metric Decrease: T9872a T9872b T9872c TcPlugin_RewritePerf (cherry picked from commit 4a59b3eece9b7106fcbe73d2d06a49755be4ea8f) - - - - - 588765fd by Andreas Klebinger at 2026-07-15T16:50:45+05:30 Fix a profiling race condition resulting in segfaults. StgToCmm: Don't assume tagged FUN closures in closureCodeBody. When entering a closure the self/node pointer might not be tagged in some situations when a thunk is evaluated by multiple threads. So we most AND away the tag bits rather than subtracting an expected tag. Apply.cmm: Fix a race condition occuring when a thunk is mutated during GC. In stg_ap_0_fast when might need to run GC before entering a thunk. If this happens another thread or the GC itself might mutate the closure making entering it no longer valid. We now check for this. Add test and changelog for #27123 fixes. (cherry picked from commit ed09895d7de1ca116a561868c151fd825a16ad0c) - - - - - e86a5193 by Cheng Shao at 2026-07-15T16:50:45+05:30 ghc-heap: fix invalid srtlen returned by peekItbl when no-TNTC This patch fixes the no-TNTC code path of `peekItbl` so that it looks at the right memory address when reading the `srt` field from the `StgInfoTable_` struct. Also adds a `T27465` regression test that reproduces the bug on no-TNTC builds before the fix. Fixes #27465. Co-authored-by: Codex <codex@openai.com> (cherry picked from commit 67c03eb2c762fdfeb646eb8345341173dd4268b2) - - - - - c603d701 by Cheng Shao at 2026-07-15T16:50:45+05:30 compiler: fix miscompiled %load_relaxed, add missing %store_relaxed This patch fixes the %load_relaxed cmm primop compilation logic to correctly use relaxed memory ordering, and adds the missing %store_relaxed primop. Parsing logic of %load/%store with explicit ordering is covered in the AtomicFetch test case. Fixes #27483. Co-authored-by: Codex <codex@openai.com> (cherry picked from commit eee8ec5b25ef0f83ba4822e7a0a941df7b0bec5f) - - - - - acc488d1 by Cheng Shao at 2026-07-15T16:50:45+05:30 rts: fix missing UNTAG in stg_readTVarIOzh This patch fixes missing UNTAG on the current value closure read from StgTVar. UNTAG is a no-op when it's stg_TREC_HEADER_info which is word aligned; it may be a tagged closure, and reading info table from the tagged address is an unaligned load which may cause issues on platforms with strict alignment requirements. Co-authored-by: Codex <codex@openai.com> (cherry picked from commit d377e83e51d39a06e1f0bf2e35a923a3210b21a2) - - - - - 4c16d073 by Cheng Shao at 2026-07-15T16:50:46+05:30 rts: fix missing UNTAG in stg_control0zh_ll This patch fixes missing UNTAG on the cont closure returned by captureContinuationAndAbort. In case it's not NULL, captureContinuationAndAbort returns a tagged StgContinuation closure, in which case it must be untagged before accessing the apply_mask_frame field. In the past it worked out of luck: when apply_mask_frame was NULL then mask_frame_offset is also 0 so the control flow didn't diverge to a wrong path. Still, this is horribly wrong and will crash once StgContinuation struct is refactored and fields are shuffled around. Co-authored-by: Codex <codex@openai.com> (cherry picked from commit 8ed038421a20e3e4e681973b2f5098e5bd2144b5) - - - - - 0906c7dc by Cheng Shao at 2026-07-15T16:50:46+05:30 compiler: fix redundant AP thunk codegen when not using -ticky-ap-thunk This patch fixes a double negation confusion in !7525 that results in some redundant AP thunk code generation when not using -ticky-ap-thunk. Now, we use `stgToCmmUseStdApThunk` to indicate whether precomputed AP thunks in the RTS should be used, which defaults to `True`, unless `-ticky-ap-thunk` is passed. `-finfo-table-map` now also implies `-ticky-ap-thunk`, since when doing IPE profiling we want the generated AP thunks to be unique. Fixes #27502. ------------------------- Metric Decrease: T3064 ------------------------- Co-authored-by: Codex <codex@openai.com> (cherry picked from commit 5aa7000ae246ae6a706437799338295b5801a629) - - - - - 138 changed files: - .gitlab/test-metrics.sh - + changelog.d/T26978 - + changelog.d/T27046 - + changelog.d/T27047 - + changelog.d/T27123.md - + changelog.d/fix-absent-dict-projection - + changelog.d/fix-cmm-atomic-load-store - + changelog.d/fix-compacting-gc-ap-27434 - + changelog.d/fix-exponential-case-desugar-27383 - + changelog.d/fix-layout-stack-fcall - + changelog.d/fix-peekitbl-no-tntc - + changelog.d/fix-use-std-ap-thunk - + changelog.d/reexported-module-errors - changelog.d/semaphore-v2 - + changelog.d/tag-inference-27005 - compiler/GHC/Cmm/LayoutStack.hs - compiler/GHC/Cmm/Parser.y - compiler/GHC/CmmToAsm/AArch64/CodeGen.hs - compiler/GHC/CmmToAsm/AArch64/Instr.hs - compiler/GHC/CmmToAsm/AArch64/Ppr.hs - compiler/GHC/CmmToAsm/RV64/CodeGen.hs - compiler/GHC/CmmToAsm/RV64/Instr.hs - compiler/GHC/CmmToAsm/RV64/Ppr.hs - compiler/GHC/CmmToAsm/RV64/Regs.hs - compiler/GHC/Core/Make.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/Opt/WorkWrap.hs - compiler/GHC/Core/Opt/WorkWrap/Utils.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/CoreToStg/Prep.hs - compiler/GHC/Driver/Config/StgToCmm.hs - compiler/GHC/Driver/Errors.hs - compiler/GHC/Driver/Flags.hs - compiler/GHC/HsToCore/Arrows.hs - compiler/GHC/HsToCore/Expr.hs - compiler/GHC/HsToCore/Match.hs - compiler/GHC/HsToCore/Match.hs-boot - compiler/GHC/HsToCore/Pmc.hs - compiler/GHC/Iface/Errors.hs - compiler/GHC/Iface/Errors/Ppr.hs - compiler/GHC/Iface/Errors/Types.hs - compiler/GHC/Rename/HsType.hs - compiler/GHC/Rename/Splice.hs-boot - compiler/GHC/Stg/EnforceEpt.hs - compiler/GHC/Stg/EnforceEpt/Rewrite.hs - compiler/GHC/Stg/EnforceEpt/TagSig.hs - compiler/GHC/Stg/EnforceEpt/Types.hs - compiler/GHC/StgToCmm/Bind.hs - compiler/GHC/StgToCmm/Config.hs - compiler/GHC/Types/Error.hs - compiler/GHC/Types/Literal.hs - compiler/GHC/Unit/Finder.hs - compiler/GHC/Unit/Finder/Types.hs - compiler/GHC/Unit/State.hs - compiler/GHC/Utils/Logger.hs - + docs/users_guide/9.14.2-notes.rst - + docs/users_guide/diagnostics-as-json-schema-1_2.json - docs/users_guide/release-notes.rst - docs/users_guide/using.rst - ghc/GHCi/UI/Exception.hs - hadrian/src/Settings/Warnings.hs - + libraries/ghc-heap/tests/T27465.hs - + libraries/ghc-heap/tests/T27465.stdout - libraries/ghc-heap/tests/all.T - libraries/ghc-internal/src/GHC/Internal/Heap/InfoTable.hsc - libraries/ghc-internal/src/GHC/Internal/Heap/InfoTableProf.hsc - libraries/process - libraries/semaphore-compat - rts/Apply.cmm - rts/ContinuationOps.cmm - rts/PrimOps.cmm - rts/sm/Compact.c - rts/sm/Evac.h - testsuite/driver/testlib.py - testsuite/tests/cmm/should_run/AtomicFetch.hs - testsuite/tests/cmm/should_run/AtomicFetch_cmm.cmm - + testsuite/tests/cmm/should_run/T27447.hs - + testsuite/tests/cmm/should_run/T27447.stdout - + testsuite/tests/cmm/should_run/T27447_cmm.cmm - testsuite/tests/cmm/should_run/all.T - + testsuite/tests/codeGen/should_gen_asm/aarch64-sxth-mul2.asm - + testsuite/tests/codeGen/should_gen_asm/aarch64-sxth-mul2.cmm - + testsuite/tests/codeGen/should_gen_asm/aarch64-sxtw.asm - + testsuite/tests/codeGen/should_gen_asm/aarch64-sxtw.cmm - testsuite/tests/codeGen/should_gen_asm/all.T - testsuite/tests/codeGen/should_run/T16617.hs - testsuite/tests/codeGen/should_run/T16617.stdout - + testsuite/tests/codeGen/should_run/T27046.hs - + testsuite/tests/codeGen/should_run/T27046_cmm.cmm - + testsuite/tests/codeGen/should_run/aarch64-sxtw-cmm.cmm - + testsuite/tests/codeGen/should_run/aarch64-sxtw-run.hs - + testsuite/tests/codeGen/should_run/aarch64-sxtw-run.stdout - testsuite/tests/codeGen/should_run/all.T - testsuite/tests/core-to-stg/T14895.stderr - + testsuite/tests/core-to-stg/T25924/B.hs - + testsuite/tests/core-to-stg/T25924/Main.hs - + testsuite/tests/core-to-stg/T25924/all.T - + testsuite/tests/core-to-stg/T25924a.hs - + testsuite/tests/core-to-stg/T25924a.stdout - testsuite/tests/core-to-stg/all.T - + testsuite/tests/deSugar/should_compile/T27383.hs - testsuite/tests/deSugar/should_compile/all.T - testsuite/tests/dmdanal/should_compile/T18982.stderr - testsuite/tests/driver/json.stderr - testsuite/tests/driver/json_warn.stderr - testsuite/tests/ghci/prog003/prog003.T - testsuite/tests/ghci/prog003/prog003.script - + testsuite/tests/package/ImportReexport.hs - + testsuite/tests/package/ImportReexport.stderr - testsuite/tests/package/all.T - + testsuite/tests/rts/T27123.hs - + testsuite/tests/rts/T27434.hs - + testsuite/tests/rts/T27434.stdout - testsuite/tests/rts/all.T - testsuite/tests/simplCore/should_compile/T4201.stdout - + testsuite/tests/simplCore/should_run/T27005.hs - + testsuite/tests/simplCore/should_run/T27005.stdout - + testsuite/tests/simplCore/should_run/T27005_aux.hs - testsuite/tests/simplCore/should_run/all.T - testsuite/tests/simplStg/should_compile/T24806.hs - testsuite/tests/simplStg/should_compile/T24806.stderr - + testsuite/tests/simplStg/should_compile/T27005b.hs - + testsuite/tests/simplStg/should_compile/T27005b.stderr - testsuite/tests/simplStg/should_compile/all.T - testsuite/tests/simplStg/should_compile/inferTags004.hs - testsuite/tests/simplStg/should_compile/inferTags004.stderr - + testsuite/tests/simplStg/should_run/T27005a.hs - + testsuite/tests/simplStg/should_run/T27005a.stdout - testsuite/tests/simplStg/should_run/all.T - + testsuite/tests/th/T26098A_quote.hs - + testsuite/tests/th/T26098A_splice.hs - + testsuite/tests/th/T26098_local.hs - + testsuite/tests/th/T26098_local.stderr - + testsuite/tests/th/T26098_quote.hs - + testsuite/tests/th/T26098_quote.stderr - + testsuite/tests/th/T26098_splice.hs - + testsuite/tests/th/T26098_splice.stderr - testsuite/tests/th/all.T The diff was not included because it is too large. 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