November 2025 - ghc-commits

[Git][ghc/ghc][wip/T23162-part2] WIP [skip ci]
by Simon Peyton Jones (＠simonpj) 13 Nov '25

13 Nov '25

Simon Peyton Jones pushed to branch wip/T23162-part2 at Glasgow Haskell Compiler / GHC Commits: 827aaf71 by Simon Peyton Jones at 2025-11-13T17:32:23+00:00 WIP [skip ci] improving the injectivity calculation - - - - - 3 changed files: - compiler/GHC/Core/FamInstEnv.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/Tc/Solver/FunDeps.hs Changes: ===================================== compiler/GHC/Core/FamInstEnv.hs ===================================== @@ -611,7 +611,7 @@ injectiveBranches injectivity -- See Note [Verifying injectivity annotation], case 1. = let getInjArgs = filterByList injectivity in_scope = mkInScopeSetList (tvs1 ++ tvs2) - in case tcUnifyTyForInjectivity True in_scope rhs1 rhs2 of + in case tcUnifyTysForInjectivity True in_scope [rhs1] [rhs2] of -- True = two-way pre-unification Nothing -> InjectivityAccepted -- RHS are different, so equations are injective. ===================================== compiler/GHC/Core/Unify.hs ===================================== @@ -12,7 +12,7 @@ module GHC.Core.Unify ( -- Side-effect free unification tcUnifyTy, tcUnifyTys, tcUnifyFunDeps, tcUnifyDebugger, - tcUnifyTysFG, tcUnifyTyForInjectivity, + tcUnifyTysFG, tcUnifyTysForInjectivity, BindTvFun, BindFamFun, BindFlag(..), matchBindTv, alwaysBindTv, alwaysBindFam, dontCareBindFam, UnifyResult, UnifyResultM(..), MaybeApartReason(..), @@ -381,7 +381,7 @@ Wrinkles (ATF7) There is one other, very special case of matching where we /do/ want to bind type families in `um_fam_env`, namely in GHC.Tc.Solver.Equality, the call - to `tcUnifyTyForInjectivity False` in `improve_injective_wanted_top`. + to `tcUnifyTysForInjectivity False` in `improve_injective_wanted_top`. Consider of a match. Consider type family G6 a = r | r -> a @@ -814,25 +814,25 @@ tcUnifyFunDeps qtvs tys1 tys2 -- | Unify or match a type-family RHS with a type (possibly another type-family RHS) -- Precondition: kinds are the same -tcUnifyTyForInjectivity +tcUnifyTysForInjectivity :: AmIUnifying -- ^ True <=> do two-way unification; -- False <=> do one-way matching. -- See end of sec 5.2 from the paper -> InScopeSet -- Should include the free tyvars of both Type args - -> Type -> Type -- Types to unify + -> [Type] -> [Type] -- Types to unify -> Maybe Subst -- This algorithm is an implementation of the "Algorithm U" presented in -- the paper "Injective type families for Haskell", Figures 2 and 3. -- The code is incorporated with the standard unifier for convenience, but -- its operation should match the specification in the paper. -tcUnifyTyForInjectivity unif in_scope t1 t2 +tcUnifyTysForInjectivity unif in_scope tys1 tys2 = case tc_unify_tys alwaysBindFam alwaysBindTv unif -- Am I unifying? True -- Do injectivity checks False -- Don't check outermost kinds RespectMultiplicities rn_env emptyTvSubstEnv emptyCvSubstEnv - [t1] [t2] of + tys1 tys2 of Unifiable (tv_subst, _cv_subst) -> Just $ maybe_fix tv_subst MaybeApart _reason (tv_subst, _cv_subst) -> Just $ maybe_fix tv_subst -- We want to *succeed* in questionable cases. ===================================== compiler/GHC/Tc/Solver/FunDeps.hs ===================================== @@ -25,7 +25,7 @@ import GHC.Core.FamInstEnv import GHC.Core.Coercion import GHC.Core.Predicate( EqRel(..) ) import GHC.Core.TyCon -import GHC.Core.Unify( tcUnifyTyForInjectivity, typeListsAreApart ) +import GHC.Core.Unify( tcUnifyTysForInjectivity, typeListsAreApart ) import GHC.Core.Coercion.Axiom import GHC.Core.TyCo.Subst( elemSubst ) @@ -545,14 +545,35 @@ mkTopClosedFamEqFDs :: CoAxiom Branched -> [TcType] -> Xi -> TcS [FunDepEqns] mkTopClosedFamEqFDs ax work_args work_rhs = do { let branches = fromBranches (coAxiomBranches ax) ; traceTcS "mkTopClosed" (ppr branches $$ ppr work_args $$ ppr work_rhs) - ; case filter relevant_branch branches of - [CoAxBranch { cab_tvs = qtvs, cab_lhs = lhs_tys }] + ; case getRelevantBranches ax work_args work_rhs of + [CoAxBranch { cab_tvs = qtvs, cab_lhs = lhs_tys }] -> return [FDEqns { fd_qtvs = qtvs , fd_eqs = zipWith Pair lhs_tys work_args }] _ -> return [] } + +getRelevantBranches ax work_args work_rhs + = go [] (fromBranches (coAxiomBranches ax)) where - relevant_branch (CoAxBranch { cab_lhs = lhs_tys, cab_rhs = rhs_ty }) - = eqnIsRelevant lhs_tys rhs_ty work_args work_rhs + work_tys = work_rhs : work_args + work_fvs = tyCoVarsOfTypes work_tys + + go preceding [] = [] + go preceding (CoAxBranch { cab_qtvs = qtvs, cab_lhs = lhs_tys, cab_rhs = rhs_ty } : rest) + | is_relevant = br : go (br:preceding) rest + | otherwise = go (br:preceding) rest + where + is_relevant = case tcUnifyTysForInjectivity True branch_fvs work_tys (rhs_ty:lhs_tys) of + Nothing -> False + Just subst -> no_match (substTy subst lhs_tys) preceding + + branch_fvs = extendVarSetList work_fvs qtvs + + no_match lhs_tys [] = True + no_match lhs_tys (CoAxBranch { cab_qtvs = qtvs1, cab_lhs = lhs_tys1 }) + = isNothing (tcUnifyTysForInjectivity False lhs_tys1 lhs_tys) + where + all_fvs = branch_fvs `extendVarSetList` qtvs1 + mkTopOpenFamEqFDs :: TyCon -> [Bool] -> [TcType] -> Xi -> TcS [FunDepEqns] -- Implements (INJFAM:Wanted/top) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/827aaf71386a685c00ff5dcaaa97554… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/827aaf71386a685c00ff5dcaaa97554… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26425] 18 commits: build: Relax ghc/ghc-boot Cabal bound to 3.16
by Simon Peyton Jones (＠simonpj) 13 Nov '25

13 Nov '25

Simon Peyton Jones pushed to branch wip/T26425 at Glasgow Haskell Compiler / GHC Commits: b5508f2c by Rodrigo Mesquita at 2025-11-04T14:10:56+00:00 build: Relax ghc/ghc-boot Cabal bound to 3.16 Fixes #26202 - - - - - c5b3541f by Rodrigo Mesquita at 2025-11-04T14:10:56+00:00 cabal-reinstall: Use haddock-api +in-tree-ghc Fixes #26202 - - - - - c6d4b945 by Rodrigo Mesquita at 2025-11-04T14:10:56+00:00 cabal-reinstall: Pass --strict to Happy This is necessary to make the generated Parser build successfully This mimics Hadrian, which always passes --strict to happy. Fixes #26202 - - - - - 79df1e0e by Rodrigo Mesquita at 2025-11-04T14:10:56+00:00 genprimopcode: Require higher happy version I've bumped the happy version to forbid deprecated Happy versions which don't successfully compile. - - - - - fa5d33de by Simon Peyton Jones at 2025-11-05T08:35:40-05:00 Add a HsWrapper optimiser This MR addresses #26349, by introduceing optSubTypeHsWrapper. There is a long Note [Deep subsumption and WpSubType] in GHC.Tc.Types.Evidence that explains what is going on. - - - - - ea58cae5 by Simon Peyton Jones at 2025-11-05T08:35:40-05:00 Improve mkWpFun_FRR This commit ensures that `mkWpFun_FRR` directly produces a `FunCo` in the cases where it can. (Previously called `mkWpFun` which in turn optimised to a `FunCo`, but that made the smarts in `mkWpFun` /essential/ rather than (as they should be) optional. - - - - - 5cdcfaed by Ben Gamari at 2025-11-06T09:01:36-05:00 compiler: Exclude units with no exposed modules from unused package check Such packages cannot be "used" in the Haskell sense of the word yet are nevertheless necessary as they may provide, e.g., C object code or link flags. Fixes #24120. - - - - - 74b8397a by Brandon Chinn at 2025-11-06T09:02:19-05:00 Replace deprecated argparse.FileType - - - - - 36ddf988 by Ben Gamari at 2025-11-06T09:03:01-05:00 Bump unix submodule to 2.8.8.0 Closes #26474. - - - - - c32b3a29 by fendor at 2025-11-06T09:03:43-05:00 Fix assertion in `postStringLen` to account for \0 byte We fix the assertion to handle trailing \0 bytes in `postStringLen`. Before this change, the assertion looked like this: ASSERT(eb->begin + eb->size > eb->pos + len + 1); Let's assume some values to see why this is actually off by one: eb->begin = 0 eb->size = 1 eb->pos = 0 len = 1 then the assertion would trigger correctly: 0 + 1 > 0 + 1 + 1 => 1 > 2 => false as there is not enough space for the \0 byte (which is the trailing +1). However, if we change `eb->size = 2`, then we do have enough space for a string of length 1, but the assertion still fails: 0 + 2 > 0 + 1 + 1 => 2 > 2 => false Which causes the assertion to fail if there is exactly enough space for the string with a trailing \0 byte. Clearly, the assertion should be `>=`! If we switch around the operand, it should become more obvious that `<=` is the correct comparison: ASSERT(eb->pos + len + 1 <= eb->begin + eb->size); This is expresses more naturally that the current position plus the length of the string (and the null byte) must be smaller or equal to the overall size of the buffer. This change also is in line with the implementation in `hasRoomForEvent` and `hasRoomForVariableEvent`: ``` StgBool hasRoomForEvent(EventsBuf *eb, EventTypeNum eNum) { uint32_t size = ...; if (eb->pos + size > eb->begin + eb->size) ... ``` the check `eb->pos + size > eb->begin + eb->size` is identical to `eb->pos + size <= eb->begin + eb->size` plus a negation. - - - - - 3034a6f2 by Ben Gamari at 2025-11-06T09:04:24-05:00 Bump os-string submodule to 2.0.8 - - - - - 39567e85 by Cheng Shao at 2025-11-06T09:05:06-05:00 rts: use computed goto for instruction dispatch in the bytecode interpreter This patch uses computed goto for instruction dispatch in the bytecode interpreter. Previously instruction dispatch is done by a classic switch loop, so executing the next instruction requires two jumps: one to the start of the switch loop and another to the case block based on the instruction tag. By using computed goto, we can build a jump table consisted of code addresses indexed by the instruction tags themselves, so executing the next instruction requires only one jump, to the destination directly fetched from the jump table. Closes #12953. - - - - - 93fc7265 by sheaf at 2025-11-06T21:33:24-05:00 Correct hasFixedRuntimeRep in matchExpectedFunTys This commit fixes a bug in the representation-polymormorphism check in GHC.Tc.Utils.Unify.matchExpectedFunTys. The problem was that we put the coercion resulting from hasFixedRuntimeRep in the wrong place, leading to the Core Lint error reported in #26528. The change is that we have to be careful when using 'mkWpFun': it expects **both** the expected and actual argument types to have a syntactically fixed RuntimeRep, as explained in Note [WpFun-FRR-INVARIANT] in GHC.Tc.Types.Evidence. On the way, this patch improves some of the commentary relating to other usages of 'mkWpFun' in the compiler, in particular in the view pattern case of 'tc_pat'. No functional changes, but some stylistic changes to make the code more readable, and make it easier to understand how we are upholding the WpFun-FRR-INVARIANT. Fixes #26528 - - - - - c052c724 by Simon Peyton Jones at 2025-11-06T21:34:06-05:00 Fix a horrible shadowing bug in implicit parameters Fixes #26451. The change is in GHC.Tc.Solver.Monad.updInertDicts where we now do /not/ delete /Wanted/ implicit-parameeter constraints. This bug has been in GHC since 9.8! But it's quite hard to provoke; I contructed a tests in T26451, but it was hard to do so. - - - - - b253013e by Georgios Karachalias at 2025-11-07T17:21:57-05:00 Remove the `CoreBindings` constructor from `LinkablePart` Adjust HscRecompStatus to disallow unhydrated WholeCoreBindings from being passed as input to getLinkDeps (which would previously panic in this case). Fixes #26497 - - - - - ac7b737e by Sylvain Henry at 2025-11-07T17:22:51-05:00 Testsuite: pass ext-interp test way (#26552) Note that some tests are still marked as broken with the ext-interp way (see #26552 and #14335) - - - - - d6a48d8a by Simon Peyton Jones at 2025-11-13T14:59:01+00:00 Add a fast-path for args=[] to occAnalApp In the common case of having not arguments, occAnalApp was doing redundant work. - - - - - 06960766 by Simon Peyton Jones at 2025-11-13T14:59:32+00:00 Fix a performance hole in the occurrence analyser As #26425 showed, the clever stuff in Note [Occurrence analysis for join points] does a lot of duplication of usage details. This patch improved matters with a little fancy footwork. It is described in the new (W5) of the same Note. Compile-time allocations go down slightly: T18282(normal) 128,465,466 125,877,688 -2.0% T18698a(normal) 208,425,826 202,141,296 -3.0% T26425(normal) 3,344,308,317 2,458,450,080 -26.5% geo. mean -0.5% minimum -26.5% maximum +0.5% Metric Decrease: T18282 T18698a T26425 - - - - - 58 changed files: - cabal.project-reinstall - compiler/GHC/Core/Coercion.hs - compiler/GHC/Core/Opt/OccurAnal.hs - compiler/GHC/Driver/Main.hs - compiler/GHC/Driver/Make.hs - compiler/GHC/Driver/Pipeline.hs - compiler/GHC/Hs/Syn/Type.hs - compiler/GHC/HsToCore/Binds.hs - compiler/GHC/HsToCore/Match.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Linker/Deps.hs - compiler/GHC/Linker/Types.hs - compiler/GHC/Tc/Errors/Hole.hs - compiler/GHC/Tc/Gen/App.hs - compiler/GHC/Tc/Gen/Expr.hs - compiler/GHC/Tc/Gen/Head.hs - compiler/GHC/Tc/Gen/Pat.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Types/Evidence.hs - compiler/GHC/Tc/Utils/Concrete.hs - compiler/GHC/Tc/Utils/Instantiate.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Tc/Zonk/Type.hs - compiler/GHC/Types/Unique/FM.hs - compiler/GHC/Types/Unique/Set.hs - compiler/GHC/Types/Var/Env.hs - compiler/GHC/Unit/Home/ModInfo.hs - compiler/GHC/Unit/Module/Status.hs - compiler/GHC/Unit/Module/WholeCoreBindings.hs - compiler/Setup.hs - compiler/ghc.cabal.in - docs/users_guide/compare-flags.py - libraries/base/tests/all.T - libraries/ghc-boot/Setup.hs - libraries/ghc-boot/ghc-boot.cabal.in - libraries/os-string - libraries/unix - rts/Interpreter.c - rts/eventlog/EventLog.c - rts/gen_event_types.py - rts/include/rts/Bytecodes.h - testsuite/driver/runtests.py - testsuite/driver/testlib.py - testsuite/tests/driver/T20696/all.T - + testsuite/tests/driver/T24120.hs - testsuite/tests/driver/all.T - testsuite/tests/driver/fat-iface/all.T - + testsuite/tests/rep-poly/T26528.hs - testsuite/tests/rep-poly/all.T - + testsuite/tests/simplCore/should_compile/T26349.hs - + testsuite/tests/simplCore/should_compile/T26349.stderr - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/simplCore/should_compile/rule2.stderr - testsuite/tests/splice-imports/all.T - + testsuite/tests/typecheck/should_compile/T26451.hs - testsuite/tests/typecheck/should_compile/all.T - utils/genprimopcode/genprimopcode.cabal The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/af4a33da076d8d9bb227090008ac14… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/af4a33da076d8d9bb227090008ac14… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26425] Try making occ_nested_lets strict
by Simon Peyton Jones (＠simonpj) 13 Nov '25

13 Nov '25

Simon Peyton Jones pushed to branch wip/T26425 at Glasgow Haskell Compiler / GHC Commits: af4a33da by Simon Peyton Jones at 2025-11-13T10:29:08+00:00 Try making occ_nested_lets strict - - - - - 1 changed file: - compiler/GHC/Core/Opt/OccurAnal.hs Changes: ===================================== compiler/GHC/Core/Opt/OccurAnal.hs ===================================== @@ -2932,7 +2932,7 @@ data OccEnv -- See Note [Occurrence analysis for join points] , occ_join_points :: !JoinPointInfo - , occ_nested_lets :: IdSet -- Non-top-level, non-rec-bound lets + , occ_nested_lets :: !IdSet -- Non-top-level, non-rec-bound lets -- I tried making this field strict, but -- doing so slightly increased allocation } View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/af4a33da076d8d9bb227090008ac14b… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/af4a33da076d8d9bb227090008ac14b… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/fendor/infoprov-id] 17 commits: Testsuite: pass ext-interp test way (#26552)
by Hannes Siebenhandl (＠fendor) 12 Nov '25

12 Nov '25

Hannes Siebenhandl pushed to branch wip/fendor/infoprov-id at Glasgow Haskell Compiler / GHC Commits: ac7b737e by Sylvain Henry at 2025-11-07T17:22:51-05:00 Testsuite: pass ext-interp test way (#26552) Note that some tests are still marked as broken with the ext-interp way (see #26552 and #14335) - - - - - 3c2f4bb4 by sheaf at 2025-11-11T11:47:28-05:00 Preserve user-written kinds in data declarations This commit ensures that we preserve the user-written kind for data declarations, e.g. in type T2T = Type -> Type type D :: T2T data D a where { .. } that we preserve the user-written kind of D as 'T2T', instead of expanding the type synonym 'T2T' during kind checking. We do this by storing 'tyConKind' separately from 'tyConResKind'. This means that 'tyConKind' is not necessarily equal to 'mkTyConKind binders res_kind', as e.g. in the above example the former is 'T2T' while the latter is 'Type -> Type'. This is explained in Note [Preserve user-written TyCon kind] in GHC.Core.TyCon. This is particularly important for Haddock, as the kinds stored in interface files affect the generated documentation, and we want to preserve the user-written types as much as possible. - - - - - 19859584 by sheaf at 2025-11-11T11:47:28-05:00 Store user-written datacon tvs in interface files This commit ensures we store the user-written quantified type variables of data constructors in interface files, e.g. in data D a where MkD1 :: forall x. x -> D x MkD2 :: forall u v. u -> v -> D v The previous behaviour was to rename the universal variables to match the universal variables of the data constructor. This was undesirable because the names that end up in interface files end up mattering for generated Haddock documentation; it's better to preserve the user-written type variables. Moreover, the universal variables may not have been user-written at all, e.g. in an example such as: type T2T = Type -> Type data G :: T2T where MkG :: forall x. D x Here GHC will invent the type variable name 'a' for the first binder of the TyCon G. We really don't want to then rename the user-written 'x' into the generated 'a'. - - - - - 034b2056 by sheaf at 2025-11-11T11:47:28-05:00 DataCon univ_tvs names: pick TyCon over inferred This commit changes how we compute the names of universal type variables in GADT data constructors. This augments the existing logic that chose which type variable name to use, in GHC.Tc.TyCl.mkGADTVars. We continue to prefer DataCon tv names for user-written binders, but we now prefer TyCon tv names for inferred (non-user-written) DataCon binders. This makes a difference in examples such as: type (:~~:) :: k1 -> k2 -> Type data a :~~: b where HRefl :: a :~~: a Before this patch, we ended up giving HRefl the type: forall {k2}. forall (a :: k2). a :~~: a whereas we now give it the type: forall {k1}. forall (a :: k1). a :~~: a The important part isn't really 'k1' or 'k2', but more that the inferred type variable names of the DataCon can be arbitrary/unpredictable (as they are chosen by GHC and depend on how unification proceeds), so it's much better to use the more predictable TyCon type variable names. - - - - - 95078d00 by sheaf at 2025-11-11T11:47:28-05:00 Backpack Rename: use explicit record construction This commit updates the Backpack boilerplate in GHC.Iface.Rename to use explicit record construction rather than record update. This makes sure that the code stays up to date when the underlying constructors change (e.g. new fields are added). The rationale is further explained in Note [Prefer explicit record construction]. - - - - - 2bf36263 by sheaf at 2025-11-11T11:47:28-05:00 Store # eta binders in TyCon and use for Haddock This commit stores the number of TyCon binders that were introduced by eta-expansion (by the function GHC.Tc.Gen.HsType.splitTyConKind). This is then used to pretty-print the TyCon as the user wrote it, e.g. for type Effect :: (Type -> Type) -> Type -> Type data State s :: Effect where {..} -- arity 3 GHC will eta-expand the data declaration to data State s a b where {..} but also store in the 'TyCon' that the number of binders introduced by this eta expansion is 2. This allows us, in 'Haddock.Convert.synifyTyConKindSig', to recover the original user-written syntax, preserving the user's intent in Haddock documentation. See Note [Inline kind signatures with GADTSyntax] in Haddock.Convert. - - - - - 6c91582f by Matthew Pickering at 2025-11-11T11:48:12-05:00 driver: Properly handle errors during LinkNode steps Previously we were not properly catching errors during the LinkNode step (see T9930fail test). This is fixed by wrapping the `LinkNode` action in `wrapAction`, the same handler which is used for module compilation. Fixes #26496 - - - - - e1e1eb32 by Matthew Pickering at 2025-11-11T11:48:54-05:00 driver: Remove unecessary call to hscInsertHPT This call was left-over from e9445c013fbccf9318739ca3d095a3e0a2e1be8a If you follow the functions which call `upsweep_mod`, they immediately add the interface to the HomePackageTable when `upsweep_mod` returns. - - - - - b22777d4 by ARATA Mizuki at 2025-11-11T11:49:44-05:00 LLVM backend: Pass the +evex512 attribute to LLVM 18+ if -mavx512f is set The newer LLVM requires the +evex512 attribute to enable use of ZMM registers. LLVM exhibits a backward-compatible behavior if the cpu is `x86-64`, but not if `penryn`. Therefore, on macOS, where the cpu is set to `penryn`, we need to explicitly pass +evex512. Fixes #26410 - - - - - 6ead7d06 by Vladislav Zavialov at 2025-11-11T11:50:26-05:00 Comments only in GHC.Parser.PostProcess.Haddock Remove outdated Note [Register keyword location], as the issue it describes was addressed by commit 05eb50dff2fcc78d025e77b9418ddb369db49b9f. - - - - - 43fa8be8 by sheaf at 2025-11-11T11:51:18-05:00 localRegistersConflict: account for assignment LHS This commit fixes a serious oversight in GHC.Cmm.Sink.conflicts, specifically the code that computes which local registers conflict between an assignment and a Cmm statement. If we have: assignment: <local_reg> = <expr> node: <local_reg> = <other_expr> then clearly the two conflict, because we cannot move one statement past the other, as they assign two different values to the same local register. (Recall that 'conflicts (local_reg,expr) node' is False if and only if the assignment 'local_reg = expr' can be safely commuted past the statement 'node'.) The fix is to update 'GHC.Cmm.Sink.localRegistersConflict' to take into account the following two situations: (1) 'node' defines the LHS local register of the assignment, (2) 'node' defines a local register used in the RHS of the assignment. The bug is precisely that we were previously missing condition (1). Fixes #26550 - - - - - 79dfcfe0 by sheaf at 2025-11-11T11:51:18-05:00 Update assigned register format when spilling When we come to spilling a register to put new data into it, in GHC.CmmToAsm.Reg.Linear.allocRegsAndSpill_spill, we need to: 1. Spill the data currently in the register. That is, do a spill with a format that matches what's currently in the register. 2. Update the register assignment, allocating a virtual register to this real register, but crucially **updating the format** of this assignment. Due to shadowing in the Haskell code for allocRegsAndSpill_spill, we were mistakenly re-using the old format. This could lead to a situation where: a. We were using xmm6 to store a Double#. b. We want to store a DoubleX2# into xmm6, so we spill the current content of xmm6 to the stack using a scalar move (correct). c. We update the register assignment, but we fail to update the format of the assignment, so we continue to think that xmm6 stores a Double# and not a DoubleX2#. d. Later on, we need to spill xmm6 because it is getting clobbered by another instruction. We then decide to only spill the lower 64 bits of the register, because we still think that xmm6 only stores a Double# and not a DoubleX2#. Fixes #26542 - - - - - aada5db9 by ARATA Mizuki at 2025-11-11T11:52:07-05:00 Fix the order of spill/reload instructions The AArch64 NCG could emit multiple instructions for a single spill/reload, but their order was not consistent between the definition and a use. Fixes #26537 Co-authored-by: sheaf <sam.derbyshire(a)gmail.com> - - - - - 64ec82ff by Andreas Klebinger at 2025-11-11T11:52:48-05:00 Add hpc to release script - - - - - 741da00c by Ben Gamari at 2025-11-12T03:38:20-05:00 template-haskell: Better describe getQ semantics Clarify that the state is a type-indexed map, as suggested by #26484. - - - - - 8b080e04 by ARATA Mizuki at 2025-11-12T03:39:11-05:00 Fix incorrect markups in the User's Guide * Correct markup for C--: "C-\-" in reST * Fix internal links * Fix code highlighting * Fix inline code: Use ``code`` rather than `code` * Remove extra backslashes Fixes #16812 Co-authored-by: sheaf <sam.derbyshire(a)gmail.com> - - - - - 04a90100 by fendor at 2025-11-12T12:03:18+01:00 Add 'ipId' to 'InfoProv' and add decoders The 'InfoProv' was changed to use a stable Id, for the eventlog and for general identification. This change simply exposes the stable id and allows you to quickly query it. - - - - - 131 changed files: - .gitlab/rel_eng/upload_ghc_libs.py - compiler/GHC/Builtin/Types.hs - compiler/GHC/Builtin/Types/Literals.hs - compiler/GHC/Cmm/Sink.hs - compiler/GHC/CmmToAsm/Reg/Linear.hs - compiler/GHC/CmmToAsm/Reg/Liveness.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Type.hs - compiler/GHC/Driver/Make.hs - compiler/GHC/Driver/Pipeline/Execute.hs - compiler/GHC/Iface/Decl.hs - compiler/GHC/Iface/Rename.hs - compiler/GHC/Iface/Syntax.hs - compiler/GHC/IfaceToCore.hs - compiler/GHC/Parser/PostProcess/Haddock.hs - compiler/GHC/Tc/Gen/HsType.hs - compiler/GHC/Tc/TyCl.hs - compiler/GHC/Tc/TyCl/Build.hs - compiler/GHC/Tc/TyCl/Instance.hs - docs/users_guide/bugs.rst - docs/users_guide/debug-info.rst - docs/users_guide/debugging.rst - docs/users_guide/extending_ghc.rst - docs/users_guide/exts/arrows.rst - docs/users_guide/exts/derive_any_class.rst - docs/users_guide/exts/deriving_extra.rst - docs/users_guide/exts/deriving_inferred.rst - docs/users_guide/exts/deriving_strategies.rst - docs/users_guide/exts/gadt.rst - docs/users_guide/exts/generics.rst - docs/users_guide/exts/overloaded_labels.rst - docs/users_guide/exts/overloaded_strings.rst - docs/users_guide/exts/pattern_synonyms.rst - docs/users_guide/exts/poly_kinds.rst - docs/users_guide/exts/primitives.rst - docs/users_guide/exts/rank_polymorphism.rst - docs/users_guide/exts/rebindable_syntax.rst - docs/users_guide/exts/required_type_arguments.rst - docs/users_guide/exts/scoped_type_variables.rst - docs/users_guide/exts/standalone_deriving.rst - docs/users_guide/exts/template_haskell.rst - docs/users_guide/exts/tuple_sections.rst - docs/users_guide/exts/type_data.rst - docs/users_guide/exts/type_defaulting.rst - docs/users_guide/gone_wrong.rst - docs/users_guide/hints.rst - docs/users_guide/javascript.rst - docs/users_guide/phases.rst - docs/users_guide/profiling.rst - docs/users_guide/separate_compilation.rst - docs/users_guide/using.rst - docs/users_guide/wasm.rst - docs/users_guide/win32-dlls.rst - libraries/base/tests/all.T - libraries/ghc-internal/src/GHC/Internal/InfoProv/Types.hsc - libraries/ghc-internal/src/GHC/Internal/TH/Monad.hs - libraries/ghci/GHCi/Message.hs - testsuite/driver/testlib.py - testsuite/tests/backpack/should_fail/T19244a.stderr - + testsuite/tests/codeGen/should_run/T26537.hs - + testsuite/tests/codeGen/should_run/T26537.stdout - testsuite/tests/codeGen/should_run/all.T - testsuite/tests/dependent/should_fail/T11334b.stderr - testsuite/tests/driver/T20696/all.T - testsuite/tests/driver/fat-iface/all.T - testsuite/tests/generics/T10604/T10604_deriving.stderr - testsuite/tests/ghc-e/should_fail/T9930fail.stderr - testsuite/tests/ghc-e/should_fail/all.T - testsuite/tests/ghci.debugger/scripts/print012.stdout - testsuite/tests/ghci/scripts/T10321.stdout - testsuite/tests/ghci/scripts/T24459.stdout - testsuite/tests/ghci/scripts/T7730.stdout - testsuite/tests/ghci/scripts/ghci065.stdout - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.hs - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/interface-stability/base-exports.stdout-ws-32 - testsuite/tests/profiling/should_run/staticcallstack001.stdout - testsuite/tests/profiling/should_run/staticcallstack002.stdout - testsuite/tests/rename/should_fail/rnfail055.stderr - testsuite/tests/rts/ipe/T24005/t24005.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables01.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables02.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables03.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables04.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables05.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables06.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables07.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables08.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables09.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables10.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables11.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables12.stdout - testsuite/tests/rts/ipe/distinct-tables/distinct_tables13.stdout - testsuite/tests/saks/should_compile/saks023.stdout - testsuite/tests/saks/should_compile/saks034.stdout - testsuite/tests/saks/should_compile/saks035.stdout - testsuite/tests/showIface/Makefile - + testsuite/tests/showIface/T26246a.hs - + testsuite/tests/showIface/T26246a.stdout - testsuite/tests/showIface/all.T - + testsuite/tests/simd/should_run/T26410_ffi.hs - + testsuite/tests/simd/should_run/T26410_ffi.stdout - + testsuite/tests/simd/should_run/T26410_ffi_c.c - + testsuite/tests/simd/should_run/T26410_prim.hs - + testsuite/tests/simd/should_run/T26410_prim.stdout - + testsuite/tests/simd/should_run/T26542.hs - + testsuite/tests/simd/should_run/T26542.stdout - + testsuite/tests/simd/should_run/T26550.hs - + testsuite/tests/simd/should_run/T26550.stdout - testsuite/tests/simd/should_run/all.T - testsuite/tests/splice-imports/all.T - testsuite/tests/typecheck/T16127/T16127.stderr - testsuite/tests/typecheck/should_compile/T22560d.stdout - testsuite/tests/typecheck/should_fail/T15629.stderr - utils/haddock/haddock-api/src/Haddock/Convert.hs - utils/haddock/html-test/ref/Bug1004.html - utils/haddock/html-test/ref/Bug1050.html - + utils/haddock/html-test/ref/Bug26246.html - utils/haddock/html-test/ref/Bug85.html - utils/haddock/html-test/ref/Bug923.html - utils/haddock/html-test/ref/BundledPatterns.html - utils/haddock/html-test/ref/BundledPatterns2.html - utils/haddock/html-test/ref/ConstructorPatternExport.html - utils/haddock/html-test/ref/GADTRecords.html - utils/haddock/html-test/ref/LinearTypes.html - utils/haddock/html-test/ref/PromotedTypes.html - + utils/haddock/html-test/src/Bug26246.hs - utils/haddock/latex-test/ref/LinearTypes/LinearTypes.tex The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/58644c6db8155e82cf5258af47afb2… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/58644c6db8155e82cf5258af47afb2… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/bytecode-library-combined] Load bytecode libraries to satisfy package dependencies
by Matthew Pickering (＠mpickering) 12 Nov '25

12 Nov '25

Matthew Pickering pushed to branch wip/bytecode-library-combined at Glasgow Haskell Compiler / GHC Commits: c66a5039 by Matthew Pickering at 2025-11-12T10:27:07+00:00 Load bytecode libraries to satisfy package dependencies This commit allows you to use a bytecode library to satisfy a package dependency when using the interpreter. If a user enables `-fprefer-byte-code`, then if a package provides a bytecode library, that will be loaded and used to satisfy the dependency. The main change is to separate the relevant parts of the `LoaderState` into external and home package byte code. Bytecode is loaded into either the home package or external part (similar to HPT/EPS split), HPT bytecode can be unloaded. External bytecode is never unloaded. The unload function has also only been called with an empty list of "stable linkables" for a long time. It has been modified to directly implement a complete unloading of the home package bytecode linkables. At the moment, the bytecode libraries are found in the "library-dirs" field from the package description. In the future when `Cabal` implements support for "bytecode-library-dirs" field, we can read the bytecode libraries from there. No changes to the Cabal submodule are necessary at the moment. Four new tests are added in testsuite/tests/cabal, which generate fake package descriptions and test loading the libraries into GHCi. Fixes #26298 - - - - - 36 changed files: - compiler/GHC/ByteCode/Linker.hs - compiler/GHC/Driver/Backpack.hs - compiler/GHC/Driver/Make.hs - compiler/GHC/Linker/Loader.hs - compiler/GHC/Linker/Types.hs - compiler/GHC/Runtime/Debugger.hs - compiler/GHC/Runtime/Eval.hs - compiler/GHC/Unit/Info.hs - compiler/GHC/Unit/State.hs - docs/users_guide/phases.rst - libraries/ghc-boot/GHC/Unit/Database.hs - testsuite/config/ghc - testsuite/mk/boilerplate.mk - + testsuite/tests/cabal/Bytecode.hs - + testsuite/tests/cabal/BytecodeForeign.c - + testsuite/tests/cabal/BytecodeForeign.hs - testsuite/tests/cabal/Makefile - testsuite/tests/cabal/all.T - + testsuite/tests/cabal/bytecode.pkg - + testsuite/tests/cabal/bytecode.script - + testsuite/tests/cabal/bytecode_foreign.pkg - + testsuite/tests/cabal/bytecode_foreign.script - testsuite/tests/cabal/ghcpkg03.stderr - testsuite/tests/cabal/ghcpkg03.stderr-mingw32 - testsuite/tests/cabal/ghcpkg05.stderr - testsuite/tests/cabal/ghcpkg05.stderr-mingw32 - + testsuite/tests/cabal/pkg_bytecode.stderr - + testsuite/tests/cabal/pkg_bytecode.stdout - + testsuite/tests/cabal/pkg_bytecode_foreign.stderr - + testsuite/tests/cabal/pkg_bytecode_foreign.stdout - + testsuite/tests/cabal/pkg_bytecode_with_gbc.stderr - + testsuite/tests/cabal/pkg_bytecode_with_gbc.stdout - + testsuite/tests/cabal/pkg_bytecode_with_o.stderr - + testsuite/tests/cabal/pkg_bytecode_with_o.stdout - testsuite/tests/driver/bytecode-object/all.T - utils/ghc-pkg/Main.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c66a5039366b4d835abeefc27afcc72… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c66a5039366b4d835abeefc27afcc72… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][master] Fix incorrect markups in the User's Guide
by Marge Bot (＠marge-bot) 12 Nov '25

12 Nov '25

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 8b080e04 by ARATA Mizuki at 2025-11-12T03:39:11-05:00 Fix incorrect markups in the User's Guide * Correct markup for C--: "C-\-" in reST * Fix internal links * Fix code highlighting * Fix inline code: Use ``code`` rather than `code` * Remove extra backslashes Fixes #16812 Co-authored-by: sheaf <sam.derbyshire(a)gmail.com> - - - - - 34 changed files: - docs/users_guide/bugs.rst - docs/users_guide/debug-info.rst - docs/users_guide/debugging.rst - docs/users_guide/extending_ghc.rst - docs/users_guide/exts/arrows.rst - docs/users_guide/exts/derive_any_class.rst - docs/users_guide/exts/deriving_extra.rst - docs/users_guide/exts/deriving_inferred.rst - docs/users_guide/exts/deriving_strategies.rst - docs/users_guide/exts/gadt.rst - docs/users_guide/exts/generics.rst - docs/users_guide/exts/overloaded_labels.rst - docs/users_guide/exts/overloaded_strings.rst - docs/users_guide/exts/pattern_synonyms.rst - docs/users_guide/exts/poly_kinds.rst - docs/users_guide/exts/primitives.rst - docs/users_guide/exts/rank_polymorphism.rst - docs/users_guide/exts/rebindable_syntax.rst - docs/users_guide/exts/required_type_arguments.rst - docs/users_guide/exts/scoped_type_variables.rst - docs/users_guide/exts/standalone_deriving.rst - docs/users_guide/exts/template_haskell.rst - docs/users_guide/exts/tuple_sections.rst - docs/users_guide/exts/type_data.rst - docs/users_guide/exts/type_defaulting.rst - docs/users_guide/gone_wrong.rst - docs/users_guide/hints.rst - docs/users_guide/javascript.rst - docs/users_guide/phases.rst - docs/users_guide/profiling.rst - docs/users_guide/separate_compilation.rst - docs/users_guide/using.rst - docs/users_guide/wasm.rst - docs/users_guide/win32-dlls.rst The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8b080e048d51defa19fe9a484ec922b… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8b080e048d51defa19fe9a484ec922b… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][master] template-haskell: Better describe getQ semantics
by Marge Bot (＠marge-bot) 12 Nov '25

12 Nov '25

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 741da00c by Ben Gamari at 2025-11-12T03:38:20-05:00 template-haskell: Better describe getQ semantics Clarify that the state is a type-indexed map, as suggested by #26484. - - - - - 1 changed file: - libraries/ghc-internal/src/GHC/Internal/TH/Monad.hs Changes: ===================================== libraries/ghc-internal/src/GHC/Internal/TH/Monad.hs ===================================== @@ -904,8 +904,17 @@ addModFinalizer act = Q (qAddModFinalizer (unQ act)) addCorePlugin :: String -> Q () addCorePlugin plugin = Q (qAddCorePlugin plugin) --- | Get state from the 'Q' monad. Note that the state is local to the --- Haskell module in which the Template Haskell expression is executed. +-- | Get state from the 'Q' monad. The state maintained by 'Q' is isomorphic to +-- a type-indexed finite map. That is, +-- +-- @ +-- do putQ @Int 42 +-- putQ @Char 'a' +-- getQ @Int -- == (Just 42) +-- @ +-- +-- Note that the state is local to the Haskell module in which the Template +-- Haskell expression is executed. getQ :: Typeable a => Q (Maybe a) getQ = Q qGetQ View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/741da00c0b27ee515926d24f6354b71… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/741da00c0b27ee515926d24f6354b71… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 2 commits: template-haskell: Better describe getQ semantics
by Marge Bot (＠marge-bot) 12 Nov '25

12 Nov '25

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 0f62414b by Ben Gamari at 2025-11-11T21:07:50-05:00 template-haskell: Better describe getQ semantics Clarify that the state is a type-indexed map, as suggested by #26484. - - - - - 31d13b0e by ARATA Mizuki at 2025-11-11T21:07:57-05:00 Fix incorrect markups in the User's Guide * Correct markup for C--: "C-\-" in reST * Fix internal links * Fix code highlighting * Fix inline code: Use ``code`` rather than `code` * Remove extra backslashes Fixes #16812 Co-authored-by: sheaf <sam.derbyshire(a)gmail.com> - - - - - 35 changed files: - docs/users_guide/bugs.rst - docs/users_guide/debug-info.rst - docs/users_guide/debugging.rst - docs/users_guide/extending_ghc.rst - docs/users_guide/exts/arrows.rst - docs/users_guide/exts/derive_any_class.rst - docs/users_guide/exts/deriving_extra.rst - docs/users_guide/exts/deriving_inferred.rst - docs/users_guide/exts/deriving_strategies.rst - docs/users_guide/exts/gadt.rst - docs/users_guide/exts/generics.rst - docs/users_guide/exts/overloaded_labels.rst - docs/users_guide/exts/overloaded_strings.rst - docs/users_guide/exts/pattern_synonyms.rst - docs/users_guide/exts/poly_kinds.rst - docs/users_guide/exts/primitives.rst - docs/users_guide/exts/rank_polymorphism.rst - docs/users_guide/exts/rebindable_syntax.rst - docs/users_guide/exts/required_type_arguments.rst - docs/users_guide/exts/scoped_type_variables.rst - docs/users_guide/exts/standalone_deriving.rst - docs/users_guide/exts/template_haskell.rst - docs/users_guide/exts/tuple_sections.rst - docs/users_guide/exts/type_data.rst - docs/users_guide/exts/type_defaulting.rst - docs/users_guide/gone_wrong.rst - docs/users_guide/hints.rst - docs/users_guide/javascript.rst - docs/users_guide/phases.rst - docs/users_guide/profiling.rst - docs/users_guide/separate_compilation.rst - docs/users_guide/using.rst - docs/users_guide/wasm.rst - docs/users_guide/win32-dlls.rst - libraries/ghc-internal/src/GHC/Internal/TH/Monad.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/4c0b12090ed054cb72cd54cabe7b4d… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/4c0b12090ed054cb72cd54cabe7b4d… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T23162-part2] better still
by Simon Peyton Jones (＠simonpj) 11 Nov '25

11 Nov '25

Simon Peyton Jones pushed to branch wip/T23162-part2 at Glasgow Haskell Compiler / GHC Commits: 82df99d9 by Simon Peyton Jones at 2025-11-11T17:48:59+00:00 better still - - - - - 1 changed file: - compiler/GHC/Tc/Solver/FunDeps.hs Changes: ===================================== compiler/GHC/Tc/Solver/FunDeps.hs ===================================== @@ -545,24 +545,14 @@ mkTopClosedFamEqFDs :: CoAxiom Branched -> [TcType] -> Xi -> TcS [FunDepEqns] mkTopClosedFamEqFDs ax work_args work_rhs = do { let branches = fromBranches (coAxiomBranches ax) ; traceTcS "mkTopClosed" (ppr branches $$ ppr work_args $$ ppr work_rhs) - ; return (go branches) } + ; case filter relevant_branch branches of + [CoAxBranch { cab_tvs = qtvs, cab_lhs = lhs_tys }] + -> return [FDEqns { fd_qtvs = qtvs + , fd_eqs = zipWith Pair lhs_tys work_args }] + _ -> return [] } where - go :: [CoAxBranch] -> [FunDepEqns] - go [] = [] - - go (branch : later_branches) - | CoAxBranch { cab_tvs = qtvs, cab_lhs = lhs_tys - , cab_rhs = rhs_ty, cab_incomps = incomps } <- branch - , not (eqnIsIrrelevant lhs_tys rhs_ty work_args work_rhs) - , all irrelevant_branch incomps - , all irrelevant_branch later_branches - = [FDEqns { fd_qtvs = qtvs, fd_eqs = zipWith Pair lhs_tys work_args }] - - | otherwise - = go later_branches - - irrelevant_branch (CoAxBranch { cab_lhs = lhs_tys, cab_rhs = rhs_ty }) - = eqnIsIrrelevant lhs_tys rhs_ty work_args work_rhs + relevant_branch (CoAxBranch { cab_lhs = lhs_tys, cab_rhs = rhs_ty }) + = eqnIsRelevant lhs_tys rhs_ty work_args work_rhs mkTopOpenFamEqFDs :: TyCon -> [Bool] -> [TcType] -> Xi -> TcS [FunDepEqns] -- Implements (INJFAM:Wanted/top) @@ -738,13 +728,13 @@ getInertFamEqsFor fam_tc work_args work_rhs , eq_rhs = inert_rhs }) <- equal_ct_list , NomEq == eq_rel - , not (eqnIsIrrelevant inert_args inert_rhs work_args work_rhs) ] } + , eqnIsRelevant inert_args inert_rhs work_args work_rhs ] } -eqnIsIrrelevant :: [TcType] -> TcType +eqnIsRelevant :: [TcType] -> TcType -> [TcType] -> TcType -> Bool -eqnIsIrrelevant lhs_tys1 rhs_ty1 lhs_tys2 rhs_ty2 - = (rhs_ty1:lhs_tys1) `typeListsAreApart` (rhs_ty2:lhs_tys2) +eqnIsRelevant lhs_tys1 rhs_ty1 lhs_tys2 rhs_ty2 + = not ((rhs_ty1:lhs_tys1) `typeListsAreApart` (rhs_ty2:lhs_tys2)) {- Note [Type inference for type families with injectivity] View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/82df99d998eb356ccebbf2130bc6f79… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/82df99d998eb356ccebbf2130bc6f79… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26425] Wibbles
by Simon Peyton Jones (＠simonpj) 11 Nov '25

11 Nov '25

Simon Peyton Jones pushed to branch wip/T26425 at Glasgow Haskell Compiler / GHC Commits: fcc38ef7 by Simon Peyton Jones at 2025-11-11T17:47:50+00:00 Wibbles - - - - - 2 changed files: - compiler/GHC/Core/Opt/OccurAnal.hs - compiler/GHC/Core/Opt/Simplify/Iteration.hs Changes: ===================================== compiler/GHC/Core/Opt/OccurAnal.hs ===================================== @@ -660,18 +660,35 @@ through A, so it should have ManyOcc. Bear this case in mind! * In occ_env, the new (occ_join_points :: IdEnv OccInfoEnv) maps each in-scope non-recursive join point, such as `j` above, to a "zeroed form" of its RHS's usage details. The "zeroed form" + * has only occ_nested_lets in its domain (see (W5) below) * deletes ManyOccs * maps a OneOcc to OneOcc{ occ_n_br = 0 } - In our example, occ_join_points will be extended with + In our example, assuming `v` is locally-let-bound, occ_join_points will + be extended with [j :-> [v :-> OneOcc{occ_n_br=0}]] See `addJoinPoint` and (W5) below. * At an occurrence of a join point, we do everything as normal, but add in the UsageDetails from the occ_join_points. See mkOneOcc. -* Crucially, at the NonRec binding of the join point, in `occAnalBind`, we use - `combineJoinPointUDs`, not `andUDs` to combine the usage from the RHS with - the usage from the body. +* Crucially, at the NonRec binding of a join point `j`, in `occAnalBind`, + we use `combineJoinPointUDs`, not `andUDs` to combine the usage from the + RHS with the usage from the body. `combineJoinPointUDs` behaves like this: + + * For all variables than `occ_nested_lets`, use `andUDs`, just like for + any normal let-binding. + + * But for a variable `v` in `occ_nested_lets`, use `orUDs`: + - If `v` occurs `ManyOcc` in the join-point RHS, the variable won't be in + `occ_join_points`; but we'll get `ManyOcc` anyway. + - If `v` occurs `OneOcc` in the join-point RHS, the variable will be in + `occ_join_points` and we'll thereby get a `OneOcc{occ_n_br=0}` from + each of j's tail calls. We can `or` that with the `OncOcc{occ_n_br=n}` + from j's RHS. + + The only reason for `occ_nested_lets` is to reduce the size of the info + duplicate at each tail call; see (W5). It would sound to put *all* variables + into `occ_nested_lets`. Here are the consequences @@ -682,8 +699,9 @@ Here are the consequences There are two lexical occurrences of `v`! (NB: `orUDs` adds occ_n_br together, so occ_n_br=1 is impossible, too.) -* In the tricky (P3) we'll get an `andUDs` of - * OneOcc{occ_n_br=0} from the occurrences of `j`) +* In the tricky (P3), when analysing `case (f v) of ...`, we'll get + an `andUDs` of + * OneOcc{occ_n_br=0} from the occurrences of `j` * OneOcc{occ_n_br=1} from the (f v) These are `andUDs` together in `addOccInfo`, and hence `v` gets ManyOccs, just as it should. Clever! @@ -739,7 +757,7 @@ Wrinkles (W1) and (W2) are very similar to Note [Binder swap] (BS3). will use only one of them. So again, we can use `combineJoinPointUDs` to combine usage info from all these alternatives RHSs. -(W5) Other things being equal, we want keep the OccInfoEnv in the range of +(W5) Other things being equal, we want keep the OccInfoEnv stored in `occ_join_points` as small as possible, because it is /duplicated/ at /every occurrence/ of the join point. We really only want to include OccInfo for @@ -759,9 +777,10 @@ Wrinkles (W1) and (W2) are very similar to Note [Binder swap] (BS3). not `x` (lambda bound) nor `z` (occurs many times). To exploit this: - * `occ_local_lets` tracks which Ids are local, non-recursive lets + * `occ_nested_lets` tracks which Ids are + nested (not-top-level), non-recursive lets * `addJoinPoint` only populates j's entry with occ-info for the "tracked Ids" - of `j`; that is, that are (a) in occ_local_lets and (b) have OneOcc. + of `j`; that is, that are (a) in occ_nested_lets and (b) have OneOcc. * `combineJoinPointUDs` uses orLocalOcc for local-let Ids andLocalOcc for non-local-let Ids @@ -2913,7 +2932,7 @@ data OccEnv -- See Note [Occurrence analysis for join points] , occ_join_points :: !JoinPointInfo - , occ_local_lets :: IdSet -- Non-top-level non-rec-bound lets + , occ_nested_lets :: IdSet -- Non-top-level, non-rec-bound lets -- I tried making this field strict, but -- doing so slightly increased allocation } @@ -2968,7 +2987,7 @@ initOccEnv , occ_join_points = emptyVarEnv , occ_bs_env = emptyVarEnv , occ_bs_rng = emptyVarSet - , occ_local_lets = emptyVarSet } + , occ_nested_lets = emptyVarSet } noBinderSwaps :: OccEnv -> Bool noBinderSwaps (OccEnv { occ_bs_env = bs_env }) = isEmptyVarEnv bs_env @@ -3209,19 +3228,19 @@ postprocess_uds bndrs bad_joins uds | otherwise = env addLocalLet :: OccEnv -> TopLevelFlag -> Id -> OccEnv -addLocalLet env@(OccEnv { occ_local_lets = ids }) top_lvl id +addLocalLet env@(OccEnv { occ_nested_lets = ids }) top_lvl id | isTopLevel top_lvl = env - | otherwise = env { occ_local_lets = ids `extendVarSet` id } + | otherwise = env { occ_nested_lets = ids `extendVarSet` id } addJoinPoint :: OccEnv -> Id -> UsageDetails -> OccEnv -addJoinPoint env@(OccEnv { occ_join_points = join_points, occ_local_lets = local_lets }) +addJoinPoint env@(OccEnv { occ_join_points = join_points, occ_nested_lets = nested_lets }) join_bndr (UD { ud_env = rhs_occs }) | isEmptyVarEnv zeroed_form = env | otherwise = env { occ_join_points = extendVarEnv join_points join_bndr zeroed_form } where - zeroed_form = mapMaybeUniqSetToUFM do_one local_lets + zeroed_form = mapMaybeUniqSetToUFM do_one nested_lets -- See Note [Occurrence analysis for join points] for "zeroed form" do_one :: Var -> Maybe LocalOcc @@ -3748,12 +3767,12 @@ orUDs = combineUsageDetailsWith (\_uniq -> orLocalOcc) combineJoinPointUDs :: OccEnv -> UsageDetails -> UsageDetails -> UsageDetails -- See (W5) in Note [Occurrence analysis for join points] -combineJoinPointUDs (OccEnv { occ_local_lets = local_lets }) uds1 uds2 +combineJoinPointUDs (OccEnv { occ_nested_lets = nested_lets }) uds1 uds2 = combineUsageDetailsWith combine uds1 uds2 where combine uniq occ1 occ2 - | uniq `elemVarSetByKey` local_lets = orLocalOcc occ1 occ2 - | otherwise = andLocalOcc occ1 occ2 + | uniq `elemVarSetByKey` nested_lets = orLocalOcc occ1 occ2 + | otherwise = andLocalOcc occ1 occ2 mkOneOcc :: OccEnv -> Id -> InterestingCxt -> JoinArity -> UsageDetails mkOneOcc !env id int_cxt arity ===================================== compiler/GHC/Core/Opt/Simplify/Iteration.hs ===================================== @@ -4595,21 +4595,13 @@ mkLetUnfolding :: SimplEnv -> TopLevelFlag -> UnfoldingSource -> InId -> Bool -- True <=> this is a join point -> OutExpr -> SimplM Unfolding mkLetUnfolding env top_lvl src id is_join new_rhs --- | is_join --- , UnfNever <- guidance --- = -- For large join points, don't keep an unfolding at all if it is large --- -- This is just an attempt to keep residency under control in --- -- deeply-nested join-point such as those arising in #26425 --- return NoUnfolding - - | otherwise - = return (mkCoreUnfolding src is_top_lvl new_rhs Nothing guidance) - -- We make an unfolding *even for loop-breakers*. - -- Reason: (a) It might be useful to know that they are WHNF - -- (b) In GHC.Iface.Tidy we currently assume that, if we want to - -- expose the unfolding then indeed we *have* an unfolding - -- to expose. (We could instead use the RHS, but currently - -- we don't.) The simple thing is always to have one. + = return (mkUnfolding uf_opts src is_top_lvl is_bottoming is_join new_rhs Nothing) + -- We make an unfolding *even for loop-breakers*. + -- Reason: (a) It might be useful to know that they are WHNF + -- (b) In GHC.Iface.Tidy we currently assume that, if we want to + -- expose the unfolding then indeed we *have* an unfolding + -- to expose. (We could instead use the RHS, but currently + -- we don't.) The simple thing is always to have one. where -- !opts: otherwise, we end up retaining all the SimpleEnv !uf_opts = seUnfoldingOpts env @@ -4620,9 +4612,6 @@ mkLetUnfolding env top_lvl src id is_join new_rhs -- See Note [Force bottoming field] !is_bottoming = isDeadEndId id - is_top_bottoming = is_top_lvl && is_bottoming - guidance = calcUnfoldingGuidance uf_opts is_top_bottoming is_join new_rhs - ------------------- simplStableUnfolding :: SimplEnv -> BindContext -> InId View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/fcc38ef7a460f92e4d785bb845524ea… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/fcc38ef7a460f92e4d785bb845524ea… You're receiving this email because of your account on gitlab.haskell.org.

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