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ea4c2cbd
by Brandon Chinn at 2026-02-27T16:22:38-08:00
Implement QualifiedStrings (#26503)
See Note [Implementation of QualifiedStrings]
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08bc245b
by sheaf at 2026-03-01T11:11:54-05:00
Clean up join points, casts & ticks
This commit shores up the logic dealing with casts and ticks occurring
in between a join point binding and a jump.
Fixes #26642 #26929 #26693
Makes progress on #14610 #26157 #26422
Changes:
- Remove 'GHC.Types.Tickish.TickishScoping' in favour of simpler
predicates 'tickishHasNoScope'/'tickishHasSoftScope', as things were
before commit 993975d3. This makes the code easier to read and
document (fewer indirections).
- Introduce 'canCollectArgsThroughTick' for consistent handling of
ticks around PrimOps and other 'Id's that cannot be eta-reduced.
See overhauled Note [Ticks and mandatory eta expansion].
- New Note [JoinId vs TailCallInfo] in GHC.Core.SimpleOpt that explains
robustness of JoinId vs fragility of TailCallInfo.
- Allow casts/non-soft-scoped ticks to occur in between a join point
binder and a jump, but only in Core Prep.
See Note [Join points, casts, and ticks] and
Note [Join points, casts, and ticks... in Core Prep]
in GHC.Core.Opt.Simplify.Iteration.
Also update Core Lint to account for this.
See Note [Linting join points with casts or ticks] in GHC.Core.Lint.
- Update 'GHC.Core.Utils.mergeCaseAlts' to avoid pushing a cast in
between a join point binding and its jumps. This fixes #26642.
See the new (MC5) and (MC6) in Note [Merge Nested Cases].
- Update float out to properly handle source note ticks. They are now
properly floated out instead of being discarded.
This increases the number of ticks in certain tests with -g.
Test cases: T26642 and TrickyJoins.
Metric increase due to more source note ticks with -g:
-------------------------
Metric Increase:
libdir
size_hello_artifact
size_hello_unicode
-------------------------
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476c4cdf
by Sean D. Gillespie at 2026-03-02T10:14:37-05:00
Add SIMD absolute value on x86 and LLVM
On x86, absolute value of 32 bits or less is implemented with
PABSB/PABSW/PABSD if SSSE3 is available. Otherwise, there is a fallback
for SSE2. For 64 bit integers it uses VPABSQ, required by AVX-512VL,
with fallbacks for SSE4.2 and SSE2.
There is no dedicated instruction for floating point absolute value on
x86, so it is simulated using bitwise AND.
Absolute value for signed integers and floats are implemented by the
"llvm.abs/llvm.fabs" standard library intrinsics. This implementation
uses MachOps constructors, unlike non-vector floating point absolute
value, which uses CallishMachOps.
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709448c0
by Sean D. Gillespie at 2026-03-02T10:14:46-05:00
Add SIMD floating point square root
On x86, this is implemented with the SQRTPS and SQRTPD instructions. On
LLVM, it uses the sqrt library intrinstic.
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0deadf66
by Sean D. Gillespie at 2026-03-02T10:14:47-05:00
Improve error message for SIMD on aarch64
When encountering vector literals on aarch64, previously it would
throw:
<no location info>: error:
panic! (the 'impossible' happened)
GHC version 9.15.20251219:
getRegister' (CmmLit:CmmVec):
Now it is more consistent with the other vector operations:
<no location info>: error:
sorry! (unimplemented feature or known bug)
GHC version 9.15.20251219:
SIMD operations on AArch64 currently require the LLVM backend
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7d64031b
by Vladislav Zavialov at 2026-03-03T11:09:28-05:00
Replace maybeAddSpace with spaceIfSingleQuote
Simplify pretty-printing of HsTypes by using spaceIfSingleQuote.
This allows us to drop the unwieldy lhsTypeHasLeadingPromotionQuote
helper function.
Follow-up to 178c1fd830c78377ef5d338406a41e1d8eb5f0da
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20b2d918
by Joseph Fourment at 2026-03-03T23:29:51+00:00
Add type-lets into Core
The plan for #20264 is to introduce let-bound types to have observable sharing in types.
To avoid the need to carry an environment when dealing with occurrences of these type variables,
we embed the types they're bound to (if any) in a `tv_unfolding :: Maybe Type` attribute.
This way, one can look through let-bound type variables using `coreView` and friends.
In particular, definitional equality looks through unfoldings.
simple-opt: don't inline type-lets
specialise: fix type-lets in DFun unfoldings
During specialisation, a dictionary being specialised gets a new unfolding by turning
`DFun \ bndrs -> MkD @<T1> ... @<Tm> <op1> ... <opn>` into
`DFun \ spec_bndrs -> MkD @((\ bndrs -> TYPE: <T1>) spec_args) ... ((\ bndrs -> <opn>) spec_args)`
which in turns gets beta-reduced into
`DFun \ spec_bndrs -> MkD (let { bndrs = spec_args } in TYPE: <T1>) ... (let { bndrs = spec_args } in <opn>)`.
Previously, such let binders would immediately be substituted into the type so it didn't cause any issue,
but now we want to avoid inlining.
Arguments of the form `let { bndrs = spec_args } in TYPE: <T1>` are not considered as type arguments since they're
not of the canonical form `TYPE: something`.
This commit restores the previous behavior of substituting the specialised type arguments.
Alternatively, we could attach some floated type bindings to `DFun`s.
occur-anal: implement occurence analysis for type variables
In order to find out let-bound type variables that are used only once, in the hope of inlining them,
we need to track type variables as well in the occurrence analiser. Just like Id's, we attach an
`OccInfo` to each (immutable) type variable, and we walk into types and coercions to accurately gather
occurrences.
simplifier: don't inline type-lets
Keep propagating type-lets further down the pipeline, in the simplifier.
We also update CallArity, CprAnal, DmdAnal, WorkWrap, and Specialise to ignore type-lets.
prep: make type-lets pass through CorePrep
As a first attempt, ignore type-lets in CorePrep to avoid crashes.
However, this is not enough: CorePrep also does some let-floating.
If we don't float type-lets along with value-level let-bindings,
the latter can float out of the scope of a type variable in use.
simple-opt: fix simple_type_bind
Also:
- Inline small types using a new typeIsSmallEnoughToInline predicate
- Inline single-occurrence variables
simple-opt: make beta-reduction use simple_bind_type
iface: add IfaceTypeLetBndr to represent non-top-level type-let binders
IfaceLetBndr isn't fit to represent type-let binders, as it includes a
bunch of vacuous flags for Ids only.
Instead of putting squares in circles, I added a new constructor for type binders.
The downside is that it breaks existing iface files, so since we can't bootstrap
yet so we have to bootstrap a cherry-picked branch and then checkout again to build
with --freeze1.
To avoid similar issues in the future, IfaceTyVarInfoItem serialises with a tag
despite there being only one constructor for now.
dmd-anal: prefix unused variable with _ to avoid warning
type: inline unfoldView in sORTKind_maybe
tidy: deal with type-lets
notes: add Note [Type and coercion lets]
notes: update Note [Comparing nullary type synonyms] to account for type variables
While updating backlinks, I noticed the optimisation for type variables
could be performed in more places.
simplifier: inline single-occurring type-lets
cleanup: remove NOINLINE on tyVarOccInfo
Wibbles
Wibbles
Progress
Progress
More progress
Progress
...doesn't compile though
Mostly working now
Aggressively create type-lets
more progress
More progress
Temp debug printing
Remove bogus assert
Fix anoher couple of bugs
in SimpleOpt and exprIsTrivial
Improve zonking of foreign decls to avoid TcTyVars escaping
Wibbles
Some small wibbles
Improvements
Rmmove trace
Wibbles
Use lambda, not let, in WorkWrap
Using type let did not work right with type lets and shadowing
Requires Lint to be OK join points under beta redexes -- but it is!
Needs better documentation
Wibbles
More improvements
More improvements
* Less cloning in SpecConstr
* Lint checks RULES for imported binders
Comments only
Wibble
Wibbles
Wibbles
.. getting Lint errors when compiling GHC.Internal.Classes
Wibbles
More improvements
..now getting to the back end an interface file generation
Wibbles
Wibble unsed var
Missing case in tyThingEntityInfo
Add IfaceExtTyVar
Wibbles
Start to make OccAnal count TyCoVars properly [skip ci]
Proper occurrence analysis for TyCoVars
Wibble imports
Wibble imports again
Fix two tricky buglets
More small fixes
Add missing mkAbsCoreApps
...which caused bad Lint errors
More wibbles
More wibbles exp around mkPolyAbsLams
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7ed656f2
by Simon Peyton Jones at 2026-03-03T23:29:54+00:00
Make it compile again
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cc99af3a
by Simon Peyton Jones at 2026-03-03T23:29:54+00:00
Simplify mkcoreAbsLams a bit
..Needs documentation
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65cdc8ed
by Simon Peyton Jones at 2026-03-03T23:32:48+00:00
Fix build
Several important fixes, need better docs
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c63f69e8
by Simon Peyton Jones at 2026-03-03T23:32:51+00:00
Wibbles
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5e50af53
by Simon Peyton Jones at 2026-03-03T23:32:51+00:00
Make it compile
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66c8805b
by Simon Peyton Jones at 2026-03-03T23:32:51+00:00
Improve Lint error message slightly
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d90339ab
by Simon Peyton Jones at 2026-03-03T23:32:51+00:00
Wibble lint rules
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da7c3120
by Simon Peyton Jones at 2026-03-03T23:32:51+00:00
Wibbles
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30a4be88
by Simon Peyton Jones at 2026-03-03T23:33:49+00:00
Wibbles
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1538568e
by Simon Peyton Jones at 2026-03-03T23:33:49+00:00
Expand tyvars in Specialise
Pretty important!
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4eabfe97
by Simon Peyton Jones at 2026-03-03T23:33:49+00:00
Comments only
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fb3ca68c
by Simon Peyton Jones at 2026-03-03T23:33:50+00:00
More wibbles
* `bindAuxiliaryTyVars` in Specialise
* `trivial_expr_fold` needs to accept big coercions in CoreToStg
because the binder-swap can duplicate big coercions (boo)
Plus renaming in Specialise
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f0bdb345
by Simon Peyton Jones at 2026-03-03T23:33:50+00:00
Onward
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e2837f76
by Simon Peyton Jones at 2026-03-03T23:34:59+00:00
More wibbles
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84ddae32
by Simon Peyton Jones at 2026-03-03T23:35:02+00:00
Wibbles
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f2d502b9
by Simon Peyton Jones at 2026-03-03T23:40:57+00:00
Wibbles