[Git][ghc/ghc][wip/simplifier-tweaks] 23 commits: Improve toInteger @Word32 on 64-bit platforms
Simon Peyton Jones (@simonpj)
gitlab at gitlab.haskell.org
Tue Mar 26 13:59:46 UTC 2024
Simon Peyton Jones pushed to branch wip/simplifier-tweaks at Glasgow Haskell Compiler / GHC
Commits:
8a8ac65a by Matthew Craven at 2024-03-23T00:20:52-04:00
Improve toInteger @Word32 on 64-bit platforms
On 64-bit platforms, every Word32 fits in an Int, so we can
convert to Int# without having to perform the overflow check
integerFromWord# uses internally.
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0c48f2b9 by Apoorv Ingle at 2024-03-23T00:21:28-04:00
Fix for #24552 (see testcase T24552)
Fixes for a bug in desugaring pattern synonyms matches, introduced
while working on on expanding `do`-blocks in #18324
The `matchWrapper` unecessarily (and incorrectly) filtered out the
default wild patterns in a match. Now the wild pattern alternative is
simply ignored by the pm check as its origin is `Generated`.
The current code now matches the expected semantics according to the language spec.
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b72705e9 by Simon Peyton Jones at 2024-03-23T00:22:04-04:00
Print more info about kinds in error messages
This fixes #24553, where GHC unhelpfully said
error: [GHC-83865]
• Expected kind ‘* -> * -> *’, but ‘Foo’ has kind ‘* -> * -> *’
See Note [Showing invisible bits of types in error messages]
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8f7cfc7e by Tristan Cacqueray at 2024-03-23T00:22:44-04:00
docs: remove the don't use float hint
This hint is outdated, ``Complex Float`` are now specialised,
and the heap space suggestion needs more nuance so it should
be explained in the unboxed/storable array documentation.
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5bd8ed53 by Andreas Klebinger at 2024-03-23T16:18:33-04:00
NCG: Fix a bug in jump shortcutting.
When checking if a jump has more than one destination account for the
possibility of some jumps not being representable by a BlockId.
We do so by having isJumpishInstr return a `Maybe BlockId` where Nothing
represents non-BlockId jump destinations.
Fixes #24507
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8d67f247 by Ben Gamari at 2024-03-23T16:19:09-04:00
docs: Drop old release notes, add for 9.12.1
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7db8c992 by Cheng Shao at 2024-03-25T13:45:46-04:00
rts: fix clang compilation on aarch64
This patch fixes function prototypes in ARMOutlineAtomicsSymbols.h
which causes "error: address argument to atomic operation must be a
pointer to _Atomic type" when compiling with clang on aarch64.
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237194ce by Sylvain Henry at 2024-03-25T13:46:27-04:00
Lexer: fix imports for Alex 3.5.1 (#24583)
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810660b7 by Cheng Shao at 2024-03-25T22:19:16-04:00
libffi-tarballs: bump libffi-tarballs submodule to libffi 3.4.6
This commit bumps the libffi-tarballs submodule to libffi 3.4.6, which
includes numerous upstream libffi fixes, especially
https://github.com/libffi/libffi/issues/760.
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d2ba41e8 by Alan Zimmerman at 2024-03-25T22:19:51-04:00
EPA: do not duplicate comments in signature RHS
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d1371219 by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Several improvements to the handling of coercions
* Make `mkSymCo` and `mkInstCo` smarter
Fixes #23642
* Fix return role of `SelCo` in the coercion optimiser.
Fixes #23617
* Make the coercion optimiser `opt_trans_rule` work better for newtypes
Fixes #23619
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1eebfb65 by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
FloatOut: improve floating for join point
See the new Note [Floating join point bindings].
* Completely get rid of the complicated join_ceiling nonsense, which
I have never understood.
* Do not float join points at all, except perhaps to top level.
* Some refactoring around wantToFloat, to treat Rec and NonRec more
uniformly
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ccf34222 by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Improve eta-expansion through call stacks
See Note [Eta expanding through CallStacks] in GHC.Core.Opt.Arity
This is a one-line change, that fixes an inconsistency
- || isCallStackPredTy ty
+ || isCallStackPredTy ty || isCallStackTy ty
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1c4a2e14 by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Spelling, layout, pretty-printing only
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e5e487da by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Improve exprIsConApp_maybe a little
Eliminate a redundant case at birth. This sometimes reduces
Simplifier iterations.
See Note [Case elim in exprIsConApp_maybe].
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42fd4071 by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Inline GHC.HsToCore.Pmc.Solver.Types.trvVarInfo
When exploring compile-time regressions after meddling with the Simplifier, I
discovered that GHC.HsToCore.Pmc.Solver.Types.trvVarInfo was very delicately
balanced. It's a small, heavily used, overloaded function and it's important
that it inlines. By a fluke it was before, but at various times in my journey it
stopped doing so. So I just added an INLINE pragma to it; no sense in depending
on a delicately-balanced fluke.
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5e37b4d5 by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Slight improvement in WorkWrap
Ensure that WorkWrap preserves lambda binders, in case of join points. Sadly I
have forgotten why I made this change (it was while I was doing a lot of
meddling in the Simplifier, but
* it does no harm,
* it is slightly more efficient, and
* presumably it made something better!
Anyway I have kept it in a separate commit.
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d4c04c9f by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Use named record fields for the CastIt { ... } data constructor
This is a pure refactor
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f330f0ab by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Remove a long-commented-out line
Pure refactoring
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0edce85a by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Simplifier improvements
This MR started as: allow the simplifer to do more in one pass,
arising from places I could see the simplifier taking two iterations
where one would do. But it turned into a larger project, because
these changes unexpectedly made inlining blow up, especially join
points in deeply-nested cases.
The main changes are below. There are also many new or rewritten Notes.
Avoiding simplifying repeatedly
~~~~~~~~~~~~~~~
See Note [Avoiding simplifying repeatedly]
* The SimplEnv now has a seInlineDepth field, which says how deep
in unfoldings we are. See Note [Inline depth] in Simplify.Env.
Currently used only for the next point: avoiding repeatedly
simplifying coercions.
* Avoid repeatedly simplifying coercions.
see Note [Avoid re-simplifying coercions] in Simplify.Iteration
As you'll see from the Note, this makes use of the seInlineDepth.
* Allow Simplify.Iteration.simplAuxBind to inline used-once things.
This is another part of Note [Post-inline for single-use things], and
is really good for reducing simplifier iterations in situations like
case K e of { K x -> blah }
wher x is used once in blah.
* Make GHC.Core.SimpleOpt.exprIsConApp_maybe do some simple case
elimination. Note [Case elim in exprIsConApp_maybe]
postInlineUnconditionally
~~~~~~~~~~~~~~~~~~~~~~~~~
* Allow Simplify.Utils.postInlineUnconditionally to inline variables
that are used exactly once. See Note [Post-inline for single-use things].
* Do not postInlineUnconditionally join point, ever.
Doing so does not reduce allocation, which is the main point,
and with join points that are used a lot it can bloat code.
See point (1) of Note [Duplicating join points] in
GHC.Core.Opt.Simplify.Iteration.
* Do not postInlineUnconditionally a strict (demanded) binding.
It will not allocate a thunk (it'll turn into a case instead)
so again the main point of inlining it doesn't hold. Better
to check per-call-site.
* Improve occurrence analyis for bottoming function calls, to help
postInlineUnconditionally. See Note [Bottoming function calls]
in GHC.Core.Opt.OccurAnal
Inlining generally
~~~~~~~~~~~~~~~~~~
* In GHC.Core.Opt.Simplify.Utils.interestingCallContext,
use RhsCtxt NonRecursive (not BoringCtxt) for a plain-seq case.
See Note [Seq is boring]
* In GHC.Core.Opt.Simplify.Utils.interestingArg,
- return ValueArg for OtherCon [c1,c2, ...], but
- return NonTrivArg for OtherCon []
This makes a function a little less likely to inline if all we
know is that the argument is evaluated, but nothing else.
* isConLikeUnfolding is no longer true for OtherCon {}.
This propagates to exprIsConLike. Con-like-ness has /positive/
information.
Join points
~~~~~~~~~~~
* Be very careful about inlining join points.
See these two long Notes
Note [Duplicating join points] in GHC.Core.Opt.Simplify.Iteration
Note [Inlining join points] in GHC.Core.Opt.Simplify.Inline
* When making join points, don't do so if the join point is so small
it will immediately be inlined; check uncondInlineJoin.
* In GHC.Core.Opt.Simplify.Inline.tryUnfolding, improve the inlining
heuristics for join points. In general we /do not/ want to inline
join points /even if they are small/. See Note [Duplicating join points]
GHC.Core.Opt.Simplify.Iteration.
But sometimes we do: see Note [Inlining join points] in
GHC.Core.Opt.Simplify.Inline.
* Do not add an unfolding to a join point at birth. This is a tricky one
and has a long Note [Do not add unfoldings to join points at birth]
It shows up in two places
- In `mkDupableAlt` do not add an inlining
- (trickier) In `simplLetUnfolding` don't add an unfolding for a
fresh join point
I am not fully satisifed with this, but it works and is well documented.
* In GHC.Core.Unfold.sizeExpr, make jumps small, so that we don't penalise
having a non-inlined join point.
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cfd5e4a1 by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Testsuite message changes from simplifier improvements
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2ee2620f by Simon Peyton Jones at 2024-03-26T11:39:22+00:00
Account for bottoming functions in OccurAnal
This fixes #24582, a small but long-standing bug
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2cf3c6e7 by Simon Peyton Jones at 2024-03-26T13:59:29+00:00
Move mergeCaseAlts to prepareAlts
This makes it happen on InAlts, which reduces the number of Simplifier
iterations by one.
- - - - -
23 changed files:
- compiler/GHC/CmmToAsm/AArch64/Instr.hs
- compiler/GHC/CmmToAsm/BlockLayout.hs
- compiler/GHC/CmmToAsm/Instr.hs
- compiler/GHC/CmmToAsm/PPC/Instr.hs
- compiler/GHC/CmmToAsm/Reg/Graph/SpillClean.hs
- compiler/GHC/CmmToAsm/Reg/Linear/JoinToTargets.hs
- compiler/GHC/CmmToAsm/Reg/Liveness.hs
- compiler/GHC/CmmToAsm/X86/Instr.hs
- compiler/GHC/Core.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Coercion/Opt.hs
- compiler/GHC/Core/Map/Type.hs
- compiler/GHC/Core/Opt/Arity.hs
- compiler/GHC/Core/Opt/FloatOut.hs
- compiler/GHC/Core/Opt/Monad.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/Pipeline.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/Simplify/Env.hs
- compiler/GHC/Core/Opt/Simplify/Inline.hs
- compiler/GHC/Core/Opt/Simplify/Iteration.hs
- compiler/GHC/Core/Opt/Simplify/Monad.hs
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d66a7c832871a7cb537f4f03d555a469ffcb6a31...2cf3c6e74d31c4635d5d47276042ada323523403
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d66a7c832871a7cb537f4f03d555a469ffcb6a31...2cf3c6e74d31c4635d5d47276042ada323523403
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