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<h3>
Ben Gamari pushed to branch wip/T15304
at <a href="https://gitlab.haskell.org/ghc/ghc">Glasgow Haskell Compiler / GHC</a>
</h3>
<h4>
Commits:
</h4>
<ul>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/ef7576c40f8de391ed8b1c81c38156202e6d17cf">ef7576c4</a></strong>
<div>
<span>by Zubin Duggal</span>
<i>at 2020-04-03T06:24:56-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Add outputable instances for the types in GHC.Iface.Ext.Types, add -ddump-hie
flag to dump pretty printed contents of the .hie file
Metric Increase:
hie002
Because of the regression on i386:
compile_time/bytes allocated increased from i386-linux-deb9 baseline @ HEAD~10:
Expected hie002 (normal) compile_time/bytes allocated: 583014888.0 +/-10%
Lower bound hie002 (normal) compile_time/bytes allocated: 524713399
Upper bound hie002 (normal) compile_time/bytes allocated: 641316377
Actual hie002 (normal) compile_time/bytes allocated: 877986292
Deviation hie002 (normal) compile_time/bytes allocated: 50.6 %
*** unexpected stat test failure for hie002(normal)
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9462452a4843a2c42fe055a0a7e274d5164d1dc0">9462452a</a></strong>
<div>
<span>by Andreas Klebinger</span>
<i>at 2020-04-03T06:25:33-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Improve and refactor StgToCmm codegen for DataCons.
We now differentiate three cases of constructor bindings:
1)Bindings which we can "replace" with a reference to
an existing closure. Reference the replacement closure
when accessing the binding.
2)Bindings which we can "replace" as above. But we still
generate a closure which will be referenced by modules
importing this binding.
3)For any other binding generate a closure. Then reference
it.
Before this patch 1) did only apply to local bindings and we
didn't do 2) at all.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/a214d2142c1bafa71fe52cb3823351ff9322d336">a214d214</a></strong>
<div>
<span>by Moritz Bruder</span>
<i>at 2020-04-03T06:26:11-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Add singleton to NonEmpty in libraries/base
This adds a definition to construct a singleton non-empty list
(Data.List.NonEmpty) according to issue #17851.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/f7597aa0c028ced898ac97e344754dd961b70c57">f7597aa0</a></strong>
<div>
<span>by Sylvain Henry</span>
<i>at 2020-04-03T06:26:54-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Testsuite: measure compiler stats for T16190
We were mistakenly measuring program stats
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/a485c3c4049fff09e989bfd7d2ba47035c92a69b">a485c3c4</a></strong>
<div>
<span>by Sylvain Henry</span>
<i>at 2020-04-03T06:26:54-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Move blob handling into StgToCmm
Move handling of big literal strings from CmmToAsm to StgToCmm. It
avoids the use of `sdocWithDynFlags` (cf #10143). We might need to move
this handling even higher in the pipeline in the future (cf #17960):
this patch will make it easier.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/cc2918a0407e1581e824ebd90a1fcbb0637d5744">cc2918a0</a></strong>
<div>
<span>by Sylvain Henry</span>
<i>at 2020-04-03T06:26:54-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Refactor CmmStatics
In !2959 we noticed that there was some redundant code (in GHC.Cmm.Utils
and GHC.Cmm.StgToCmm.Utils) used to deal with `CmmStatics` datatype
(before SRT generation) and `RawCmmStatics` datatype (after SRT
generation).
This patch removes this redundant code by using a single GADT for
(Raw)CmmStatics.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9e60273db47364fc08aeb5a389caf67559e0d353">9e60273d</a></strong>
<div>
<span>by Maxim Koltsov</span>
<i>at 2020-04-03T06:27:32-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Fix haddock formatting in Control.Monad.ST.Lazy.Imp.hs
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/1b7e8a94cb3334fc0e513dec2db323f32c3a0713">1b7e8a94</a></strong>
<div>
<span>by Andreas Klebinger</span>
<i>at 2020-04-03T06:28:08-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Turn newlines into spaces for hadrian/ghci.
The newlines break the command on windows.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4291bddaea3148908c55f235ee8978e1d9aa6f20">4291bdda</a></strong>
<div>
<span>by Simon Peyton Jones</span>
<i>at 2020-04-03T06:28:44-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Major improvements to the specialiser
This patch is joint work of Alexis King and Simon PJ. It does some
significant refactoring of the type-class specialiser. Main highlights:
* We can specialise functions with types like
f :: Eq a => a -> Ord b => b => blah
where the classes aren't all at the front (#16473). Here we can
correctly specialise 'f' based on a call like
f @Int @Bool dEqInt x dOrdBool
This change really happened in an earlier patch
commit 2d0cf6252957b8980d89481ecd0b79891da4b14b
Author: Sandy Maguire <sandy@sandymaguire.me>
Date: Thu May 16 12:12:10 2019 -0400
work that this new patch builds directly on that work, and refactors
it a bit.
* We can specialise functions with implicit parameters (#17930)
g :: (?foo :: Bool, Show a) => a -> String
Previously we could not, but now they behave just like a non-class
argument as in 'f' above.
* We can specialise under-saturated calls, where some (but not all of
the dictionary arguments are provided (#17966). For example, we can
specialise the above 'f' based on a call
map (f @Int dEqInt) xs
even though we don't (and can't) give Ord dictionary.
This may sound exotic, but #17966 is a program from the wild, and
showed significant perf loss for functions like f, if you need
saturation of all dictionaries.
* We fix a buglet in which a floated dictionary had a bogus demand
(#17810), by using zapIdDemandInfo in the NonRec case of specBind.
* A tiny side benefit: we can drop dead arguments to specialised
functions; see Note [Drop dead args from specialisations]
* Fixed a bug in deciding what dictionaries are "interesting"; see
Note [Keep the old dictionaries interesting]
This is all achieved by by building on Sandy Macguire's work in
defining SpecArg, which mkCallUDs uses to describe the arguments of
the call. Main changes:
* Main work is in specHeader, which marched down the [InBndr] from the
function definition and the [SpecArg] from the call site, together.
* specCalls no longer has an arity check; the entire mechanism now
handles unders-saturated calls fine.
* mkCallUDs decides on an argument-by-argument basis whether to
specialise a particular dictionary argument; this is new.
See mk_spec_arg in mkCallUDs.
It looks as if there are many more lines of code, but I think that
all the extra lines are comments!
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/40a85563a46c682eaab5fdf970f7c46afca78cb3">40a85563</a></strong>
<div>
<span>by Ömer Sinan Ağacan</span>
<i>at 2020-04-03T18:26:19+03:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Revert accidental change in 9462452
[ci skip]
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/bd75e5da0f1f05f107325733b570bf28b379d2f2">bd75e5da</a></strong>
<div>
<span>by Ryan Scott</span>
<i>at 2020-04-04T07:07:58-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">Enable ImpredicativeTypes internally when typechecking selector bindings
This is necessary for certain record selectors with higher-rank
types, such as the examples in #18005. See
`Note [Impredicative record selectors]` in `TcTyDecls`.
Fixes #18005.
</pre>
</li>
<li>
<strong><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/37bc7a6cbbfe885fe7c0f22dde6892c0f9a6ed11">37bc7a6c</a></strong>
<div>
<span>by Ben Gamari</span>
<i>at 2020-04-04T18:05:15-04:00</i>
</div>
<pre class="commit-message" style="white-space: pre-wrap; margin: 0;">simplifier: Kill off ufKeenessFactor
We used to have another factor, ufKeenessFactor, which would scale the
discounts before they were subtracted from the size. This was justified
with the following comment:
-- We multiple the raw discounts (args_discount and result_discount)
-- ty opt_UnfoldingKeenessFactor because the former have to do with
-- *size* whereas the discounts imply that there's some extra
-- *efficiency* to be gained (e.g. beta reductions, case reductions)
-- by inlining.
However, this is highly suspect since it means that we subtract a
*scaled* size from an absolute size, resulting in crazy (e.g. negative)
scores in some cases (#15304). We consequently killed off
ufKeenessFactor and bumped up the ufUseThreshold to compensate.
Adjustment of unfolding use threshold
=====================================
Since this removes a discount from our inlining heuristic, I revisited our
default choice of -funfolding-use-threshold to minimize the change in
overall inlining behavior. Specifically, I measured runtime allocations
and executable size of nofib and the testsuite performance tests built
using compilers (and core libraries) built with several values of
-funfolding-use-threshold.
This comes as a result of a quantitative comparison of testsuite
performance and code size as a function of ufUseThreshold, comparing
GHC trees using values of 50, 60, 70, 80, 90, and 100. The test set
consisted of nofib and the testsuite performance tests.
A full summary of these measurements are found in the description of
!2608
Comparing executable sizes (relative to the base commit) across all
nofib tests, we see that sizes are similar to the baseline:
gmean min max median
thresh
50 -6.36% -7.04% -4.82% -6.46%
60 -5.04% -5.97% -3.83% -5.11%
70 -2.90% -3.84% -2.31% -2.92%
80 -0.75% -2.16% -0.42% -0.73%
90 +0.24% -0.41% +0.55% +0.26%
100 +1.36% +0.80% +1.64% +1.37%
baseline +0.00% +0.00% +0.00% +0.00%
Likewise, looking at runtime allocations we see that 80 gives slightly
better optimisation than the baseline:
gmean min max median
thresh
50 +0.16% -0.16% +4.43% +0.00%
60 +0.09% -0.00% +3.10% +0.00%
70 +0.04% -0.09% +2.29% +0.00%
80 +0.02% -1.17% +2.29% +0.00%
90 -0.02% -2.59% +1.86% +0.00%
100 +0.00% -2.59% +7.51% -0.00%
baseline +0.00% +0.00% +0.00% +0.00%
Finally, I had to add a NOINLINE in T4306 to ensure that `upd` is
worker-wrappered as the test expects. This makes me wonder whether the
inlining heuristic is now too liberal as `upd` is quite a large
function. The same measure was taken in T12600.
Wall clock time compiling Cabal with -O0
thresh 50 60 70 80 90 100 baseline
build-Cabal 93.88 89.58 92.59 90.09 100.26 94.81 89.13
Also, this change happens to avoid the spurious test output in
`plugin-recomp-change` and `plugin-recomp-change-prof` (see #17308).
Metric Decrease:
hie002
T12234
T13035
T13719
T14683
T4801
T5631
T5642
T9020
T9872d
T9961
Metric Increase:
T12150
T12425
T13701
T14697
T15426
T1969
T3064
T5837
T9203
T9872a
T9872b
T9872c
T9872d
haddock.Cabal
haddock.base
haddock.compiler
</pre>
</li>
</ul>
<h4>30 changed files:</h4>
<ul>
<li class="file-stats">
<a href="#f73a4fa90a8eb153bccdcfcc9f63c15edcd66785">
compiler/GHC/Cmm.hs
</a>
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<li class="file-stats">
<a href="#92b713d88390e6ea489e24b6cff8a3960384c0d0">
compiler/GHC/Cmm/DebugBlock.hs
</a>
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<li class="file-stats">
<a href="#47cba74ae8965f1665cd11bf2b023760ea27594e">
compiler/GHC/Cmm/Info.hs
</a>
</li>
<li class="file-stats">
<a href="#2d3721ad8de95e1144493ca545db846672cb109f">
compiler/GHC/Cmm/Info/Build.hs
</a>
</li>
<li class="file-stats">
<a href="#71e696f452eb493722d70306c6f304fc9b2f6a95">
compiler/GHC/Cmm/Parser.y
</a>
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<li class="file-stats">
<a href="#00d7e888201d1d21d9b428cc9fd4aea68631c109">
compiler/GHC/Cmm/Ppr/Decl.hs
</a>
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<li class="file-stats">
<a href="#f9f29a5a64a0b66967f0a7c538dbf8ad06a9f5bb">
compiler/GHC/Cmm/Utils.hs
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<li class="file-stats">
<a href="#f71fa75baa7807186473f09c45a9ada1b72f4c6c">
compiler/GHC/CmmToAsm/PPC/CodeGen.hs
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<li class="file-stats">
<a href="#3022d7d8a06ba257d13bbd18a3347522287aa684">
compiler/GHC/CmmToAsm/PPC/Ppr.hs
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<li class="file-stats">
<a href="#99b1dfe8e0e3d0c174cd8552df7d2ae70d35800a">
compiler/GHC/CmmToAsm/PPC/RegInfo.hs
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<li class="file-stats">
<a href="#1684e8db5c0d415248dabe224ffe70205adc6b0f">
compiler/GHC/CmmToAsm/Ppr.hs
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<li class="file-stats">
<a href="#e76eae04dea432f874db91c25e4a5725d7cc127b">
compiler/GHC/CmmToAsm/SPARC/CodeGen.hs
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<li class="file-stats">
<a href="#d021ec82e5a3150376cf05ea98f89bcf0daa611e">
compiler/GHC/CmmToAsm/SPARC/CodeGen/Gen32.hs
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<li class="file-stats">
<a href="#90616aa9a81a082a329014ed30f6e887c8c55be7">
compiler/GHC/CmmToAsm/SPARC/Ppr.hs
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<a href="#13521cd94ac37285ab80cca8b3993ba32433db90">
compiler/GHC/CmmToAsm/SPARC/ShortcutJump.hs
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<li class="file-stats">
<a href="#2bae5947e9412f6deebf4db7dcb89d780913130f">
compiler/GHC/CmmToAsm/X86/CodeGen.hs
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<li class="file-stats">
<a href="#7b360ca84c1b9aaecc0f9de207a7698dc36514fe">
compiler/GHC/CmmToAsm/X86/Instr.hs
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<li class="file-stats">
<a href="#335d279236d65dcf13f2bab3891e515cb803203c">
compiler/GHC/CmmToAsm/X86/Ppr.hs
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<li class="file-stats">
<a href="#76664ab267df4fc0bec2465efd78bf0afacfe3a7">
compiler/GHC/CmmToC.hs
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<li class="file-stats">
<a href="#1aff3a222f2ec5c5498930c3d145b401cc300028">
compiler/GHC/CmmToLlvm.hs
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<li class="file-stats">
<a href="#c74cd867f4159f4c755af854485b9cc98fbc55fe">
compiler/GHC/CmmToLlvm/Data.hs
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<li class="file-stats">
<a href="#41223cea954a6fb02becb6018d5d7ff7467b31fc">
compiler/GHC/CmmToLlvm/Ppr.hs
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<li class="file-stats">
<a href="#d52bc1e90d7432064a2998de2a2751b6fecb7680">
compiler/GHC/Core/Op/Specialise.hs
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<a href="#708fab0a51bd47227233eda4698e750ff6de66e0">
compiler/GHC/Core/Subst.hs
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<a href="#2811a7297b8aa206197ac1f5dabd0818e3c7ec5a">
compiler/GHC/Core/Unfold.hs
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<li class="file-stats">
<a href="#2e5692f568fd7b67a6b172e2a60469da8392508c">
compiler/GHC/Driver/Flags.hs
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<li class="file-stats">
<a href="#9a679a2680ef6061397f1987091ea9f96ffe095d">
compiler/GHC/Driver/Main.hs
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<li class="file-stats">
<a href="#774d88050336ef660c7a219fb06c480c2fc639bc">
compiler/GHC/Driver/Session.hs
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<li class="file-stats">
<a href="#65e2067fbb7377818b6cadff0531f44029499948">
compiler/GHC/HsToCore/Binds.hs
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<li class="file-stats">
<a href="#d29ec9f7b91b6b1c871d5cd8fe463ef9952e9597">
compiler/GHC/Iface/Ext/Debug.hs
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</ul>
<h5>The diff was not included because it is too large.</h5>
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