[Git][ghc/ghc][wip/T13253] 5 commits: Make arityType deal with join points
Ben Gamari
gitlab at gitlab.haskell.org
Fri Jun 26 19:08:13 UTC 2020
Ben Gamari pushed to branch wip/T13253 at Glasgow Haskell Compiler / GHC
Commits:
a82fb6c4 by Simon Peyton Jones at 2020-06-26T19:07:43+00:00
Make arityType deal with join points
As Note [Eta-expansion and join points] describes,
this patch makes arityType deal correctly with join points.
What was there before was not wrong, but yielded lower
arities than it could.
Fixes #18328
In base GHC this makes no difference to nofib.
Program Size Allocs Runtime Elapsed TotalMem
--------------------------------------------------------------------------------
n-body -0.1% -0.1% -1.2% -1.1% 0.0%
--------------------------------------------------------------------------------
Min -0.1% -0.1% -55.0% -56.5% 0.0%
Max -0.0% 0.0% +16.1% +13.4% 0.0%
Geometric Mean -0.0% -0.0% -30.1% -31.0% -0.0%
But it starts to make real difference when we land the change to the
way mkDupableAlts handles StrictArg, in fixing #13253 and friends.
I think this is because we then get more non-inlined join points.
- - - - -
44f37086 by Simon Peyton Jones at 2020-06-26T19:07:43+00:00
Improve eta-expansion using ArityType
As #18355 shows, we were failing to preserve one-shot info when
eta-expanding. It's rather easy to fix, by using ArityType more,
rather than just Arity.
This patch is important to suport the one-shot monad trick;
see #18202.
- - - - -
24171cb1 by Simon Peyton Jones at 2020-06-26T19:07:43+00:00
Reduce result discount in conSize
Ticket #18282 showed that the result discount given by conSize
was massively too large. This patch reduces that discount to
a constant 10, which just balances the cost of the constructor
application itself.
Note [Constructor size and result discount] elaborates, as
does the ticket #18282.
Reducing result discount reduces inlining, which affects perf. I
found that I could increase the unfoldingUseThrehold from 80 to 90 in
compensation; in combination with the result discount change I get
these overall nofib numbers:
Program Size Allocs Runtime Elapsed TotalMem
--------------------------------------------------------------------------------
boyer -0.3% +5.4% +0.7% +1.0% 0.0%
cichelli -0.3% +5.9% -9.9% -9.5% 0.0%
compress2 -0.4% +9.6% +7.2% +6.4% 0.0%
constraints -0.3% +0.2% -3.0% -3.4% 0.0%
cryptarithm2 -0.3% -3.9% -2.2% -2.4% 0.0%
gamteb -0.4% +2.5% +2.8% +2.8% 0.0%
life -0.3% -2.2% -4.7% -4.9% 0.0%
lift -0.3% -0.3% -0.8% -0.5% 0.0%
linear -0.3% -0.1% -4.1% -4.5% 0.0%
mate -0.2% +1.4% -2.2% -1.9% -14.3%
parser -0.3% -2.1% -5.4% -4.6% 0.0%
puzzle -0.3% +2.1% -6.6% -6.3% 0.0%
simple -0.4% +2.8% -3.4% -3.3% -2.2%
veritas -0.1% +0.7% -0.6% -1.1% 0.0%
wheel-sieve2 -0.3% -19.2% -24.9% -24.5% -42.9%
--------------------------------------------------------------------------------
Min -0.4% -19.2% -24.9% -24.5% -42.9%
Max +0.1% +9.6% +7.2% +6.4% +33.3%
Geometric Mean -0.3% -0.0% -3.0% -2.9% -0.3%
I'm ok with these numbers, remembering that this change removes
an *exponential* increase in code size in some in-the-wild cases.
I investigated compress2. The difference is entirely caused by this
function no longer inlining
WriteRoutines.$woutputCodes
= \ (w :: [CodeEvent]) ->
let result_s1Sr
= case WriteRoutines.outputCodes_$s$woutput w 0# 0# 8# 9# of
(# ww1, ww2 #) -> (ww1, ww2)
in (# case result_s1Sr of (x, _) ->
map @Int @Char WriteRoutines.outputCodes1 x
, case result_s1Sr of { (_, y) -> y } #)
It was right on the cusp before, driven by the excessive result
discount. Too bad!
Metric Decrease:
T12227
T12545
T15263
T1969
T5030
T9872a
T9872c
- - - - -
d6d70c7e by Simon Peyton Jones at 2020-06-26T19:07:43+00:00
This patch addresses the exponential blow-up in the simplifier.
Specifically:
#13253 exponential inlining
#10421 ditto
#18140 strict constructors
#18282 another nested-function call case
This patch makes two significant changes:
1. For Ids that are used at most once in each branch of a case,
make the occurrence analyser record the total number of
syntactic occurrences. Then in postInlineUnconditionally
use that info to avoid inling something many many times.
Actual changes:
* See the occ_n_br field of OneOcc.
* postInlineUnconditionally
See Note [Suppress exponential blowup] in GHC.Core.Opt.Simplify.Utils
2. Change the way that mkDupableCont handles StrictArg.
The details are explained in GHC.Core.Opt.Simplify
Note [Duplicating StrictArg]
Current nofib run
Program Size Allocs Runtime Elapsed TotalMem
--------------------------------------------------------------------------------
VS -0.3% +115.9% +12.1% +11.2% 0.0%
boyer2 -0.3% +10.0% +3.5% +4.0% 0.0%
cryptarithm2 -0.3% +39.0% +16.6% +16.1% 0.0%
gamteb -0.3% +4.1% -0.0% +0.4% 0.0%
last-piece -0.3% +1.4% -1.1% -0.4% 0.0%
mate -0.4% -11.1% -8.5% -9.0% 0.0%
multiplier -0.3% -2.2% -1.5% -1.5% 0.0%
transform -0.3% +3.4% +0.5% +0.8% 0.0%
--------------------------------------------------------------------------------
Min -0.8% -11.1% -8.5% -9.0% 0.0%
Max -0.3% +115.9% +30.1% +26.4% 0.0%
Geometric Mean -0.3% +1.0% +1.0% +1.0% -0.0%
Should investigate these numbers.
But the tickets are indeed cured, I think.
- - - - -
c0c2a452 by GHC GitLab CI at 2020-06-26T19:07:43+00:00
testsuite: Add --top flag to driver
This allows us to make `config.top` a proper Path. Previously it was a
str, which caused the Ghostscript detection logic to break.
- - - - -
30 changed files:
- compiler/GHC/Core/Opt/Arity.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
- compiler/GHC/Core/SimpleOpt.hs
- compiler/GHC/Core/Unfold.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Types/Basic.hs
- compiler/GHC/Types/Id/Info.hs
- hadrian/src/Settings/Builders/RunTest.hs
- testsuite/driver/runtests.py
- testsuite/driver/testglobals.py
- testsuite/driver/testlib.py
- testsuite/mk/test.mk
- testsuite/tests/deSugar/should_compile/T13208.stdout
- testsuite/tests/deSugar/should_compile/T16615.stderr
- testsuite/tests/numeric/should_compile/T14170.stdout
- testsuite/tests/numeric/should_compile/T14465.stdout
- testsuite/tests/numeric/should_compile/T7116.stdout
- + testsuite/tests/perf/compiler/T10421.hs
- + testsuite/tests/perf/compiler/T10421_Form.hs
- + testsuite/tests/perf/compiler/T10421_Y.hs
- + testsuite/tests/perf/compiler/T13253-spj.hs
- + testsuite/tests/perf/compiler/T13253.hs
- + testsuite/tests/perf/compiler/T18140.hs
- testsuite/tests/perf/compiler/all.T
- testsuite/tests/profiling/should_run/T5654-O1.prof.sample
- testsuite/tests/profiling/should_run/T5654b-O1.prof.sample
- testsuite/tests/profiling/should_run/ioprof.stderr
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/df525f2b1d18d2c21c42dae1612d31ef1ced489e...c0c2a4524cccab5e283a850ba8fe52f1e73d2fb9
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/df525f2b1d18d2c21c42dae1612d31ef1ced489e...c0c2a4524cccab5e283a850ba8fe52f1e73d2fb9
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