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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2020-06-11 15:45:53 +0100 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2020-07-11 12:18:08 -0400 |
| commit | f250606761b8120799a276eafc858bfb94743df9 (patch) | |
| tree | b1f1f527c6ca9fc8012402af45537f12befb208a /compiler/GHC/Core/SimpleOpt.hs | |
| parent | b9f0d5832afe2605c6b49be806f78223007f4f0a (diff) | |
| download | haskell-wip/simon-perf.tar.gz | |
This patch addresses the exponential blow-up in the simplifier.wip/simon-perf
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.
Diffstat (limited to 'compiler/GHC/Core/SimpleOpt.hs')
| -rw-r--r-- | compiler/GHC/Core/SimpleOpt.hs | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/GHC/Core/SimpleOpt.hs b/compiler/GHC/Core/SimpleOpt.hs index 8525fb292f..3735cded34 100644 --- a/compiler/GHC/Core/SimpleOpt.hs +++ b/compiler/GHC/Core/SimpleOpt.hs @@ -433,7 +433,7 @@ simple_bind_pair env@(SOE { soe_inl = inl_env, soe_subst = subst }) safe_to_inline IAmALoopBreaker{} = False safe_to_inline IAmDead = True safe_to_inline OneOcc{ occ_in_lam = NotInsideLam - , occ_one_br = InOneBranch } = True + , occ_n_br = 1 } = True safe_to_inline OneOcc{} = False safe_to_inline ManyOccs{} = False |