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  • Glasgow Haskell CompilerGlasgow Haskell Compiler
  • GHCGHC
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  • #14738
Closed
Open
Issue created Jan 30, 2018 by Tobias Dammers@tdammers🦈Developer

Investigate performance of CoreTidy

Considering the following profile output (compiling https://ghc.haskell.org/trac/ghc/attachment/ticket/14683/Grammar.hs):

	Thu Jan 25 13:11 2018 Time and Allocation Profiling Report  (Final)

	   ghc-stage2 +RTS -p -RTS -B/home/tobias/well-typed/devel/ghc/inplace/lib Grammar.hs -ddump-stg -ddump-simpl -ddump-to-file -fforce-recomp

	total time  =       20.99 secs   (20989 ticks @ 1000 us, 1 processor)
	total alloc = 29,250,375,256 bytes  (excludes profiling overheads)

COST CENTRE           MODULE     SRC                                                 %time %alloc

CoreTidy              HscMain    compiler/main/HscMain.hs:1253:27-67                  24.2   28.5
Stg2Stg               HscMain    compiler/main/HscMain.hs:1489:12-44                  20.3   24.2
simplCast             Simplify   compiler/simplCore/Simplify.hs:871:62-87             18.7   15.9
tc_rn_src_decls       TcRnDriver compiler/typecheck/TcRnDriver.hs:(494,4)-(556,7)      9.0    6.9
addCoerce-pushCoTyArg Simplify   compiler/simplCore/Simplify.hs:(1236,12)-(1237,72)    7.4    6.4
subst_ty              TyCoRep    compiler/types/TyCoRep.hs:2237:28-32                  4.3    5.1
zonkTopDecls          TcRnDriver compiler/typecheck/TcRnDriver.hs:(445,16)-(446,43)    1.4    1.1
coercionKind          Coercion   compiler/types/Coercion.hs:1725:3-7                   1.3    3.0
simplExprF1-Lam       Simplify   compiler/simplCore/Simplify.hs:896:5-39               1.0    1.1
  1. ..the amount of time spent in CoreTidy is striking, and should be investigated.
Trac metadata
Trac field Value
Version 8.2.2
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler
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