[GHC] #12545: Compilation time/space regression in GHC 8.0/8.1 (search in type-level lists and -O)

[GHC]

#12545: Compilation time/space regression in GHC 8.0/8.1 (search in type-level
lists and -O)
-------------------------------------+-------------------------------------
        Reporter:                    |                Owner:
  mikhail.vorozhtsov                 |
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:  Inlining
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by mikhail.vorozhtsov):

 Here are some numbers from `-v4` logs:

 {{{
 $ grep -E '(=====|^Result|coercions)' out-7_10.log | grep -v 'RHS size' |
 head -40
 ==================== Parser ====================
 ==================== Source Statistics ====================
 ==================== Occurrence analysis ====================
 ==================== Desugar (after optimization) ====================
 Result size of Desugar (after optimization)
   = {terms: 2,144, types: 128,368, coercions: 415,496}
 ==================== Occurrence analysis ====================
 Result size of Simplifier iteration=1
   = {terms: 3,200, types: 173,424, coercions: 415,528}
 ==================== Occurrence analysis ====================
 Result size of Simplifier
   = {terms: 3,200, types: 173,424, coercions: 415,528}
 ==================== Specialise ====================
 Result size of Specialise
   = {terms: 12,416, types: 658,320, coercions: 455,704}
 ==================== FloatOut stats: ====================
 Result size of Float out(FOS {Lam = Just 0,
   = {terms: 13,472, types: 739,808, coercions: 455,704}
 ==================== Occurrence analysis ====================
 Result size of Simplifier iteration=1
   = {terms: 30,336, types: 1,848,096, coercions: 6,417,128}
 ==================== Occurrence analysis ====================
 Result size of Simplifier
   = {terms: 30,336, types: 1,848,096, coercions: 6,417,128}
 ==================== Occurrence analysis ====================
 Result size of Simplifier
   = {terms: 30,336, types: 1,848,096, coercions: 6,417,128}
 ==================== Occurrence analysis ====================
 Result size of Simplifier
   = {terms: 30,336, types: 1,848,096, coercions: 6,417,128}
 Result size of Float inwards
   = {terms: 30,336, types: 1,848,096, coercions: 6,417,128}
 ==================== Called arity analysis ====================
 Result size of Called arity analysis
   = {terms: 30,336, types: 1,848,096, coercions: 6,417,128}
 ==================== Occurrence analysis ====================
 }}}

 for 7.10.3 versus

 {{{
 $ grep -E '(=====|^Result|coercions)' out-8_0.log | grep -v 'RHS size' |
 head -40
 ==================== Parser ====================
 ==================== Source Statistics ====================
 ==================== Occurrence analysis ====================
 ==================== Desugar (after optimization) ====================
 Result size of Desugar (after optimization)
   = {terms: 3,835, types: 147,262, coercions: 549,848}
 ==================== Occurrence analysis ====================
 Result size of Simplifier iteration=1
   = {terms: 4,897, types: 161,681, coercions: 549,849}
 ==================== Occurrence analysis ====================
 Result size of Simplifier
   = {terms: 4,897, types: 161,681, coercions: 549,849}
 ==================== Specialise ====================
 Result size of Specialise
   = {terms: 17,793, types: 899,977, coercions: 3,094,577}
 ==================== FloatOut stats: ====================
 Result size of Float out(FOS {Lam = Just 0,
   = {terms: 20,769, types: 1,109,785, coercions: 3,094,577}
 ==================== Occurrence analysis ====================
 Result size of Simplifier iteration=1
   = {terms: 16,553, types: 871,953, coercions: 2,232,281}
 ==================== Occurrence analysis ====================
 Result size of Simplifier
   = {terms: 16,429, types: 864,761, coercions: 2,184,448}
 ==================== Occurrence analysis ====================
 Result size of Simplifier
   = {terms: 16,429, types: 864,761, coercions: 2,184,448}
 ==================== Occurrence analysis ====================
 Result size of Simplifier iteration=1
   = {terms: 87,357, types: 4,366,893, coercions: 10,008,352}
 ==================== Occurrence analysis ====================
 Result size of Simplifier
   = {terms: 87,357, types: 4,366,893, coercions: 10,008,352}
 Result size of Float inwards
   = {terms: 87,357, types: 4,366,893, coercions: 10,008,352}
 ==================== Called arity analysis ====================
 Result size of Called arity analysis
   = {terms: 87,357, types: 4,366,893, coercions: 10,008,352}
 ==================== Occurrence analysis ====================
 }}}

 for 8.0.1

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12545#comment:6>
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