[GHC] #14688: Note [Lone variables] leads to missing a case-of-case opportunity

GHC ghc-devs at haskell.org
Tue Jan 23 12:10:42 UTC 2018


#14688: Note [Lone variables] leads to missing a case-of-case opportunity
-------------------------------------+-------------------------------------
        Reporter:  mpickering        |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by mpickering):

 Nofib results, so generally reduced allocations but very little change
 overall.

 {{{
 --------------------------------------------------------------------------------
         Program           Size    Allocs   Runtime   Elapsed  TotalMem
 --------------------------------------------------------------------------------
              CS           0.0%      0.0%     0.183     0.183      0.0%
             CSD           0.0%      0.0%     -0.1%     -0.1%      0.0%
              FS           0.0%      0.0%     +0.4%     +0.5%      0.0%
               S           0.0%      0.0%     -0.4%     -0.5%      0.0%
              VS           0.0%      0.0%     +0.3%     +0.3%      0.0%
             VSD           0.0%      0.0%     0.009     0.009      0.0%
             VSM           0.0%      0.0%     -0.4%     -0.4%      0.0%
            anna          +0.0%     +0.3%     0.062     0.062      0.0%
            ansi           0.0%      0.0%     0.000     0.000      0.0%
            atom           0.0%      0.0%     0.175     0.175      0.0%
          awards          -0.0%     -0.2%     0.000     0.000      0.0%
          banner           0.0%      0.0%     0.000     0.000      0.0%
      bernouilli           0.0%      0.0%     0.095     0.095      0.0%
    binary-trees           0.0%      0.0%     -0.0%     +0.0%      0.0%
           boyer           0.0%      0.0%     0.022     0.022      0.0%
          boyer2          +0.0%      0.0%     0.004     0.004      0.0%
            bspt          +0.0%     -0.1%     0.004     0.004      0.0%
       cacheprof           0.0%     -0.0%     -0.1%     -0.1%      0.0%
        calendar           0.0%      0.0%     0.000     0.000      0.0%
        cichelli           0.0%      0.0%     0.043     0.043      0.0%
         circsim           0.0%      0.0%     +0.3%     +0.3%      0.0%
        clausify           0.0%      0.0%     0.020     0.020      0.0%
   comp_lab_zift          -0.0%     -0.0%     0.105     0.105      0.0%
        compress           0.0%      0.0%     0.073     0.073      0.0%
       compress2          +0.1%     -0.7%     0.077     0.077     -4.0%
     constraints           0.0%      0.0%     +0.2%     +0.2%      0.0%
    cryptarithm1           0.0%      0.0%     -0.1%     +0.1%      0.0%
    cryptarithm2           0.0%      0.0%     0.004     0.004      0.0%
             cse           0.0%      0.0%     0.001     0.001      0.0%
    digits-of-e1           0.0%      0.0%     +0.0%     +0.0%      0.0%
    digits-of-e2           0.0%      0.0%     -0.3%     -0.3%      0.0%
           eliza          +0.0%     -2.4%     0.000     0.000      0.0%
           event           0.0%      0.0%     0.083     0.083      0.0%
     exact-reals          -0.0%      0.0%     +2.7%     +2.6%      0.0%
          exp3_8           0.0%      0.0%     0.132     0.132      0.0%
          expert           0.0%      0.0%     0.000     0.000      0.0%
  fannkuch-redux           0.0%      0.0%     -1.7%     -1.7%      0.0%
           fasta           0.0%      0.0%     -0.5%     -0.5%      0.0%
             fem          +0.0%     -0.0%     0.013     0.013      0.0%
             fft           0.0%      0.0%     0.019     0.019      0.0%
            fft2           0.0%      0.0%     0.027     0.027      0.0%
        fibheaps           0.0%      0.0%     0.014     0.014      0.0%
            fish           0.0%      0.0%     0.006     0.006      0.0%
           fluid          +0.0%     +0.1%     0.004     0.004      0.0%
          fulsom          +0.1%    -13.3%     0.158     0.158   +190.0%
          gamteb           0.0%      0.0%     0.023     0.023      0.0%
             gcd           0.0%      0.0%     0.024     0.024      0.0%
     gen_regexps           0.0%      0.0%     0.000     0.000      0.0%
          genfft           0.0%      0.0%     0.018     0.018      0.0%
              gg          +0.0%     -0.1%     0.005     0.005      0.0%
            grep           0.0%      0.0%     0.000     0.000      0.0%
          hidden          +0.0%      0.0%     -4.2%     -4.2%      0.0%
             hpg           0.0%      0.0%     0.048     0.048      0.0%
             ida          +0.0%     +0.3%     0.052     0.052      0.0%
           infer           0.0%      0.0%     0.029     0.029      0.0%
         integer           0.0%      0.0%     -0.4%     -0.4%      0.0%
       integrate           0.0%      0.0%     0.070     0.070      0.0%
    k-nucleotide           0.0%      0.0%     +4.9%     +4.9%      0.0%
           kahan           0.0%      0.0%     0.195     0.195      0.0%
         knights           0.0%      0.0%     0.002     0.002      0.0%
          lambda           0.0%      0.0%     +0.3%     +0.3%      0.0%
      last-piece           0.0%      0.0%     +0.6%     +0.6%      0.0%
            lcss           0.0%      0.0%     -0.3%     -0.4%      0.0%
            life           0.0%      0.0%     0.136     0.136      0.0%
            lift          +0.0%     -0.1%     0.001     0.001      0.0%
          linear           0.0%      0.0%     +0.2%     +0.2%      0.0%
       listcompr           0.0%      0.0%     0.056     0.056      0.0%
        listcopy           0.0%      0.0%     0.060     0.060      0.0%
        maillist           0.0%      0.0%     0.035     0.035     +1.9%
          mandel           0.0%      0.0%     0.040     0.040      0.0%
         mandel2           0.0%      0.0%     0.002     0.002      0.0%
            mate          +0.0%     -5.2%     -3.2%     -3.2%      0.0%
         minimax           0.0%      0.0%     0.001     0.001      0.0%
         mkhprog           0.0%      0.0%     0.001     0.001      0.0%
      multiplier           0.0%      0.0%     0.056     0.056      0.0%
          n-body           0.0%      0.0%     -0.5%     -0.5%      0.0%
        nucleic2           0.0%      0.0%     0.046     0.046      0.0%
            para          -0.0%      0.0%     0.165     0.166      0.0%
       paraffins           0.0%      0.0%     0.064     0.064      0.0%
          parser          +0.0%     -0.0%     0.015     0.015      0.0%
         parstof          +0.0%     -0.0%     0.003     0.003      0.0%
             pic           0.0%      0.0%     0.004     0.004      0.0%
        pidigits           0.0%      0.0%     +0.2%     +0.1%      0.0%
           power           0.0%      0.0%     0.196     0.196      0.0%
          pretty          +0.0%     -2.8%     0.000     0.000      0.0%
          primes           0.0%      0.0%     0.040     0.040      0.0%
       primetest           0.0%      0.0%     0.061     0.061      0.0%
          prolog           0.0%      0.0%     0.001     0.001      0.0%
          puzzle           0.0%      0.0%     0.070     0.070      0.0%
          queens           0.0%      0.0%     0.008     0.008      0.0%
         reptile          -0.0%     -0.0%     0.006     0.006      0.0%
 reverse-complem           0.0%      0.0%     0.064     0.063      0.0%
         rewrite          +0.1%     -0.0%     0.010     0.010      0.0%
            rfib           0.0%      0.0%     0.009     0.009      0.0%
             rsa           0.0%      0.0%     0.014     0.014      0.0%
             scc           0.0%      0.0%     0.000     0.000      0.0%
           sched           0.0%      0.0%     0.011     0.011      0.0%
             scs          +0.0%     -0.0%     +3.1%     +3.1%      0.0%
          simple          +0.1%     -0.2%     0.112     0.112      0.0%
           solid          +0.1%     +0.0%     0.074     0.074      0.0%
         sorting           0.0%      0.0%     0.001     0.001      0.0%
   spectral-norm           0.0%      0.0%     -0.7%     -0.7%      0.0%
          sphere          +0.0%     -0.0%     0.029     0.029      0.0%
          symalg           0.0%      0.0%     0.005     0.005      0.0%
             tak           0.0%      0.0%     0.006     0.006      0.0%
       transform           0.0%      0.0%     0.192     0.192      0.0%
        treejoin          -0.0%     -0.0%     0.076     0.076      0.0%
       typecheck           0.0%      0.0%     0.141     0.141      0.0%
         veritas          +0.2%     -1.0%     0.001     0.001      0.0%
            wang          +0.0%     -1.6%     0.055     0.055      0.0%
       wave4main           0.0%      0.0%     0.156     0.156      0.0%
    wheel-sieve1           0.0%      0.0%     -0.2%     -0.2%      0.0%
    wheel-sieve2          +0.0%     -0.0%     0.115     0.115      0.0%
            x2n1           0.0%      0.0%     0.001     0.001      0.0%
 --------------------------------------------------------------------------------
             Min          -0.0%    -13.3%     -4.2%     -4.2%     -4.0%
             Max          +0.2%     +0.3%     +4.9%     +4.9%   +190.0%
  Geometric Mean          +0.0%     -0.2%     -0.0%     -0.0%     +0.9%
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14688#comment:4>
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