[GHC] #3744: Comparisons against minBound/maxBound not optimised for (Int|Word)(8|16|32) (was: Comparisons against minBound/maxBound not optimised)

[GHC]

#3744: Comparisons against minBound/maxBound not optimised for (Int|Word)(8|16|32)
-------------------------------------+-------------------------------------
              Reporter:  rl          |            Owner:
                  Type:  feature     |           Status:  new
  request                            |        Milestone:  7.10.1
              Priority:  low         |          Version:  6.13
             Component:  Compiler    |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:  Runtime     |  Related Tickets:
  performance bug                    |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
Changes (by thomie):

 * difficulty:   => Unknown
 * type:  bug => feature request


Comment:

 Status: see comment:12. Use program from comment:5 to test, and replace
 `Int` by `Int8` (`Int64` works since 7.4).


 For reference: commit d4781f3e6e8cead1cbeac5337f9f78440c8df8bc
 {{{
 Author: Michal Terepeta <>
 Date:   Wed Oct 27 18:40:54 2010 +0000

     Optimise comparisons against min/maxBound (ticket #3744).

     This optimises away comparisons with minBound or maxBound
     that are always false or always true.
 }}}

 commit fe5821233d439c35c441cfc6c9d2029e5fd01342
 {{{
 Author: Ian Lynagh <>
 Date:   Wed Sep 19 22:37:01 2012 +0100

     Make some uses of minBound/maxBound use the target Int/Word sizes
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3744#comment:17>
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