[GHC] #7460: Double literals generated bad core

[GHC]

#7460: Double literals generated bad core
-------------------------------------+-------------------------------------
              Reporter:  tibbe       |            Owner:  tibbe
                  Type:  bug         |           Status:  closed
              Priority:  normal      |        Milestone:  7.10.1
             Component:  Compiler    |          Version:  7.4.2
            Resolution:  fixed       |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  Runtime     |       Blocked By:
  performance bug                    |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
Changes (by thomie):

 * status:  new => closed
 * resolution:   => fixed


Comment:

 The word2Float and word2Double primops were added, which solved this
 issue. The output of `ghc-7.6.3 -ddump-simpl -O2 test.hs` contained calls
 to `doubleFromInteger`, but the same command using `ghc-7.8.3` does not
 (which is good). Other things must have changed as well, because the code
 is about twice as fast with 7.8.3, while comment:8 talked about a
 difference of only 20%.

 commit 2e8c769422740c001e0a247bfec61d4f78598582
 {{{
 Author: Johan Tibell <>
 Date:   Wed Dec 5 19:08:48 2012 -0800

     Implement word2Float# and word2Double#
 }}}
 commit cd01e48fbc548ff8d81ab547108bfdde8a113cd7
 {{{
 Author: Johan Tibell <>
 Date:   Thu Dec 13 12:03:40 2012 -0800

     Add test for word2Double# and word2Float#
 }}}
 commit a18cf9cbdfec08732f5b7e0c886a5d899a6a5998
 {{{
 Author: Johan Tibell <>
 Date:   Thu Dec 13 14:49:58 2012 -0800

     Add fromIntegral/Word->Double and fromIntegral/Word-Float rules
 }}}
 commit 8cd4ced57dccc1f4f54d242982209ec61e145700
 {{{
 Author: Johan Tibell <>
 Date:   Tue Dec 18 14:40:02 2012 +0100

     perf test for Word->Float/Double conversion
 }}}
 commit 6d5f25f5e0b33173fb2e7983cab40808c723f220
 {{{
 Author: Geoffrey Mainland <>
 Date:   Thu Jan 3 16:59:03 2013 +0000

     Fix LLVM code generated for word2Float# and word2Double#.
 }}}
 commit 744035fdd4b882c17ef7c6e4439b9e7099e7ec3d
 {{{
 Author: Johan Tibell <>
 Date:   Mon Jan 7 21:35:07 2013 -0800

     Fix Word2Float# test on 32-bit
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7460#comment:15>
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