[GHC] #8887: Double double assignment in optimized Cmm on SPARC

[GHC]

#8887: Double double assignment in optimized Cmm on SPARC
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       Reporter:  kgardas   |             Owner:
           Type:  bug       |            Status:  new
       Priority:  normal    |         Milestone:
      Component:  Compiler  |           Version:  7.6.3
       Keywords:            |  Operating System:  Solaris
   Architecture:  sparc     |   Type of failure:  Runtime performance bug
     Difficulty:  Unknown   |         Test Case:
     Blocked By:            |          Blocking:
Related Tickets:            |
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 Hello,
 while reading ffi003 asm/opt-cmm for fixing this on SPARC I've noticed
 this code, this is optimized Cmm dump:
 {{{
     112       c1or:
     113           _s1nw::F64 = F64[_s1nv::P32 + 3];
     114           _c1oj::I32 = sin;
     115           _c1ok::F64 = _s1nw::F64;
 }}}
 this assignment to _s1nw::F64 looks useless as we may assign directly to
 _c1ok::F64, may we not?
 Both optimized and non-optimized Cmms attached.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8887>
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