Re: [GHC] #10870: PPC.Ppr: Shift by 32 bits is not allowed.

13 Sep 2015

      #10870: PPC.Ppr: Shift by 32 bits is not allowed.
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        Reporter:  nomeata             |                   Owner:
            Type:  bug                 |                  Status:  new
        Priority:  normal              |               Milestone:
       Component:  Compiler (CodeGen)  |                 Version:  7.10.2
      Resolution:                      |                Keywords:
Operating System:  Unknown/Multiple    |            Architecture:  powerpc
 Type of failure:  None/Unknown        |               Test Case:
      Blocked By:                      |                Blocking:
 Related Tickets:                      |  Differential Revisions:
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Comment (by erikd):

 I'm currently working on the ghc-7.10 branch because the master branch
 currently does not compile on PowerPC due to #7830.

 I have a test program:

 {{{
 import Data.Bits
 import Data.Int
 import Data.Word

 shift32R :: (Bits a, Num a) => a -> a
 shift32R x = unsafeShiftR x 32

 main :: IO ()
 main = do
     print $ map shift32R [ 123456, 0x7fffffff :: Int ]
     print $ map shift32R [ 123456, 0xffffffff :: Word ]
     print $ map shift32R [ 123456678, 123456678123456678 :: Int64 ]
     print $ map shift32R [ 123456678, 123456678123456678 :: Word64 ]
 }}}

 and I have a fix that seems to work (PowerPC output is same as for x86_64
 and Arm), but the compiler prints 14 identical instances of the warning:

 {{{
 WARNING: file compiler/simplCore/SimplEnv.hs, line 530 showl_a1O5
 }}}

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10870#comment:3
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