Optimiser bug on linux-powerpc
Found a small chunk of code in the cryptocipher package that when compiled and run, produces a difference result when optimised compared to compiling un-optimised.
Note this is only a problem with PowerPC. On x86-64 there is no difference in the output between the optimised version and the un-optimised version.
I have two simple files (Camellia.hs):
module Camellia where
import Data.Bits
import Data.Word
import Debug.Trace
fl :: Word64 -> Word64 -> Word64
fl fin sk =
let (x1, x2) = w64tow32 fin in
let (k1, k2) = w64tow32 sk in
let y2 = x2 `xor` ((x1 .&. k1) `rotateL` 1) in
let y1 = x1 `xor` (y2 .|. k2) in
trace (show fin ++ " " ++ show sk ++ " -> " ++ show (w32tow64 (y1, y2))) $ w32tow64 (y1, y2)
w64tow32 :: Word64 -> (Word32, Word32)
w64tow32 w = (fromIntegral (w `shiftR` 32), fromIntegral (w .&. 0xffffffff))
w32tow64 :: (Word32, Word32) -> Word64
w32tow64 (x1, x2) = ((fromIntegral x1) `shiftL` 32) .|. (fromIntegral x2)
and a main program (camellia-test.hs):
import Data.Word
import qualified Camellia as Camellia
a, b :: Word64
a = 1238988323332265734
b = 11185553392205053542
main :: IO ()
main =
putStrLn $ "Camellia.fl " ++ show a ++ " " ++ show b ++ " -> " ++ show (Camellia.fl a b)
I'm also using this Makefile:
TARGETS = camilla-test-std camilla-test-opt
check : $(TARGETS)
./camilla-test-std
./camilla-test-opt
clean :
make clean-temp-files
rm -f $(TARGETS)
clean-temp-files :
rm -f camilla-test.o camilla-test.hi Camellia.o Camellia.hi
camilla-test-opt : camilla-test.hs Camellia.hs
ghc -Wall -O2 --make -i:Tests $< -o $@
make clean-temp-files
camilla-test-std : camilla-test.hs Camellia.hs
ghc -Wall --make -i:Tests $< -o $@
make clean-temp-files
When I run the two programs I get:
./camilla-test-std
1238988323332265734 11185553392205053542 -> 18360184157246690566
Camellia.fl 1238988323332265734 11185553392205053542 -> 18360184157246690566
./camilla-test-opt
1238988323332265734 11185553392205053542 -> 3698434091925017862
Camellia.fl 38662 15974 -> 3698434091925017862
So there are two problems here:
a) Showing Word64 values is not working correctly in the optimised version.
b) The function Camelia.fl produces the wrong result in the optimised version.
Trac metadata
Trac field | Value |
---|---|
Version | 7.4.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |