#1261: 15x performance regression between HEAD and 6.6
-------------------------------------------------+--------------------------
Reporter: Stefan O'Rear <[EMAIL PROTECTED]> | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.7
Severity: normal | Keywords:
Difficulty: Unknown | Testcase:
Architecture: x86 | Os: Linux
-------------------------------------------------+--------------------------
GHC 6.7.20070213 and all later versions I have fail to unbox this:
[EMAIL PROTECTED]:~/memset$ cat Memtest.hs
import Foreign
wset :: Int -> Int -> Ptr Int -> IO ()
wset x y z | x `seq` y `seq` z `seq` False = undefined
wset 0 vl pt = return ()
wset ct vl pt = poke pt vl >> wset (ct - 1) vl (pt `advancePtr` 1)
main = mallocArray (2^26) >>= wset (2^26) 42
with a resultant 15x performance regression:
[EMAIL PROTECTED]:~/memset$ ghc-6.7.20070213 -O3 Memtest.hs ; time ./a.out
real 0m5.774s
user 0m4.904s
sys 0m0.768s
[EMAIL PROTECTED]:~/memset$ ghc-6.6 -O3 Memtest.hs ; time ./a.out
real 0m1.043s
user 0m0.304s
sys 0m0.724s
(Toggling -fasm/-fvia-C makes no appreciable difference.)
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1261>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
_______________________________________________
Glasgow-haskell-bugs mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
