#9431: integer-gmp small Integer multiplication does two multiplications on x86 -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.9 Component: Compiler | Keywords: (NCG) | Architecture: Unknown/Multiple Resolution: | Difficulty: Unknown Operating System: | Blocked By: Unknown/Multiple | Related Tickets: Type of failure: Runtime | performance bug | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by thomie): * cc: simonmar (added) * failure: None/Unknown => Runtime performance bug * component: Compiler => Compiler (NCG) Comment: For reference, from `libraries/integer-gmp2/src/GHC/Integer/Type.hs`: {{{#!haskell -- | Multiply two 'Integer's timesInteger :: Integer -> Integer -> Integer timesInteger _ (S# 0#) = S# 0# timesInteger (S# 0#) _ = S# 0# timesInteger x (S# 1#) = x timesInteger (S# 1#) y = y timesInteger x (S# -1#) = negateInteger x timesInteger (S# -1#) y = negateInteger y timesInteger (S# x#) (S# y#) = case mulIntMayOflo# x# y# of 0# -> S# (x# *# y#) _ -> timesInt2Integer x# y# }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9431#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler