#8195: Different floating point results with -msse2 on 32bit Linux ------------------------------------------------+-------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (NCG) | Version: 7.7 Resolution: | Keywords: Operating System: Linux | Architecture: x86 Type of failure: None/Unknown | Difficulty: Test Case: perf/should_run/Conversions | Unknown Blocking: | Blocked By: | Related Tickets: ------------------------------------------------+-------------------------- Comment (by rwbarton): Yeah, the fact that `-msse2` affects the output is expected for the reason carter stated. This issue is discussed generally at http://www.haskell.org/ghc/docs/latest/html/users_guide/bugs.html#bugs-ghc (last bullet point of 14.2.1). The reason your tail loop optimization affected the output is probably that with the optimization the code compiles to a loop in which `acc` lives in an 80-bit x87 register for the entire duration, while before the optimization `acc` was pushed on the stack as a 32-bit value for the recursive call. (Or possibly it was spilled to memory for some other reason.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8195#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler