#14619: Output value of program changes upon compiling with -O optimizations -------------------------------------+------------------------------------- Reporter: sheaf | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.4.1 Component: Compiler | Version: 8.2.2 Resolution: | Keywords: Operating System: Windows | Architecture: x86_64 Type of failure: Incorrect result | (amd64) at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by carter): summary notes of findings / information so far. 1) reproducible in 64bit windows/ mingw32 windows 64bit build. Phyx- indicated that the bug is observable with ghc 8.2 and old, but not with 8.4/head? 2) O2 and disabling the CMM SINK optimization pass makes the bug go away, which seems to indicate / hint at the issue being some piece of compilation / optimization that interacts with the CMM Sink algorithm using platform dependent data is incorrect theres not that many places (seemingly) where the information / action differs at this layer between different x86_64 compiler targets. So i think one of the spots in cmm/ native code gen that does something different when the platform in MinGW32 is the culptrit? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14619#comment:23 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler