Note how R2, R3 and R4 are live across the C call. This is wrong, because on Win64, R3 and R4 are caller-saves and therefore clobbered by
#8834: 64-bit windows cabal.exe segfaults in GC ----------------------------------+---------------------------------- Reporter: awson | Owner: Type: bug | Status: patch Priority: highest | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc2 Resolution: | Keywords: Operating System: Windows | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by jstolarek): the C call. Just to clarify: floating of R2 is correct? `MachRegs.h` defines R3 and R4 correctly as caller saves: {{{ #if !defined(mingw32_HOST_OS) #define CALLER_SAVES_R3 #define CALLER_SAVES_R4 #endif }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8834#comment:36 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler