#15696: Derived Ord instance for enumerations with more than 8 elements seems to be incorrect -------------------------------------+------------------------------------- Reporter: mrkkrp | Owner: (none) Type: bug | Status: patch Priority: highest | Milestone: 8.6.2 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D5196 Wiki Page: | -------------------------------------+------------------------------------- Comment (by dfeuer): Replying to [comment:24 osa1]:
Thinking about this more. I think the only case where we can actually avoid entering the argument of `dataToTag#` is when the argument is a static closure. For anything else (a dynamic closure, a CAF) we need to enter it.
I'm a tad confused. If the tag bits are non-zero, can't we just use them and avoid dereferencing the pointer? Or is that already folded into "enter it"? Or am I just wrong? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15696#comment:25 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler