#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 simonpj):
I get this STG with GHC HEAD, -O0:
That's what you get for monoidal's code in comment:18. Note the missing eval before the `dataToTag#`. But it is ''not'' what you get for the code in comment:13. The evals are there, as comment:14 shows. And yet we get the wrong answer. But why? That is the second bug. Can you see why that happens? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15696#comment:32 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler