#14214: Users guide lies about default optimization level -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.2.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Documentation | Unknown/Multiple bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by harendra): There are a number of issues with the documentation of optimization options. I guess all those can be dealt with in this ticket. 1) The inconsistency described above in the ticket description is in the "Flag Reference" chapter: {{{ Flag Description Type Reverse -O0 Disable optimisations (default) dynamic -O }}} 2) I would also suggest that we have another column in the "6.6.15. Individual optimisations" section to indicate which optimization levels enable each option. It could be in the form "0, 1, 2". This will really help in quickly identifying the options applicable to a particular level. 3) 6.3.1. -O*: convenient “packages” of optimisation flags. This section should perhaps mention what is the default? 4) 6.3.1. -O*: convenient “packages” of optimisation flags. This section says: "The easiest way to see what -O (etc.) “really mean” is to run with -v, then stand back in amazement." But when I tried it "-v" did not tell me what options are enabled. 5) Some flags are documented like this: {{{ -fno-opt-coercion Default: off Turn off the coercion optimiser. }}} This is confusing. It says "Default: off", the double negation would mean that "-fopt-coercion" is "on". Is that the case? Is there a "-fopt- coercion"? If yes, can we document that instead? If not, we can be more explicit about the double negation. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14214#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler