Re: [GHC] #16029: Inadequate absence analysis

#16029: Inadequate absence analysis -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones ): In [changeset:"d77501cd5b9060e38acd50e11e0c5aae89d75b65/ghc" d77501cd/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="d77501cd5b9060e38acd50e11e0c5aae89d75b65" Improvements to demand analysis This patch collects a few improvements triggered by Trac #15696, and fixing Trac #16029 * Stop making toCleanDmd behave specially for unlifted types. This special case was the cause of stupid behaviour in Trac #16029. And to my joy I discovered the let/app invariant rendered it unnecessary. (Maybe the special case pre-dated the let/app invariant.) Result: less special-case handling in the compiler, and better perf for the compiled code. * In WwLib.mkWWstr_one, treat seqDmd like U(AAA). It was not being so treated before, which again led to stupid code. * Update and improve Notes There are .stderr test wibbles because we get slightly different strictness signatures for an argumment of unlifted type: rather than for Int# rather than for Int }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16029#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler