#6135: Unboxed Booleans -------------------------------+-------------------------------------------- Reporter: benl | Owner: jstolarek Type: feature request | Status: patch Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.4.1 Resolution: | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Difficulty: Unknown Testcase: | Blockedby: Blocking: | Related: #605 -------------------------------+-------------------------------------------- Comment(by simonpj): I think we should treat all Bool-returning primops identically. I think it's just the `sameX` family of operators, and they can perfectly well return `Int#` in the same way that `eqInt#` now does. Then you can eliminate those cases from the codegen path, which is great. One thing I'm puzzled about is this. If `>#` yields an `Int#`, how does that `Int#` get into a register? Do we get code like {{{ cmp x,y bne L1 ld R1, 1 goto L2 L1: ld R1, 0 L2: ...now R1 has the Int#... }}} Getting the info from the status flags into a value, which we then compare with 0, would be silly. How is this avoided? Esp when there are several tests and you do logical operations on the `Int#`? I looked on the wiki page http://hackage.haskell.org/trac/ghc/wiki/PrimBool, but could not figure it out. Maybe worth adding a section to explain this? Thanks Simon Simon -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/6135#comment:69 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler