#8832: Constant-folding regression wrt `clearBit (bit 0) 0 ` -------------------------------------+------------------------------------- Reporter: hvr | Owner: Type: bug | Status: new Priority: high | Milestone: 7.10.1 Component: Compiler | Version: 7.8.1-rc2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | simplCore/should_compile/T8832 Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by thomie): * owner: thoughtpolice => * status: closed => new * resolution: fixed => Comment: `z` is still not properly constant-folded. The test is deceiving. It greps for '#', and there is no '#' in the output for `z` (not until #8274 is implemented, which I'm working on). {{{ $ ghc-7.10.0.20150123 Temp.hs -ddump-simpl -fforce-recomp -dsuppress-all -O [1 of 1] Compiling M ( Temp.hs, Temp.o ) ==================== Tidy Core ==================== Result size of Tidy Core = {terms: 10, types: 3, coercions: 0} z2 z2 = bitInteger 0 z1 z1 = complementInteger z2 z z = andInteger z2 z1 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8832#comment:20 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler