#8971: Native Code Generator 7.8.1 RC2 is not as optimized as 7.6.3... --------------------------------------------+------------------------------ Reporter: GordonBGood | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (NCG) | Version: 7.8.1-rc2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime performance bug | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: --------------------------------------------+------------------------------ Comment (by ezyang): Doesn't seem to be a problem on 64-bit: {{{ .Lc4cz: cmpq %r8,%rbx jg .Lc4cJ .Lc4cK: movq %rbx,%rdx sarq $6,%rdx movl $1,%edi movq %rcx,%r9 movq %rbx,%rcx andq $63,%rcx shlq %cl,%rdi xorq $-1,%rdi leaq 16(%rax),%rcx movq (%rcx,%rdx,8),%rcx andq %rdi,%rcx leaq 16(%rax),%rdi movq %rcx,(%rdi,%rdx,8) addq %r9,%rbx .Ln4g8: movq %r9,%rcx jmp .Lc4cz }}} What happens if you use `-freg-graph`? If you could post C-- dumps that would also be helpful. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8971#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler