[GHC] #10750: silly assembly for comparing Doubles

[GHC]

#10750: silly assembly for comparing Doubles
-------------------------------------+-------------------------------------
        Reporter:  rwbarton          |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.11
  (CodeGen)                          |
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:  #10137, #10677    |  Differential Revisions:
-------------------------------------+-------------------------------------

Comment (by nomeata):

 Weird. With your example, compiled with `./inplace/bin/ghc-stage2
 -fforce-recomp -O -ddump-asm T10677.hs`, I get assembly like this:

 {{{
 ==================== Asm code ====================
 .text
         .align 8
         .long   S1vB_srt-(Zero.f_info)+0
         .long   0
         .quad   4294967301
         .quad   0
         .quad   12884901903
 .globl Zero.f_info
 .type Zero.f_info, @object
 Zero.f_info:
 _c1vs:
         leaq -32(%rbp),%rax
         cmpq %r15,%rax
         jb _c1vt
 _c1vu:
         movq $block_c1vm_info,-8(%rbp)
         movq %r14,%rax
         movl $GHC.Classes.$fOrdDouble_closure,%r14d
         movq $stg_ap_pp_info,-32(%rbp)
         movq %rax,-24(%rbp)
         movq $Zero.f3_closure+1,-16(%rbp)
         addq $-32,%rbp
         jmp GHC.Classes.>_info
 .text
         .align 8
         .quad   0
         .quad   32
 block_c1vm_info:
 _c1vm:
         andl $7,%ebx
         cmpq $1,%rbx
         jne _c1vq
 _c1vp:
         movl $Zero.f2_closure+1,%ebx
         addq $8,%rbp
         jmp *(%rbp)
 _c1vq:
         movl $Zero.f1_closure+1,%ebx
         addq $8,%rbp
         jmp *(%rbp)
 _c1vt:
         movl $Zero.f_closure,%ebx
         jmp *-8(%r13)
         .size Zero.f_info, .-Zero.f_info
 }}}
 so unless I am reading this wrong, it did not inline specialize or `>`.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10750#comment:4>
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