sum.s sum_tail.s
 1 sum:                                                                                                                                                                  
 2 .LFB24:                                                                                                                                                               
 3     .cfi_startproc
 4     testq   %rsi, %rsi                                                                                                                                                
 5     je  .L4                                                                                                                                                           
 6     addq    $1, %rsi                                                                                                                                                  
 7     movl    $1, %ecx                                                                                                                                                  
 8     xorl    %r8d, %r8d                                                                                                                                                
 9     xorl    %eax, %eax
10     jmp .L3                                                                                                                                                           
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11     .p2align 4,,10
12     .p2align 3
13 .L6:                                                                                                                                                                  
14     movq    %rcx, %r8                                                                                                                                                 
15     movq    %rdx, %rcx                                                                                                                                                
16 .L3:                                                                                                                                                                  
17     leaq    1(%rcx), %rdx                                                                                                                                             
18     addl    (%rdi,%r8,4), %eax                                                                                                                                        
19     cmpq    %rsi, %rdx                                                                                                                                                
20     jne .L6                                                                                                                                                           
21     rep ret
22 .L4:                                                                                                                                                                  
23     xorl    %eax, %eax                                                                                                                                                
24     ret                                                                                                                                                               
25     .cfi_endproc
 1 sum_tail:                                                                                                                                                             
 2 .LFB26:                                                                                                                                                               
 3     .cfi_startproc
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 4     xorl    %eax, %eax
 5     testq   %rsi, %rsi                                                                                                                                                
 6     je  .L17                                                                                                                                                          
 7     .p2align 4,,10
 8     .p2align 3
 9 .L18:                                                                                                                                                                 
10     addl    -4(%rdi,%rsi,4), %eax                                                                                                                                     
11     subq    $1, %rsi                                                                                                                                                  
12     jne .L18                                                                                                                                                          
13 .L17:                                                                                                                                                                 
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14     rep ret
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15     .cfi_endproc