KeilC51 can not compile this code correctly

hi: I have a code below:

     char pop_value = 0X80;
     if(pop_value == 0X80)
     {
         pop_value = pop_value;//point 1

     }
     pop_value = pop_value;//point 2

I would have thought the code would jump to point 1 after logical judge, but the simulating result exceed my expectations that the code jumped to point 2. I watch the Disassembly code :

    82:             pop_value = 0X80; 
C:0x0A68    7853     MOV      R0,#pop_value(0x53)
C:0x0A6A    7680     MOV      @R0,#P0(0x80)
     83:             if(pop_value == 0X80) 
C:0x0A6C    E6       MOV      A,@R0
C:0x0A6D    FF       MOV      R7,A
C:0x0A6E    FD       MOV      R5,A
C:0x0A6F    33       RLC      A
C:0x0A70    95E0     SUBB     A,ACC(0xE0)
C:0x0A72    FC       MOV      R4,A
C:0x0A73    ED       MOV      A,R5
C:0x0A74    6480     XRL      A,#P0(0x80)
C:0x0A76    4C       ORL      A,R4
C:0x0A77    7002     JNZ      C:0A7B
    84:             {
    85:             pop_value = pop_value;
    86: 
C:0x0A79    A607     MOV      @R0,0x07
    87:             }
C:0x0A7B    22       RET
                 PUTCHAR:

I can not find the error happened.so I also compile this C code in another project. the code can jump to point 1 after logical judge ,nor jump to point 2.I watch the the Disassembly code at once:

    61:      item = 0X80; 
C:0x0A94    752400   MOV      0x24,#malloc_mempool(0x00)
C:0x0A97    752580   MOV      0x25,#P0(0x80)
    62:      if( item== 0x80) 
C:0x0A9A    E525     MOV      A,0x25
C:0x0A9C    6480     XRL      A,#P0(0x80)
C:0x0A9E    4524     ORL      A,0x24
C:0x0AA0    7006     JNZ      C:0AA8
    63:      {
    64:      item =item; 
C:0x0AA2    852424   MOV      0x24,0x24
C:0x0AA5    852525   MOV      0x25,0x25
    65:      }

my keiC51 version is V8.16. I don't know why the same C code has different assemble code in different project. The important thing is that the compiler make a wrong logical judge.