What this mean "dead: 1" and "dead: 0 1" on each tb block start?

[tugouxp]

HI folks:

  on each tb block start, there are following ir code, and the most confusing me is that  the postfix of each line "dead:" flag, what it is represent precisely?

i guess it may be related to the register or varible liveness for help generating tghe target machine code, but i cant get the precisely connection of the dead attrribute with qemu  internal varibles.

for example, why the line 61 use "dead:1" and the line 63 use "dead: 0, 1"?  what is the precisely meaning of the number after the "dead:" word?

thank you!     

    60 OP after optimization and liveness analysis:

     61  ld_i32 tmp5,env,$0xffffffffffffffec                 dead: 1

     62  movi_i32 tmp6,$0x0

     63  brcond_i32 tmp5,tmp6,lt,$L0                      dead: 0 1

     64  

     65  ---- 60000004 00000000 00000e04

     66  movi_i32 tmp5,$0x60000010

     67  mov_i32 tmp7,tmp5                                dead: 1

     68  qemu_ld_i32 tmp6,tmp7,leul,3                     dead: 1

     69  mov_i32 r1,tmp6                                  sync: 0  dead: 0 1

     70  goto_tb $0x1

     71  movi_i32 pc,$0x60000008                          sync: 0  dead: 0

     72  exit_tb $0x7f8e8ef58101

     73  set_label $L0

     74  exit_tb $0x7f8e8ef58103

     75