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

[Richard Henderson]

On 7/29/20 7:27 AM, tugouxp wrote:
> 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

The numbers are the index of the argument that is dead.

E.g. here, both tmp5 and tmp6 are dead.


r~