[LLVMdev] liveness question

[Bill Wendling]

On Aug 17, 2011, at 11:54 AM, shreyas krishnan wrote:

> Hi
>   if I have a function that has an formal argument assigned to  say
> register R0 and I have the following code fragment as my first basic
> block
> 
> 
> BB#0
>   %reg100023<dead> =   // for some reason could not be removed
>      ...
>                   = R0 <kill>
> 
> 
> What prevents R0 from being allocated to %reg100023
> 
The fact that R0 is live on entry to the block and its value is used after %reg100023 has been assigned.

-bw