On 10/25/06, Devang Patel <[EMAIL PROTECTED]> wrote:
> > One way to achieve this is to mark n_1 (in your example) as
> > "do not dead strip because I know it is used" , kind of attribute((used)).
>
> This is what as I understand LOOP_HEADER is used for.
Big difference. New tree vs TREE_USED or DECL_PRESERVE_P bit.
DECL_PRESERVE_P wouldn't work, because afaiu the number of iterations
is stored in an SSA_NAME tree node , not a *DECL node.
You could use TREE_USED, but your suggestion implies that dead code
should be retained in the program, just for the sake of knowing how
many iterations a loop has. I wouldn't be surprised if some passes are
not prepared to handle that, and it sounds like just a really bad
idea.
Gr.
Steven
