On 10/25/06, Steven Bosscher <[EMAIL PROTECTED]> wrote:
So you would mark n_1 with TREE_USED, and never let it be removed? What would happen if e.g. the entire loop turns out to be dead code? Or if the loop is rewritten (e.g. vectorized) in a way that changes the number of iterations of the loop? Then the assignment to n_1 would be _really_ dead, but there wouldn't be any way to tell.
When it is really dead, you'll have to remove LOOP_HEADER node anyway. Right ? Why not instead reset the TREE_USED bit and let DCE do its job ? I do not want to drag this discussion further, so I'll stop now. - Devang
