On 10/27/23 11:39, Andrew Waterman wrote:
On Fri, Oct 27, 2023 at 6:44 AM Jeff Law <jeffreya...@gmail.com> wrote:
On 10/27/23 01:37, juzhe.zh...@rivai.ai wrote:
LGTM from my side.
The original integer division COST seems too low.
Almost certainly, though there may be good reasons why it was initially
set so low. I'm generally hesitant to change things like that without
either someone with knowledge of the code/uarch stepping in with a
recommendation or some kind of analysis showing their wrong.
It is probably just a bug, as the cores I'm familiar with mentioned in
the original post do benefit from converting division by constant into
multiplication. (We should make sure we continue emitting a division
instruction when optimizing for size, though.)
Yes. When optimizing for size we have a special tune info which
explicitly turns off the divmod expansion.
jeff
