[PATCH] Add zero-overhead looping for xtensa backend
augustine.sterling@gmail.com
augustine.sterling@gmail.com
Fri Oct 24 06:49:00 GMT 2014
On Thu, Oct 23, 2014 at 11:40 PM, Yangfei (Felix) <felix.yang@huawei.com> wrote:
> 1. The original xtensa port never generates "loop" instruction at all.
> 2. A port doesn't need to implement hwloop_pattern_reg hook if it has no zero-cost loop instruction.
>
> Is that clear?
We are talking in circles. I understand very well what goes on here.
My point is:
1. Right now, today, GCC generates loops with branch instructions even
when the trip count is spilled.
2. Branch instructions and loop instructions have identical register
requirements.
Therefore:
3. loop instructions should be generatable when the trip count is spilled.
More information about the Gcc-patches
mailing list