On Thu, Oct 23, 2014 at 9:12 PM, Yangfei (Felix) <felix.y...@huawei.com> wrote: >> Here the key point is we need a general purpose register for the "loop" >> instruction.
So the question to ask here is, "How does this work today, without loop instructions?" Somehow--even when it has been spilled--a branch instruction can test the trip count. There should be no difference. >> And we cannot use zero-cost looping in this situation. >> And that's why I spilt the zero_cost_loop_end into a normal test and branch. > Also note that the hwloop_pattern_reg interface also expects a general > purpose register in the doloop_end pattern. If there were no loop instruction, how would this work?
