search for: reduceloopcount

...into our VLIW backend, and so far we've managed to get it working with some nice speedups. Unlike Hexagon however, our backend doesn't generate hardware loop instructions and so all our loops are a combination of induction variables, comparisons and branches. So when it came to implementing reduceLoopCount for our TargetInstrInfo, we found that we didn't have enough information from analyzeLoop to reduce the loops. Currently the signatures look like this: bool analyzeLoop(MachineLoop &L, MachineInstr *&IndVarInst, MachineInstr *&CmpInst) unsigned TargetIn...

...factor this from scratch. I'm therefore looking for direction in factoring in an incremental fashion. I think there are a couple of areas that I'd like to change, and I'd appreciate your ideas and opinions because I clearly don't know enough about the edge cases here. a) TII->reduceLoopCount() is hard to understand. Understanding the intended semantics of this hook from the documentation, I've found, is hard. Its use appears to be strongly fit to Hexagon (there is even a comment about the removal of LOOP0 in the MachinePipeliner target agnostic code, which really shouldn't be t...

...factor this from scratch. I'm therefore looking for direction in factoring in an incremental fashion. I think there are a couple of areas that I'd like to change, and I'd appreciate your ideas and opinions because I clearly don't know enough about the edge cases here.   a) TII->reduceLoopCount() is hard to understand. Understanding the intended semantics of this hook from the documentation, I've found, is hard. Its use appears to be strongly fit to Hexagon (there is even a comment about the removal of LOOP0 in the MachinePipeliner target agnostic code, which really shouldn't be t...

...ends with a conditional jump to Epilog 1): Y X Kernel: Z, Y, X Epilog 0: Z Epilog 1: Y Z The instructions in the prolog and epilog are generate in original program order within each stage, but in the last epilog stage, the instruction Y generates a value used by the subsequent Z. The reduceLoopCount function is needed for an architecture that has a hardware loop instruction like Hexagon’s LOOP0. For each prolog generated, the loop counter in the instruction needs to be decremented. This could have been done only in the last prolog block, but it’s done every time a prolog block is generated in...