On 05/01/2018 03:30 PM, Jeff Law wrote:
On 01/22/2018 06:46 AM, Luis Machado wrote:The following patch adds an option to control software prefetching of memory references with non-constant/unknown strides. Currently we prefetch these references if the pass thinks there is benefit to doing so. But, since this is all based on heuristics, it's not always the case that we end up with better performance. For Falkor there is also the problem of conflicts with the hardware prefetcher, so we need to be more conservative in terms of what we issue software prefetch hints for. This also aligns GCC with what LLVM does for Falkor. Similarly to the previous patch, the defaults guarantee no change in behavior for other targets and architectures. I've regression-tested and bootstrapped it on aarch64-linux. No problems found. Ok? 2018-01-22 Luis Machado <luis.mach...@linaro.org> Introduce option to control whether the software prefetch pass should issue prefetch hints for non-constant strides. gcc/ * config/aarch64/aarch64-protos.h (cpu_prefetch_tune) <prefetch_dynamic_strides>: New const unsigned int field. * config/aarch64/aarch64.c (generic_prefetch_tune): Update to include prefetch_dynamic_strides. (exynosm1_prefetch_tune): Likewise. (thunderxt88_prefetch_tune): Likewise. (thunderx_prefetch_tune): Likewise. (thunderx2t99_prefetch_tune): Likewise. (qdf24xx_prefetch_tune): Likewise. Set prefetch_dynamic_strides to 0. (aarch64_override_options_internal): Update to set PARAM_PREFETCH_DYNAMIC_STRIDES. * doc/invoke.texi (prefetch-dynamic-strides): Document new option. * params.def (PARAM_PREFETCH_DYNAMIC_STRIDES): New. * params.h (PARAM_PREFETCH_DYNAMIC_STRIDES): Define. * tree-ssa-loop-prefetch.c (should_issue_prefetch_p): Account for prefetch-dynamic-strides setting.OK for the trunk. jeff
Thanks. Committed as r259996.
