On Fri, Nov 21, 2014 at 6:44 PM, Philipp Tomsich <philipp.toms...@theobroma-systems.com> wrote: > The following patch-series adds optimized support for the APM X-Gene 1 > by providing a cost-model and pipeline-model. The pipeline-model has a > few long reservation-chains, but looking at the stats for the generated > NDA shows that it's well below other AArch64 cores (e.g. Cortex-A53) in > overall size. > > This includes all the requested enhancements and cleans up the naming of > the various states and reservations in 'xgene1.md'. > > Even though it isn't wired into the 32bit ARM backend yet, we've decided > to keep the machine-description in config/arm... after all, the X-Gene > family is backwards compatible with ARMv7 and our benchmarking has shown > good potential for performance improvements from improving the instruction > selection and scheduling when using ARMv7 code (after all, X-Gene 1 is a > 4-way superscalar design).
Good, this being the case I would strongly suggest that -mcpu=xgene1 is wired up properly in the ARM backend by the end of stage3. It's better to do this sooner rather than later in order to minimize issues late in the release cycle. Afterwards its just bug fixing / tuning specifically for xgene. As I've said in the past I would strongly discourage an options break between the 2 backends, it will only come back to haunt the backends. i.e. please wire up xgene1 in config/arm/arm-cores.def Please also submit a patch to changes.html for AArch64 and ARM backends once this patch is reviewed / queued. Ramana > > After having a few further discussions with my colleagues regarding the > latencies and modelling of divides in the pipeline, we've readjusted the > modelling of the divides another time... even though it doesn't make a > difference in real-world benchmarks. > > Thanks to everyone who took the time to review and comment. > > > Philipp Tomsich (2): > Core definition for APM XGene-1 and associated cost-table. > Pipeline model for APM XGene-1. > > gcc/ChangeLog | 14 + > gcc/config/aarch64/aarch64-cores.def | 1 + > gcc/config/aarch64/aarch64-tune.md | 2 +- > gcc/config/aarch64/aarch64.c | 62 ++++ > gcc/config/aarch64/aarch64.md | 3 +- > gcc/config/arm/aarch-cost-tables.h | 101 +++++++ > gcc/config/arm/xgene1.md | 532 > +++++++++++++++++++++++++++++++++++ > gcc/doc/invoke.texi | 3 +- > 8 files changed, 715 insertions(+), 3 deletions(-) > create mode 100644 gcc/config/arm/xgene1.md > > -- > 1.9.1 >
