topperc wrote: > > JFYI, I don't find the AArch64 data particularly convincing for RISCV. The > > magnitude of the change even on AArch64 is small, and could easily be swung > > one direction or the other by differences in implementation between the > > backends. > > Yeah! The result will differ for different targets/CPUs. One RISCV data for > SPEC 2006 (which is not universal I think) on an OoO RISCV CPU, options: > `-march=rv64gc_zba_zbb_zicond -O3`: > > ``` > 400.perlbench 0.538% > 401.bzip2 0.018% > 403.gcc 0.105% > 429.mcf 1.028% > 445.gobmk -0.221% > 456.hmmer 1.582% > 458.sjeng -0.026% > 462.libquantum -0.090% > 464.h264ref 0.905% > 471.omnetpp -0.776% > 473.astar 0.205% > ``` > > The geomean is: 0.295%. The result can be better with PGO I think (haven't > tried it). Some related discussions: > https://discourse.llvm.org/t/rfc-cmov-vs-branch-optimization. So I think we > can be just like AArch64, make it a tune feature and processors can add it if > needed.
Do we have any data without Zicond? The worst case Zicond sequence is czero.eqz+czero.nez+or which is kind of expensive. Curious if this is pointing to Zicond being used too aggressively. https://github.com/llvm/llvm-project/pull/80124 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
