Does anyone use llvm-exegesis? Feedback wanted

Code Generation
5

Here’s a faithful X-Ray trace (in chrome trace format) of

./bin/llvm-exegesis --mode=uops --benchmark-phase=assemble-measured-code --num-repetitions=100000 --opcode-name=VADDPSrr

exegesis-xray-ctf-trace.json.xz.txt (813.7 KB)
(rename to exegesis-xray-ctf-trace.json.xz, un-xz it, and e.g. upload to https://ui.perfetto.dev/)
As we can see, we spend all the time in llvm::exegesis::assembleToStream() (1.2 s in the example),
and there are 3 main places where it spends time:

  • DuplicateSnippetRepetitor::repeat() (0.2 s)
  • MachineVerifier (0.2 s)
  • llvm::AsmPrinter::emitFunctionBody() (0.8 s)