[all-commits] [llvm/llvm-project] 680b33: [X86] AMD Zen 3 sched model: FMA ops have inverse ...

[Roman Lebedev via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 680b33b66e8d2a93f75c98875b6c4b4efe52037d
      https://github.com/llvm/llvm-project/commit/680b33b66e8d2a93f75c98875b6c4b4efe52037d
  Author: Roman Lebedev <lebedev.ri at gmail.com>
  Date:   2022-12-11 (Sun, 11 Dec 2022)

  Changed paths:
    M llvm/lib/Target/X86/X86ScheduleZnver3.td
    M llvm/test/tools/llvm-mca/X86/Znver3/resources-fma.s

  Log Message:
  -----------
  [X86] AMD Zen 3 sched model: FMA ops have inverse throughput of 0.5

Now that exegesis produces meaningful snippets to measure throughtput
for instructions with tied operands:
https://github.com/llvm/llvm-project/commit/2ffe225d113031cc211d20d8d2cb82eeaa1a34a2
the measurements clearly show these instructions to have
more optimistic throughtput.

There's still some noise in the reports, especially around instructions
with memory operands. I'm not sure if we measure those correctly.

Fixes https://github.com/llvm/llvm-project/issues/59325