This PR addresses a single review comment on benchmark.sh: the summary awk logic could divide by zero when u1 (branch average user ms) rounded to 0. The change is intentionally scoped to that path only.

• Summary ratio safety

  • Added an explicit u1 == 0 guard before computing cmp_branch = u2 / u1.
  • Preserved existing summary semantics for normal cases (u1 > 0).

• Zero-baseline handling

  • u1 == 0 && u2 == 0 → mark as equal, show ratio as 1.00x.
  • u1 == 0 && u2 > 0 → mark as branch faster, show ratio as inf.
  • Avoids awk runtime failure while keeping output readable and deterministic.

if (u1 == 0) {
  if (u2 == 0) {
    cmp_branch = 1
    note = "equal"
    sp = sprintf("%9.2fx", cmp_branch)
  } else {
    note = "branch faster"
    sp = sprintf("%9s", "inf")
  }
} else {
  cmp_branch = u2 / u1
  ...
}