This reduces the number of branches to bounds check non-empty slices
from 5 to 3. It does also increase the number of branches to handle
empty slices from 1 to 3; but for non-panicking calls, they should all
be predictable.
Updates #48798.
Change-Id: I3ffa66857096486f4dee417e1a66eb8fdf7a3777
Reviewed-on: https://go-review.googlesource.com/c/go/+/355490
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>