Intrinsics are ok to inline as they don't rewrite to actual calls.

Change-Id: Ieb19c834c61579823c62c6d1a1b425d6c4d4de23
Reviewed-on: https://go-review.googlesource.com/34272
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>