After newobject, we don't need to write zeroes to initialize the
object. It has already been zeroed by the allocator.
This is already handled in most cases, but because we run builtin
decomposition after the opt pass, we don't handle cases where the zero
of a compound builtin is being written. Improve the zero detector to
handle those cases.
Fixes#68845
Change-Id: If3dde2e304a05e5a6a6723565191d5444b334bcc
Reviewed-on: https://go-review.googlesource.com/c/go/+/605255
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Auto-Submit: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
