cmd/compile: soften type matching when allocating stack slots
Currently we use pointer equality on types when deciding whether we can
reuse a stack slot. That's too strict, as we don't guarantee pointer
equality for the same type. In particular, it can vary based on whether
PtrTo has been called in the frontend or not.
Instead, use the type's LinkString, which is guaranteed to both be
unique for a type, and to not vary given two different type structures
describing the same type.
Update #65783
Change-Id: I64f55138475f04bfa30cfb819b786b7cc06aebe4
Reviewed-on: https://go-review.googlesource.com/c/go/+/565436 Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>