The stackalloc code needs to run a liveness pass to build the
interference graph between stack slots. Because the values that we need
liveness over is so sparse, we can optimize the analysis by using a path
exploration algorithm rather than a iterative dataflow one
In local testing, this cuts 74.05 ms of CPU time off a build of cmd/compile.
Change-Id: I765ace87d5e8aae177e65eb63da482e3d698bea7
Reviewed-on: https://go-review.googlesource.com/c/go/+/718540 Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Keith Randall <khr@golang.org> Reviewed-by: Junyang Shao <shaojunyang@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Keith Randall <khr@google.com>