cmd/compile: update README to reflect dead code elimination changes
The description of middle-end dead code elimination is inconsistent with the current implementation.
The early dead code elimination pass of IR nodes is no longer located in cmd/compile/internal/deadcode and is no longer called by gc/main.go:Main. It has been moved to the unified IR writer phase. This update modifies the README to reflect this architectural change.
Change-Id: I78bd486edefd6b02948fee7de9ce6c83b147bc1d
GitHub-Last-Rev:
76493ce8b08cd585d761d65d29b984360f7ee628
GitHub-Pull-Request: golang/go#68134
Reviewed-on: https://go-review.googlesource.com/c/go/+/593638
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org>