I found this article benchmarking Replace vs Regexp,
https://medium.com/codezillas/golang-replace-vs-regexp-de4e48482f53

See,
$ gometalinter --vendor --deadline 10m --disable-all --enable=megacheck ./...
pkg/tsdb/graphite/graphite.go:167:28:warning: regular expression does not contain any meta characters (SA6004) (megacheck)
pkg/tsdb/graphite/graphite.go:172:28:warning: regular expression does not contain any meta characters (SA6004) (megacheck)