This bug has been introduced in the following revision:

changeset:   11404:26dceba5c610
user:        Ivan Krasin <krasin@golang.org>
date:        Mon Jan 23 09:19:39 2012 -0500
summary:     compress/flate: reduce memory pressure at cost of additional arithmetic operation.

This is the review page for that CL: https://golang.org/cl/5555070/

R=rsc, imkrasin
CC=golang-dev
https://golang.org/cl/6249067