D-Programming-Language/phobos — pull request #1695 by rainers (2013-11-16 16:39:35+00:00)
Title: fix issue 11528: crashes or undefined behaviour of appender's first allocation

https://d.puremagic.com/issues/show_bug.cgi?id=11528

bsr is undefined for argument 0 (i.e. leaves destination register untouched).