diff(1) goes into cpu-hogging endless loop

Hi, A "diff" of 2 files:

1  77,933,904 bytes
2  63,013,818 bytes

, goes into an endless loop, whilst "gdiff" completes the operation in
about 5 seconds.

I tested using the latest "diff" from current, and get the same result.

Splitting both files into 10Mb chunks, and diffing these was successful.

A ktrace of the "diff" actually stops producing any output after about
5 seconds, whilst the cpu looping continues.

Any ideas on what to do next? Does anyone else get the same result?

The files are just utf-8 freebsd git logs, and are available here if
anyone would like to test:

http://www.catflap.org/jamie/1.xz (13,282,864 bytes)
http://www.catflap.org/jamie/2.xz (12,221,164 bytes)

Cheers, Jamie