On Thu, 2016-04-28 at 19:43 +0800, zengzhaoxiu at 163.com wrote:

From: Zhaoxiu Zeng <redacted>

Because some architectures (alpha, armv6, etc.) don't provide 
hardware division, the mod operation is slow! Binary GCD algorithm 
uses simple arithmetic operations, it replaces division with 
arithmetic shifts, comparisons, and subtractions.

I have compiled successfully with x86_64_defconfig and 
i386_defconfig.

What's the reason for wanting to optimize this and thus have to
maintain (and test) two separate code paths, which is a significant
expense? As far as I can see, gcd() is mosly used in finding optimal
clocks for operations, which is usually done at start of day and not
time critical.

James