Beautiful branchless binary search

Nice algorithm. I don't agree that it is branchless however. Cmov is a branching instruction for sure. And it doesn't really matter whether a branch can be well predicted. The reason you mainly want branchless code is for security reasons where a timing sidechannel could reveal information. Calling this algorithm branchless devalues the term into something meaningless.

Edit: Everybody in the comments is focusing on performance. For performance sensitive code the point is not that it's branchless, the point is that it is fast, that some branchless code is faster than branching code is an implementation detail. During encryption the point is that it certain codepaths MUST be branchless.

> The reason you mainly want branchless code is for security reasons

That just isn’t true.

Which part isn't true? I think the qualifier 'mainly' definitely weakens the statement, but I'm struggling to think of how it could certainly be false statement.

This is certainly true for at minimum DDoS attacks, and I would absolutely consider that a security risk.