Editing Branch (computer science) (section)

=== Branch prediction hints ===
Historically, branch prediction took statistics, and used the result to optimize code.  A programmer would compile a test version of a program, and run it with test data.  The test code counted how the branches were actually taken. The statistics from the test code were then used by the compiler to optimize the branches of released code. The optimization would arrange that the fastest branch direction (taken or not) would always be the most frequently taken control flow path. To permit this, CPUs must be designed with (or at least have) predictable branch timing. Some CPUs have instruction sets (such as the [[Power ISA]]) that were designed with "branch hints" so that a compiler can tell a CPU how each branch is to be taken.

The problem with software branch prediction is that it requires a complex software development process.