Derick Rethans has been working on some updates to a tool he's developed, VLD, to make it more helpful and effecting in optimizing the opcodes in your scripts and find the dead opcodes and paths. He talks about these updates in this recent post.

Recently I've been working on some new functionality to visualise all the code paths that make up each function. These new routines sit on top of the routines that do dead code analysis. These new routines sit on top of the routines that do dead code analysis. Every branch instruction (such as if, but also for and foreach) is analysed and a list of branches is created. [...] Once all the branches and their links are found, another algorithm runs to figure out which paths can be created out of all the branches.

He illustrates with a few examples, showing both the command that was executed and the resulting output with the new path information of a simple test file using a "for" loop and an "if/else" conditional.