We have an established testing program with automated testing tools, what good will it do to add pre-compile analysis step to our software development process?

Improves quality and saves money

"Testing alone will not determine if code will work on different platforms, if it is written efficiently and whether it adheres to particular coding guidelines or standards... Programmers can start improving code by using advanced linter tools... Programmers may find that inspections on code of more than 1,000 lines will help find bugs that testing would not turn up and which would be more expensive to correct later."

C.R. Dichter in "Two Sets of Eyes: How Code Inspections Improve Software Quality and Save Money"

Static analysis is four times more effective

Static testing is four times more effective than dynamic testing, according to Grady and Caswell in "Software Metrics: Establishing a Company-Wide Program" (Prentice-Hall). See "Efficiency of software test methods" below.

Improves software quality

"Finding and fixing defects early in the software development life cycle is much cheaper than finding and fixing the same defects later on, and results in higher quality software." - Marilyn Bush, "Improving Software Quality: The Use of Formal Inspections at the Jet Propulsion Laboratory" Proceedings of the 12th International Conference on Software Engineering, IEEE Computer Society Press

Increases ROI

"Detecting software defects early reduces the cost of dealing with the defects later in the development cycle. One HP entity used metrics data from several software projects and an industry profit and loss model to show the high cost of finding and fixing defects late in the development cycle and during post-release..." and found that ROI increased proportionally the earlier problems were identified. - Louis A. Franz and Jonathan C. Shih, "Estimating the Value of Inspections and Early Testing for Software Projects" Hewlett Packard Journal.