``Bottom-up'' Deletion Algorithm

• ``Bottom-up'' deletion algorithm is more optimistic.
• Much of the analysis information that depend on the deleted clauses can still be correct.
• In the best case we do not need to reexamine large parts of the program that top-down algorithm would re-analyze.
• In the worst case it may spend a large amount of time re-analyzing calling patterns that end up being useless.
• Reanalysis with the bottom-up deletion algorithm may take longer than re-analyzing the program from scratch using the non-incremental algorithm.
• ``Bottom-up'' deletion of clauses produces the same analysis results as non-incremental analysis.
• If the changes are few and have local extent, the bottom-up algorithm will be faster than the top-down.