In computer programming, a dead store is a local variable that is assigned a value but is read by no following instruction. Dead stores waste processor time and memory, and may be detected through the use of static program analysis, and removed by an optimizing compiler.
If the purpose of a store is intentionally to overwrite data, for example when a password is being removed from memory, dead store optimizations can cause the write not to happen, leading to a security issue.[1] Some system libraries have specific functions designed to avoid such dangerous optimizations, e.g. explicit_bzero on OpenBSD.[2]