Why is this an issue?
A dead store happens when a local variable is assigned a value that is not read by any subsequent instruction. Calculating or retrieving a value
only to then overwrite it or throw it away, could indicate a serious error in the code. Even if it’s not an error, it is at best a waste of resources.
Therefore all calculated values should be used.
Noncompliant code example
i = a + b; // Noncompliant; calculation result not used before value is overwritten
i = compute();
i = a + b;
i += compute();
This rule ignores:
- variable declarations initializers
- prefix and postfix increments and decrements
- null pointer assignments
x = NULL;
- self assignments (i.e.
x = x;)