FALSE POSITIVE: `zerodiv` reports inside an infeasible pointer equality branch

[Rodri]

Hi, I found a false positive in Cppcheck 2.21.0 when a division is guarded by an infeasible pointer equality.

Affected tool

Cppcheck 2.21.0

Affected checker

Cppcheck zerodiv

Minimal reproducer

int divide_on_impossible_pointer_equality(char *pointer) {
  int zero = 0;
  if (pointer == pointer + 1)
    return 1 / zero;
  return 0;
}

Reproduction command

cppcheck --version
cppcheck --enable=warning --std=c11 --checkers-report=checkers.txt --template='{file}:{line}:{column}: [{id}] {message}' cppcheck-zerodiv-fp-impossible-pointer-equality.c

Current behavior

Cppcheck reports cppcheck-zerodiv-fp-impossible-pointer-equality.c:4:14: [zerodiv] Division by zero.

Expected behavior

Cppcheck should not report zerodiv. In a defined execution, a pointer cannot equal the pointer to its next element, so the division is unreachable.

[CHR]

Thanks for reporting, ticket is here: https://trac.cppcheck.net/ticket/15002