FALSE NEGATIVE: `zerodiv` misses a scalar zeroed by `memset`

[Rodri]

Hi, I found a false negative in Cppcheck 2.21.0 and 2.22 dev when memset zeroes a local integer before it is used as a divisor.

Affected tool

Cppcheck 2.21.0; also reproduced with Cppcheck 2.22 dev

Affected checker

Cppcheck CheckOther::checkZeroDivision (zerodiv / zerodivcond)

Minimal reproducer

#include <cstring>

int test() {
  int value = 1;
  std::memset(&value, 0, sizeof(value));
  return 1 / value;
}

Reproduction command

cppcheck --version
cppcheck --enable=warning --std=c++17 --checkers-report=checkers.txt --template='{file}:{line}:{column}: [{id}] {message}' cppcheck-zerodiv-fn-memset.cpp

Current behavior

Cppcheck produces neither a zerodiv nor a zerodivcond diagnostic. The checker report lists CheckOther::checkZeroDivision as active.

Expected behavior

Cppcheck should report line 6 because memset sets every byte of the local integer to zero.

[CHR]

See https://trac.cppcheck.net/ticket/14239