| Issue |
81734
|
| Summary |
[clang] False positive clang-analyzer-core.DivideZero with loop over container
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
chrchr-github
|
~~~c++
#include <vector>
int f(const std::vector<int>& v) {
if (v.empty())
return 0;
int h = 0;
for (auto it = v.begin(); it != v.end(); ++it) {
h = std::max(h, *it);
}
int x = 512;
if (h < x)
h = h * (x / h + 1);
return h;
}
~~~
~~~
<source>:12:20: warning: Division by zero [clang-analyzer-core.DivideZero]
12 | h = h * (x / h + 1);
| ~~^~~
<source>:3:9: note: Assuming the condition is false]
3 | if (v.empty())
| ^~~~~~~~~
<source>:3:5: note: Taking false branch]
3 | if (v.empty())
| ^
<source>:5:5: note: 'h' initialized to 0
5 | int h = 0;
| ^~~~~
<source>:6:5: note: Loop condition is false. Execution continues on line 10
6 | for (auto it = v.begin(); it != v.end(); ++it) {
| ^
<source>:11:9: note: 'h' is < 'x'
11 | if (h < x)
| ^
<source>:11:5: note: Taking true branch
11 | if (h < x)
| ^
<source>:12:20: note: Division by zero
12 | h = h * (x / h + 1);
| ~~^~~
~~~
There could be division by zero if the vector holds only numbers <= 0. However, the diagnostic seems to imply that the vector might be empty, which is impossible.
https://godbolt.org/z/cbKh7axxd
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