| Issue |
127004
|
| Summary |
Misreported number of branches in conditional when ternary is introduced
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
mitchgrout
|
With the following source file:
```c
/* test.c */
int ex1(int x, int y)
{
if (x || y) { return 1; }
return 0;
}
#define M(x) (x? 1 : 0)
int ex2(int x, int y)
{
if (x || M(y)) { return 1; }
return 0;
}
int main(void)
{
ex1(0, 0); ex1(0, 1); ex1(1, 0); ex1(1, 1);
ex2(0, 0); ex2(0, 1); ex2(1, 0); ex2(1, 1);
return 0;
}
```
Compile with `clang --coverage -o test test.c`, execute it, and generate the coverage report via `llvm-cov gcov test-test.gcda --branch-counts --branch-probabilities`; the resulting `test.c.gcov` file will contain:
```text
...
-: 1:/* test.c */
-: 2:
function ex1 called 4 returned 100% blocks executed 100%
4: 3:int ex1(int x, int y)
-: 4:{
4: 5: if (x || y) { return 1; }
branch 0 taken 2
branch 1 taken 2
branch 2 taken 1
branch 3 taken 1
1: 6: return 0;
4: 7:}
-: 8:
-: 9:#define M(x) (x? 1 : 0)
function ex2 called 4 returned 100% blocks executed 87%
4: 10:int ex2(int x, int y)
-: 11:{
4: 12: if (x || M(y)) { return 1; }
branch 0 taken 2
branch 1 taken 2
branch 2 taken 1
branch 3 taken 1
branch 4 taken 0
branch 5 taken 1
1: 13: return 0;
4: 14:}
-: 15:
...
```
`ex1` has 4 branches with 100% coverage, as expected. `ex2`, which should be equivalent to `ex1`, instead has 6 branches, with only 5/6 being taken. It's not clear why clang has opted to introduce a new branch, and it is similarly not clear how this branch would be executed.
---
System:
```text
Ubuntu clang version 19.1.7 (++20250114103238+cd708029e0b2-1~exp1~20250114103342.77)
Target: x86_64-pc-linux-gnu
Thread model: posix
```
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