| Issue |
125563
|
| Summary |
False branch coverage
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
amal-khailtash
|
We were using version `llvm/19.1.5` and we also moved to latest version `llvm/19.1.7` and the same problem persists. We have this piece of code as part of a bigger multi-threaded code that seems to show a problematic branch coverage that I cannot explain.
The `some_function` only returns if one of those `avail` flags is `true`. There is NO possibility of that function returning with all `avail` values being `false`. This has been confirmed by adding assertions to the code as below.
```CPP
/* 3.91k */ bool avail[3];
/* 3.91k */ some_function(avail);
{
/* 3.91k */ if ( avail[2] )
// Branch: [True: 0, False: 3.91k]
/* 3.91k */ {
/* 3.91k */ ...
}
/* 3.91k */ else if ( avail[0] )
// Branch: [True: 3.91k, False: 4]
/* 3.91k */ {
/* 3.91k */ ...
/* 3.91k */ }
/* 4 */ else if ( avail[1] )
// Branch: [True: 0, False: 4]
/* 0 */ {
/* 0 */ ...
/* 0 */ }
/* 4 */ else
/* 4 */ {
/* 4 */ assert(0);
// Branch: [Folded - Ignored]
/* 4 */ ...
/* 4 */ }
/* 4 */ }
/* 3.91k */ if ( avail == 0 )
// Branch: [True: 0, False: 3.91k]
/* 0 */ {
/* 0 */ assert(0);
// Branch: [Folded - Ignored]
/* 0 */ ...
/* 0 */ }
```
The problem is the 4 hits on the else branch here:
```CPP
/* 4 */ else if ( avail[1] )
// Branch: [True: 0, False: 4]
/* 0 */ {
/* 0 */ ...
/* 0 */ }
/* 4 */ else
/* 4 */ {
/* 4 */ assert(0);
// Branch: [Folded - Ignored]
/* 4 */ ...
/* 4 */ }
/* 4 */ }
```
I cannot see that we reach this point of the program and hitting the else branch! But `llvm-cov` seems to indicate that we do.
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