<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Issue</th>
<td>
<a href=https://github.com/llvm/llvm-project/issues/59753>59753</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>
LLVM no longer optimizes isEven loop to a test
</td>
</tr>
<tr>
<th>Labels</th>
<td>
new issue
</td>
</tr>
<tr>
<th>Assignees</th>
<td>
</td>
</tr>
<tr>
<th>Reporter</th>
<td>
y21
</td>
</tr>
</table>
<pre>
Up to clang 14.0.0, this (silly) C++ code:
```c++
bool is_even(int n) {
bool even = true;
int num = 0;
while (num != n) {
even = !even;
num++;
}
return even;
}
```
compiled to just:
```asm
is_even(int): # @is_even(int)
test dil, 1
sete al
ret
```
Since clang 15.0.0, it doesn't seem to understand this anymore and compiles to a loop.
Godbolt: [before](https://godbolt.org/z/WPYoa4M7K) | [now](https://godbolt.org/z/dc9eoKMze)
</pre>
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