<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/78825>78825</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang is sometimes suboptimal for `copysign(x, y)` when the sign of y is known
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          k-arrows
      </td>
    </tr>
</table>

<pre>
    Test case:
https://godbolt.org/z/6hjYTvjW8
```c
#include <math.h>

float f(float x)
{    
     return copysignf(1.0f, x * x); 
}

float g(float x) 
{ 
     return (x > 0.0f) ? copysignf(1.0f, x) : 1.0f; 
}
```

If `-ffast-math` is specified, clang can optimize `f`.
</pre>
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