<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/133182>133182</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang-cl does not support MSVC x86(64) div intrinsics
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          davidben
      </td>
    </tr>
</table>

<pre>
    MSVC has intrinsics corresponding to the x86 DIV instruction:
https://learn.microsoft.com/en-us/cpp/intrinsics/udiv64?view=msvc-170
https://learn.microsoft.com/en-us/cpp/intrinsics/udiv128?view=msvc-170
https://learn.microsoft.com/en-us/cpp/intrinsics/div64?view=msvc-170
https://learn.microsoft.com/en-us/cpp/intrinsics/div128?view=msvc-170

These operations (well, the unsigned ones) are useful in implementing big integer arithmetic. Sadly, clang-cl does not seem to support them. (I'm having to special-case clang-cl from MSVC in some code right now.)

Even with a clang-cl special case, these are not easily accessible from LLVM without inline asm, from what I can tell, because the x86 instructions trap when the quotient doesn't fit in a single word. A priori, trying to divide, say, uint128_t by uint64_t may give a 128-bit result.
</pre>
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