<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/148166>148166</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            riscv64: `preserve_mostcc`is not supported
        </td>
    </tr>

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

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

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

<pre>
    see https://godbolt.org/z/13qTn3bTa

```llvm
target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "riscv64-unknown-linux-gnu"

define preserve_mostcc void @foo(ptr align 8 %_1) unnamed_addr {
start:
  ret void
}
```

Many architectures do support the `preserve_mostcc` calling convention (or at least do not crash on it), e.g. x86, aarch64, arm, wasm, s390x and powerpc. 

This came up in https://github.com/rust-lang/rust/issues/143319
</pre>
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