<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/115733>115733</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            @llvm.experimental.stackmap intrinsic crashes when the second parameter (numShadowBytes) is a variable instead of a constant
        </td>
    </tr>

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

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

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

<pre>
    # Description
The llvm.experimental.stackmap intrinsic currently crashes when the numShadowBytes parameter is provided as a variable rather than a constant. According to the syntax, llvm.experimental.stackmap is expected to record the location of specified values in the stack map without generating code. However, when attempting to pass a variable as the second argument (numShadowBytes), the compiler fails, leading to a segmentation fault during the X86 DAG->DAG Instruction Selection pass.

Example code that triggers the crash:
```
@G = global i16 0
@G.1 = global i32 2147483647

define void @f(i32 %nelems) {
entry:
  %B = sub i32 %nelems, 65536
  %mem = alloca i32, i32 %nelems, align 4
  call void (i64, i32, ...) @llvm.experimental.stackmap(i64 0, i32 %B, ptr %mem)
  ret void
}

; Function Attrs: nocallback nofree nosync willreturn
declare void @llvm.experimental.stackmap(i64, i32, ...) #0

attributes #0 = { nocallback nofree nosync willreturn }
```

https://godbolt.org/z/eM46jdv7r
</pre>
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