<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/225041>225041</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang] __builtin_object_size with an out-of-range type argument is not rejected inside _Static_assert / enum and asserts in the constant evaluator
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          captainnemo9292
      </td>
    </tr>
</table>

<pre>
    https://godbolt.org/z/MnTvfYoYP (`-O0`)

```c
_Static_assert(__builtin_object_size((void*)0, 4), "");
```
```
clang: clang/lib/AST/ExprConstant.cpp:17034: bool {anonymous}::IntExprEvaluator::VisitBuiltinCallExpr(const clang::CallExpr*, unsigned int): Assertion `Type <= 3 && "unexpected type"' failed.
 #10 (anonymous namespace)::IntExprEvaluator::VisitBuiltinCallExpr(clang::CallExpr const*, unsigned int)
 #13 Evaluate(...)
 #15 CheckEvalInICE(clang::Expr const*, clang::ASTContext const&)
 #16 CheckICE(clang::Expr const*, clang::ASTContext const&)
 #18 clang::Expr::isIntegerConstantExpr(clang::ASTContext const&) const
 #19 clang::Sema::VerifyIntegerConstantExpression(...)
 #21 clang::Sema::BuildStaticAssertDeclaration(...)
```

In an ordinary context the type argument is range-checked: `int x = __builtin_object_size((void*)0, 4);` gives `argument value 4 is outside the valid range [0, 3]`. Inside `_Static_assert` (or an enumerator initializer) that check does not fire and the ICE check evaluates the call with type 4, which the evaluator only asserts on. Clang trunk, assertions build.
</pre>
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