<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/65223>65223</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang][AST] clang::Type::isSpecificBuiltinType slows down compilation
        </td>
    </tr>

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

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

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

<pre>
    I've profiled a clang release build (from main 39191c45771564b8a0930d71b4c229147cf839db) compiling sqlite3 (from llvm-test-suite/CTMark) on Windows and `clang::Type::isSpecificBuiltinType` consumes a relatively large portion of compilation time/samples. If we could speed up the function itself or optimize/reduce the usages, we could improve the compilation time of sqlite3 and potentially many other projects.
The following profile shows that `isSpecificBuiltinType` consumes more than 2% of all samples:
The line `if (const BuiltinType *BT = getAs<BuiltinType>()) {` seems to consume more than half of the samples.
</pre>
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