<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/139970>139970</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Long and memory-wasting debug symbols generation
        </td>
    </tr>

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

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

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

<pre>
    ### Steps to reproduce
1. Save attached [main.cpp.txt](https://github.com/user-attachments/files/20214729/main.cpp.txt) as cpp file
2. Compile it with debug information and O2/O3 optimizations. I use: `clang++ main.cpp -g -O2`
3. Uncomment lines one by one and compile again

### Expected
Compile time is almost instantly.

### Actually 
Compile time grows twice with every uncommented line. Memory usage exceeds 20GB with uncommented line with `f24`

| Last uncommented line | Compile time on my PC, seconds |
|--------|--------|
| f16 | 0.945 |
| f17 | 1.627 |
| f18 | 3.170 |
| f19 | 6.121 |
| f20 | 12.355 | 
| f21 | 25.471 | 
| f22 | 51.952 | 
| f23 | 1:46.11 | 

### Environment

```text
$clang++ --version
clang version 19.1.7
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
```
```text
$uname -a
Linux 6.14.6-arch1-1 #1 SMP PREEMPT_DYNAMIC Fri, 09 May 2025 17:36:18 +0000 x86_64 GNU/Linux
```
Despite I use clang installed as package from archlinux repos, the same issue observed on [godbolt](https://godbolt.org/) site with various clang versions and targets.
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJx8VE2P2zgM_TXKhbAh01_xIQdnpikKdNrBtj3sqZAtxtGuLRmSnEn21y8kZ9pmtthAgOJHkXykqCecU4Mm2rFyz8rHjVj8ydidm8mdFqv6TWfkdccwXxd88TQ78AYszdbIpSfG2yyFL-JMILwX_YkksHI_CaXTfp5Tf_GsfGS4PXk_O5a3DA8MD4Pyp6VLezMxPCyObLJ6T6S9Y3g4qpHCjhyzosaG4eEuJDYgHPTzDOEk4y2m8GCmWY0EysOL8ieQ1C0DKH00dhJeGQ1CS_iMDA-fczCzV5P6JxpcCh9gccTyFljF-1HogeGe4R5es0IyQPIZWcUZb_MUvuneTIEtjEqTA6MJumvcQpb-xkUMQmnG27B-dPHdZabek2S8feXs1USgHIhxMs6D0s4L7cdr-ta37f0ixvEKb50Ha14c-BfV01o-ncleYXnlSTIyTeGJJhMMTgwEdOmJpAPk7_er21uHFWUVP2KxVh9W_QAfhfP_PR0sd7yMhukKzw8MH8BRb7R04dAaJLn97v_eEhyzKobjaVOU8CteRzxLK6zv8G3E8zSr-R3eRLxKM8x-xZGvcTDNy5gAfljiOcAyLers3oLxs8zSpsR7S75GY3lbVGn20-3u6vVZWaNDx26miq_L0yVCWPw6fklyJuuUCTMUcbh9Q9akWVoz3n4VdiAfRveyrb5XRTL3yaj0ckkGvQT7yZKQMBlJYzg1G6cujLcfwoyNI8lHZePgh4doGR66dWJfif2e5KLFRJAIxtuPIVnobpFWibD9KUsyYJhn8OXpGZ7_ePfu6fnr98c_P7VPHx7gYFUYBd7Ak7gCciwhq1ne5hXL23CDuOec81sx8P7TN4aHmOINqUdys_K0vlxYm6NeawrqMIv-7zDjR2smCLxiV4J0GRco-BOBE_HduYXAdI7smWSYWFbuByM7M_5evFZTauwQgQZcIBIfyllYZRYHd5floib4eFEu3chdLpu8ERvaZXVRY5UVGW5OOyzqSvZS8LzpjpkU-bbhjeQd9tutxLrfqF3oFy-zAhHzHNNjLusqr_OyFiX1UrKC0yTUmI7jeQr8NrG2XZY3Tc03o-hodFHsETW9rJUzxKD9dheckm4ZHCv4qJx3P8N45UfafTR6iKVMUUOSF-G80sNNad116szoYCBNNurqZrHj7n-EP4S_bclszV_Ue4aHSCqI_431eYf_BgAA__9ZMgH7">