<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/55888>55888</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Compile-time regression in 15.0.0
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          Daniel-Atanasov
      </td>
    </tr>
</table>

<pre>
    I've noticed a huge regression in compile-times on one of my projects (Win11-x64):
14.0.4
```
[build] ===-------------------------------------------------------------------------===
[build]                           Clang front-end time report
[build] ===-------------------------------------------------------------------------===
[build]   Total Execution Time: 0.5156 seconds (0.5249 wall clock)
[build] 
[build]    ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
[build]    0.4688 (100.0%)   0.0469 (100.0%)   0.5156 (100.0%)   0.5249 (100.0%)  Clang front-end timer
[build]    0.4688 (100.0%)   0.0469 (100.0%)   0.5156 (100.0%)   0.5249 (100.0%)  Total
```

15.0.0 (ed71a0b45b6c927333fa2c91e16f75a251408691)
```
[build] ===-------------------------------------------------------------------------===
[build]                           Clang front-end time report
[build] ===-------------------------------------------------------------------------===
[build]   Total Execution Time: 7.7188 seconds (7.8246 wall clock)
[build] 
[build]    ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
[build]    7.6719 (100.0%)   0.0469 (100.0%)   7.7188 (100.0%)   7.8246 (100.0%)  Clang front-end timer
[build]    7.6719 (100.0%)   0.0469 (100.0%)   7.7188 (100.0%)   7.8246 (100.0%)  Total
```

Times are from `-ftime-report`, only difference is in "Clang front-end time report" and the rest of the times don't seem any different.
Build is just as slow in debug.
I couldn't reproduce a minimal example, but here are the compile options:
Cmake properties:
```
C_STANDARD 23
C_EXTENSIONS ON
CXX_STANDARD 23
CXX_EXTENSIONS ON
```
Compiler arguments
```
-ftime-report
-fno-exceptions
-fno-rtti
-fno-builtin
-ffreestanding
-fdiagnostics-absolute-paths
-ferror-limit=0
-fmacro-backtrace-limit=0
-fdiagnostics-color
-nodefaultlibs
-nostdlib
-Wno-microsoft-template

Debug:
-Og
-g

Release:
-Ofast
-flto
-march=native
```
Linker arguments:
```
LINKER:/subsystem:console,/entry:entry_point
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJztVk1v2zgQ_TXyhZBAUV_2wYckToFgCwdIskhuBSWNZDYUaZBUmvz7HUqy4yZKF9jdoj2sIVjk42jmDWeGw1LXL-urgBVPQJR2ooKacLLrWyAGWgPWCq2IUKTS3V5ICJ3owBLEtAKiG9K9kL3RX6FylgRseS9UHIfPeRqwVZCcBXQT0LM4jWiUjuMgp9MzTrPzsheyDrINCZLN-IT_1e-o8b2xj38XkquWNEYrF4KqifcYN2OvjfvlnO-045JcPkPVOx-YO-SG20xolMVZTixUWtVDIBBh6Yp841KSSurq0QfkPf25fUESf1owg3IcD8jti3XQTdCAeJGAnY8LExbee3PH7_zfluPuebfmLGFW5MulpxtTGtGAZchywGmar-bwwc053Dv7Fp-LpPkVRIawzef_WCAZFgj1n0FdxJyWaVbm1YoVSZI0nFWrGOK8KTLOsjily3wVv0bz_3r6F5w_qqciKmLMh5N6KqIlS_PfvJ6KKC_i2XSdT-PJzRl8cPaf19NPJvJ39XQ3NCluwJPtCK6GjScbTmmH0uwCO5h8IbVoGjCgKiDC-kYXMPajjGWMcA_tPGKdb4F-PLbFWitspQ7zBmPL1at2F43Ezv0eeUNfe_yWW2Kl_uat1lD27SR0hc22l_WoCs0aXfdIj5NOKNFhvsIz7_YSvA9l78gOLQzOeiJTnyZ67xPaHnvwRccfwbfqPRgn4HXhzQZefLm9O9tuzm42hCUH6PLh7nJ7e3W9vSXX2wl8eJiRRHBG9q2JkaJBzm3f4ebYWbHvQzZBSofwXMHk3CtonBMnU5-LTqgD0hjAWGHchGoPWC14q7TFK48NeWm17B2Ee-52R7VgjDahFJ1weHwcWXW8MmiBV4_O8AreC5xqrrTUU4mEStfQ8F46KUp7xKyrcT5N75F7J1C_1Y0L8SDYS-7gNLU3PlGOwQuvD_60p0I3IIFbOBFruD3uoXR6GnbcVDukrrgTTzAbhc9CPX4Xqg_y5vPV9o_LG7_KPtm-tMMxhlM8QHFvfa7iAiowLwgO7y97LZR7o2xRr5N6laz4wgknYX1xcu18cyMdm-aiN3K9c25vR9v4tMLt-jLCSsCJlE-HVzhdVHEqrO2xBtinLFsul4vdOinqPIOsKWnJV5AXPElSRguaQ1IuixQWkpcg7RrPOTwCFGDRehU4xhNvIdaMMkZzmrEkobSIkmVFCx7XFSvjmOdlkFLouJCR5xFp0y7MeqCEwbS4KIV19nWRo5OtAhjMoX7eu5026w1XAmR4hpnMrX5aDBTWgwt_Ae3gJ48">