[llvm-bugs] [Bug 136635] File extremely slow to compile

[LLVM Bugs via llvm-bugs]

Issue	136635
Summary	File extremely slow to compile
Labels	new issue
Assignees
Reporter	jcelerier

    The attached file takes a very long time to build at higher optimization levels. clang-19 as provided by archlinux (x86-64).
With optimizations and debug info it's been running for 20 minutes and I haven't seen it end yet so I assume it's stuck.

For reference my machine can do a clean LLVM+clang build in roughly 7 minutes (420 seconds)

Flags |  Timings |
_________|_______|
-O0         |  30s |
-O0  -g       |  40s    |
-O1         |  72s    |
-O1  -g       |  ??? |
-O2         |  109s    |
-O2 -march=native | 139s |
-O3 | 126s |
-O3 -march=native -g | ??? |

[slow.zip](https://github.com/user-attachments/files/19841388/slow.zip)

when tracing the performance with one of the stuck processes it seems that it is due to the removeredundantdebugvalues pass: 

![Image](https://github.com/user-attachments/assets/562ab6f5-6191-45cb-b60a-69bdde269c8d)

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