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TPDE-LLVM: Faster LLVM -O0 Back-End

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164 points mpweiher | 2 comments | 30 Aug 25 06:55 UTC | HN request time: 0s | source
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SleepyMyroslav ◴[03 Sep 25 19:02 UTC] No.45119326[source]▶
Judging from a lot of points people find -O0 code useful. May I ask if someone from those people tell me how you find it useful? The question is based on following experience: if we have lots of C++ code then all of the std lib and ours abstractions are becoming zero cost only after inlining. Inlining implies at least -O1. Why people even build -O0 for large projects? And if a project is not large one then build times should not be that much of a problem.
replies(2): >>45119492 #>>45119860 #
saagarjha ◴[03 Sep 25 19:19 UTC] No.45119492[source]▶
Debug builds don’t need to be fast. Or, at least, the benefits you get from faster compilation or better symbols outweigh the downsides.
replies(1): >>45119696 #
1. cout ◴[03 Sep 25 19:44 UTC] No.45119696[source]▶
They do need to not be slow though, which is why I usually stick with -Og.
replies(1): >>45119801 #
2. saagarjha ◴[03 Sep 25 19:57 UTC] No.45119801[source]▶
-Og trashes debug info