BOLT binary optimiser

[aw1cks]

So I recently read about BOLT, which seems like an interesting concept. It could have significant performance gains for certain applications, for example their 'test case' was running it against clang compiled with PGO & LTO, with a healthy performance improvement. Could something like this be implemented?

[ionenwks]

Post-link optimizing sounds interesting indeed (especially if need on-the-fly optimization for a specific task without recompiling every times), but has same problem as any profile-based optimizations, it's hard to automate for a general use-case unless the package already provides some mean to collect perf data in a relevant way (aka pgo ebuilds).

[InBetweenNames]

I'm curious how this compares with AutoFDO, which also uses perf to gather statistics.

[jonesmz]

There's also Google's "Propeller Framework" that's similar to BOLT:
https://groups.google.com/forum/#!msg/llvm-dev/ef3mKzAdJ7U/1shV64BYBAAJ
https://www.phoronix.com/scan.php?page=news_item&px=Google-Propeller-Some-Upstream