> I don’t care what type of weird tricks the compiler did for optimizations.

you might not, but plenty of others do. on the jvm for example, anyone building a performance sensitive application has to care about what the compiler emits + how the jit behaves. simple things like accidental boxing, megamorphic call preventing inlining, etc. have massive effects.

i've spent many hours benchmarking, inspecting in jitwatch, etc.

And 95%+ developers aren’t writing performance sensitive code. In my career, most bottlenecks I’ve seen are because of bad database design, network latency, or other infrastructure related issuesor in the cloud days startup latency for anything serviceless.

Yes I know every millisecond a company like Google can shave off, is multiplied by billions of transactions a day and can save real money on infrastructure. But even at a second tier company like Salesforce, it probably doesn’t matter

Which is a good example on how managed runtimes are already not deterministic and how hard it is to reproduce scenarios.