Am I imagining things, or does the new IR compiler...

# javascript

[spierce7]

Am I imagining things, or does the new IR compiler compile much slower?

[turansky]

x1.5 in my cases

[turansky]

Legacy - 3m 34s
IR - 5m 13s

[bashor]

Depends on workload, actually, it’s hard to make a fair comparison. The biggest difference between compiler backends is that IR compiler backend does the most of work at last stage -- generating executable, it’s required to get smaller outputs. Another compiler backend distributes works between parts, so it needs to generate code only for a current module/project.

[bashor]

When we fairly compared backends last time IR was slightly faster, but the real world isn’t fair 🙂

[bashor]

Anyway, we are going to continue working on performance on real projects when using the new compiler backend.

[bashor]

It would be nice if you could also measure and share with us build time with -Xir-dce-driven option. And please make sure you use clean build ,

[turansky]

-Xir-dce-driven - how can I check if it works?

[spierce7]

I’m less concerned with clean build, and more concerned with incremental compile times. I’ve tried some simple, apps with the IR compiler, and I’ve noticed that every time I compile, it takes longer than expected

[spierce7]

I’m assuming the IR compiler is just new, and that it will get significantly faster over time.

[bashor]

Incremental compilation for the IR compiler is not fully ready yet. It’s enabled only for part of pipeline.

[bashor]

@turansky

...
js {
...
  compilations["main"].kotlinOptions {
      freeCompilerArgs += "-Xir-dce-driven"
  }
...
}

[turansky]

@bashor I mean in result js file

[bashor]

@turansky I’d expect that the size of output is the same as from prod build, but content could be slightly different.

[spierce7]

Incremental compilation for the IR compiler is not fully ready yet

That’s why I’m noticing the big difference in compile times then. Thanks

[spierce7]

@bashor I’m assuming that the IR compiler is at least partially shared between jvm, js, and native. That’s the case, right?

[bashor]

@spierce7 right, IR compiler backends (native, new js, new jvm) share a lot of code.