wasm-opt for Substrate

[xermicus]

wasm-opt brings some great optimizations and we should use it (cargo contract uses it for ink contracts). For example, the Wasm blob of our flipper example (compile --release) goes down from 2.2kb to 1.2kb.

[seanyoung]

Enabling the wasm_opt feature without the llvm feature makes no sense, but I don't know what we can do about that (and if it matters).

[xermicus]

Agreed, however we can't tie it together with the llvm flag, because the other way round, e.g. enabling llvm but not wasm_opt, it does make sense.

But what we can do is to automatically enable llvm for the wasm_opt feature, WDYT?

[seanyoung]

But what we can do is to automatically enable llvm for the wasm_opt feature, WDYT?

The more I think about it, the more I think it doesn't matter

[xermicus]

@LucasSte yeah I forgot to commit that, thanks