It specifically rely on the CacheIR data collected by the baseline tiers, with the new architecture also described as being more maintainable and unlocks additional SpiderMonkey improvements.
Firefox 83 made debut on November 17, with Warp as shown to be faster than Ion, the SpiderMonkey’s previous optimizing JiT, boasting of a 20 percent improvement on load time.
Although both IonBuilder and WarpBuilder produce Ion MIR, which is an intermediate representation used by the optimizing JiT backend, IonBuilder offered a lot of complex code that are unnecessary in WarpBuilder. And Warp can also do more work off-thread and requires fewer recompilations.
As Warp is based on CacheIR enabled removal of code through the engine that was needed to track globaltype inference data used by IonBuilder, it results in speed boosts for the browser's performance.
What's Next in the Warp update for Firefox?
Warp replacing the front end MIR building phase of the IonMonkey JiT, also means the removing of the old code and architecture, which will most likely happen in Firefox 85.