1815928 - Investigate coalescing nursery space checks for back-to-back allocations

Status: NEW

(Core :: JavaScript Engine: JIT, task, P3)

Description

[Ted Campbell [:tcampbell]]

When we allocate two small objects in Ion, we emit checks for nursery free space for each object. When we look at the same thing in V8, they are able to use a single coalesced check (and then initialize each object similar to what we do).

These types of checks are probably pretty cheap on the CPU, but it is still a small opportunity for improvements to codegen (and code size).