[Vm-dev] Why spaceOkay test needed?

Out of curiosity, does anybody know why in...

primitiveNew "Allocate a new fixed-size instance. Fail if the allocation would leave less than lowSpaceThreshold bytes free. May cause a GC" | class spaceOkay | class := self stackTop. "The following may cause GC!" spaceOkay := self sufficientSpaceToInstantiate: class indexableSize: 0. self success: spaceOkay. successFlag ifTrue: [ self push: (self instantiateClass: self popStack indexableSize: 0) ]

... there is the call to #sufficientSpaceToInstantiate:indexableSize: although #instantiateClass:indexableSize: also indirectly calls #sufficientSpaceToAllocate:? Both, the primitive fallback code and the vm code signal the low space sem in case of failure.

Adrian