As without_locs/2 and ahead_as_check/2: the instructions is without their source positions, each check_ahead now the check of its whole range, whose early bytes are tested with the access's own.

A block before fusion.

As temp_defs/3, its names: every definition of a temporary, the parameters ps, then each block's phis and instructions.

The names ns counted: each maps to whether it occurs more than once.

Whether the name n is defined more than once.

As single_proofs/3: the proof q mapped to its checked pointer p for each heap check let(tmp(Q), a, check(...), [P]) where q has one definition in the function and p, if a temporary, has no more than one. Only these may be reused in another block: reloading p there gives the value that was checked.

The proofs of a block so far, as pr(ByQ, ByP): by_q maps each proof q to its checked pointer, and by_p each name n to the proofs once paired with tmp(N), so that a new definition of n drops its pairs without a scan of the others.

As proofs_empty/1.

As proofs_add/3: pr with the proof q of the pointer p.

As proofs_kill/3: pr once d is defined again: without d's own pair and without each pair whose pointer is tmp(D). Emission reloads the pointer from its slot, so its old proofs are of another value.

Which protocols a fused pointer access may declare: a heap object's or a named local's.

As proven_access/4 (heap) and proven_local_access/4 (local): the raw access i, which reads the proof q, as the access at the place p. A pointer access must declare a protocol of its storage: the heap's or the atomic helpers', or the local's.

As access_pointer/3, its offset: the access a is at its place plus this.

The proof and the offset of an access that may be reused: a non-pointer raw load or store, or a pointer load by the heap's load protocol.

As unchecked_access/1 and implicit_flight/1, for the checked IR: an instruction that must not reach emission by itself: a raw access or call not fused with its check, a call of a pointer, or pointer arithmetic outside a flight.

Whether access_check//2 can emit the check c: of the bytes from the pointer up to a positive size below 2^31, aligned to 1, 2, 4 or 8.

As fused_inst/5: the instruction i fused with the one after it in rest, if it is a check, and whether that one was taken. Nothing if i is a check without its access, a check the first version does not emit, or an instruction that is not_emitted.

One step of fused_insts/5: the instruction i under the block's proofs pr and the function's single proofs. An access whose proof is among them is reused, at the proof's pointer, if its offset fits 32 bits; anything else is fused_inst's.

As fused_insts/5: the instructions is fused, in front of the reversed acc. Each instruction's definition first forgets the proofs it invalidates; a check then adds its own; and what the fused instruction defines, a load's destination perhaps, forgets again.

A block after fusion: its instructions are finsts.

As fused_blocks/5: the blocks bs of a function with the parameters ps, fused. fused_blocks/5 also throws unless every cycle polls, which is the validator's to check here.