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class v5 shadow rule: the rotate-merge arm is the census's (the same rotate with the same amount or amount register, the source untouched), not every rotate pair, since every op reads its own destination; the tests allow what acceptance does (it reads the shadow, so a redrawn block can move the accepted attempt and the base program): an unredrawn seed is the amended v4 draw for draw, a redrawn seed's first v4 block was over the bound, and the redraw rate stays near the census's 4e-3

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Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
This commit is contained in:
igneum-labs 2026-10-07 18:37:58 +00:00
parent 03173925f2
commit bcf2daf895
1 changed files with 26 additions and 8 deletions
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34
igneum-pow/src/generator.rs
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@ -1315,7 +1315,12 @@ pub fn shadow_removable_count(block: &[Instr]) -> usize {
let same_operands = prev.src == ins.src && prev.imm == ins.imm && prev.imm2 == ins.imm2 && prev.src2 == ins.src2 && prev.rot == ins.rot && prev.bit == ins.bit && prev.mask == ins.mask;
let hit = match (prev.op, ins.op) {
(Op::Xor, Op::Xor) | (Op::Or, Op::Or) => same_operands && src_untouched,
(Op::Rotl, Op::Rotl) | (Op::Rotr, Op::Rotr) | (Op::Rotl, Op::Rotr) | (Op::Rotr, Op::Rotl) => true,
// every op reads its own destination (`d = d op a`), so two rotates on one register always fold on
// paper; the census counts "written twice from one source": the same rotate with the same amount
// (rotl, an immediate) or the same amount register unwritten between (rotr), which keeps the
// metric at the census's 0.62 percent average instead of every rotate pair
(Op::Rotl, Op::Rotl) => prev.rot == ins.rot,
(Op::Rotr, Op::Rotr) => prev.src == ins.src && src_untouched,
(Op::Add, Op::Sub) | (Op::Sub, Op::Add) => same_operands && src_untouched,
_ => false,
};
@ -2030,10 +2035,14 @@ mod tests {
let v5 = generate_from_seed_bytes_program_class(&seed, seed.as_bytes(), ProgramClass::V5, Some(&era));
assert!(shadow_removable_count(&v5.shadow) * 1000 <= v5.shadow.len() * SHADOW_REMOVABLE_MAX_PERMILLE, "{seed}: a v5 block over the bound");
let v4 = generate_from_seed_bytes_program_class(&seed, seed.as_bytes(), ProgramClass::V4, Some(&era));
assert_eq!(v5.instrs, v4.instrs, "{seed}: the base program never moves");
if v5.shadow != v4.shadow {
if v5.shadow == v4.shadow {
assert_eq!(v5.instrs, v4.instrs, "{seed}: an unredrawn seed is the amended v4 draw for draw");
} else {
// the acceptance rules read the shadow (the freshness fixpoint), so a redrawn block can move the accepted
// attempt and with it the base program; what must hold is that the first v4 block was over the bound
redrawn += 1;
assert!(shadow_removable_count(&v4.shadow) * 1000 > v4.shadow.len() * SHADOW_REMOVABLE_MAX_PERMILLE, "{seed}: v5 redrew a block the rule admits");
let first = candidate_class(&seed, seed.as_bytes(), v4.attempt, v4.class);
assert!(shadow_removable_count(&first.shadow) * 1000 > first.shadow.len() * SHADOW_REMOVABLE_MAX_PERMILLE || v5.attempt != v4.attempt, "{seed}: v5 redrew a block the rule admits");
}
scanned += 1;
if redrawn >= 2 && scanned >= 1_000 {
@ -2041,6 +2050,7 @@ mod tests {
}
}
assert!(redrawn >= 1, "no redraw in {scanned} seeds (the census says about 4e-3 per draw)");
assert!(redrawn * 50 <= scanned, "{redrawn} redraws in {scanned} seeds: the metric is far above the census's 4e-3");
}
/// Class v5 (docs/design/class-v5-stored-state.md) takes the amended class v4 draw (AP-F8-1) as the chain draws it:
@ -2065,9 +2075,15 @@ mod tests {
for seed in ["igneum-genesis", "igneum-epoch-7", "igneum-epoch-99"] {
let v4 = generate_from_seed_bytes_program_class(seed, seed.as_bytes(), ProgramClass::V4, Some(&era));
let v5 = generate_from_seed_bytes_program_class(seed, seed.as_bytes(), ProgramClass::V5, Some(&era));
assert_eq!(v5.instrs, v4.instrs, "{seed}: the base program is the amended v4's");
assert_eq!(v5.shadow, v4.shadow, "{seed}: and the shadow block");
assert_eq!((v5.seed, v5.attempt), (v4.seed, v4.attempt));
if v5.shadow == v4.shadow {
assert_eq!(v5.instrs, v4.instrs, "{seed}: the base program is the amended v4's");
assert_eq!((v5.seed, v5.attempt), (v4.seed, v4.attempt));
} else {
// the AP-F1-1 shadow rule redrew this seed's block (and the acceptance, which reads the shadow, may have
// moved the attempt): the first v4 block must have been over the bound
let first = candidate_class(seed, seed.as_bytes(), v4.attempt, v4.class);
assert!(shadow_removable_count(&first.shadow) * 1000 > first.shadow.len() * SHADOW_REMOVABLE_MAX_PERMILLE || v5.attempt != v4.attempt, "{seed}: v5 differs from v4 without a redraw");
}
// the draw equality above is the claim; sub-version 3's own freshness rule (dataflow, with the last resort after
// the 256 cap) is what the chain applies, so the sub-version 1 scan below is informational for v5
let _ = scan(&v5);
@ -2076,7 +2092,9 @@ mod tests {
assert_ne!(v5.program_id(), v4.program_id());
let r1 = generate_from_seed_bytes_program_class_shadow(seed, seed.as_bytes(), ProgramClass::V5, Some(&era), 35);
let r1v4 = generate_from_seed_bytes_program_class_shadow(seed, seed.as_bytes(), ProgramClass::V4, Some(&era), 35);
assert_eq!(r1.instrs, r1v4.instrs, "{seed}: rung 1 too");
if r1.shadow == r1v4.shadow {
assert_eq!(r1.instrs, r1v4.instrs, "{seed}: rung 1 too");
}
let _ = scan(&r1);
assert_eq!(r1.class, v5_class_at(35).with_era_of(&r1v4.class));
}