From 5d6932cbbf754bf13cd07b74bfbca0af0ae7e5f6 Mon Sep 17 00:00:00 2001
From: Eli White <github@eli-white.com>
Date: Mon, 20 Apr 2026 00:02:20 -0700
Subject: [PATCH] perf: skip BigInt in blake3 b2Compress counter conversion
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blake3.b2Compress was calling fromBig(BigInt(counter), true) on every
call to split the chunk counter into a (h, l) 32-bit pair. The counter
is always a small safe integer — creating a BigInt and running BigInt
bitwise ops just to split it burned allocations on every hash step.

Inline the split directly:
  h = counter >>> 0
  l = Math.floor(counter / 4294967296) >>> 0

Output is bit-identical to fromBig(..., true).

Measured on autoresearch-scan (2000 charts, 8 workers, 2-run avg):
  previous (S2): 2.67 ms mean (3 runs: 2.634, 2.667, 2.717)
  this  (S5):    2.59 ms mean (2 runs: 2.620, 2.556)
  delta:         ~−3 to −6% mean

0 hash mismatches, 442/442 tests green. Patch extends
@noble+hashes+1.8.0.patch with the blake3.js diff.
---
 patches/@noble+hashes+1.8.0.patch | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/patches/@noble+hashes+1.8.0.patch b/patches/@noble+hashes+1.8.0.patch
index 2e5c1e9..848e7dc 100644
--- a/patches/@noble+hashes+1.8.0.patch
+++ b/patches/@noble+hashes+1.8.0.patch
@@ -70,3 +70,20 @@ index 0000000..0000001 100644
      }
      return { v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15 };
  }
+diff --git a/node_modules/@noble/hashes/blake3.js b/node_modules/@noble/hashes/blake3.js
+index 0000000..0000002 100644
+--- a/node_modules/@noble/hashes/blake3.js
++++ b/node_modules/@noble/hashes/blake3.js
+@@ -85,7 +85,11 @@ class BLAKE3 extends blake2_ts_1.BLAKE2 {
+     set() { }
+     b2Compress(counter, flags, buf, bufPos = 0) {
+         const { state: s, pos } = this;
+-        const { h, l } = (0, _u64_ts_1.fromBig)(BigInt(counter), true);
++        // Inlined fromBig(BigInt(counter), true) — counter is always a small
++        // safe integer (chunk index), so we can skip the BigInt alloc path.
++        // `le=true` returns { h: low 32, l: high 32 }.
++        const h = counter >>> 0;
++        const l = Math.floor(counter / 4294967296) >>> 0;
+         // prettier-ignore
+         const { v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15 } = (0, blake2_ts_1.compress)(B3_SIGMA, bufPos, buf, 7, s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7], B3_IV[0], B3_IV[1], B3_IV[2], B3_IV[3], h, l, pos, flags);
+         s[0] = v0 ^ v8;