Changes

Performance improvements:

• Code size: 1919 → 994 bytes (48% reduction)
• Stack usage: 1104 → 32 bytes (640 bytes saved, 10 fewer XMM saves)
• Hot loop: eliminated ~40 constant vector loads per iteration

Optimizations:

• Hoisted constants - moved rotation/permutation vectors to static readonly fields, eliminating redundant vector creations and memory loads in the hot loop
• Improved instruction scheduling - restructured Keccak round function to overlap independent operations:
  • Theta: use 3-way TernaryLogic XOR to avoid materializing intermediate results
  • Rho+Pi: pipeline permutes immediately after rotates complete
  • Pi: rewrite using matrix transpose (unpack/shuffle) instead of 25× PermuteVar8x64x2 calls
• Cache optimization - increased KeccakCache entry size from 96 to 128 bytes (align to 2 cache lines), added SSE prefetch hints
• Benchmarking - added BenchmarkHash method for AVX-512 vs scalar comparison

Assembly impact:

Before: hot loop with 40+ memory loads for constant vectors, poor instruction interleaving

vmovups  zmm18, zmmword ptr [reloc @RWD64]
vmovaps  zmm19, zmm18
vpermi2q zmm19, zmm6, zmm7
vmovups  zmm20, zmmword ptr [reloc @RWD128]  ; repeated 40+ times

After: no constant loads, better scheduling

vpternlogq zmm0, zmm24, zmm25, -106  ; direct use of hoisted constants
vprolvq  zmm0, zmm0, zmm19
vpermq   zmm1, zmm16, zmm1            ; overlapped execution

Types of changes

What types of changes does your code introduce?

• Optimization

Testing

Requires testing

• No

Documentation

Requires documentation update

• No

Requires explanation in Release Notes

• No

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