crypto: Use local accumulator t[] in mul_amm_256 to avoid aliasing#1477
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #1477 +/- ##
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Coverage 97.36% 97.36%
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Files 163 163
Lines 14495 14497 +2
Branches 3387 3387
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+ Hits 14113 14115 +2
Misses 280 280
Partials 102 102
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Use a local array t[4] instead of writing directly to the output span r, which may alias the inputs x or y. This allows the compiler to keep the accumulator in registers without reloading after stores. The result is copied to r at the end. ~6% speedup on 256-bit modexp benchmarks (25846 → 24256 cycles).
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Use a local array t[4] instead of writing directly to the output span r, which may alias the inputs x or y. This allows the compiler to keep the accumulator in registers without reloading after stores. The result is copied to r at the end.
~6% speedup on 256-bit modexp benchmarks (25846 → 24256 cycles).