zeroize: remove internal use of optimization_barrier - #1535
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We replaced our previous use of compiler fences with `optimization_barrier` under the assumption it would be a zero-cost abstraction, but per #1504 that is not the case as it caused a performance regression. The use of either of these was effectively redundant and a belt-and-suspenders defense as volatile writes alone are already sufficient to guarantee zeroization will not be removed by the compiler. This removes the use of `optimization_barrier` to restore the previous performance. Closes #1504.
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We replaced our previous use of compiler fences with
optimization_barrierunder the assumption it would be a zero-cost abstraction, but per #1504 that is not the case as it caused a performance regression.The use of either of these was effectively redundant and a belt-and-suspenders defense as volatile writes alone are already sufficient to guarantee zeroization will not be removed by the compiler.
This removes the use of
optimization_barrierto restore the previous performance.Closes #1504.