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A comment on JEP Draft: Deprecate memory-access methods in sun.misc.unsafe for removal. Parent comment

Re:JEP Draft: Deprecate memory-access methods in sun.misc.un... by xxs on Wednesday January 17, 2024 @02:15AM (#39024341)
>With that said, convincing a compiler to elide bounds checks (especially Java's JIT compiler) is a hugely frustrating (and for some algorithms futile) task.

Adding explicit checks does work to a certain degree but it can change with the compiler, and it requires to keep checking the generated assembly - not fun (no unsafe, either but still)

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Re:JEP Draft: Deprecate memory-access methods in sun.misc.un... by iscoelho on Wednesday January 17, 2024 @03:49AM (#39025081)
These explicit checks are basically what I mean by "convincing the compiler" (and sometimes, it isn't quite convinced!) - Yeah. Not fun at all.

Especially in Java, because "the assembly" can change as the JIT evolves. What is optimized today may not be tomorrow.

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Re:JEP Draft: Deprecate memory-access methods in sun.misc.un... by xxs on Wednesday January 17, 2024 @03:56AM (#39025146)
Some 12-13y back (time does fly) Cliff Click (hotspot architect) had a series of blogs on optimizations, incl. the lattice checks (i.e. within bounds). Was quite insightful. It was called: "Too Much Theory" [0]

>What is optimized today may not be tomorrow.

Exactly. (Also most developers will have exceptionally hard time maintaining such code)

[0]: https://web.archive.org/web/20120328222841/http://cliffc.org...

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