RFR: 8324433: Introduce a way to determine if an expression is evaluated as a constant by the Jit compiler [v5]

[Quan Anh Mai]

On Wed, 24 Jan 2024 06:27:20 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> I think of this as an expression that is always evaluated to the same value. The value itself is not interesting, it is the set of values that this expression can take that we are talking about.
>
> This seems really weird to me for Java code. The method doesn't get the original "expression" it only gets the value of that expression after it has been evaluated. Is there some kind of weird "magic" happening here?

@dholmes-ora Indeed it's a compiler magic, albeit not really weird. While the method execution only receives the evaluated value of `expr`, the method compilation has the expression in its original form. As a result, it can determine the result based on this information.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17527#discussion_r1464415357