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

[Quan Anh Mai]

On Thu, 25 Jan 2024 05:06:12 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> I agree. All values are produced by evaluating expressions. In this case we want to query whether a value produced by the compiler evaluating its expression is a constant value (inputs to the expression are constants and the expression had no material side-effects). Meaning if the method returns true then we could use that knowledge in subsequent expressions that may also produce constants or some specific behavior.
>
>> the method compilation has the expression in its original form
> 
> So the JIT analyses the bytecode used to place the result on the call stack, before the call, and from that determines if the expression were a constant? This kind of self-analysis is not something I was aware of.

I see, changed `expr` to `val`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17527#discussion_r1466418470