RFR: 8355488: Add stress mode for C2 loop peeling [v3]

[Tobias Hartmann]

On Thu, 15 May 2025 12:13:58 GMT, Marc Chevalier <mchevalier at openjdk.org> wrote:

>> Should I use `#ifdef ASSERT`? My thinking is that I want the code to be there whenever the flag is available. This is decided here:
>> https://github.com/openjdk/jdk/blob/a989245a2424d136f5d2a828eda666c3867b0f48/src/hotspot/share/runtime/flags/jvmFlag.cpp#L552-L556
>> (called from `JVMFlag::find_flag` with `return_flag == false`, from `Arguments::find_jvm_flag`, from `Arguments::parse_argument` from `Arguments::process_argument`) with
>> https://github.com/openjdk/jdk/blob/a989245a2424d136f5d2a828eda666c3867b0f48/src/hotspot/share/runtime/flags/jvmFlag.cpp#L60-L66
>> 
>> My thinking is that it's unintuitive to me to offer a flag that could have no effect. Why don't we want it in optimized non-product build? We can still stress-peel and even if we won't hit an assert, we could still observe unexpected behaviors or crashes. Does that make sense?
>
> As discussed, I came back to `PRODUCT` for consistency.

Thanks for the details!

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PR Review Comment: https://git.openjdk.org/jdk/pull/25140#discussion_r2091158677