RFR: 8253765: C2: Control randomization in StressLCM and StressGCM

[Tobias Hartmann]

On Fri, 9 Oct 2020 08:09:05 GMT, Roberto Castañeda Lozano <github.com+8792647+robcasloz at openjdk.org> wrote:

> Use the compilation-local seed in `StressLCM` and `StressGCM` rather than the global one. As a consequence, these
> options use by default a fresh seed in every compilation, unless `StressSeed=N` is specified, in which case they behave
> deterministically. Annotate tests that use `StressLCM` and `StressGCM` with the `stress` and `randomness` keys to
> reflect this change in default behavior.  Tested on `tier1` and on all test cases that use `StressLCM` and `StressGCM`
> (10 times each).

Otherwise looks good.

src/hotspot/share/opto/c2_globals.hpp line 56:

> 54:                                                                             \
> 55:   product(uint, StressSeed, 0, DIAGNOSTIC,                                  \
> 56:           "Seed for randomized stress testing (if unset, a random one is "  \

The description string misses a `)`

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Marked as reviewed by thartmann (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/572