The changes in JDK-8323582 introduced a regression of around 2% in C2 execution time across the DaCapo 23 benchmarks, see the attached plot (thick dots indicate statistically significant regressions).

The regression was found on linux-x64 and macosx-aarch64 by comparing C2's bytes/s as reported by -XX:+CITime (averaged over a number of repetitions) before and after the integration of JDK-8323582, using the JVM flags -Xbatch -XX:-TieredCompilation for stability.