Phoronix published Benchmarks Of JCC Erratum: A New Intel CPU Bug With Performance Implications On Skylake Through Cascade Lake A quote from the article:

Intel is today making public the Jump Conditional Code (JCC) erratum. This is a bug involving the CPU's Decoded ICache where on Skylake and derived CPUs where unpredictable behavior could happen when jump instructions cross cache lines. Unfortunately addressing this error in software comes with a performance penalty but ultimately Intel engineers are working to offset that through a toolchain update. Here are the exclusive benchmarks out today of the JCC erratum performance impact as well as when trying to recover that performance through the updated GNU Assembler.

  Benchmarks Of JCC Erratum: A New Intel CPU Bug With Performance Implications On Skylake Through Cascade Lake