With the Intel Downfall vulnerability made public last week (also known as GDS – “Gather Data Sampling”) there can be a sizable hit to AVX workloads making use of the GATHER instructions. For helping to lower the impact of Downfall/GDS on mitigated systems, Intel has made a change to the GNU Compiler Collection to disable GATHER generation in vectorization for Intel CPU families affected by this vulnerability…

Source: Phoronix – GCC Compiler Adds Software Workaround To Avoid Intel Downfall Performance Hit