I had recently a quick look at http://www.phoronix.com/scan.php?page=article&item=gcc7-clang4-jan&num=2 EP-DGEMM where Phoronix claims clang is over 2.5x faster than gcc and in my limited understanding pretty much all time is spent in the system libraries not compiled with the test (blas, and even one written in fortran), so I don't understand any difference at all on that test (unless it uses very different libraries or very different configuration, e.g. using C blas instead of Fortran blas or vice versa etc.).  After all, LLVM doesn't have a viable Fortran FE anyway.

Note that I tried to reproduce from https://www.phoronix.com/review/gcc13-clang16-raptorlake/3
also tsvc (on zen3 machine) and there performance seems OK (GCC does 2168417 nodes/s and clang 2159913)

liquid-dsp fails for me:

    pts/liquid-dsp-1.0.0:
        Test Installation 1 of 1
        1 File Needed [0.74 MB / 1 Minute]
        File Found: liquid-dsp-20210131.tar.xz                                                                                                                                                                                                             [0.74MB]
        Approximate Install Size: 68 MB
        Estimated Install Time: 6 Seconds
        Installing Test @ 20:09:38
            The installer exited with a non-zero exit status.
            ERROR: /usr/lib64/gcc/x86_64-suse-linux/13/../../../../x86_64-suse-linux/bin/ld: cannot find -lliquid: No such file or directory
            Installing the package 'file' might fix this error.
            LOG: ~/.phoronix-test-suite/installed-tests/pts/liquid-dsp-1.0.0/install-failed.log

seems the build script is broken and actually links to the system wide libquid-dsp