VM_Version::platform_features() in vm_version_solaris_sparc.cpp uses sysinfo(SI_ISALIST, ...) to determine hardware features. Unfortunately it not possible to find out all instruction set extensions like popc, which is required for 6378821.
A similar function to getisax(2) should be used to determine all possible instruction set extensions.
It seems that the auxv file is not trustworthy on systems where getisax(2) is not supported. We will use getisax(2) on systems where it's available (Solaris 10 or later) and the old legacy code for all other systems.