Seemingly, no one uses assembly nowadays other than to develop device drivers, or the very core of OS kernels etc. Anyone has knowledge of it being currently used for other thin
Boost, being as modern C++ as it is, uses inline assembly for low-level performance-critical bits like atomic shared counters.
Edit: as @TokenMacGuy correctly notes, "performance" is a wrong word here. Boost uses assembly language for things that cannot be accomplished in standard C++ such as atomics (and compiler intrinsics are not available for some reason.)