Interesting. Haskell (or at least GHC) uses software transactional memory pretty heavily. They currently use llvm as the back end, though, so won't benefit from these changes in glibc. I wonder if whatever library used there by default will start to incorporate these features anytime soon?
The libc one uses is orthogonal to the compiler, modulo support for any language extensions the libc might use. LLVM supports glibc just fine, and will use it by default on Linux systems.
That said, whether GHC can make more use of glibc's TSX support (as opposed to generating TSX instructions itself) than any arbitrary C program depends on any impedance mismatch that may exist between the elided lock wrappers and GHC's own STM semantics. No idea if GHC has a way to reason about libc-managed locks.
