The Sista VM, an incredible JIT optimiser for Smalltalk, has now released an alpha:
miniblog.
Related Posts
C++ compiler beating hand written assembly: https://stackoverflow.com/questions/40354978/why-is-this-c-code-faster-than-my-hand-written-assembly-for-testing-the-collat
If you haven't measured the cycle time of the different instructions, the optimiser can often do better!
It's remarkable how much of Emacs' byte-compiler optimiser is unchanged from 1992!
Microsoft have written a SSA optimiser for their C++ toolchain! https://blogs.msdn.microsoft.com/vcblog/2016/05/04/new-code-optimizer/ (pretty accessible blog post for a compiler)

