merge with develop
- overall improvements on generated code performance
- swapstack implementation
- machine-level loop analysis
- bug fixes and improvements in register allocation (more heuristics regarding loops)
- bug fixes and improvements in both x86_64 and aarch64 backends
- bug fixes in a few passes (peephole optimisations, branch adjustment)
- switching CI to use native shell (instead of docker)
- performance CI with
mubench(http://squirrel.anu.edu.au/mubench/) - some initial preparation to support SEL4-rumprun
- IR validation
- Output for Mu IR complies with
muctext form