It can be difficult to keep up with the latest browsers, so what is new in Firefox 18 and Chrome 24 both of which have just become available on the release channels.
- Run various algorithms to optimize the IR.
- Translate the final IR to machine code.
The optimizations include:
- Loop-Invariant Code Motion (LICM), or moving instructions outside of loops when possible.
- Sparse Global Value Numbering (GVN), a powerful form of redundant code elimination.
- Linear Scan Register Allocation (LSRA), the register allocation scheme used in the HotSpot JVM (and until recently, LLVM).
- Dead Code Elimination (DCE), removing unused instructions.
- Range Analysis; eliminating bounds checks
The other two important features are:
- Support for Retina Display on OS X 10.7 and up.
- Preliminary support for WebRTC.
It does, however, appear to be experiencing teething troubles so if you have the option don't be amongst the very first to upgrade.
Once the dust has settled, Firefox 18 and Chrome 24 are both welcome new versions and overall the fast and automatic upgrade policies adopted by Google and Mozilla seem to be delivering more benefits than problems but the days of the "big new browser" seem to be over. It all raises the question of where are the browsers going in the future. For most of us the big issues are adding new features to make web apps not only possible but attractive. At the moment all three major browsers are being slow to catch up with reality - with IE being the slowest.