Electrical Fire Optimizations

We are considering including the following kinds of optimizations in ElectricalFire:

Initial

• Straight-line dataflow analysis (mainly there to speed up the compiler by folding the most common optimizations into the compiler's primitive graph generation)
• Constant propagation and folding
• Dead code elimination
• Strength reduction
• Rudimentary register allocation
• Method dispatch optimizations

Near term

• Iterative dataflow analysis
• Better phi-node assignment strategy
• Better constant propagation and strength reduction
• Null pointer check elimination

Medium term

• Common subexpression elimination (CSE) or partial redundancy elimination
• Partial redundancy elimination in branches of if statements
• Global code motion or one of its variants
• Undoing some CSE optimization for x86 code generation to relieve register pressure
• Value range analysis for eliminating array bounds checks
• Better register allocation
• Better instruction scheduling
• Better interface dispatching

After first release

• Function inlining together with the decision-making process of when to inline
• Duplicating and specializing code within a function to handle common cases faster (i.e. combining all array bounds checks into one conservative one at the beginning of a loop, with a backup loop to execute if the conservative check fails)
• Specialized library optimizations for things like string and vector operations

Farther future

• Limited interprocedural dataflow analysis
• Alias analysis of memory locations (hard because of Java's concurrency semantics)
• Synchronization point (monitorenter/exit) elimination or motion
• Object lifetime analysis
• Interprocedural object lifetime analysis