Dynamic Compilation Group Meeting 10/23

Attendance: Susan, Craig, Wilson, Joel, Matthai, Brian, Scott

Issues

• Correctness
• Performance

Platform Enhancements

• Optimization phase reordering (do some opts. first)
• CG inefficiencies
• scratch registers
• code motion above region
• predicated execution: disable or reenable?
• ATOM & Multiflow
• CSE of loads / don't reload RTconst
• static: eliminate redundant loads of float & pointer constants at compile-time
• dynamic: CSE of loads of big ints at stitch time when the sizes of integer RTconsts are known
• Fortran front end
• M3 front end
• Real annotations in C (and other front ends)
• Better switch/case statements
• Offset off SP?
• "Stack" code to register code (rename array positions to registers)
• Interprocedural opts
• inlining
• statically known callee
• dynamically known callee
• memoization?
• cosine
• recursion?
• Multiway loop unrolling
• Nested dynamic regions
• Static computation guarded by dynamic conditionals
• relates to nested dynamic regions
• if (dyn) then DR1 else DR2
• correctness issues with static code after dynamic branch
• problems
• setup code with side effects (e.g., div by zero)
• nonterminating code
• big loops to unroll
• staged setup code
• Semi-constants and recompiling - shortcuts on changing RTconsts
• relates to staged setup code
• relates to cacheing

Benchmarks

• *POV
• *Sort
• Robot (scottc)
• *Simple C Sparse
• Fortran Sparse (grant)
• *Xlisp
• MSQL
• *Dispatcher (mock)
• `C interpreter?
• Przemek's peephole opts.

Studies

• Sizes of RTconsts?
• small
• medium
• large
• How many dynamically allocatable scratch registers are needed?