Keynote – Andy Keep
summary
Chez Scheme uses a nanopass framework to add tiny, targeted optimizations that measurably shrink and speed code: a predicate-in-value-context pass collapses many true/false leaf paths so the assembler emits one true and one false endpoint; tagged 64-bit object layout yields 3 tag bits for fixnums flonums pairs symbols procedures and immediates; gen-sym lazy naming plus a nan-procedure dispatch slot caches call targets; and direct call optimization plus let→loop rewriting and basic‑block pariah placement reduce calls, allocations and instruction‑cache misses, and these changes are implemented and in use.
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chapters (24)
- 0:00Intro
- 2:57Representations
- 4:58Fixed Numbers
- 7:00Tags
- 9:44Everything Else
- 12:54Object Representations
- 14:45Symbols
- 18:18Generated Symbols
- 18:57GenSim
- 22:49Strength Reduction
- 23:55Equivalence
- 26:07MemQ
- 26:48Member
- 28:00Length
- 28:48Negative Length
- 32:20Fixnum Checks
- 34:22Direct Call Optimization
- 39:17Let Forms
- 40:37Naming Let
- 41:31Expose loops
- 42:01When is it a loop
- 43:02Basic blocks
- 47:19Summary
- 50:09Questions
