perf: right-size register tuple allocations#153
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davydog187 merged 1 commit intomainfrom Feb 27, 2026
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Replace the hard-coded 256-register top-level allocation and the +64 over-allocation on every callee call with values derived from the prototype's max_registers field. - vm.ex: proto.max_registers + 16 (was 256) - executor.ex: max(max_registers, param_count) + 16 (was + 64) The +16 buffer accounts for multi-return expansion slots that the codegen doesn't always track in max_registers. This cuts register tuple waste significantly for recursive workloads like fib(N). Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Summary
vm.exwithproto.max_registers + 16+64over-allocation on every callee call inexecutor.exwith+16This cuts register tuple waste significantly for recursive workloads. For
fib(30)(~30 recursive calls), this saves ~48 wasted nil slots per call frame (75% reduction from +64 to +16).The
+16buffer (vs the ideal+4) is necessary because the codegen'smax_registersdoesn't always track multi-return expansion result slots — call results can land beyond the stated max register. The vararg Lua 5.3 suite test confirmed+4was insufficient.Test plan
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