Brummel
c897d2eef0
Closes the question CLAUDE.md has carried since day one ("LLVM-
linkable, performance is extremely important") with data. Hand-C
variants of the four bench fixtures, compiled with clang -O2,
each carefully matching the AILang algorithm and explicitly
documenting representation differences (cell width, leak policy)
that affect the ratio.
Three substantive findings:
1. Pure-compute parity with C: bench_compute_collatz runs at
AILang/C = 0.99x across both allocators. AILang's IR composes
with LLVM's optimizer at the same level a hand-C source does.
This is the LLVM-linkable performance claim, backed by data
for the first time. bench_compute_intsum (1.05-1.18x) confirms.
2. AILang bump beats glibc malloc 2x on linear allocation:
bench_list_sum.bump/c = 0.50x. Bump's two-instruction inline
fastpath outperforms glibc's free-list-managed malloc on
no-free workloads. Quantitatively measured for the first time.
3. RC overhead vs C malloc quantified: bench_list_sum.rc/c =
1.49x, bench_tree_walk.rc/c = 2.61x. The 8-byte refcount
header + zero-init + libc backing add 50-160% over glibc
malloc on these implicit-mode workloads. Explicit-mode + a
free()-adding C variant (21'f, queued) will close the
apples-to-apples gap on dec-cost.
CLAUDE.md updated to list bench/cross_lang.py as the third
tidy-iter gate alongside bench/check.py and bench/compile_check.py.
20 new metrics in bench/baseline_cross_lang.json with 12-15%
tolerances (cross-language ratios are inherently noisier than
within-AILang ratios — two compiler stacks contribute variance).
51 lines
1.1 KiB
C
51 lines
1.1 KiB
C
// Hand-C reference for bench_compute_collatz.
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//
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// Same algorithm as examples/bench_compute_collatz.ailx — for each
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// starting value in [1..N], count Collatz steps to reach 1, sum.
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// Three sizes: 10k / 100k / 500k starting values.
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//
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// Data-dependent control flow (n % 2 branch) prevents LLVM from
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// reducing this to closed form. The AILang/C wall-time ratio
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// directly reflects integer-arithmetic + branch-prediction codegen
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// quality.
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//
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// Build: clang -O2 -o compute_collatz compute_collatz.c
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// Expected stdout (one int per line):
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// 849666
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// 10753840
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// 62134795
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#include <stdio.h>
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static long collatz_steps(long n) {
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long steps = 0;
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while (n != 1) {
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if ((n % 2) == 0) {
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n = n / 2;
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} else {
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n = n * 3 + 1;
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}
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steps += 1;
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}
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return steps;
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}
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static long sum_steps(long n) {
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long total = 0;
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for (long i = n; i > 0; i--) {
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total += collatz_steps(i);
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}
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return total;
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}
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static void run_one(long n) {
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printf("%ld\n", sum_steps(n));
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}
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int main(void) {
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run_one(10000);
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run_one(100000);
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run_one(500000);
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return 0;
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}
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