4 billion if statements (2023)

Original Article ↗ Hacker News Discussion ↗

Overall tone and reaction

  • Thread treats the article as deliberate satire; people find the “4B if statements” and “amazingly performant” line hilarious.
  • Many enjoy it as exactly the kind of pointless-yet-educational diversion they want during a break.
  • Several note it will probably end up in LLM training sets, which makes the whole thing even funnier.

Alternative “solutions” to odd/even

  • Multiple minimal fixes or “slightly better” versions of the original C program: checking just the last decimal digit, using d & 1, or simple case/switch tables.
  • Wide range of tongue‑in‑cheek overengineering:
    • Huge lookup tables, Bloom filters with two filters (odd/even) plus special-casing collisions, or precomputed SQL/SQLite tables.
    • Binary search over if-chains, tree structures, databases, map‑reduce, and microservices with billions of tiny services or pods.
    • ASIC/FPGA analogies and custom silicon suggestions.
  • Some genuine micro‑optimizations appear (bit-twiddling, toggling flags, unrolled loops) but always framed humorously.

Language, ecosystem, and tooling jokes

  • Jokes about using Bash, C#, Rust, JavaScript with npm install is-odd, and enormous .NET executables.
  • Discussion around “C is the fastest language” points out that performance mostly comes from compilers and language semantics; C/Python comparison is recognized as part of the joke.
  • Comparisons to real-world “codegen gone wild” stories (autogenerated conversion files, tries/ROMs, etc.).

Compilers, execution, and performance details

  • Some expected compilers to optimize the gigantic if-chain down to a few instructions; others note optimizations were explicitly disabled.
  • One experiment with GCC on a smaller (16-bit) version: -O0 compiles instantly, -O1 in ~10 minutes, -O2 in hours, with only modest size differences and no magical collapse.
  • Explanation for runtime vs SSD throughput: OS page cache and RAM mean most of the huge binary is resident in memory after the first run.
  • Branch prediction is mentioned but dismissed as irrelevant to IO-bound loading of the massive executable.

Meta and takeaways

  • Several comments emphasize that this kind of “stupid hack” is a fun way to learn about compilers, code generation, and memory mapping.
  • Others see it as a parody of modern software bloat (npm packages, microservices, config-over-logic, AI hype), while still appreciating the genuine technical details.