scriptc/packages/compiler/test/integer-bitwise-arithmetic.test.ts

import { mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { expect, test } from "vitest";
import { compile, deserializeModule } from "../src/index.js";
import { emitCModule } from "../src/backend/c/c-emitter.js";
import { emitLlvmModule } from "../src/backend/llvm/emitter.js";

test("bounded integer arithmetic emits integer operations and leaves uncertain numbers alone", async () => {
  const dir = await mkdtemp(join(tmpdir(), "scriptc-integer-bits-"));
  try {
    const entry = join(dir, "main.ts");
    const outPath = join(dir, "main.ir.json");
    await writeFile(entry, `
function safe(input: number): number {
  let h = input >>> 0;
  h = h ^ (h << 13);
  h = h + (h << 3);
  return h >>> 0;
}
function unknown(input: number): number { return (input + 1) >>> 0; }
function negativeZero(): number { const x = -0; return x + x; }
console.log(safe(17), unknown(1.5), 1 / negativeZero());
`);
    const result = await compile(entry, { outDir: dir, outPath, outputKind: "ir" });
    if (!result.ok) throw new Error(result.diagnostics.map((d) => `${d.code}: ${d.message}`).join("\n"));
    const mod = deserializeModule(await readFile(outPath, "utf8"));
    const c = emitCModule(mod);
    const ll = emitLlvmModule(mod);
    const cBody = (name: string): string => c.match(new RegExp(`static [^\\n]+ sc_f_${name}\\([^\\n]*\\) \\{([\\s\\S]*?)\\n\\}`))![1]!;
    const llBody = (name: string): string => ll.match(new RegExp(`define internal [^\\n]+ @sc_f_${name}\\([^\\n]*\\) #0 \\{([\\s\\S]*?)\\n\\}`))![1]!;
    expect(cBody("safe").match(/scr_bit_/g)).toHaveLength(1);
    expect(cBody("safe")).toContain("(double)((int64_t)");
    expect(llBody("safe")).toContain(" = add nsw i54 ");
    // Only the arbitrary input's slow ToUint32 path still adds doubles.
    expect(llBody("safe").match(/ = fadd double /g)).toHaveLength(1);
    expect(cBody("unknown")).toContain("scr_bit_ushr(");
    expect(llBody("unknown")).toContain("uint32.coerce.slow");
    expect(llBody("unknown")).toContain(" = fadd double ");
    expect(llBody("negativeZero")).toContain(" = fadd double ");
  } finally { await rm(dir, { recursive: true, force: true }); }
});