Hojun-Cho
83f5956df2
Every section banner dies (103 -> 0) across test/lang, the observer suites, the C carriers, and the five comment-heavy corpus fixtures; banner provenance (#N cites, carrier numbers, repair-cluster labels) folded into headers or adjacent WHY comments. Narration deleted; row provenance, ref cites, divergence pins, and layout contracts kept (fwd-ref decl-order guards and bootstrap-gate corpus rationale restored where the sweep over-cut). Comment-only proven: all 3742 wwbuild workdir .s byte-identical before/after; test-commit and test-byteid (161 lang + 1399 data, 0 pinned-divergent) green.
55 lines
2.4 KiB
Plaintext
55 lines
2.4 KiB
Plaintext
// An unsigned value returned from a CALL must select
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// the UNSIGNED opcode (DIVQ / SHRQ / JA) on the div / mod / shift / relational
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// path, keyed by the callee's RETURN type, migrated from
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// test/wcc/906_callret_unsigned_arith_run.c (#168, the N_CALL twin of #134 /
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// gunsigned's #25). The wwstage nodeisunsigned had no N_CALL arm, so a
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// call-result operand fell to `return false` (signed) → signed IDIVQ/SARQ/JG
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// on an unsigned-returning call → silent wrong arithmetic (cstage already read
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// the N_CALL result stamp).
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//
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// The subject IS the CALL-RESULT shape, so each operand MUST flow through a
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// real fn call: a `let a = uval();` local-bind would land on the N_IDENT arm
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// (which strconv already exercised) and HIDE the bug — gate-blind, the
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// bootstrap never divides/shifts a call result by an unsigned type. So the
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// rows are distinct call-result SHAPES (div / mod / shift / relational), not a
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// data table, mirroring gunsigned's "shapes not data" reasoning.
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//
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// Every unsigned row uses the high-bit value 0x8000000000000001 so the
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// unsigned vs signed op diverges at RUNTIME (not just in the .s) — the @test
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// asserts the unsigned semantics directly; the .s byte-id net stays in the
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// .c. The signed-returning CONTROL guards against an over-broad fix: a signed
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// callee must STILL pick IDIVQ/SARQ.
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package callret_unsigned_test;
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fn uval() u64 = { return 0x8000000000000001u64; };
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fn sval() i64 = { return -100i64; };
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fn sshift() i64 = { return -8i64; };
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@test fn callret_unsigned_path() void = {
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// u64_div_callret: 0x8000..1 / 2 unsigned == 0x4000..0 (signed IDIVQ
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// sign-extends the high-bit dividend → 0xC000..1).
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assert(uval() / 2u64 == 0x4000000000000000u64);
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// u64_mod_callret: unsigned rem == 1 (signed rem == -1).
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assert(uval() % 2u64 == 1u64);
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// u64_shr_callret: SHRQ (logical) == 0x4000..0 (SARQ sign-fills the set
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// MSB → 0xC000..0).
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assert(uval() >> 1u64 == 0x4000000000000000u64);
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// u64_cmp_callret: 0x8000..1 > 1 is true unsigned (JA), false signed
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// (JG reads the high bit as the sign).
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assert(uval() > 1u64);
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};
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@test fn callret_signed_ctl() void = {
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// i64_div_callret control: -100 / 7 == -14 (toward zero); must KEEP
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// IDIVQ — an unsigned div of -100-as-u64 would be huge, not -14.
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assert(sval() / 7i64 == -14i64);
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// i64_shr_callret control: -8 >> 1 == -4 via SARQ; SHRQ would zero-fill
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// to a large positive.
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assert(sshift() >> 1i64 == -4i64);
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};
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