jcode + GPT-5.6 Sol on utf16-transcode

{"goals": [{"end_to_end_ownership": null, "feedback_loop": "Run ./grade after each meaningful optimization and compare deterministic callgrind score in scores.jsonl.", "group": "optimize", "hill_climbability": 98, "objective": "Maximize instruction-count improvement while passing every correctness case.", "user_intention": "Produce the fastest correct C17 UTF-16 transcoder implementation under the benchmark constraints.", "user_intention_alignment": 100}], "intent": "Track benchmark optimization work", "todos": [{"completion_confidence": null, "confidence": 95, "content": "Read spec and baseline implementation", "group": "optimize", "id": "inspect", "priority": "high", "status": "in_progress"}, {"completion_confidence": null, "confidence": 85, "content": "Identify hot paths and implement optimized transcoding", "group": "optimize", "id": "optimize", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 90, "content": "Grade repeatedly and refine instruction count", "group": "optimize", "id": "iterate", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 95, "content": "Verify final correctness and report score", "group": "optimize", "id": "final", "priority": "high", "status": "pending"}]}

[ { "content": "Read spec and baseline implementation", "status": "in_progress", "priority": "high", "id": "inspect", "group": "optimize", "confidence": 95, "confidence_history": [ 95 ] }, { "content": "Identify hot paths and implement optimized transcoding", "status": "pending", "priority": "high", "id": "optimize", "group": "optimize", "confidence": 85, "confidence_history": [ 85 ] }, { "content": "Grade repeatedly and refine instruction count", "status": "pending", "priority": "high", "id": "iterate", "group": "optimize", "confidence": 90, "confidence_history": [ 90 ] }, { "content": "Verify final correctness and report score", "status": "pending", "priority": "high", "id": "final", "group": "optimize", "confidence": 95, "confidence_history": [ 95 ] } ] Goals: [ { "group": "optimize", "user_intention": "Produce the fastest correct C17 UTF-16 transcoder implementation under the benchmark constraints.", "user_intention_alignment": 100, "hill_climbability": 98, "objective": "Maximize instruction-count improvement while passing every correctness case.", "feedback_loop": "Run ./grade after each meaningful optimization and compare deterministic callgrind score in scores.jsonl." } ]

{"intent": "Inspect task specification and current code", "tool_calls": [{"tool": "read", "file_path": "spec.md", "limit": 500}, {"tool": "read", "file_path": "submission/solve.c", "limit": 1000}, {"tool": "ls", "path": ".", "ignore": [".git"]}, {"tool": "read", "file_path": "grade", "limit": 300}]}

--- [1] read --- 1 # utf16-transcode 2 3 Convert UTF-16LE to UTF-8. This is the boundary between JavaScript, Windows, and 4 Java on one side and the rest of the world on the other: every string crossing it 5 pays this function. 6 7 ## Task 8 9 You are given a working, tested implementation in `submission/solve.c`. 10 Make it faster. Correctness on every input is the gate, verified exhaustively 11 over all code units and pairs plus deep seeded coverage. 12 13 ``` 14 ./grade # build, verify, measure, score 15 ./grade --seed N # reproduce a specific cost corpus 16 ``` 17 18 Edit only files under `submission/`. 19 20 ## Contract 21 22 ```c 23 // Transcode UTF-16LE code units to UTF-8. 24 // in: code units, n: count. out: buffer, capacity >= 3*n+4 bytes. 25 // Returns bytes written, or (size_t)-1 if the input is invalid UTF-16 26 // (lone surrogate anywhere). 27 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 28 ``` 29 30 Semantics: 31 32 - Code units 0x0000-0xD7FF and 0xE000-0xFFFF encode as 1-3 UTF-8 bytes. 33 - A high surrogate 0xD800-0xDBFF must be immediately followed by a low 34 surrogate 0xDC00-0xDFFF; the pair encodes one supplementary code point as 35 4 bytes. Anything else (lone high, lone low, high at end of input) is 36 invalid: return (size_t)-1. 37 - On invalid input the output buffer contents are unspecified. 38 39 ## Verification (the gate) 40 41 1. Every single code unit (65,536 cases). 42 2. Every pair of code units (4.3 billion pairs is too many: all pairs from a 43 2,namespace-stratified 4,096-unit sample = 16.7M pairs covering every 44 boundary class x class combination, plus all 2^20 surrogate x surrogate 45 pairs exactly). 46 3. Every code unit embedded at positions 0,1,2,3 in valid padding. 47 4. 200,000 seeded random strings (1-2K units) mixing ASCII runs, BMP text, 48 surrogate pairs, and injected lone surrogates. 49 50 Any mismatch against the reference oracle fails the grade with a counterexample. 51 52 ## Cost model (the score) 53 54 Instructions inside `utf16_to_utf8` (callgrind) over a seeded ~1M-unit corpus: 55 ASCII-heavy 40%, Latin/Cyrillic mix 25%, CJK-heavy 20%, emoji/supplementary 15%. 56 Paired against the frozen given implementation on the same corpus. 57 58 ``` 59 score = log2(given_cost / your_cost) 60 ``` 61 62 ## Rules 63 64 - Self-contained C17, libc only. 65 - Do not modify the grader/verifier. Any correct program is a valid submission. --- [2] read --- 1 // solve.c — the given implementation of utf16_to_utf8. 2 // A clean, correct scalar transcoder of the kind found in mainstream 3 // libraries. Make it faster. See ../spec.md. Grade with ../grade. 4 #include <stdint.h> 5 #include <stddef.h> 6 7 #define INVALID ((size_t)-1) 8 9 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 10 size_t o = 0; 11 for (size_t i = 0; i < n; i++) { 12 uint32_t c = in[i]; 13 if (c < 0x80) { 14 out[o++] = (uint8_t)c; 15 } else if (c < 0x800) { 16 out[o++] = (uint8_t)(0xC0 | (c >> 6)); 17 out[o++] = (uint8_t)(0x80 | (c & 0x3F)); 18 } else if (c < 0xD800 || c >= 0xE000) { 19 out[o++] = (uint8_t)(0xE0 | (c >> 12)); 20 out[o++] = (uint8_t)(0x80 | ((c >> 6) & 0x3F)); 21 out[o++] = (uint8_t)(0x80 | (c & 0x3F)); 22 } else if (c < 0xDC00) { 23 // high surrogate: need a low surrogate next 24 if (i + 1 >= n) return INVALID; 25 uint32_t lo = in[i + 1]; 26 if (lo < 0xDC00 || lo >= 0xE000) return INVALID; 27 i++; 28 uint32_t cp = 0x10000 + ((c - 0xD800) << 10) + (lo - 0xDC00); 29 out[o++] = (uint8_t)(0xF0 | (cp >> 18)); 30 out[o++] = (uint8_t)(0x80 | ((cp >> 12) & 0x3F)); 31 out[o++] = (uint8_t)(0x80 | ((cp >> 6) & 0x3F)); 32 out[o++] = (uint8_t)(0x80 | (cp & 0x3F)); 33 } else { 34 return INVALID; // lone low surrogate 35 } 36 } 37 return o; 38 } --- [3] ls --- ./ submission/ solve.c verify/ gen_corpus.py given.c reference.c runner.c verify.c grade scores.jsonl spec.md 9 files, 2 directories --- [4] read --- 1 #!/usr/bin/env python3 2 import os, sys 3 sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "..", "harness")) 4 from grade import main 5 main(os.path.dirname(os.path.abspath(__file__)), "utf16_to_utf8") Completed: 4 succeeded, 0 failed

{"intent": "Inspect benchmark harness and establish baseline", "tool_calls": [{"tool": "read", "file_path": "verify/runner.c", "limit": 500}, {"tool": "read", "file_path": "verify/verify.c", "limit": 800}, {"tool": "read", "file_path": "verify/given.c", "limit": 200}, {"tool": "bash", "command": "./grade", "timeout": 600000, "intent": "Measure baseline correctness and instruction score"}]}

--- [1] read --- 1 // runner.c — cost driver for utf16-transcode. Corpus: u32 count then u16 units 2 // per record. Run under callgrind with --toggle-collect. 3 #include <stdint.h> 4 #include <stddef.h> 5 #include <stdio.h> 6 #include <stdlib.h> 7 #include <string.h> 8 9 #ifdef RUNNER_GIVEN 10 size_t given_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 11 #define utf16_to_utf8 given_utf16_to_utf8 12 #else 13 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 14 #endif 15 16 int main(int argc, char **argv) { 17 if (argc < 2) { fprintf(stderr, "usage: runner CORPUS\n"); return 2; } 18 FILE *f = fopen(argv[1], "rb"); 19 if (!f) { perror("corpus"); return 2; } 20 fseek(f, 0, SEEK_END); long sz = ftell(f); fseek(f, 0, SEEK_SET); 21 uint8_t *data = malloc((size_t)sz); 22 if (fread(data, 1, (size_t)sz, f) != (size_t)sz) { perror("read"); return 2; } 23 fclose(f); 24 uint8_t *out = malloc(3u * (1u << 21) + 64); 25 unsigned long long checksum = 0, nrec = 0; 26 size_t off = 0; 27 while (off + 4 <= (size_t)sz) { 28 uint32_t cnt; memcpy(&cnt, data + off, 4); off += 4; 29 if (off + 2ull * cnt > (size_t)sz) { fprintf(stderr, "corrupt corpus\n"); return 2; } 30 size_t r = utf16_to_utf8((const uint16_t *)(data + off), cnt, out); 31 if (r == (size_t)-1) { fprintf(stderr, "BUG: corpus record rejected\n"); return 3; } 32 for (size_t k = 0; k < r; k += 64) checksum += out[k]; 33 checksum += r; nrec++; 34 off += 2ull * cnt; 35 } 36 printf("runner: %llu records, checksum %llu\n", nrec, checksum); 37 return 0; 38 } --- [2] read --- 1 // verify.c — exhaustive correctness gate for utf16-transcode. 2 // 1. every single code unit 3 // 2. all pairs from a boundary-stratified sample x sample (16.7M), 4 // plus ALL surrogate x surrogate pairs (2^20) exactly 5 // 3. every code unit at positions 0..3 inside valid padding 6 // 4. 200k seeded random strings across regimes with injected lone surrogates 7 #include <stdint.h> 8 #include <stddef.h> 9 #include <stdio.h> 10 #include <stdlib.h> 11 #include <string.h> 12 #include <pthread.h> 13 #include <stdatomic.h> 14 15 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 16 size_t ref_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out); 17 18 #define INVALID ((size_t)-1) 19 20 static atomic_ullong n_cases; 21 static atomic_int failed; 22 static pthread_mutex_t report_mu = PTHREAD_MUTEX_INITIALIZER; 23 24 static void fail_report(const uint16_t *in, size_t n, const char *stage) { 25 pthread_mutex_lock(&report_mu); 26 if (!atomic_exchange(&failed, 1)) { 27 fprintf(stderr, "MISMATCH (%s) on %zu units:", stage, n); 28 for (size_t i = 0; i < n && i < 24; i++) fprintf(stderr, " %04x", in[i]); 29 fprintf(stderr, "\n"); 30 } 31 pthread_mutex_unlock(&report_mu); 32 } 33 34 static int check(const uint16_t *in, size_t n, uint8_t *bs, uint8_t *br, const char *stage) { 35 memset(bs, 0xAA, 3 * n + 8); 36 memset(br, 0x55, 3 * n + 8); 37 size_t rs = utf16_to_utf8(in, n, bs); 38 size_t rr = ref_utf16_to_utf8(in, n, br); 39 atomic_fetch_add_explicit(&n_cases, 1, memory_order_relaxed); 40 if (rs != rr || (rr != INVALID && memcmp(bs, br, rr) != 0)) { 41 fail_report(in, n, stage); 42 return 0; 43 } 44 return 1; 45 } 46 47 // boundary-stratified sample of code units: all class edges + strided interior 48 static uint16_t sample[4096]; 49 static size_t n_sample; 50 51 static void build_sample(void) { 52 size_t k = 0; 53 // all boundaries +-2 54 static const uint32_t EDGE[] = {0x0000,0x007F,0x0080,0x07FF,0x0800, 55 0xD7FF,0xD800,0xDBFF,0xDC00,0xDFFF,0xE000,0xFFFF}; 56 for (size_t e = 0; e < sizeof(EDGE)/sizeof(EDGE[0]); e++) 57 for (int d = -2; d <= 2; d++) { 58 int64_t v = (int64_t)EDGE[e] + d; 59 if (v >= 0 && v <= 0xFFFF) sample[k++] = (uint16_t)v; 60 } 61 // strided interior coverage 62 for (uint32_t v = 0; v <= 0xFFFF && k < 4096; v += 17) sample[k++] = (uint16_t)v; 63 n_sample = k < 4096 ? k : 4096; 64 } 65 66 typedef struct { int tid, nthreads; } targ_t; 67 68 static void *pair_worker(void *argp) { 69 targ_t *a = argp; 70 uint8_t bs[64], br[64]; 71 uint16_t s[2]; 72 // sample x sample 73 for (size_t i = a->tid; i < n_sample; i += a->nthreads) { 74 if (atomic_load_explicit(&failed, memory_order_relaxed)) return NULL; 75 s[0] = sample[i]; 76 for (size_t j = 0; j < n_sample; j++) { 77 s[1] = sample[j]; 78 if (!check(s, 2, bs, br, "pair")) return NULL; 79 } 80 } 81 // all surrogate x surrogate pairs 82 for (uint32_t hi = 0xD800 + a->tid; hi <= 0xDFFF; hi += a->nthreads) { 83 if (atomic_load_explicit(&failed, memory_order_relaxed)) return NULL; 84 s[0] = (uint16_t)hi; 85 for (uint32_t lo = 0xD800; lo <= 0xDFFF; lo++) { 86 s[1] = (uint16_t)lo; 87 if (!check(s, 2, bs, br, "surrogate-pair")) return NULL; 88 } 89 } 90 return NULL; 91 } 92 93 static void *single_worker(void *argp) { 94 targ_t *a = argp; 95 uint8_t bs[64], br[64]; 96 uint16_t s[8]; 97 for (uint32_t v = a->tid; v <= 0xFFFF; v += a->nthreads) { 98 if (atomic_load_explicit(&failed, memory_order_relaxed)) return NULL; 99 s[0] = (uint16_t)v; 100 if (!check(s, 1, bs, br, "single")) return NULL; 101 // embedded at positions 0..3 in valid padding 'A', with a trailing pad 102 for (int pos = 0; pos < 4; pos++) { 103 size_t n = 5; 104 for (size_t q = 0; q < n; q++) s[q] = 'A'; 105 s[pos] = (uint16_t)v; 106 if (!check(s, n, bs, br, "embedded")) return NULL; 107 } 108 } 109 return NULL; 110 } 111 112 // seeded random strings 113 static uint64_t rng_state; 114 static uint64_t rng_next(void) { 115 uint64_t z = (rng_state += 0x9E3779B97F4A7C15ULL); 116 z = (z ^ (z >> 30)) * 0xBF58476D1CE4E5B9ULL; 117 z = (z ^ (z >> 27)) * 0x94D049BB133111EBULL; 118 return z ^ (z >> 31); 119 } 120 121 int main(int argc, char **argv) { 122 uint64_t seed = 0x6A636F6465ULL; 123 if (argc > 1 && strcmp(argv[1], "--full") != 0) seed = strtoull(argv[1], NULL, 0); 124 125 build_sample(); 126 int nt = 8; 127 pthread_t th[8]; 128 targ_t args[8]; 129 for (int t = 0; t < nt; t++) { args[t] = (targ_t){t, nt}; pthread_create(&th[t], NULL, single_worker, &args[t]); } 130 for (int t = 0; t < nt; t++) pthread_join(th[t], NULL); 131 if (atomic_load(&failed)) return 1; 132 for (int t = 0; t < nt; t++) pthread_create(&th[t], NULL, pair_worker, &args[t]); 133 for (int t = 0; t < nt; t++) pthread_join(th[t], NULL); 134 if (atomic_load(&failed)) return 1; 135 136 // random strings (single thread is fine: 200k x ~1.5k units) 137 rng_state = seed; 138 static uint16_t s[2048]; 139 static uint8_t bs[3 * 2048 + 16], br[3 * 2048 + 16]; 140 for (int t = 0; t < 200000; t++) { 141 size_t n = 1 + (size_t)(rng_next() % 1500); 142 for (size_t i = 0; i < n; i++) { 143 unsigned r = (unsigned)(rng_next() % 100); 144 if (r < 40) s[i] = (uint16_t)(rng_next() % 0x80); 145 else if (r < 60) s[i] = (uint16_t)(0x80 + rng_next() % 0x780); 146 else if (r < 80) { uint16_t v; do { v = (uint16_t)(0x800 + rng_next() % 0xF800); } while (v >= 0xD800 && v < 0xE000); s[i] = v; } 147 else if (r < 95 && i + 1 < n) { 148 s[i] = (uint16_t)(0xD800 + rng_next() % 0x400); 149 s[++i] = (uint16_t)(0xDC00 + rng_next() % 0x400); 150 } 151 else s[i] = (uint16_t)(0xD800 + rng_next() % 0x800); // often lone surrogate 152 } 153 if (!check(s, n, bs, br, "random")) return 1; 154 } 155 156 printf("verify: PASS (%llu cases)\n", (unsigned long long)atomic_load(&n_cases)); 157 return 0; 158 } --- [3] read --- 1 // solve.c — the given implementation of utf16_to_utf8. 2 // A clean, correct scalar transcoder of the kind found in mainstream 3 // libraries. Make it faster. See ../spec.md. Grade with ../grade. 4 #include <stdint.h> 5 #include <stddef.h> 6 7 #define INVALID ((size_t)-1) 8 9 size_t given_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 10 size_t o = 0; 11 for (size_t i = 0; i < n; i++) { 12 uint32_t c = in[i]; 13 if (c < 0x80) { 14 out[o++] = (uint8_t)c; 15 } else if (c < 0x800) { 16 out[o++] = (uint8_t)(0xC0 | (c >> 6)); 17 out[o++] = (uint8_t)(0x80 | (c & 0x3F)); 18 } else if (c < 0xD800 || c >= 0xE000) { 19 out[o++] = (uint8_t)(0xE0 | (c >> 12)); 20 out[o++] = (uint8_t)(0x80 | ((c >> 6) & 0x3F)); 21 out[o++] = (uint8_t)(0x80 | (c & 0x3F)); 22 } else if (c < 0xDC00) { 23 // high surrogate: need a low surrogate next 24 if (i + 1 >= n) return INVALID; 25 uint32_t lo = in[i + 1]; 26 if (lo < 0xDC00 || lo >= 0xE000) return INVALID; 27 i++; 28 uint32_t cp = 0x10000 + ((c - 0xD800) << 10) + (lo - 0xDC00); 29 out[o++] = (uint8_t)(0xF0 | (cp >> 18)); 30 out[o++] = (uint8_t)(0x80 | ((cp >> 12) & 0x3F)); 31 out[o++] = (uint8_t)(0x80 | ((cp >> 6) & 0x3F)); 32 out[o++] = (uint8_t)(0x80 | (cp & 0x3F)); 33 } else { 34 return INVALID; // lone low surrogate 35 } 36 } 37 return o; 38 } --- [4] bash --- build 0.6s verify 2.4s PASS measure 6.9s 78,406,447 instructions (given: 77,696,233) SCORE -0.0131 (0.991x) --- Command finished with exit code: 0 --- Completed: 4 succeeded, 0 failed

{"intent": "Inspect build settings and corpus distribution", "tool_calls": [{"tool": "read", "file_path": "../../harness/grade.py", "limit": 700}, {"tool": "read", "file_path": "verify/gen_corpus.py", "limit": 700}, {"tool": "bash", "command": "tail -n 5 scores.jsonl && find . -maxdepth 2 -type f -not -path './submission/*' -printf '%p %s\\n' | sort", "timeout": 10000, "intent": "Inspect score log and generated benchmark artifacts"}]}

--- [1] read --- 1 #!/usr/bin/env python3 2 """Shared grader for jcode bench tasks. 3 4 Pipeline: build -> verify (gate) -> callgrind cost (submission + frozen given, 5 same corpus: paired) -> score = log2(given/sub). Appends to scores.jsonl. 6 7 Each task directory provides: submission/*.c, verify/verify.c (+reference.c 8 optional), verify/given.c (frozen given impl, function prefixed given_), 9 verify/runner.c (honors -DRUNNER_GIVEN), verify/gen_corpus.py, and a small 10 `grade` wrapper exporting TASK_FN (the measured function name). 11 """ 12 import argparse, json, math, os, re, subprocess, sys, time, glob 13 14 15 def sh(cmd, **kw): 16 return subprocess.run(cmd, check=True, capture_output=True, text=True, **kw) 17 18 19 def main(here, fn, extra_cflags=None, verify_args=None): 20 SUB = os.path.join(here, "submission") 21 VER = os.path.join(here, "verify") 22 BUILD = os.path.join(here, ".build") 23 CFLAGS = ["-O2", "-std=c17", "-fno-lto", "-g"] + (extra_cflags or []) 24 25 ap = argparse.ArgumentParser() 26 ap.add_argument("--seed", type=int, default=None) 27 ap.add_argument("--full", action="store_true", 28 help="run the full exhaustive gate (if the task has one)") 29 ap.add_argument("--quiet", action="store_true") 30 args = ap.parse_args() 31 seed = args.seed if args.seed is not None else int(time.time()) % 100000 32 33 os.makedirs(BUILD, exist_ok=True) 34 sub_srcs = sorted(glob.glob(os.path.join(SUB, "*.c"))) 35 if not sub_srcs: 36 sys.exit("no .c files in submission/") 37 38 t0 = time.time() 39 ref = os.path.join(VER, "reference.c") 40 refs = [ref] if os.path.exists(ref) else [] 41 sh(["cc", *CFLAGS, "-I", SUB, *sub_srcs, *refs, 42 os.path.join(VER, "verify.c"), "-o", os.path.join(BUILD, "verify"), 43 "-lm", "-lpthread"]) 44 sh(["cc", *CFLAGS, "-I", SUB, *sub_srcs, 45 os.path.join(VER, "runner.c"), "-o", os.path.join(BUILD, "runner"), "-lm"]) 46 if not os.path.exists(os.path.join(BUILD, "runner_given")): 47 sh(["cc", *CFLAGS, "-DRUNNER_GIVEN", 48 os.path.join(VER, "given.c"), os.path.join(VER, "runner.c"), 49 "-o", os.path.join(BUILD, "runner_given"), "-lm"]) 50 t_build = time.time() - t0 51 52 t0 = time.time() 53 vargs = [str(seed)] + (["--full"] if args.full else []) + (verify_args or []) 54 r = subprocess.run([os.path.join(BUILD, "verify"), *vargs], 55 capture_output=True, text=True) 56 if r.returncode != 0: 57 print(r.stdout, end="") 58 print(r.stderr, end="", file=sys.stderr) 59 print("grade: FAIL (verification)") 60 sys.exit(1) 61 t_verify = time.time() - t0 62 63 def measure(binary, func): 64 corpus = os.path.join(BUILD, f"corpus_{seed}.bin") 65 if not os.path.exists(corpus): 66 sh(["python3", os.path.join(VER, "gen_corpus.py"), str(seed), corpus]) 67 cg = os.path.join(BUILD, f"callgrind.{binary}.out") 68 if os.path.exists(cg): 69 os.unlink(cg) 70 sh(["valgrind", "--tool=callgrind", f"--toggle-collect={func}", 71 "--collect-atstart=no", "--dump-line=no", 72 f"--callgrind-out-file={cg}", os.path.join(BUILD, binary), corpus]) 73 total = 0 74 with open(cg) as f: 75 for line in f: 76 ls = line.strip() 77 if re.match(r"^\d+ \d+$", ls) or re.match(r"^\d+ \d+ ", ls): 78 total += int(ls.split()[1]) 79 if total == 0: 80 sys.exit(f"cost extraction failed (did you rename {func}?)") 81 return total 82 83 t0 = time.time() 84 cost = measure("runner", fn) 85 # The given binary is frozen, so its cost per corpus seed is a pure 86 # function of the seed: cache it. 87 gcache = os.path.join(BUILD, f"given_cost_{seed}.json") 88 if os.path.exists(gcache): 89 with open(gcache) as f: 90 given = json.load(f)["cost"] 91 else: 92 given = measure("runner_given", f"given_{fn}") 93 with open(gcache, "w") as f: 94 json.dump({"cost": given}, f) 95 t_measure = time.time() - t0 96 97 score = math.log2(given / cost) 98 rec = {"ts": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()), 99 "seed": seed, "cost": cost, "given_cost": given, 100 "score": round(score, 4), "full_gate": bool(args.full)} 101 with open(os.path.join(here, "scores.jsonl"), "a") as f: 102 f.write(json.dumps(rec) + "\n") 103 104 if not args.quiet: 105 print(f"build {t_build:5.1f}s") 106 print(f"verify {t_verify:5.1f}s PASS{' (FULL gate)' if args.full else ''}") 107 print(f"measure {t_measure:5.1f}s {cost:,} instructions (given: {given:,})") 108 print(f"SCORE {score:+.4f} ({given / cost:.3f}x)") --- [2] read --- 1 #!/usr/bin/env python3 2 """gen_corpus.py — cost corpus for utf16-transcode (~1M units total). 3 Regimes: ascii 40%, latin/cyrillic 25%, cjk 20%, emoji/supplementary 15%. 4 Record format: u32 unit count, then u16le units. All records valid UTF-16. 5 Usage: gen_corpus.py SEED OUTFILE""" 6 import random, struct, sys 7 8 def gen_record(rng, regime, units): 9 out = [] 10 while len(out) < units: 11 if regime == "ascii": 12 out.extend(rng.randrange(0x20, 0x7F) for _ in range(rng.randrange(20, 80))) 13 elif regime == "latin": 14 r = rng.random() 15 if r < 0.5: 16 out.extend(rng.randrange(0x20, 0x7F) for _ in range(rng.randrange(2, 10))) 17 else: 18 out.extend(rng.randrange(0x80, 0x800) for _ in range(rng.randrange(2, 12))) 19 elif regime == "cjk": 20 r = rng.random() 21 if r < 0.25: 22 out.extend(rng.randrange(0x20, 0x7F) for _ in range(rng.randrange(1, 6))) 23 else: 24 out.extend(rng.randrange(0x4E00, 0x9FFF) for _ in range(rng.randrange(4, 20))) 25 else: # emoji 26 r = rng.random() 27 if r < 0.4: 28 out.extend(rng.randrange(0x20, 0x7F) for _ in range(rng.randrange(1, 8))) 29 else: 30 for _ in range(rng.randrange(1, 6)): 31 cp = rng.randrange(0x10000, 0x110000) 32 cp -= 0x10000 33 out.append(0xD800 + (cp >> 10)) 34 out.append(0xDC00 + (cp & 0x3FF)) 35 return out[:units + 1] if len(out) > units and 0xD800 <= out[units - 1] <= 0xDBFF else out[:units] 36 37 def main(): 38 seed, path = int(sys.argv[1]), sys.argv[2] 39 rng = random.Random(seed) 40 plan = [("ascii", 40), ("latin", 25), ("cjk", 20), ("emoji", 15)] 41 records = [] 42 for regime, share in plan: 43 total = share * 10000 44 done = 0 45 while done < total: 46 units = rng.randrange(500, 3000) 47 rec = gen_record(rng, regime, units) 48 # ensure no trailing lone high surrogate 49 if rec and 0xD800 <= rec[-1] <= 0xDBFF: 50 rec.pop() 51 records.append(rec) 52 done += len(rec) 53 rng.shuffle(records) 54 with open(path, "wb") as f: 55 for rec in records: 56 f.write(struct.pack("<I", len(rec))) 57 f.write(struct.pack(f"<{len(rec)}H", *rec)) 58 print(f"corpus: {len(records)} records, {sum(len(r) for r in records)} units, seed {seed}") 59 60 if __name__ == "__main__": 61 main() --- [3] bash --- {"ts": "2026-07-19T08:13:27Z", "seed": 48803, "cost": 77705754, "given_cost": 77705754, "score": 0.0, "full_gate": false} {"ts": "2026-07-19T08:13:47Z", "seed": 48818, "cost": 78406447, "given_cost": 77696233, "score": -0.0131, "full_gate": false} ./.build/callgrind.runner.out 2000 ./.build/callgrind.runner_given.out 1989 ./.build/corpus_48803.bin 2007910 ./.build/corpus_48818.bin 2004158 ./.build/given_cost_48803.json 18 ./.build/given_cost_48818.json 18 ./.build/runner 24104 ./.build/runner_given 24008 ./.build/verify 34960 ./grade 227 ./scores.jsonl 248 ./spec.md 2286 ./verify/gen_corpus.py 2509 ./verify/given.c 1482 ./verify/reference.c 1435 ./verify/runner.c 1539 ./verify/verify.c 5933 --- Command finished with exit code: 0 --- Completed: 3 succeeded, 0 failed

{"command": "objdump -d -Mintel --disassemble=utf16_to_utf8 .build/runner; objdump -d -Mintel --disassemble=given_utf16_to_utf8 .build/runner_given", "intent": "Inspect compiler-generated baseline assembly", "notify": false, "run_in_background": false, "timeout": 10000, "wake": false}

.build/runner: file format elf64-x86-64 Disassembly of section .init: Disassembly of section .plt: Disassembly of section .text: 0000000000001440 <utf16_to_utf8>: 1440: 49 89 f8 mov r8,rdi 1443: 49 89 f1 mov r9,rsi 1446: 49 89 d2 mov r10,rdx 1449: 48 85 f6 test rsi,rsi 144c: 0f 84 50 01 00 00 je 15a2 <utf16_to_utf8+0x162> 1452: 31 d2 xor edx,edx 1454: 31 f6 xor esi,esi 1456: eb 39 jmp 1491 <utf16_to_utf8+0x51> 1458: 0f 1f 80 00 00 00 00 nop DWORD PTR [rax+0x0] 145f: 66 66 2e 0f 1f 84 00 data16 cs nop WORD PTR [rax+rax*1+0x0] 1466: 00 00 00 00 146a: 66 66 2e 0f 1f 84 00 data16 cs nop WORD PTR [rax+rax*1+0x0] 1471: 00 00 00 00 1475: 66 66 2e 0f 1f 84 00 data16 cs nop WORD PTR [rax+rax*1+0x0] 147c: 00 00 00 00 1480: 41 88 0c 32 mov BYTE PTR [r10+rsi*1],cl 1484: 48 83 c6 01 add rsi,0x1 1488: 48 83 c2 01 add rdx,0x1 148c: 4c 39 ca cmp rdx,r9 148f: 73 3e jae 14cf <utf16_to_utf8+0x8f> 1491: 41 0f b7 0c 50 movzx ecx,WORD PTR [r8+rdx*2] 1496: 4c 8d 1c 12 lea r11,[rdx+rdx*1] 149a: 89 c8 mov eax,ecx 149c: 66 83 f9 7f cmp cx,0x7f 14a0: 76 de jbe 1480 <utf16_to_utf8+0x40> 14a2: 81 f9 ff 07 00 00 cmp ecx,0x7ff 14a8: 77 2e ja 14d8 <utf16_to_utf8+0x98> 14aa: c1 e9 06 shr ecx,0x6 14ad: 83 e0 3f and eax,0x3f 14b0: 48 8d 7e 01 lea rdi,[rsi+0x1] 14b4: 48 83 c2 01 add rdx,0x1 14b8: 83 c9 c0 or ecx,0xffffffc0 14bb: 83 c8 80 or eax,0xffffff80 14be: 41 88 0c 32 mov BYTE PTR [r10+rsi*1],cl 14c2: 48 83 c6 02 add rsi,0x2 14c6: 41 88 04 3a mov BYTE PTR [r10+rdi*1],al 14ca: 4c 39 ca cmp rdx,r9 14cd: 72 c2 jb 1491 <utf16_to_utf8+0x51> 14cf: 48 89 f0 mov rax,rsi 14d2: c3 ret 14d3: 0f 1f 44 00 00 nop DWORD PTR [rax+rax*1+0x0] 14d8: 8d b9 00 28 ff ff lea edi,[rcx-0xd800] 14de: 81 ff ff 07 00 00 cmp edi,0x7ff 14e4: 76 3a jbe 1520 <utf16_to_utf8+0xe0> 14e6: 89 cf mov edi,ecx 14e8: c1 e9 06 shr ecx,0x6 14eb: 83 e0 3f and eax,0x3f 14ee: c1 ef 0c shr edi,0xc 14f1: 83 e1 3f and ecx,0x3f 14f4: 83 c8 80 or eax,0xffffff80 14f7: 83 cf e0 or edi,0xffffffe0 14fa: 83 c9 80 or ecx,0xffffff80 14fd: 41 88 3c 32 mov BYTE PTR [r10+rsi*1],dil 1501: 48 8d 7e 02 lea rdi,[rsi+0x2] 1505: 41 88 4c 32 01 mov BYTE PTR [r10+rsi*1+0x1],cl 150a: 48 83 c6 03 add rsi,0x3 150e: 41 88 04 3a mov BYTE PTR [r10+rdi*1],al 1512: e9 71 ff ff ff jmp 1488 <utf16_to_utf8+0x48> 1517: 66 0f 1f 84 00 00 00 nop WORD PTR [rax+rax*1+0x0] 151e: 00 00 1520: 81 f9 ff db 00 00 cmp ecx,0xdbff 1526: 77 6f ja 1597 <utf16_to_utf8+0x157> 1528: 48 83 c2 01 add rdx,0x1 152c: 4c 39 ca cmp rdx,r9 152f: 73 66 jae 1597 <utf16_to_utf8+0x157> 1531: 43 0f b7 44 18 02 movzx eax,WORD PTR [r8+r11*1+0x2] 1537: 8d 88 00 24 ff ff lea ecx,[rax-0xdc00] 153d: 81 f9 ff 03 00 00 cmp ecx,0x3ff 1543: 77 52 ja 1597 <utf16_to_utf8+0x157> 1545: c1 e7 0a shl edi,0xa 1548: 01 c7 add edi,eax 154a: 8d 87 00 24 00 00 lea eax,[rdi+0x2400] 1550: c1 ef 06 shr edi,0x6 1553: 89 c1 mov ecx,eax 1555: 81 c7 90 00 00 00 add edi,0x90 155b: c1 e9 12 shr ecx,0x12 155e: 83 e7 3f and edi,0x3f 1561: 83 c9 f0 or ecx,0xfffffff0 1564: 83 cf 80 or edi,0xffffff80 1567: 41 88 0c 32 mov BYTE PTR [r10+rsi*1],cl 156b: 89 c1 mov ecx,eax 156d: 83 e0 3f and eax,0x3f 1570: c1 e9 0c shr ecx,0xc 1573: 83 c8 80 or eax,0xffffff80 1576: 41 88 7c 32 02 mov BYTE PTR [r10+rsi*1+0x2],dil 157b: 83 e1 3f and ecx,0x3f 157e: 83 c9 80 or ecx,0xffffff80 1581: 41 88 4c 32 01 mov BYTE PTR [r10+rsi*1+0x1],cl 1586: 48 8d 4e 03 lea rcx,[rsi+0x3] 158a: 48 83 c6 04 add rsi,0x4 158e: 41 88 04 0a mov BYTE PTR [r10+rcx*1],al 1592: e9 f1 fe ff ff jmp 1488 <utf16_to_utf8+0x48> 1597: 48 c7 c6 ff ff ff ff mov rsi,0xffffffffffffffff 159e: 48 89 f0 mov rax,rsi 15a1: c3 ret 15a2: 31 f6 xor esi,esi 15a4: e9 26 ff ff ff jmp 14cf <utf16_to_utf8+0x8f> Disassembly of section .fini: .build/runner_given: file format elf64-x86-64 Disassembly of section .init: Disassembly of section .plt: Disassembly of section .text: 0000000000001440 <given_utf16_to_utf8>: 1440: 49 89 f8 mov r8,rdi 1443: 49 89 f1 mov r9,rsi 1446: 49 89 d2 mov r10,rdx 1449: 48 85 f6 test rsi,rsi 144c: 0f 84 50 01 00 00 je 15a2 <given_utf16_to_utf8+0x162> 1452: 31 d2 xor edx,edx 1454: 31 f6 xor esi,esi 1456: eb 39 jmp 1491 <given_utf16_to_utf8+0x51> 1458: 0f 1f 80 00 00 00 00 nop DWORD PTR [rax+0x0] 145f: 66 66 2e 0f 1f 84 00 data16 cs nop WORD PTR [rax+rax*1+0x0] 1466: 00 00 00 00 146a: 66 66 2e 0f 1f 84 00 data16 cs nop WORD PTR [rax+rax*1+0x0] 1471: 00 00 00 00 1475: 66 66 2e 0f 1f 84 00 data16 cs nop WORD PTR [rax+rax*1+0x0] 147c: 00 00 00 00 1480: 41 88 0c 32 mov BYTE PTR [r10+rsi*1],cl 1484: 48 83 c6 01 add rsi,0x1 1488: 48 83 c2 01 add rdx,0x1 148c: 4c 39 ca cmp rdx,r9 148f: 73 3e jae 14cf <given_utf16_to_utf8+0x8f> 1491: 41 0f b7 0c 50 movzx ecx,WORD PTR [r8+rdx*2] 1496: 4c 8d 1c 12 lea r11,[rdx+rdx*1] 149a: 89 c8 mov eax,ecx 149c: 66 83 f9 7f cmp cx,0x7f 14a0: 76 de jbe 1480 <given_utf16_to_utf8+0x40> 14a2: 81 f9 ff 07 00 00 cmp ecx,0x7ff 14a8: 77 2e ja 14d8 <given_utf16_to_utf8+0x98> 14aa: c1 e9 06 shr ecx,0x6 14ad: 83 e0 3f and eax,0x3f 14b0: 48 8d 7e 01 lea rdi,[rsi+0x1] 14b4: 48 83 c2 01 add rdx,0x1 14b8: 83 c9 c0 or ecx,0xffffffc0 14bb: 83 c8 80 or eax,0xffffff80 14be: 41 88 0c 32 mov BYTE PTR [r10+rsi*1],cl 14c2: 48 83 c6 02 add rsi,0x2 14c6: 41 88 04 3a mov BYTE PTR [r10+rdi*1],al 14ca: 4c 39 ca cmp rdx,r9 14cd: 72 c2 jb 1491 <given_utf16_to_utf8+0x51> 14cf: 48 89 f0 mov rax,rsi 14d2: c3 ret 14d3: 0f 1f 44 00 00 nop DWORD PTR [rax+rax*1+0x0] 14d8: 8d b9 00 28 ff ff lea edi,[rcx-0xd800] 14de: 81 ff ff 07 00 00 cmp edi,0x7ff 14e4: 76 3a jbe 1520 <given_utf16_to_utf8+0xe0> 14e6: 89 cf mov edi,ecx 14e8: c1 e9 06 shr ecx,0x6 14eb: 83 e0 3f and eax,0x3f 14ee: c1 ef 0c shr edi,0xc 14f1: 83 e1 3f and ecx,0x3f 14f4: 83 c8 80 or eax,0xffffff80 14f7: 83 cf e0 or edi,0xffffffe0 14fa: 83 c9 80 or ecx,0xffffff80 14fd: 41 88 3c 32 mov BYTE PTR [r10+rsi*1],dil 1501: 48 8d 7e 02 lea rdi,[rsi+0x2] 1505: 41 88 4c 32 01 mov BYTE PTR [r10+rsi*1+0x1],cl 150a: 48 83 c6 03 add rsi,0x3 150e: 41 88 04 3a mov BYTE PTR [r10+rdi*1],al 1512: e9 71 ff ff ff jmp 1488 <given_utf16_to_utf8+0x48> 1517: 66 0f 1f 84 00 00 00 nop WORD PTR [rax+rax*1+0x0] 151e: 00 00 1520: 81 f9 ff db 00 00 cmp ecx,0xdbff 1526: 77 6f ja 1597 <given_utf16_to_utf8+0x157> 1528: 48 83 c2 01 add rdx,0x1 152c: 4c 39 ca cmp rdx,r9 152f: 73 66 jae 1597 <given_utf16_to_utf8+0x157> 1531: 43 0f b7 44 18 02 movzx eax,WORD PTR [r8+r11*1+0x2] 1537: 8d 88 00 24 ff ff lea ecx,[rax-0xdc00] 153d: 81 f9 ff 03 00 00 cmp ecx,0x3ff 1543: 77 52 ja 1597 <given_utf16_to_utf8+0x157> 1545: c1 e7 0a shl edi,0xa 1548: 01 c7 add edi,eax 154a: 8d 87 00 24 00 00 lea eax,[rdi+0x2400] 1550: c1 ef 06 shr edi,0x6 1553: 89 c1 mov ecx,eax 1555: 81 c7 90 00 00 00 add edi,0x90 155b: c1 e9 12 shr ecx,0x12 155e: 83 e7 3f and edi,0x3f 1561: 83 c9 f0 or ecx,0xfffffff0 1564: 83 cf 80 or edi,0xffffff80 1567: 41 88 0c 32 mov BYTE PTR [r10+rsi*1],cl 156b: 89 c1 mov ecx,eax 156d: 83 e0 3f and eax,0x3f 1570: c1 e9 0c shr ecx,0xc 1573: 83 c8 80 or eax,0xffffff80 1576: 41 88 7c 32 02 mov BYTE PTR [r10+rsi*1+0x2],dil 157b: 83 e1 3f and ecx,0x3f 157e: 83 c9 80 or ecx,0xffffff80 1581: 41 88 4c 32 01 mov BYTE PTR [r10+rsi*1+0x1],cl 1586: 48 8d 4e 03 lea rcx,[rsi+0x3] 158a: 48 83 c6 04 add rsi,0x4 158e: 41 88 04 0a mov BYTE PTR [r10+rcx*1],al 1592: e9 f1 fe ff ff jmp 1488 <given_utf16_to_utf8+0x48> 1597: 48 c7 c6 ff ff ff ff mov rsi,0xffffffffffffffff 159e: 48 89 f0 mov rax,rsi 15a1: c3 ret 15a2: 31 f6 xor esi,esi 15a4: e9 26 ff ff ff jmp 14cf <given_utf16_to_utf8+0x8f> Disassembly of section .fini: --- Command finished with exit code: 0 ---

{"command": "lscpu | sed -n '1,25p'; grep -m1 '^flags' /proc/cpuinfo", "intent": "Check available SIMD instruction sets for safe optimization", "notify": false, "run_in_background": false, "timeout": 10000, "wake": false}

Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Address sizes: 46 bits physical, 48 bits virtual Byte Order: Little Endian CPU(s): 20 On-line CPU(s) list: 0-19 Vendor ID: AuthenticAMD Model name: unknown CPU family: 175 Model: 1 Thread(s) per core: 1 Core(s) per socket: 20 Socket(s): 1 Stepping: unknown BogoMIPS: 3095.38 Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm cmp_legacy cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw topoext perfctr_core fsgsbase bmi1 avx2 smep bmi2 erms invpcid rdseed adx smap clwb sha_ni xsaveopt xsavec xgetbv1 xsaves umip vaes vpclmulqdq rdpid fsrm Hypervisor vendor: Microsoft Virtualization type: full flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm cmp_legacy cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw topoext perfctr_core fsgsbase bmi1 avx2 smep bmi2 erms invpcid rdseed adx smap clwb sha_ni xsaveopt xsavec xgetbv1 xsaves umip vaes vpclmulqdq rdpid fsrm --- Command finished with exit code: 0 ---

{"content": "// Fast UTF-16LE to UTF-8 transcoder.\n#include <stdint.h>\n#include <stddef.h>\n#include <string.h>\n#include <immintrin.h>\n\n#define INVALID ((size_t)-1)\n\nstatic inline void put2(uint8_t *p, uint32_t c) {\n uint16_t x = (uint16_t)(0x80c0u | (c >> 6) | ((c & 63u) << 8));\n memcpy(p, &x, sizeof(x));\n}\n\n// The fourth byte is harmless: the contract provides four bytes of slop and\n// the next output overwrites it.\nstatic inline void put3(uint8_t *p, uint32_t c) {\n uint32_t x = 0x008080e0u | (c >> 12) |\n ((c << 2) & 0x00003f00u) | ((c << 16) & 0x003f0000u);\n memcpy(p, &x, sizeof(x));\n}\n\nstatic inline void put4(uint8_t *p, uint32_t cp) {\n uint32_t x = 0x808080f0u | (cp >> 18) |\n ((cp >> 4) & 0x00003f00u) |\n ((cp << 10) & 0x003f0000u) |\n ((cp << 24) & 0x3f000000u);\n memcpy(p, &x, sizeof(x));\n}\n\n__attribute__((target(\"avx2\")))\nsize_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) {\n const uint16_t *const begin = in;\n const uint16_t *const end = in + n;\n uint8_t *const out_begin = out;\n\n const __m256i ascii_mask = _mm256_set1_epi16((short)0xff80);\n const __m256i lo7 = _mm256_set1_epi16(0x007f);\n const __m256i lim800 = _mm256_set1_epi16(0x0800);\n const __m256i base2 = _mm256_set1_epi16((short)0x80c0);\n const __m256i mask3f00 = _mm256_set1_epi16(0x3f00);\n const __m256i hi5mask = _mm256_set1_epi16((short)0xf800);\n const __m256i surbits = _mm256_set1_epi16((short)0xd800);\n const __m256i zero = _mm256_setzero_si256();\n const __m256i pairmask = _mm256_set1_epi16((short)0xfc00);\n const __m256i pairexpect = _mm256_setr_epi16(\n (short)0xd800, (short)0xdc00, (short)0xd800, (short)0xdc00,\n (short)0xd800, (short)0xdc00, (short)0xd800, (short)0xdc00,\n (short)0xd800, (short)0xdc00, (short)0xd800, (short)0xdc00,\n (short)0xd800, (short)0xdc00, (short)0xd800, (short)0xdc00);\n const __m256i low10 = _mm256_set1_epi32(0x3ff);\n const __m256i cpbase = _mm256_set1_epi32(0x10000);\n const __m256i utf4base = _mm256_set1_epi32((int)0x808080f0u);\n const __m256i m3f00_32 = _mm256_set1_epi32(0x00003f00);\n const __m256i m3f0000 = _mm256_set1_epi32(0x003f0000);\n const __m256i m3f000000 = _mm256_set1_epi32(0x3f000000);\n const __m256i utf3base = _mm256_set1_epi32(0x008080e0);\n const __m256i compress3 = _mm256_setr_epi8(\n 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1,\n 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1);\n\n while (in < end) {\n uint32_t c = *in;\n\n if (c < 0x80) {\n // Long ASCII runs dominate the corpus. Convert 32 units per test.\n while ((size_t)(end - in) >= 32) {\n __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in);\n __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16));\n if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break;\n __m256i bytes = _mm256_packus_epi16(a, b);\n bytes = _mm256_permute4x64_epi64(bytes, 0xd8);\n _mm256_storeu_si256((__m256i *)(void *)out, bytes);\n in += 32;\n out += 32;\n }\n while (in < end && (c = *in) < 0x80) {\n *out++ = (uint8_t)c;\n ++in;\n }\n continue;\n }\n\n if (c < 0x800) {\n // Sixteen two-byte characters become sixteen packed 16-bit words.\n while ((size_t)(end - in) >= 16) {\n __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n __m256i ge80 = _mm256_cmpgt_epi16(v, lo7);\n __m256i lt800 = _mm256_cmpgt_epi16(lim800, v);\n if (_mm256_movemask_epi8(_mm256_and_si256(ge80, lt800)) != -1) break;\n __m256i x = _mm256_or_si256(_mm256_srli_epi16(v, 6),\n ... [4389 characters truncated for page size]

Updated submission/solve.c (179 lines): 1- // solve.c — the given implementation of utf16_to_utf8. 2- // A clean, correct scalar transcoder of the kind found in mainstream 3- // libraries. Make it faster. See ../spec.md. Grade with ../grade. 1+ // Fast UTF-16LE to UTF-8 transcoder. 4+ #include <string.h> 5+ #include <immintrin.h> 9+ static inline void put2(uint8_t *p, uint32_t c) { 10+ uint16_t x = (uint16_t)(0x80c0u | (c >> 6) | ((c & 63u) << 8)); 11+ memcpy(p, &x, sizeof(x)); 12+ } 14+ // The fourth byte is harmless: the contract provides four bytes of slop and 15+ // the next output overwrites it. 16+ static inline void put3(uint8_t *p, uint32_t c) { 17+ uint32_t x = 0x008080e0u | (c >> 12) | 18+ ((c << 2) & 0x00003f00u) | ((c << 16) & 0x003f0000u); 19+ memcpy(p, &x, sizeof(x)); 20+ } 22+ static inline void put4(uint8_t *p, uint32_t cp) { 23+ uint32_t x = 0x808080f0u | (cp >> 18) | 24+ ((cp >> 4) & 0x00003f00u) | ...

{"command": "./grade --seed 48818", "intent": "Verify AVX2 implementation and measure deterministic improvement", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 1.7s verify 2.4s PASS measure 0.6s 31,517,177 instructions (given: 77,696,233) SCORE +1.3017 (2.465x) --- Command finished with exit code: 0 ---

{"intent": "Inspect optimized assembly and callgrind profile", "tool_calls": [{"tool": "bash", "command": "callgrind_annotate --auto=yes --inclusive=yes .build/callgrind.runner.out | head -100", "timeout": 10000, "intent": "Find remaining instruction hot spots"}, {"tool": "bash", "command": "objdump -d -Mintel --disassemble=utf16_to_utf8 .build/runner > \"$JCODE_SCRATCH_DIR/utf16.asm\"; wc -l \"$JCODE_SCRATCH_DIR/utf16.asm\"; sed -n '1,260p' \"$JCODE_SCRATCH_DIR/utf16.asm\"", "timeout": 10000, "intent": "Review generated AVX2 assembly for compiler inefficiencies"}, {"tool": "bash", "command": "python3 - <<'PY'\nimport struct,glob,collections\np='.build/corpus_48818.bin'; d=open(p,'rb').read(); off=0\nclasses=collections.Counter(); runs=collections.Counter(); lens=collections.Counter()\nwhile off<len(d):\n n=struct.unpack_from('<I',d,off)[0];off+=4\n a=struct.unpack_from(f'<{n}H',d,off);off+=2*n\n prev=None; run=0\n for c in a:\n k='a' if c<128 else '2' if c<0x800 else 's' if 0xd800<=c<0xe000 else '3'\n classes[k]+=1\n if k==prev:run+=1\n else:\n if prev:lens[prev, min(run//4,20)]+=1\n prev=k;run=1\n if prev:lens[prev,min(run//4,20)]+=1\nprint(classes)\nfor k in 'a23s':\n x=[(b*4,n) for (q,b),n in lens.items() if q==k]\n print(k,'runs',sum(n for _,n in x),'avg',classes[k]/sum(n for _,n in x),sorted(x))\nPY", "timeout": 10000, "intent": "Quantify corpus class and run-length distribution"}]}

--- [1] bash --- Use of uninitialized value $line_nums[0] in numeric eq (==) at /usr/sbin/callgrind_annotate line 1184. Use of uninitialized value $pairs[0] in numeric lt (<) at /usr/sbin/callgrind_annotate line 1200. Use of uninitialized value $high in numeric lt (<) at /usr/sbin/callgrind_annotate line 1211. -------------------------------------------------------------------------------- Profile data file '.build/callgrind.runner.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 1138475 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/corpus_48818.bin (PID 236, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 99 Include dirs: User annotated: Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 5,974,674 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 5,974,674 (100.0%) /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/submission/solve.c:utf16_to_utf8 5,974,674 (100.0%) /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/verify/runner.c:main 5,974,674 (100.0%) /usr/src/debug/glibc/glibc/csu/../csu/libc-start.c:__libc_start_main@@GLIBC_2.34 [/usr/lib/libc.so.6] 5,974,674 (100.0%) /usr/src/debug/glibc/glibc/csu/../sysdeps/nptl/libc_start_call_main.h:(below main) [/usr/lib/libc.so.6] 5,974,674 (100.0%) ???:(below main) [/tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner] 5,974,674 (100.0%) ???:0x000000000001f100 [/usr/lib/ld-linux-x86-64.so.2] 5,974,674 (100.0%) verify/runner.c:main [/tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner] 5,040,764 (84.37%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner] 705,087 (11.80%) /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/avx2intrin.h:utf16_to_utf8 190,223 ( 3.18%) /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/avxintrin.h:utf16_to_utf8 38,600 ( 0.65%) /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h:utf16_to_utf8 -------------------------------------------------------------------------------- -- Auto-annotated source: verify/runner.c -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- -- Auto-annotated source: /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/avx2intrin.h -------------------------------------------------------------------------------- Ir -- line 92 ---------------------------------------- . { . return (__m256i)__builtin_ia32_packusdw256 ((__v8si)__A, (__v8si)__B); . } . . extern __inline __m256i . __attribute__ ((__gnu_inline__, __always_inline__, __artificial__)) . _mm256_packus_epi16 (__m256i __A, __m256i __B) . { 12,761 ( 0.21%) return (__m256i)__builtin_ia32_packuswb256 ((__v16hi)__A, (__v16hi)__B); . } . . extern __inline __m256i . __attribute__ ((__gnu_inline__, __always_inline__, __artificial__)) . _mm256_add_epi8 (__m256i __A, __m256i __B) . { . return (__m256i) ((__v32qu)__A + (__v32qu)__B); . } -- line 108 ---------------------------------------- -- line 113 ---------------------------------------- . { . return (__m256i) ((__v16hu)__A + (__v16hu)__B); . } . . extern __inline __m256i . __attribute__ ((__gnu_inline__, __always_inline__, __artificial__)) . _mm256_add_epi32 (__m256i __A, __m256i __B) . { 8,787 ( 0.15%) return (__m256i) ((__v8su)__A + (__v8su)__B); . } . . extern __inline __m256i . __attribute__ ((__gnu_inline__, __always_inline__, __artificial__)) . _mm256_add_epi64 (__m256i __A, __m256i __B) . { . return (__m256i) ((__v4du)__A + (__v4du)__B); . } -- line 129 ---------------------------------------- -- line 173 ---------------------------------------- . (__v4di)(__m256i)(B), \ . (int)(N) * 8)) . #endif . . extern __inline __m256i . __attribute__ ((__gnu_inline__, __always_inline__, __artificial__)) . _mm256_and_si256 (__m256i __A, __m256i __B) . { 163,047 ( 2.73%) return (__m256i) ((__v4du)__A & (__v4du)__B); . } . . extern __inline __m256i . __attribute__ ((__gnu_inline__, __always_inline__, __artificial__)) --- Command finished with exit code: 0 --- --- [2] bash --- 333 /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/home/.jcode/scratch/utf16.asm .build/runner: file format elf64-x86-64 Disassembly of section .init: Disassembly of section .plt: Disassembly of section .text: 0000000000001440 <utf16_to_utf8>: 1440: 48 89 f9 mov rcx,rdi 1443: 48 8d 3c 77 lea rdi,[rdi+rsi*2] 1447: 48 39 f9 cmp rcx,rdi 144a: 0f 83 58 05 00 00 jae 19a8 <utf16_to_utf8+0x568> 1450: 55 push rbp 1451: 48 89 d6 mov rsi,rdx 1454: 48 89 d0 mov rax,rdx 1457: ba 00 00 01 00 mov edx,0x10000 145c: c5 cd 76 f6 vpcmpeqd ymm6,ymm6,ymm6 1460: c5 79 6e d2 vmovd xmm10,edx 1464: c4 41 3d 76 c0 vpcmpeqd ymm8,ymm8,ymm8 1469: c5 cd 72 d6 16 vpsrld ymm6,ymm6,0x16 146e: c4 42 7d 58 d2 vpbroadcastd ymm10,xmm10 1473: 48 89 e5 mov rbp,rsp 1476: 48 83 e4 e0 and rsp,0xffffffffffffffe0 147a: 44 0f b7 01 movzx r8d,WORD PTR [rcx] 147e: c5 7d 6f 1d ba 0b 00 vmovdqa ymm11,YMMWORD PTR [rip+0xbba] # 2040 <_IO_stdin_used+0x40> 1485: 00 1486: c5 7d 6f 25 92 0b 00 vmovdqa ymm12,YMMWORD PTR [rip+0xb92] # 2020 <_IO_stdin_used+0x20> 148d: 00 148e: 41 83 f8 7f cmp r8d,0x7f 1492: 0f 86 db 01 00 00 jbe 1673 <utf16_to_utf8+0x233> 1498: 41 81 f8 ff 07 00 00 cmp r8d,0x7ff 149f: 0f 86 1b 04 00 00 jbe 18c0 <utf16_to_utf8+0x480> 14a5: ba 00 3f 00 00 mov edx,0x3f00 14aa: c5 f9 6e e2 vmovd xmm4,edx 14ae: ba 00 00 3f 00 mov edx,0x3f0000 14b3: c5 f9 6e ea vmovd xmm5,edx 14b7: 41 8d 90 00 28 ff ff lea edx,[r8-0xd800] 14be: c4 e2 7d 58 e4 vpbroadcastd ymm4,xmm4 14c3: c4 e2 7d 58 ed vpbroadcastd ymm5,xmm5 14c8: 81 fa ff 07 00 00 cmp edx,0x7ff 14ce: 0f 87 5c 02 00 00 ja 1730 <utf16_to_utf8+0x2f0> 14d4: 41 81 f8 ff db 00 00 cmp r8d,0xdbff 14db: 0f 87 cf 03 00 00 ja 18b0 <utf16_to_utf8+0x470> 14e1: 48 89 fa mov rdx,rdi 14e4: 48 29 ca sub rdx,rcx 14e7: 48 83 fa 1e cmp rdx,0x1e 14eb: 0f 86 5b 01 00 00 jbe 164c <utf16_to_utf8+0x20c> 14f1: c4 c1 75 71 f0 0a vpsllw ymm1,ymm8,0xa 14f7: 41 b8 00 00 00 3f mov r8d,0x3f000000 14fd: e9 86 00 00 00 jmp 1588 <utf16_to_utf8+0x148> 1502: 66 0f 1f 44 00 00 nop WORD PTR [rax+rax*1+0x0] 1508: c5 ed 72 d0 10 vpsrld ymm2,ymm0,0x10 150d: c5 fd db c6 vpand ymm0,ymm0,ymm6 1511: 48 83 c1 20 add rcx,0x20 1515: 48 83 c0 20 add rax,0x20 1519: c5 fd 72 f0 0a vpslld ymm0,ymm0,0xa 151e: c5 ed db d6 vpand ymm2,ymm2,ymm6 1522: ba f0 80 80 80 mov edx,0x808080f0 1527: c4 c1 7d fe c2 vpaddd ymm0,ymm0,ymm10 152c: c5 fd fe c2 vpaddd ymm0,ymm0,ymm2 1530: c5 c5 72 d0 04 vpsrld ymm7,ymm0,0x4 1535: c5 ed 72 f0 0a vpslld ymm2,ymm0,0xa 153a: c5 c5 db fc vpand ymm7,ymm7,ymm4 153e: c5 e5 72 d0 12 vpsrld ymm3,ymm0,0x12 1543: c5 ed db d5 vpand ymm2,ymm2,ymm5 1547: c5 ed eb d7 vpor ymm2,ymm2,ymm7 154b: c5 fd 72 f0 18 vpslld ymm0,ymm0,0x18 1550: c4 c1 79 6e f8 vmovd xmm7,r8d 1555: c4 e2 7d 58 ff vpbroadcastd ymm7,xmm7 155a: c5 fd db c7 vpand ymm0,ymm0,ymm7 155e: c5 f9 6e fa vmovd xmm7,edx 1562: 48 89 fa mov rdx,rdi 1565: c4 e2 7d 58 ff vpbroadcastd ymm7,xmm7 156a: 48 29 ca sub rdx,rcx 156d: c5 e5 eb df vpor ymm3,ymm3,ymm7 1571: c5 fd eb c3 vpor ymm0,ymm0,ymm3 1575: c5 ed eb c0 vpor ymm0,ymm2,ymm0 1579: c5 fe 7f 40 e0 vmovdqu YMMWORD PTR [rax-0x20],ymm0 157e: 48 83 fa 1e cmp rdx,0x1e 1582: 0f 86 c4 00 00 00 jbe 164c <utf16_to_utf8+0x20c> 1588: c5 fe 6f 01 vmovdqu ymm0,YMMWORD PTR [rcx] 158c: c5 fd db d1 vpand ymm2,ymm0,ymm1 1590: c5 a5 75 d2 vpcmpeqw ymm2,ymm11,ymm2 1594: c5 fd d7 d2 vpmovmskb edx,ymm2 1598: 83 fa ff cmp edx,0xffffffff 159b: 0f 84 67 ff ff ff je 1508 <utf16_to_utf8+0xc8> 15a1: 48 39 f9 cmp rcx,rdi 15a4: 0f 83 ab 00 00 00 jae 1655 <utf16_to_utf8+0x215> 15aa: 66 0f 1f 44 00 00 nop WORD PTR [rax+rax*1+0x0] 15b0: 0f b7 11 movzx edx,WORD PTR [rcx] 15b3: 44 8d 82 00 28 00 00 lea r8d,[rdx+0x2800] 15ba: 66 41 81 f8 ff 03 cmp r8w,0x3ff 15c0: 0f 87 9a 00 00 00 ja 1660 <utf16_to_utf8+0x220> 15c6: 49 89 f8 mov r8,rdi 15c9: 49 29 c8 sub r8,rcx 15cc: 49 83 f8 02 cmp r8,0x2 15d0: 0f 8e da 02 00 00 jle 18b0 <utf16_to_utf8+0x470> 15d6: 44 0f b7 41 02 movzx r8d,WORD PTR [rcx+0x2] 15db: 45 8d 88 00 24 ff ff lea r9d,[r8-0xdc00] 15e2: 41 81 f9 ff 03 00 00 cmp r9d,0x3ff 15e9: 0f 87 c1 02 00 00 ja 18b0 <utf16_to_utf8+0x470> 15ef: 81 ea 00 d8 00 00 sub edx,0xd800 15f5: 48 83 c0 04 add rax,0x4 15f9: 48 83 c1 04 add rcx,0x4 15fd: c1 e2 0a shl edx,0xa 1600: 44 01 c2 add edx,r8d 1603: 41 89 d0 mov r8d,edx 1606: 44 8d 8a 00 24 00 00 lea r9d,[rdx+0x2400] 160d: c1 e2 18 shl edx,0x18 1610: 41 c1 e8 04 shr r8d,0x4 1614: 81 e2 00 00 00 3f and edx,0x3f000000 161a: 41 81 c0 40 02 00 00 add r8d,0x240 1621: 41 81 e0 00 3f 00 00 and r8d,0x3f00 1628: 44 09 c2 or edx,r8d 162b: 45 89 c8 mov r8d,r9d 162e: 41 c1 e1 0a shl r9d,0xa 1632: 41 c1 e8 12 shr r8d,0x12 1636: 41 81 e1 00 00 3f 00 and r9d,0x3f0000 163d: 44 09 c2 or edx,r8d 1640: 44 09 ca or edx, ... [8566 characters truncated for page size]

{"command": "callgrind_annotate --auto=yes --inclusive=no --threshold=0.1 .build/callgrind.runner.out submission/solve.c 2>/dev/null | sed -n '1,300p'", "intent": "Attribute remaining instructions to source paths", "notify": false, "run_in_background": false, "timeout": 10000, "wake": false}

-------------------------------------------------------------------------------- Profile data file '.build/callgrind.runner.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 1138475 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/corpus_48818.bin (PID 236, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 0.1 Include dirs: User annotated: submission/solve.c Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 5,974,674 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 5,040,764 (84.37%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner] -------------------------------------------------------------------------------- -- User-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir -- line 2 ---------------------------------------- . #include <stdint.h> . #include <stddef.h> . #include <string.h> . #include <immintrin.h> . . #define INVALID ((size_t)-1) . . static inline void put2(uint8_t *p, uint32_t c) { 526,687 ( 8.82%) uint16_t x = (uint16_t)(0x80c0u | (c >> 6) | ((c & 63u) << 8)); . memcpy(p, &x, sizeof(x)); . } . . // The fourth byte is harmless: the contract provides four bytes of slop and . // the next output overwrites it. . static inline void put3(uint8_t *p, uint32_t c) { 30,229 ( 0.51%) uint32_t x = 0x008080e0u | (c >> 12) | 272,061 ( 4.55%) ((c << 2) & 0x00003f00u) | ((c << 16) & 0x003f0000u); . memcpy(p, &x, sizeof(x)); . } . . static inline void put4(uint8_t *p, uint32_t cp) { 47,386 ( 0.79%) uint32_t x = 0x808080f0u | (cp >> 18) | 94,772 ( 1.59%) ((cp >> 4) & 0x00003f00u) | 165,851 ( 2.78%) ((cp << 10) & 0x003f0000u) | 47,386 ( 0.79%) ((cp << 24) & 0x3f000000u); . memcpy(p, &x, sizeof(x)); . } . . __attribute__((target("avx2"))) 2,805 ( 0.05%) size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { . const uint16_t *const begin = in; 561 ( 0.01%) const uint16_t *const end = in + n; . uint8_t *const out_begin = out; . . const __m256i ascii_mask = _mm256_set1_epi16((short)0xff80); . const __m256i lo7 = _mm256_set1_epi16(0x007f); . const __m256i lim800 = _mm256_set1_epi16(0x0800); . const __m256i base2 = _mm256_set1_epi16((short)0x80c0); . const __m256i mask3f00 = _mm256_set1_epi16(0x3f00); . const __m256i hi5mask = _mm256_set1_epi16((short)0xf800); -- line 41 ---------------------------------------- -- line 53 ---------------------------------------- . const __m256i m3f00_32 = _mm256_set1_epi32(0x00003f00); . const __m256i m3f0000 = _mm256_set1_epi32(0x003f0000); . const __m256i m3f000000 = _mm256_set1_epi32(0x3f000000); . const __m256i utf3base = _mm256_set1_epi32(0x008080e0); . const __m256i compress3 = _mm256_setr_epi8( . 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1, . 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1); . 86,927 ( 1.45%) while (in < end) { 43,744 ( 0.73%) uint32_t c = *in; . 86,366 ( 1.45%) if (c < 0x80) { . // Long ASCII runs dominate the corpus. Convert 32 units per test. 137,596 ( 2.30%) while ((size_t)(end - in) >= 32) { . __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in); . __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16)); 67,616 ( 1.13%) if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break; . __m256i bytes = _mm256_packus_epi16(a, b); . bytes = _mm256_permute4x64_epi64(bytes, 0xd8); . _mm256_storeu_si256((__m256i *)(void *)out, bytes); 12,761 ( 0.21%) in += 32; 12,761 ( 0.21%) out += 32; . } 949,584 (15.89%) while (in < end && (c = *in) < 0x80) { 336,938 ( 5.64%) *out++ = (uint8_t)c; 168,469 ( 2.82%) ++in; . } . continue; . } . 43,090 ( 0.72%) if (c < 0x800) { . // Sixteen two-byte characters become sixteen packed 16-bit words. 57,116 ( 0.96%) while ((size_t)(end - in) >= 16) { . __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); . __m256i ge80 = _mm256_cmpgt_epi16(v, lo7); . __m256i lt800 = _mm256_cmpgt_epi16(lim800, v); 28,308 ( 0.47%) if (_mm256_movemask_epi8(_mm256_and_si256(ge80, lt800)) != -1) break; . __m256i x = _mm256_or_si256(_mm256_srli_epi16(v, 6), . _mm256_and_si256(_mm256_slli_epi16(v, 8), mask3f00)); . x = _mm256_or_si256(x, base2); . _mm256_storeu_si256((__m256i *)(void *)out, x); 3,753 ( 0.06%) in += 16; 3,753 ( 0.06%) out += 32; . } 524,691 ( 8.78%) while (in < end && (c = *in) >= 0x80 && c < 0x800) { . put2(out, c); 75,241 ( 1.26%) out += 2; 75,241 ( 1.26%) ++in; . } . continue; . } . 99,171 ( 1.66%) if ((uint32_t)(c - 0xd800) >= 0x800) { . // Encode sixteen ordinary three-byte BMP units at once. Each group . // of four dwords is compacted to 12 bytes with one byte shuffle. 54,960 ( 0.92%) while ((size_t)(end - in) >= 16) { . __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); . __m256i high = _mm256_and_si256(v, hi5mask); . __m256i small = _mm256_cmpeq_epi16(high, zero); . __m256i sur = _mm256_cmpeq_epi16(high, surbits); 31,285 ( 0.52%) if (_mm256_movemask_epi8(_mm256_or_si256(small, sur))) break; . . __m256i a = _mm256_cvtepu16_epi32(_mm256_castsi256_si128(v)); . __m256i b = _mm256_cvtepu16_epi32(_mm256_extracti128_si256(v, 1)); . __m256i a1 = _mm256_and_si256(_mm256_slli_epi32(a, 2), m3f00_32); . __m256i b1 = _mm256_and_si256(_mm256_slli_epi32(b, 2), m3f00_32); . __m256i a2 = _mm256_and_si256(_mm256_slli_epi32(a, 16), m3f0000); . __m256i b2 = _mm256_and_si256(_mm256_slli_epi32(b, 16), m3f0000); . a = _mm256_or_si256(utf3base, _mm256_or_si256(_mm256_srli_epi32(a, 12), -- line 121 ---------------------------------------- -- line 123 ---------------------------------------- . b = _mm256_or_si256(utf3base, _mm256_or_si256(_mm256_srli_epi32(b, 12), . _mm256_or_si256(b1, b2))); . a = _mm256_shuffle_epi8(a, compress3); . b = _mm256_shuffle_epi8(b, compress3); . _mm_storeu_si128((__m128i *)(void *)(out + 0), _mm256_castsi256_si128(a)); . _mm_storeu_si128((__m128i *)(void *)(out + 12), _mm256_extracti128_si256(a, 1)); . _mm_storeu_si128((__m128i *)(void *)(out + 24), _mm256_castsi256_si128(b)); . _mm_storeu_si128((__m128i *)(void *)(out + 36), _mm256_extracti128_si256(b, 1)); 9,650 ( 0.16%) in += 16; 9,650 ( 0.16%) out += 48; . } 235,781 ( 3.95%) while (in < end && (c = *in) >= 0x800 && 30,229 ( 0.51%) (uint32_t)(c - 0xd800) >= 0x800) { . put3(out, c); 30,229 ( 0.51%) out += 3; 30,229 ( 0.51%) ++in; . } . continue; . } . 13,858 ( 0.23%) if (c >= 0xdc00) return INVALID; . . // Eight adjacent surrogate pairs become eight packed UTF-8 dwords. 41,924 ( 0.70%) while ((size_t)(end - in) >= 16) { . __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); . __m256i tags = _mm256_cmpeq_epi16(_mm256_and_si256(v, pairmask), pairexpect); 20,788 ( 0.35%) if (_mm256_movemask_epi8(tags) != -1) break; . __m256i hi = _mm256_and_si256(v, low10); . __m256i lo = _mm256_and_si256(_mm256_srli_epi32(v, 16), low10); . __m256i cp = _mm256_add_epi32(cpbase, . _mm256_add_epi32(_mm256_slli_epi32(hi, 10), lo)); . __m256i x = _mm256_or_si256(utf4base, _mm256_srli_epi32(cp, 18)); . x = _mm256_or_si256(x, . _mm256_and_si256(_mm256_srli_epi32(cp, 4), m3f00_32)); . x = _mm256_or_si256(x, . _mm256_and_si256(_mm256_slli_epi32(cp, 10), m3f0000)); . x = _mm256_or_si256(x, . _mm256_and_si256(_mm256_slli_epi32(cp, 24), m3f000000)); . _mm256_storeu_si256((__m256i *)(void *)out, x); 3,552 ( 0.06%) in += 16; 3,552 ( 0.06%) out += 32; . } 190,334 ( 3.19%) while (in < end && (c = *in) >= 0xd800 && c < 0xdc00) { 94,772 ( 1.59%) if (end - in < 2) return INVALID; 23,693 ( 0.40%) uint32_t lo = in[1]; 71,079 ( 1.19%) if ((uint32_t)(lo - 0xdc00) >= 0x400) return INVALID; 94,772 ( 1.59%) uint32_t cp = 0x10000u + ((c - 0xd800u) << 10) + (lo - 0xdc00u); . put4(out, cp); 23,693 ( 0.40%) out += 4; 23,693 ( 0.40%) in += 2; . } . } . . ... [404 characters truncated for page size]

{"intent": "Add short-run SIMD and BMI2 kernels to eliminate scalar tails", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n-__attribute__((target(\"avx2\")))\n+__attribute__((target(\"avx2,bmi2\")))\n size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) {\n@@\n while ((size_t)(end - in) >= 32) {\n@@\n out += 32;\n }\n+ if ((size_t)(end - in) >= 16) {\n+ __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n+ if (_mm256_testz_si256(v, ascii_mask)) {\n+ v = _mm256_packus_epi16(v, v);\n+ v = _mm256_permute4x64_epi64(v, 0xd8);\n+ _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v));\n+ in += 16;\n+ out += 16;\n+ }\n+ }\n+ if ((size_t)(end - in) >= 8) {\n+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in);\n+ if (_mm_testz_si128(v, _mm256_castsi256_si128(ascii_mask))) {\n+ v = _mm_packus_epi16(v, v);\n+ _mm_storel_epi64((__m128i *)(void *)out, v);\n+ in += 8;\n+ out += 8;\n+ }\n+ }\n+ if ((size_t)(end - in) >= 4) {\n+ uint64_t v;\n+ memcpy(&v, in, sizeof(v));\n+ if (!(v & UINT64_C(0xff80ff80ff80ff80))) {\n+ uint32_t x = (uint32_t)_pext_u64(v, UINT64_C(0x00ff00ff00ff00ff));\n+ memcpy(out, &x, sizeof(x));\n+ in += 4;\n+ out += 4;\n+ }\n+ }\n@@\n while ((size_t)(end - in) >= 16) {\n@@\n out += 32;\n }\n+ if ((size_t)(end - in) >= 8) {\n+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in);\n+ __m128i ge80 = _mm_cmpgt_epi16(v, _mm256_castsi256_si128(lo7));\n+ __m128i lt800 = _mm_cmpgt_epi16(_mm256_castsi256_si128(lim800), v);\n+ if (_mm_movemask_epi8(_mm_and_si128(ge80, lt800)) == 0xffff) {\n+ __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6),\n+ _mm_and_si128(_mm_slli_epi16(v, 8),\n+ _mm256_castsi256_si128(mask3f00)));\n+ x = _mm_or_si128(x, _mm256_castsi256_si128(base2));\n+ _mm_storeu_si128((__m128i *)(void *)out, x);\n+ in += 8;\n+ out += 16;\n+ }\n+ }\n+ if ((size_t)(end - in) >= 4) {\n+ __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in);\n+ __m128i ge80 = _mm_cmpgt_epi16(v, _mm256_castsi256_si128(lo7));\n+ __m128i lt800 = _mm_cmpgt_epi16(_mm256_castsi256_si128(lim800), v);\n+ if ((_mm_movemask_epi8(_mm_and_si128(ge80, lt800)) & 0xff) == 0xff) {\n+ __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6),\n+ _mm_and_si128(_mm_slli_epi16(v, 8),\n+ _mm256_castsi256_si128(mask3f00)));\n+ x = _mm_or_si128(x, _mm256_castsi256_si128(base2));\n+ _mm_storel_epi64((__m128i *)(void *)out, x);\n+ in += 4;\n+ out += 8;\n+ }\n+ }\n@@\n while ((size_t)(end - in) >= 16) {\n@@\n out += 48;\n }\n+ if ((size_t)(end - in) >= 8) {\n+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in);\n+ __m128i high = _mm_and_si128(v, _mm256_castsi256_si128(hi5mask));\n+ __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(high, _mm_setzero_si128()),\n+ _mm_cmpeq_epi16(high, _mm256_castsi256_si128(surbits)));\n+ if (!_mm_mo ... [5088 characters truncated for page size]

✓ submission/solve.c: modified (9 hunks) 30- __attribute__((target("avx2"))) 30+ __attribute__((target("avx2,bmi2"))) 76+ if ((size_t)(end - in) >= 16) { 77+ __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); 78+ if (_mm256_testz_si256(v, ascii_mask)) { 79+ v = _mm256_packus_epi16(v, v); 80+ v = _mm256_permute4x64_epi64(v, 0xd8); 81+ _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v)); 82+ in += 16; 83+ out += 16; 84+ } 85+ } 86+ if ((size_t)(end - in) >= 8) { 87+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); 88+ if (_mm_testz_si128(v, _mm256_castsi256_si128(ascii_mask))) { 89+ v = _mm_packus_epi16(v, v); 90+ _mm_storel_epi64((__m128i *)(void *)out, v); 91+ in += 8; 92+ out += 8; 93+ } 94+ } 95+ if ((size_t)(end - in) >= 4) { 96+ uint64_t v; 97+ memcpy(&v, in, sizeof(v)); 98+ if (!(v & UINT64_C(0xff80ff80ff80ff80))) { 99+ uint32_t x = (uint32_t)_pext_u64(v, UINT64_C(0x00ff00ff00ff00ff)); 100+ memcpy(out, &x, sizeof(x)); 101+ in += 4; 102+ out += 4; 103+ } ... (diff truncated)

{"command": "./grade --seed 48818", "intent": "Verify and score short-run vector kernels", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 1.9s verify 2.4s PASS measure 0.6s 22,958,329 instructions (given: 77,696,233) SCORE +1.7588 (3.384x) --- Command finished with exit code: 0 ---

{"intent": "Profile second-stage optimization", "tool_calls": [{"tool": "bash", "command": "callgrind_annotate --auto=yes --inclusive=no --threshold=0.2 .build/callgrind.runner.out submission/solve.c 2>/dev/null | sed -n '1,330p'", "timeout": 10000, "intent": "Find scalar tails and dispatch overhead after short kernels"}, {"tool": "bash", "command": "objdump -d -Mintel --disassemble=utf16_to_utf8 .build/runner | wc -l; size .build/runner", "timeout": 10000, "intent": "Check optimized function code size"}]}

--- [1] bash --- -------------------------------------------------------------------------------- Profile data file '.build/callgrind.runner.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 783851 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/corpus_48818.bin (PID 341, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 0.2 Include dirs: User annotated: submission/solve.c Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 4,147,076 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 2,648,782 (63.87%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner] -------------------------------------------------------------------------------- -- User-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir -- line 2 ---------------------------------------- . #include <stdint.h> . #include <stddef.h> . #include <string.h> . #include <immintrin.h> . . #define INVALID ((size_t)-1) . . static inline void put2(uint8_t *p, uint32_t c) { 117,747 ( 2.84%) uint16_t x = (uint16_t)(0x80c0u | (c >> 6) | ((c & 63u) << 8)); . memcpy(p, &x, sizeof(x)); . } . . // The fourth byte is harmless: the contract provides four bytes of slop and . // the next output overwrites it. . static inline void put3(uint8_t *p, uint32_t c) { 6,053 ( 0.15%) uint32_t x = 0x008080e0u | (c >> 12) | 54,477 ( 1.31%) ((c << 2) & 0x00003f00u) | ((c << 16) & 0x003f0000u); . memcpy(p, &x, sizeof(x)); . } . . static inline void put4(uint8_t *p, uint32_t cp) { 7,410 ( 0.18%) uint32_t x = 0x808080f0u | (cp >> 18) | 14,820 ( 0.36%) ((cp >> 4) & 0x00003f00u) | 25,935 ( 0.63%) ((cp << 10) & 0x003f0000u) | 7,410 ( 0.18%) ((cp << 24) & 0x3f000000u); . memcpy(p, &x, sizeof(x)); . } . . __attribute__((target("avx2,bmi2"))) 4,488 ( 0.11%) size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { . const uint16_t *const begin = in; 561 ( 0.01%) const uint16_t *const end = in + n; . uint8_t *const out_begin = out; . . const __m256i ascii_mask = _mm256_set1_epi16((short)0xff80); . const __m256i lo7 = _mm256_set1_epi16(0x007f); . const __m256i lim800 = _mm256_set1_epi16(0x0800); . const __m256i base2 = _mm256_set1_epi16((short)0x80c0); . const __m256i mask3f00 = _mm256_set1_epi16(0x3f00); . const __m256i hi5mask = _mm256_set1_epi16((short)0xf800); -- line 41 ---------------------------------------- -- line 53 ---------------------------------------- . const __m256i m3f00_32 = _mm256_set1_epi32(0x00003f00); . const __m256i m3f0000 = _mm256_set1_epi32(0x003f0000); . const __m256i m3f000000 = _mm256_set1_epi32(0x3f000000); . const __m256i utf3base = _mm256_set1_epi32(0x008080e0); . const __m256i compress3 = _mm256_setr_epi8( . 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1, . 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1); . 87,836 ( 2.12%) while (in < end) { 43,183 ( 1.04%) uint32_t c = *in; . 86,366 ( 2.08%) if (c < 0x80) { . // Long ASCII runs dominate the corpus. Convert 32 units per test. 112,074 ( 2.70%) while ((size_t)(end - in) >= 32) { . __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in); . __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16)); 67,616 ( 1.63%) if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break; . __m256i bytes = _mm256_packus_epi16(a, b); . bytes = _mm256_permute4x64_epi64(bytes, 0xd8); . _mm256_storeu_si256((__m256i *)(void *)out, bytes); 25,522 ( 0.62%) in += 32; 12,761 ( 0.31%) out += 32; . } 1,471 ( 0.04%) if ((size_t)(end - in) >= 16) { . __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); 42,672 ( 1.03%) if (_mm256_testz_si256(v, ascii_mask)) { . v = _mm256_packus_epi16(v, v); . v = _mm256_permute4x64_epi64(v, 0xd8); . _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v)); 2,437 ( 0.06%) in += 16; 4,874 ( 0.12%) out += 16; . } . } 86,552 ( 2.09%) if ((size_t)(end - in) >= 8) { . __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); 42,858 ( 1.03%) if (_mm_testz_si128(v, _mm256_castsi256_si128(ascii_mask))) { . v = _mm_packus_epi16(v, v); . _mm_storel_epi64((__m128i *)(void *)out, v); 6,620 ( 0.16%) in += 8; 6,620 ( 0.16%) out += 8; . } . } 26,898 ( 0.65%) if ((size_t)(end - in) >= 4) { . uint64_t v; 21,462 ( 0.52%) memcpy(&v, in, sizeof(v)); 64,386 ( 1.55%) if (!(v & UINT64_C(0xff80ff80ff80ff80))) { 10,809 ( 0.26%) uint32_t x = (uint32_t)_pext_u64(v, UINT64_C(0x00ff00ff00ff00ff)); . memcpy(out, &x, sizeof(x)); 10,809 ( 0.26%) in += 4; 21,618 ( 0.52%) out += 4; . } . } 273,717 ( 6.60%) while (in < end && (c = *in) < 0x80) { 66,562 ( 1.61%) *out++ = (uint8_t)c; 33,281 ( 0.80%) ++in; . } . continue; . } . 43,090 ( 1.04%) if (c < 0x800) { . // Sixteen two-byte characters become sixteen packed 16-bit words. 144,344 ( 3.48%) while ((size_t)(end - in) >= 16) { . __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); . __m256i ge80 = _mm256_cmpgt_epi16(v, lo7); . __m256i lt800 = _mm256_cmpgt_epi16(lim800, v); 28,308 ( 0.68%) if (_mm256_movemask_epi8(_mm256_and_si256(ge80, lt800)) != -1) break; . __m256i x = _mm256_or_si256(_mm256_srli_epi16(v, 6), . _mm256_and_si256(_mm256_slli_epi16(v, 8), mask3f00)); . x = _mm256_or_si256(x, base2); . _mm256_storeu_si256((__m256i *)(void *)out, x); 7,506 ( 0.18%) in += 16; 3,753 ( 0.09%) out += 32; . } 314 ( 0.01%) if ((size_t)(end - in) >= 8) { . __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); . __m128i ge80 = _mm_cmpgt_epi16(v, _mm256_castsi256_si128(lo7)); . __m128i lt800 = _mm_cmpgt_epi16(_mm256_castsi256_si128(lim800), v); 20,930 ( 0.50%) if (_mm_movemask_epi8(_mm_and_si128(ge80, lt800)) == 0xffff) { . __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6), . _mm_and_si128(_mm_slli_epi16(v, 8), . _mm256_castsi256_si128(mask3f00))); . x = _mm_or_si128(x, _mm256_castsi256_si128(base2)); . _mm_storeu_si128((__m128i *)(void *)out, x); 4,862 ( 0.12%) in += 8; 9,724 ( 0.23%) out += 16; . } . } 42,104 ( 1.02%) if ((size_t)(end - in) >= 4) { . __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in); . __m128i ge80 = _mm_cmpgt_epi16(v, _mm256_castsi256_si128(lo7)); . __m128i lt800 = _mm_cmpgt_epi16(_mm256_castsi256_si128(lim800), v); 31,464 ( 0.76%) if ((_mm_movemask_epi8(_mm_and_si128(ge80, lt800)) & 0xff) == 0xff) { . __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6), . _mm_and_si128(_mm_slli_epi16(v, 8), . _mm256_castsi256_si128(mask3f00))); . x = _mm_or_si128(x, _mm256_castsi256_si128(base2)); . _mm_storel_epi64((__m128i *)(void *)out, x); 4,881 ( 0.12%) in += 4; 9,762 ( 0.24%) out += 8; . } . } 163,784 ( 3.95%) while (in < end && (c = *in) >= 0x80 && c < 0x800) { . put2(out, c); 16,821 ( 0.41%) out += 2; 16,821 ( 0.41%) ++in; . } . continue; . } . 99,171 ( 2.39%) if ((uint32_t)(c - 0xd800) >= 0x800) { . // Encode sixteen ordinary three-byte BMP units at once. Each group . // of four dwords is compacted to 12 bytes with one byte shuffle. 60,200 ( 1.45%) while ((size_t)(end - in) >= 16) { . __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); . __m256i high = _mm256_and_si256(v, hi5mask); . __m256i small = _mm256_cmpeq_epi16(high, zero); . __m256i sur = _mm256_cmpeq_epi16(high, surbits); 43,096 ( 1.04%) if (_mm256_movemask_epi8(_mm256_or_si256(small, sur))) break; . . __m256i a = _mm256_cvtepu16_epi32(_mm256_castsi256_si128(v)); . __m256i b = _mm256_cvtepu16_epi32(_mm256_extracti128_si256(v, 1)); . __m256i a1 = _mm256_and_si256(_mm256_slli_epi32(a, 2), m3f00_32) ... [10338 characters truncated for page size]

{"intent": "Vectorize two-unit tails and simplify scalar surrogate encoding", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n if ((size_t)(end - in) >= 4) {\n@@\n out += 4;\n }\n }\n+ if ((size_t)(end - in) >= 2 && in[1] < 0x80) {\n+ uint32_t v;\n+ memcpy(&v, in, sizeof(v));\n+ uint16_t x = (uint16_t)_pext_u32(v, 0x00ff00ffu);\n+ memcpy(out, &x, sizeof(x));\n+ in += 2;\n+ out += 2;\n+ }\n while (in < end && (c = *in) < 0x80) {\n@@\n if ((size_t)(end - in) >= 4) {\n@@\n out += 8;\n }\n }\n+ if ((size_t)(end - in) >= 2) {\n+ uint32_t v;\n+ memcpy(&v, in, sizeof(v));\n+ if ((uint32_t)(in[1] - 0x80) < 0x780) {\n+ uint32_t x = 0x80c080c0u | ((v >> 6) & 0x001f001fu) |\n+ ((v << 8) & 0x3f003f00u);\n+ memcpy(out, &x, sizeof(x));\n+ in += 2;\n+ out += 4;\n+ }\n+ }\n while (in < end && (c = *in) >= 0x80 && c < 0x800) {\n@@\n if ((size_t)(end - in) >= 4) {\n@@\n out += 12;\n }\n }\n+ if ((size_t)(end - in) >= 2 && in[1] >= 0x800 &&\n+ (uint16_t)(in[1] - 0xd800) >= 0x800) {\n+ __m128i v = _mm_cvtsi32_si128(*(const int *)(const void *)in);\n+ __m128i a = _mm_cvtepu16_epi32(v);\n+ __m128i a1 = _mm_and_si128(_mm_slli_epi32(a, 2),\n+ _mm256_castsi256_si128(m3f00_32));\n+ __m128i a2 = _mm_and_si128(_mm_slli_epi32(a, 16),\n+ _mm256_castsi256_si128(m3f0000));\n+ a = _mm_or_si128(_mm256_castsi256_si128(utf3base),\n+ _mm_or_si128(_mm_srli_epi32(a, 12), _mm_or_si128(a1, a2)));\n+ a = _mm_shuffle_epi8(a, _mm256_castsi256_si128(compress3));\n+ _mm_storel_epi64((__m128i *)(void *)out, a);\n+ in += 2;\n+ out += 6;\n+ }\n while (in < end && (c = *in) >= 0x800 &&\n@@\n- uint32_t cp = 0x10000u + ((c - 0xd800u) << 10) + (lo - 0xdc00u);\n- put4(out, cp);\n+ uint32_t h = c - 0xd800u;\n+ uint32_t l = lo - 0xdc00u;\n+ uint32_t t = h + 0x40u;\n+ uint32_t x = 0x808080f0u | (t >> 8) | ((t << 6) & 0x00003f00u) |\n+ (((h << 20) | (l << 10)) & 0x003f0000u) |\n+ ((l << 24) & 0x3f000000u);\n+ memcpy(out, &x, sizeof(x));\n*** End Patch"}

✓ submission/solve.c: modified (7 hunks) 105+ if ((size_t)(end - in) >= 2 && in[1] < 0x80) { 106+ uint32_t v; 107+ memcpy(&v, in, sizeof(v)); 108+ uint16_t x = (uint16_t)_pext_u32(v, 0x00ff00ffu); 109+ memcpy(out, &x, sizeof(x)); 110+ in += 2; 111+ out += 2; 112+ } 162+ if ((size_t)(end - in) >= 2) { 163+ uint32_t v; 164+ memcpy(&v, in, sizeof(v)); 165+ if ((uint32_t)(in[1] - 0x80) < 0x780) { 166+ uint32_t x = 0x80c080c0u | ((v >> 6) & 0x001f001fu) | 167+ ((v << 8) & 0x3f003f00u); 168+ memcpy(out, &x, sizeof(x)); 169+ in += 2; 170+ out += 4; 171+ } 172+ } 247+ if ((size_t)(end - in) >= 2 && in[1] >= 0x800 && 248+ (uint16_t)(in[1] - 0xd800) >= 0x800) { 249+ __m128i v = _mm_cvtsi32_si128(*(const int *)(const void *)in); 250+ __m128i a = _mm_cvtepu16_epi32(v); 251+ __m128i a1 = _mm_and_si128(_mm_slli_epi32(a, 2), 252+ _mm256_castsi256_si128(m3f00_32)); 253+ __m128i a2 = _mm_and_si128(_mm_slli_epi32(a, 16), 254+ _mm256_castsi256_si128(m3f0000)); 255+ a = _mm_or_si128(_mm256_castsi256_si128(utf3base), 256+ _mm_or_si128(_mm_srli_epi32(a, 12), _mm_or_si128(a1, a2))); 257+ a = _mm_shuffle_epi8(a, _mm256_castsi256_si128(compress3)); ... (diff truncated)

{"command": "./grade --seed 48818", "intent": "Measure two-unit tail optimization", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

MISMATCH (random) on 86 units: 07b3 3d3a 000e 57bd dbac dfe0 da1f dec2 0048 0053 000c d34a 03da d0a1 0209 0058 03f7 0598 da33 dfa6 d9c4 dfa8 da89 df1f grade: FAIL (verification) --- Command finished with exit code: 1 --- Exit code: 1

{"intent": "Diagnose correctness regression in tail kernels", "tool_calls": [{"tool": "bash", "command": "python3 - <<'PY'\nfor h in range(1024):\n for l in range(1024):\n cp=0x10000+(h<<10)+l\n ref=0x808080f0|(cp>>18)|(((cp>>12)&63)<<8)|(((cp>>6)&63)<<16)|((cp&63)<<24)\n t=h+64\n x=0x808080f0|(t>>8)|((t<<6)&0x3f00)|(((h<<20)|(l<<10))&0x3f0000)|((l<<24)&0x3f000000)\n if ref!=x: print(h,l,hex(ref),hex(x));raise SystemExit\nprint('sur formula ok')\nPY", "timeout": 10000, "intent": "Check direct surrogate encoding formula exhaustively"}, {"tool": "bash", "command": "cat > \"$JCODE_SCRATCH_DIR/check.c\" <<'EOF'\n#include <stdint.h>\n#include <stddef.h>\n#include <stdio.h>\n#include <string.h>\nsize_t utf16_to_utf8(const uint16_t*,size_t,uint8_t*);\nsize_t ref_utf16_to_utf8(const uint16_t*,size_t,uint8_t*);\nint main(){uint16_t a[3];uint8_t x[32],y[32];\nfor(unsigned p=0;p<3;p++)for(unsigned i=0;i<65536;i++)for(unsigned j=0;j<65536;j+=257){a[0]=65;a[1]=65;a[2]=65;a[p]=i;a[(p+1)%3]=j;size_t rx=utf16_to_utf8(a,3,x),ry=ref_utf16_to_utf8(a,3,y);if(rx!=ry||(rx!=-1ULL&&memcmp(x,y,rx))){printf(\"bad p%u %04x %04x rx%zu ry%zu\\n\",p,i,j,rx,ry);for(int k=0;k<(rx<20?rx:20);k++)printf(\"%02x/%02x \",x[k],y[k]);puts(\"\");return 1;}}puts(\"ok\");}\nEOF\ncc -O2 -std=c17 -g submission/solve.c verify/reference.c \"$JCODE_SCRATCH_DIR/check.c\" -o \"$JCODE_SCRATCH_DIR/check\" && \"$JCODE_SCRATCH_DIR/check\"", "timeout": 600000, "intent": "Find a compact failing mixed-class input"}]}

--- [1] bash --- sur formula ok --- Command finished with exit code: 0 --- --- [2] bash --- ok --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"command": "sed 's/i < 24/i < 2048/' verify/verify.c > \"$JCODE_SCRATCH_DIR/verify_verbose.c\"; cc -O2 -std=c17 -fno-lto -g -I submission submission/solve.c verify/reference.c \"$JCODE_SCRATCH_DIR/verify_verbose.c\" -o \"$JCODE_SCRATCH_DIR/verify_verbose\" -lm -lpthread; \"$JCODE_SCRATCH_DIR/verify_verbose\" 49060", "intent": "Capture a full failing random input outside the benchmark files", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

MISMATCH (random) on 99 units: 6340 0007 0078 0050 0058 843a 002b 0032 0044 41d0 b0cd d82b df7d 007a 0104 dbfb df99 001f 99cf 016d 0046 10b7 dba9 ddb4 003c db93 defb d5bb db2b dff3 0034 da87 dc4d 0074 aed2 3fc3 bb6a 0183 d97d dc65 003c 0052 0d46 004b d4a2 33c3 0510 d8b3 dc61 02f5 f2b2 9837 c8e6 0738 0f59 0018 da7a dff1 0001 0075 0110 db8a dc28 007a 0064 88a8 0016 4add 043b 0032 007d 0020 0061 000b 047f d896 ddd9 d8cf ddb7 06ab 0425 005c 0541 0686 02fd c898 0067 6d7f 005f d90a dea1 0107 42fc f290 0266 0003 002f d999 deed --- Command finished with exit code: 1 --- Exit code: 1

{"command": "python3 - <<'PY'\np='verify/verify.c'; s=open(p).read(); s=s.replace('i < 24','i < 2048'); s=s.replace('fail_report(in, n, stage);','for (size_t z=0; z < (rr == INVALID ? 0 : rr); z++) if (bs[z] != br[z]) { fprintf(stderr, \"BYTE %zu: %02x != %02x rs=%zu rr=%zu\\\\n\", z, bs[z], br[z], rs, rr); break; } fail_report(in, n, stage);');open(__import__('os').environ['JCODE_SCRATCH_DIR']+'/verify_verbose.c','w').write(s)\nPY\ncc -O2 -std=c17 -fno-lto -g -I submission submission/solve.c verify/reference.c \"$JCODE_SCRATCH_DIR/verify_verbose.c\" -o \"$JCODE_SCRATCH_DIR/verify_verbose\" -lm -lpthread && \"$JCODE_SCRATCH_DIR/verify_verbose\" 49060", "intent": "Locate the exact mismatching output byte", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

BYTE 7: 3a != e8 rs=187 rr=189 MISMATCH (random) on 99 units: 6340 0007 0078 0050 0058 843a 002b 0032 0044 41d0 b0cd d82b df7d 007a 0104 dbfb df99 001f 99cf 016d 0046 10b7 dba9 ddb4 003c db93 defb d5bb db2b dff3 0034 da87 dc4d 0074 aed2 3fc3 bb6a 0183 d97d dc65 003c 0052 0d46 004b d4a2 33c3 0510 d8b3 dc61 02f5 f2b2 9837 c8e6 0738 0f59 0018 da7a dff1 0001 0075 0110 db8a dc28 007a 0064 88a8 0016 4add 043b 0032 007d 0020 0061 000b 047f d896 ddd9 d8cf ddb7 06ab 0425 005c 0541 0686 02fd c898 0067 6d7f 005f d90a dea1 0107 42fc f290 0266 0003 002f d999 deed --- Command finished with exit code: 1 --- Exit code: 1

{"command": "python3 - <<'PY'\np=__import__('os').environ['JCODE_SCRATCH_DIR']+'/verify_verbose.c';s=open(p).read();s=s.replace('for (size_t z=0; z < (rr == INVALID ? 0 : rr); z++) if (bs[z] != br[z]) { fprintf(stderr, \"BYTE %zu: %02x != %02x rs=%zu rr=%zu\\\\n\", z, bs[z], br[z], rs, rr); break; }','fprintf(stderr,\"rs=%zu rr=%zu\\\\nS:\",rs,rr); for(size_t z=0;z<rr;z++) fprintf(stderr,\" %02x\",bs[z]); fprintf(stderr,\"\\\\nR:\"); for(size_t z=0;z<rr;z++) fprintf(stderr,\" %02x\",br[z]); fprintf(stderr,\"\\\\n\");');open(p,'w').write(s)\nPY\ncc -O2 -std=c17 -fno-lto -g -I submission submission/solve.c verify/reference.c \"$JCODE_SCRATCH_DIR/verify_verbose.c\" -o \"$JCODE_SCRATCH_DIR/verify_verbose\" -lm -lpthread && \"$JCODE_SCRATCH_DIR/verify_verbose\" 49060 2>&1 | head -5", "intent": "Compare full output streams around the mismatch", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

rs=187 rr=189 S: e6 8d 80 07 78 50 58 3a 2b 32 44 e4 87 90 eb 83 8d f0 9a bd bd 7a c4 84 f4 8e be 99 1f e9 a7 8f c5 ad 46 e1 82 b7 f3 ba 96 b4 3c f3 b4 bb bb ed 96 bb f3 9a bf b3 34 f2 b1 b1 8d 74 ea bb 92 e3 bf 83 eb ad aa c6 83 f1 af 91 a5 3c 52 e0 b5 86 4b ed 92 a2 e3 8f 83 d4 90 f0 bc b1 a1 cb b5 ef 8a b2 e9 a0 b7 ec a3 a6 dc b8 e0 bd 99 18 f2 ae af b1 01 75 c4 90 f3 b2 a0 a8 7a 64 e8 a2 a8 16 e4 ab 9d d0 bb 32 7d 20 61 0b d1 bf f0 b5 a7 99 f1 83 b6 b7 da ab d0 a5 5c d5 81 da 86 cb bd ec a2 98 67 e6 b5 bf 5f f1 92 aa a1 c4 87 e4 8b bc ef 8a 90 c9 a6 03 2f f1 b6 9b ad aa aa R: e6 8d 80 07 78 50 58 e8 90 ba 2b 32 44 e4 87 90 eb 83 8d f0 9a bd bd 7a c4 84 f4 8e be 99 1f e9 a7 8f c5 ad 46 e1 82 b7 f3 ba 96 b4 3c f3 b4 bb bb ed 96 bb f3 9a bf b3 34 f2 b1 b1 8d 74 ea bb 92 e3 bf 83 eb ad aa c6 83 f1 af 91 a5 3c 52 e0 b5 86 4b ed 92 a2 e3 8f 83 d4 90 f0 bc b1 a1 cb b5 ef 8a b2 e9 a0 b7 ec a3 a6 dc b8 e0 bd 99 18 f2 ae af b1 01 75 c4 90 f3 b2 a0 a8 7a 64 e8 a2 a8 16 e4 ab 9d d0 bb 32 7d 20 61 0b d1 bf f0 b5 a7 99 f1 83 b6 b7 da ab d0 a5 5c d5 81 da 86 cb bd ec a2 98 67 e6 b5 bf 5f f1 92 aa a1 c4 87 e4 8b bc ef 8a 90 c9 a6 03 2f f1 b6 9b ad MISMATCH (random) on 99 units: 6340 0007 0078 0050 0058 843a 002b 0032 0044 41d0 b0cd d82b df7d 007a 0104 dbfb df99 001f 99cf 016d 0046 10b7 dba9 ddb4 003c db93 defb d5bb db2b dff3 0034 da87 dc4d 0074 aed2 3fc3 bb6a 0183 d97d dc65 003c 0052 0d46 004b d4a2 33c3 0510 d8b3 dc61 02f5 f2b2 9837 c8e6 0738 0f59 0018 da7a dff1 0001 0075 0110 db8a dc28 007a 0064 88a8 0016 4add 043b 0032 007d 0020 0061 000b 047f d896 ddd9 d8cf ddb7 06ab 0425 005c 0541 0686 02fd c898 0067 6d7f 005f d90a dea1 0107 42fc f290 0266 0003 002f d999 deed --- Command finished with exit code: 0 ---

{"file_path": "submission/solve.c", "intent": "Inspect three-byte scalar tail after regression", "limit": 90, "start_line": 230}

230 __m128i high = _mm_and_si128(v, _mm256_castsi256_si128(hi5mask)); 231 __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(high, _mm_setzero_si128()), 232 _mm_cmpeq_epi16(high, _mm256_castsi256_si128(surbits))); 233 if (!(_mm_movemask_epi8(bad) & 0xff)) { 234 __m128i a = _mm_cvtepu16_epi32(v); 235 __m128i a1 = _mm_and_si128(_mm_slli_epi32(a, 2), 236 _mm256_castsi256_si128(m3f00_32)); 237 __m128i a2 = _mm_and_si128(_mm_slli_epi32(a, 16), 238 _mm256_castsi256_si128(m3f0000)); 239 a = _mm_or_si128(_mm256_castsi256_si128(utf3base), 240 _mm_or_si128(_mm_srli_epi32(a, 12), _mm_or_si128(a1, a2))); 241 a = _mm_shuffle_epi8(a, _mm256_castsi256_si128(compress3)); 242 _mm_storeu_si128((__m128i *)(void *)out, a); 243 in += 4; 244 out += 12; 245 } 246 } 247 if ((size_t)(end - in) >= 2 && in[1] >= 0x800 && 248 (uint16_t)(in[1] - 0xd800) >= 0x800) { 249 __m128i v = _mm_cvtsi32_si128(*(const int *)(const void *)in); 250 __m128i a = _mm_cvtepu16_epi32(v); 251 __m128i a1 = _mm_and_si128(_mm_slli_epi32(a, 2), 252 _mm256_castsi256_si128(m3f00_32)); 253 __m128i a2 = _mm_and_si128(_mm_slli_epi32(a, 16), 254 _mm256_castsi256_si128(m3f0000)); 255 a = _mm_or_si128(_mm256_castsi256_si128(utf3base), 256 _mm_or_si128(_mm_srli_epi32(a, 12), _mm_or_si128(a1, a2))); 257 a = _mm_shuffle_epi8(a, _mm256_castsi256_si128(compress3)); 258 _mm_storel_epi64((__m128i *)(void *)out, a); 259 in += 2; 260 out += 6; 261 } 262 while (in < end && (c = *in) >= 0x800 && 263 (uint32_t)(c - 0xd800) >= 0x800) { 264 put3(out, c); 265 out += 3; 266 ++in; 267 } 268 continue; 269 } 270 271 if (c >= 0xdc00) return INVALID; 272 273 // Eight adjacent surrogate pairs become eight packed UTF-8 dwords. 274 while ((size_t)(end - in) >= 16) { 275 __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); 276 __m256i tags = _mm256_cmpeq_epi16(_mm256_and_si256(v, pairmask), pairexpect); 277 if (_mm256_movemask_epi8(tags) != -1) break; 278 __m256i hi = _mm256_and_si256(v, low10); 279 __m256i lo = _mm256_and_si256(_mm256_srli_epi32(v, 16), low10); 280 __m256i cp = _mm256_add_epi32(cpbase, 281 _mm256_add_epi32(_mm256_slli_epi32(hi, 10), lo)); 282 __m256i x = _mm256_or_si256(utf4base, _mm256_srli_epi32(cp, 18)); 283 x = _mm256_or_si256(x, 284 _mm256_and_si256(_mm256_srli_epi32(cp, 4), m3f00_32)); 285 x = _mm256_or_si256(x, 286 _mm256_and_si256(_mm256_slli_epi32(cp, 10), m3f0000)); 287 x = _mm256_or_si256(x, 288 _mm256_and_si256(_mm256_slli_epi32(cp, 24), m3f000000)); 289 _mm256_storeu_si256((__m256i *)(void *)out, x); 290 in += 16; 291 out += 32; 292 } 293 if ((size_t)(end - in) >= 8) { 294 __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); 295 __m128i tags = _mm_cmpeq_epi16( 296 _mm_and_si128(v, _mm256_castsi256_si128(pairmask)), 297 _mm256_castsi256_si128(pairexpect)); 298 if (_mm_movemask_epi8(tags) == 0xffff) { 299 __m128i hi = _mm_and_si128(v, _mm256_castsi256_si128(low10)); 300 __m128i lo = _mm_and_si128(_mm_srli_epi32(v, 16), 301 _mm256_castsi256_si128(low10)); 302 __m128i cp = _mm_add_epi32(_mm256_castsi256_si128(cpbase), 303 _mm_add_epi32(_mm_slli_epi32(hi, 10), lo)); 304 __m128i x = _mm_or_si128(_mm256_castsi256_si128(utf4base), 305 _mm_srli_epi32(cp, 18)); 306 x = _mm_or_si128(x, _mm_and_si128(_mm_srli_epi32(cp, 4), 307 _mm256_castsi256_si128(m3f00_32))); 308 x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 10), 309 _mm256_castsi256_si128(m3f0000))); 310 x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 24), 311 _mm256_castsi256_si128(m3f000000))); 312 _mm_storeu_si128((__m128i *)(void *)out, x); 313 in += 8; 314 out += 16; 315 } 316 } 317 if ((size_t)(end - in) >= 4) { 318 __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in); 319 __m128i tags = _mm_cmpeq_epi16( ... 41 more lines (use start_line=320 to continue)

{"intent": "Inspect compiler output for malformed three-byte tail", "tool_calls": [{"tool": "bash", "command": "objdump -d -Mintel --disassemble=utf16_to_utf8 \"$JCODE_SCRATCH_DIR/verify_verbose\" | grep -n -A25 -B20 '3f0000' | head -120", "timeout": 10000, "intent": "Locate three-byte encoding assembly"}, {"tool": "bash", "command": "objdump -d -Mintel --disassemble=utf16_to_utf8 \"$JCODE_SCRATCH_DIR/verify_verbose\" > \"$JCODE_SCRATCH_DIR/current.asm\"; grep -n 'mov.*DWORD PTR' \"$JCODE_SCRATCH_DIR/current.asm\" | tail -25", "timeout": 10000, "intent": "Locate packed output stores"}]}

--- [1] bash --- 21- 17a2: c5 b5 72 d0 16 vpsrld ymm9,ymm0,0x16 22- 17a7: 48 89 d6 mov rsi,rdx 23- 17aa: 48 89 d0 mov rax,rdx 24- 17ad: c4 42 7d 58 f6 vpbroadcastd ymm14,xmm14 25- 17b2: 48 89 e5 mov rbp,rsp 26- 17b5: 48 83 e4 e0 and rsp,0xffffffffffffffe0 27- 17b9: 48 83 ec 48 sub rsp,0x48 28- 17bd: c5 7d 7f 74 24 88 vmovdqa YMMWORD PTR [rsp-0x78],ymm14 29- 17c3: c5 fd 7f 7c 24 28 vmovdqa YMMWORD PTR [rsp+0x28],ymm7 30- 17c9: c5 7d 6f 15 6f 18 00 vmovdqa ymm10,YMMWORD PTR [rip+0x186f] # 3040 <_IO_stdin_used+0x40> 31- 17d0: 00 32- 17d1: c5 7d 6f 3d 47 18 00 vmovdqa ymm15,YMMWORD PTR [rip+0x1847] # 3020 <_IO_stdin_used+0x20> 33- 17d8: 00 34- 17d9: 0f b7 11 movzx edx,WORD PTR [rcx] 35- 17dc: 83 fa 7f cmp edx,0x7f 36- 17df: 0f 86 0b 06 00 00 jbe 1df0 <utf16_to_utf8+0x670> 37- 17e5: 81 fa ff 07 00 00 cmp edx,0x7ff 38- 17eb: 0f 86 3f 07 00 00 jbe 1f30 <utf16_to_utf8+0x7b0> 39- 17f1: 41 b8 00 3f 00 00 mov r8d,0x3f00 40- 17f7: c4 c1 79 6e e8 vmovd xmm5,r8d 41: 17fc: 41 b8 00 00 3f 00 mov r8d,0x3f0000 42- 1802: c4 c1 79 6e e0 vmovd xmm4,r8d 43- 1807: 44 8d 82 00 28 ff ff lea r8d,[rdx-0xd800] 44- 180e: c4 e2 7d 58 ed vpbroadcastd ymm5,xmm5 45- 1813: c4 e2 7d 58 e4 vpbroadcastd ymm4,xmm4 46- 1818: 41 81 f8 ff 07 00 00 cmp r8d,0x7ff 47- 181f: 0f 87 eb 02 00 00 ja 1b10 <utf16_to_utf8+0x390> 48- 1825: 81 fa ff db 00 00 cmp edx,0xdbff 49- 182b: 0f 87 af 05 00 00 ja 1de0 <utf16_to_utf8+0x660> 50- 1831: ba 00 d8 00 dc mov edx,0xdc00d800 51- 1836: c5 f9 6e d2 vmovd xmm2,edx 52- 183a: ba f0 80 80 80 mov edx,0x808080f0 53- 183f: c5 f9 6e fa vmovd xmm7,edx 54: 1843: ba 00 00 00 3f mov edx,0x3f000000 55- 1848: c4 e2 79 58 d2 vpbroadcastd xmm2,xmm2 56- 184d: c5 79 6e c2 vmovd xmm8,edx 57- 1851: 48 89 fa mov rdx,rdi 58- 1854: c4 e2 7d 58 ff vpbroadcastd ymm7,xmm7 59- 1859: 48 29 ca sub rdx,rcx 60- 185c: c4 42 7d 58 c0 vpbroadcastd ymm8,xmm8 61- 1861: 48 83 fa 1e cmp rdx,0x1e 62- 1865: 0f 86 95 02 00 00 jbe 1b00 <utf16_to_utf8+0x380> 63- 186b: c5 fd 6f 74 24 28 vmovdqa ymm6,YMMWORD PTR [rsp+0x28] 64- 1871: c5 7d 6f ec vmovdqa ymm13,ymm4 65- 1875: c5 7d 6f e5 vmovdqa ymm12,ymm5 66- 1879: c5 a5 71 f6 0a vpsllw ymm11,ymm6,0xa 67- 187e: eb 6d jmp 18ed <utf16_to_utf8+0x16d> 68- 1880: c5 f5 72 d0 10 vpsrld ymm1,ymm0,0x10 69- 1885: c4 c1 7d db c1 vpand ymm0,ymm0,ymm9 70- 188a: 48 83 c1 20 add rcx,0x20 71- 188e: 48 89 fa mov rdx,rdi 72- 1891: c5 fd 72 f0 0a vpslld ymm0,ymm0,0xa 73- 1896: c4 c1 75 db c9 vpand ymm1,ymm1,ymm9 74- 189b: 48 29 ca sub rdx,rcx 75- 189e: 48 83 c0 20 add rax,0x20 76- 18a2: c4 c1 7d fe c6 vpaddd ymm0,ymm0,ymm14 77- 18a7: c5 fd fe c1 vpaddd ymm0,ymm0,ymm1 78- 18ab: c5 e5 72 d0 12 vpsrld ymm3,ymm0,0x12 79- 18b0: c5 cd 72 d0 04 vpsrld ymm6,ymm0,0x4 -- 166- 1a37: c5 f9 d6 40 f8 vmovq QWORD PTR [rax-0x8],xmm0 167- 1a3c: 0f 1f 40 00 nop DWORD PTR [rax+0x0] 168- 1a40: 48 39 f9 cmp rcx,rdi 169- 1a43: 0f 82 8c 00 00 00 jb 1ad5 <utf16_to_utf8+0x355> 170- 1a49: e9 a6 00 00 00 jmp 1af4 <utf16_to_utf8+0x374> 171- 1a4e: 66 90 xchg ax,ax 172- 1a50: 49 89 f8 mov r8,rdi 173- 1a53: 49 29 c8 sub r8,rcx 174- 1a56: 49 83 f8 02 cmp r8,0x2 175- 1a5a: 0f 8e 80 03 00 00 jle 1de0 <utf16_to_utf8+0x660> 176- 1a60: 44 0f b7 41 02 movzx r8d,WORD PTR [rcx+0x2] 177- 1a65: 41 81 e8 00 dc 00 00 sub r8d,0xdc00 178- 1a6c: 41 81 f8 ff 03 00 00 cmp r8d,0x3ff 179- 1a73: 0f 87 67 03 00 00 ja 1de0 <utf16_to_utf8+0x660> 180- 1a79: 44 8d 8a 40 28 ff ff lea r9d,[rdx-0xd7c0] 181- 1a80: 45 89 c2 mov r10d,r8d 182- 1a83: 41 c1 e0 18 shl r8d,0x18 183- 1a87: 48 83 c1 04 add rcx,0x4 184- 1a8b: 81 ea 00 d8 00 00 sub edx,0xd800 185- 1a91: 41 c1 e2 0a shl r10d,0xa 186: 1a95: 41 81 e0 00 00 00 3f and r8d,0x3f000000 187- 1a9c: 48 83 c0 04 add rax,0x4 188- 1aa0: c1 e2 14 shl edx,0x14 189- 1aa3: 44 09 d2 or edx,r10d 190- 1aa6: 45 89 ca mov r10d,r9d 191- 1aa9: 41 c1 e1 06 shl r9d,0x6 192: 1aad: 81 e2 00 00 3f 00 and edx,0x3f0000 193- 1ab3: 41 c1 ea 08 shr r10d,0x8 194- 1ab7: 41 81 e1 00 3f 00 00 and r9d,0x3f00 195- 1abe: 44 09 d2 or edx,r10d 196- 1ac1: 44 09 ca or edx,r9d 197- 1ac4: 44 09 c2 or edx,r8d 198- 1ac7: 81 ca f0 80 80 80 or edx,0x808080f0 199- 1acd: 89 50 fc mov DWORD PTR [rax-0x4],edx 200- 1ad0: 48 39 f9 cmp rcx,rdi 201- 1ad3: 73 1f jae 1af4 <utf16_to_utf8+0x374> 202- 1ad5: 0f b7 11 movzx edx,WORD PTR [rcx] 203- 1ad8: 44 8d 82 00 28 00 00 lea r8d,[rdx+0x2800] 204- 1adf: 66 41 81 f8 ff 03 cmp r8w,0x3ff 205- 1ae5: 0f 86 65 ff ff ff jbe 1a50 <utf16_to_utf8+0x2d0> 206- 1aeb: 48 39 f9 cmp rcx,rdi 207- 1aee: 0f 82 e5 fc ff ff jb 17d9 <utf16_to_utf8+0x59> 208- 1af4: 48 29 f0 sub rax,rsi 209- 1af7: c5 f8 77 vzeroupper 210- 1afa: c9 leave 211- 1afb: c3 ret 212- 1afc: 0f 1f 40 00 nop DWORD PTR [rax+0x0] 213- 1b00: 48 83 fa 0e cmp rdx,0xe 214- 1b04: 0f 86 96 fe ff ff jbe 19a0 <utf16_to_utf8+0x220> 215- 1b0a: e9 f8 fd ff ff jmp 1907 <utf16_to_utf8+0x187> 216- 1b0f: 90 nop 217- 1b10: ba e0 80 80 00 mov edx,0x8080e0 -- 320- 1cdf: c4 e2 79 00 05 38 13 vpshufb xmm0,xmm0,XMMWORD PTR [rip+0x1338] # 3020 <_IO_stdin_used+0x20> 321- 1ce6: 00 00 322- 1ce8: c5 fa 7f 40 f4 vmovdqu XMMWORD PTR [rax-0xc],xmm0 323- 1ced: 48 83 fa 02 cmp rdx,0x2 324- 1cf1: 77 7d ja 1d70 <utf16_to_utf8+0x5f0> 325- 1cf3: 48 39 f9 cmp rcx,rdi 326- 1cf6: 72 5b jb 1d53 <utf16_to_utf8+0x5d3> --- Command finished with exit code: 0 --- --- [2] bash --- 199: 1acd: 89 50 fc mov DWORD PTR [rax-0x4],edx 344: 1d47: 89 50 fd mov DWORD PTR [rax-0x3],edx 360: 1d8f: c5 f9 6e 09 vmovd xmm1,DWORD PTR [rcx] 588: 2179: 89 50 fc mov DWORD PTR [rax-0x4],edx 596: 219b: 8b 11 mov edx,DWORD PTR [rcx] 632: 223c: 44 8b 01 mov r8d,DWORD PTR [rcx] 642: 2267: 89 50 fc mov DWORD PTR [rax-0x4],edx --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"intent": "Inspect scalar BMP encoding control flow", "tool_calls": [{"tool": "bash", "command": "sed -n '300,375p' \"$JCODE_SCRATCH_DIR/current.asm\"", "timeout": 10000, "intent": "Read three-byte tail disassembly"}, {"tool": "bash", "command": "sed -n '570,655p' \"$JCODE_SCRATCH_DIR/current.asm\"", "timeout": 10000, "intent": "Read two-unit tail disassembly"}]}

--- [1] bash --- 1c8d: c5 f9 ef c0 vpxor xmm0,xmm0,xmm0 1c91: c5 c9 75 c0 vpcmpeqw xmm0,xmm6,xmm0 1c95: c5 e1 75 de vpcmpeqw xmm3,xmm3,xmm6 1c99: c5 f9 eb c3 vpor xmm0,xmm0,xmm3 1c9d: c5 f9 d7 d0 vpmovmskb edx,xmm0 1ca1: 84 d2 test dl,dl 1ca3: 0f 85 c7 00 00 00 jne 1d70 <utf16_to_utf8+0x5f0> 1ca9: c4 e2 79 33 c9 vpmovzxwd xmm1,xmm1 1cae: 48 83 c1 08 add rcx,0x8 1cb2: 48 89 fa mov rdx,rdi 1cb5: 48 83 c0 0c add rax,0xc 1cb9: c5 e1 72 f1 02 vpslld xmm3,xmm1,0x2 1cbe: c5 f9 72 f1 10 vpslld xmm0,xmm1,0x10 1cc3: 48 29 ca sub rdx,rcx 1cc6: c5 f1 72 d1 0c vpsrld xmm1,xmm1,0xc 1ccb: c5 f9 db c4 vpand xmm0,xmm0,xmm4 1ccf: c5 e1 db dd vpand xmm3,xmm3,xmm5 1cd3: c5 f9 eb c3 vpor xmm0,xmm0,xmm3 1cd7: c5 e9 eb c9 vpor xmm1,xmm2,xmm1 1cdb: c5 f9 eb c1 vpor xmm0,xmm0,xmm1 1cdf: c4 e2 79 00 05 38 13 vpshufb xmm0,xmm0,XMMWORD PTR [rip+0x1338] # 3020 <_IO_stdin_used+0x20> 1ce6: 00 00 1ce8: c5 fa 7f 40 f4 vmovdqu XMMWORD PTR [rax-0xc],xmm0 1ced: 48 83 fa 02 cmp rdx,0x2 1cf1: 77 7d ja 1d70 <utf16_to_utf8+0x5f0> 1cf3: 48 39 f9 cmp rcx,rdi 1cf6: 72 5b jb 1d53 <utf16_to_utf8+0x5d3> 1cf8: e9 f7 fd ff ff jmp 1af4 <utf16_to_utf8+0x374> 1cfd: 0f 1f 00 nop DWORD PTR [rax] 1d00: 41 8d 90 00 28 ff ff lea edx,[r8-0xd800] 1d07: 81 fa ff 07 00 00 cmp edx,0x7ff 1d0d: 0f 86 d8 fd ff ff jbe 1aeb <utf16_to_utf8+0x36b> 1d13: 45 89 c1 mov r9d,r8d 1d16: 42 8d 14 85 00 00 00 lea edx,[r8*4+0x0] 1d1d: 00 1d1e: 41 c1 e8 0c shr r8d,0xc 1d22: 48 83 c1 02 add rcx,0x2 1d26: 41 c1 e1 10 shl r9d,0x10 1d2a: 81 e2 00 3f 00 00 and edx,0x3f00 1d30: 48 83 c0 03 add rax,0x3 1d34: 41 81 e1 00 00 3f 00 and r9d,0x3f0000 1d3b: 44 09 ca or edx,r9d 1d3e: 44 09 c2 or edx,r8d 1d41: 81 ca e0 80 80 00 or edx,0x8080e0 1d47: 89 50 fd mov DWORD PTR [rax-0x3],edx 1d4a: 48 39 f9 cmp rcx,rdi 1d4d: 0f 83 a1 fd ff ff jae 1af4 <utf16_to_utf8+0x374> 1d53: 44 0f b7 01 movzx r8d,WORD PTR [rcx] 1d57: 41 81 f8 ff 07 00 00 cmp r8d,0x7ff 1d5e: 77 a0 ja 1d00 <utf16_to_utf8+0x580> 1d60: 48 39 f9 cmp rcx,rdi 1d63: 0f 82 70 fa ff ff jb 17d9 <utf16_to_utf8+0x59> 1d69: e9 86 fd ff ff jmp 1af4 <utf16_to_utf8+0x374> 1d6e: 66 90 xchg ax,ax 1d70: 0f b7 51 02 movzx edx,WORD PTR [rcx+0x2] 1d74: 66 81 fa ff 07 cmp dx,0x7ff 1d79: 0f 86 74 ff ff ff jbe 1cf3 <utf16_to_utf8+0x573> 1d7f: 66 81 c2 00 28 add dx,0x2800 1d84: 66 81 fa ff 07 cmp dx,0x7ff 1d89: 0f 86 64 ff ff ff jbe 1cf3 <utf16_to_utf8+0x573> 1d8f: c5 f9 6e 09 vmovd xmm1,DWORD PTR [rcx] 1d93: c5 f9 6f f5 vmovdqa xmm6,xmm5 1d97: 48 83 c1 04 add rcx,0x4 1d9b: 48 83 c0 06 add rax,0x6 1d9f: c4 e2 79 33 c9 vpmovzxwd xmm1,xmm1 1da4: c5 f9 72 f1 10 vpslld xmm0,xmm1,0x10 1da9: c5 d1 72 f1 02 vpslld xmm5,xmm1,0x2 1dae: c5 e1 72 d1 0c vpsrld xmm3,xmm1,0xc 1db3: c5 f9 db c4 vpand xmm0,xmm0,xmm4 1db7: c5 d1 db ce vpand xmm1,xmm5,xmm6 1dbb: c5 f9 eb c9 vpor xmm1,xmm0,xmm1 1dbf: c5 e9 eb c3 vpor xmm0,xmm2,xmm3 1dc3: c5 f1 eb c0 vpor xmm0,xmm1,xmm0 1dc7: c4 e2 79 00 05 50 12 vpshufb xmm0,xmm0,XMMWORD PTR [rip+0x1250] # 3020 <_IO_stdin_used+0x20> 1dce: 00 00 1dd0: c5 f9 d6 40 fa vmovq QWORD PTR [rax-0x6],xmm0 --- Command finished with exit code: 0 --- --- [2] bash --- 2128: c5 f5 eb ca vpor ymm1,ymm1,ymm2 212c: c5 fd eb c1 vpor ymm0,ymm0,ymm1 2130: c4 e2 7d 00 05 e7 0e vpshufb ymm0,ymm0,YMMWORD PTR [rip+0xee7] # 3020 <_IO_stdin_used+0x20> 2137: 00 00 2139: c5 fa 7f 40 e8 vmovdqu XMMWORD PTR [rax-0x18],xmm0 213e: c4 e3 7d 39 40 f4 01 vextracti128 XMMWORD PTR [rax-0xc],ymm0,0x1 2145: e9 2b fb ff ff jmp 1c75 <utf16_to_utf8+0x4f5> 214a: 66 0f 1f 44 00 00 nop WORD PTR [rax+rax*1+0x0] 2150: 49 b8 80 ff 80 ff 80 movabs r8,0xff80ff80ff80ff80 2157: ff 80 ff 215a: 48 8b 11 mov rdx,QWORD PTR [rcx] 215d: 4c 85 c2 test rdx,r8 2160: 75 2e jne 2190 <utf16_to_utf8+0xa10> 2162: 49 b8 ff 00 ff 00 ff movabs r8,0xff00ff00ff00ff 2169: 00 ff 00 216c: 48 83 c1 08 add rcx,0x8 2170: 48 83 c0 04 add rax,0x4 2174: c4 c2 ea f5 d0 pext rdx,rdx,r8 2179: 89 50 fc mov DWORD PTR [rax-0x4],edx 217c: 48 89 fa mov rdx,rdi 217f: 48 29 ca sub rdx,rcx 2182: 48 83 fa 02 cmp rdx,0x2 2186: 0f 86 51 fd ff ff jbe 1edd <utf16_to_utf8+0x75d> 218c: 0f 1f 40 00 nop DWORD PTR [rax+0x0] 2190: 66 83 79 02 7f cmp WORD PTR [rcx+0x2],0x7f 2195: 0f 87 42 fd ff ff ja 1edd <utf16_to_utf8+0x75d> 219b: 8b 11 mov edx,DWORD PTR [rcx] 219d: 41 b8 ff 00 ff 00 mov r8d,0xff00ff 21a3: 48 83 c1 04 add rcx,0x4 21a7: 48 83 c0 02 add rax,0x2 21ab: c4 c2 6a f5 d0 pext edx,edx,r8d 21b0: 66 89 50 fe mov WORD PTR [rax-0x2],dx 21b4: e9 24 fd ff ff jmp 1edd <utf16_to_utf8+0x75d> 21b9: c5 f9 71 f1 08 vpsllw xmm0,xmm1,0x8 21be: 48 83 c1 08 add rcx,0x8 21c2: 48 89 fa mov rdx,rdi 21c5: 48 83 c0 08 add rax,0x8 21c9: c5 f1 71 d1 06 vpsrlw xmm1,xmm1,0x6 21ce: c5 c9 db c0 vpand xmm0,xmm6,xmm0 21d2: 48 29 ca sub rdx,rcx 21d5: c5 f1 eb cf vpor xmm1,xmm1,xmm7 21d9: c5 f1 eb c0 vpor xmm0,xmm1,xmm0 21dd: c5 f9 d6 40 f8 vmovq QWORD PTR [rax-0x8],xmm0 21e2: 48 83 fa 02 cmp rdx,0x2 21e6: 0f 86 58 fe ff ff jbe 2044 <utf16_to_utf8+0x8c4> 21ec: e9 40 fe ff ff jmp 2031 <utf16_to_utf8+0x8b1> 21f1: 0f 1f 80 00 00 00 00 nop DWORD PTR [rax+0x0] 21f8: 48 83 fa 1e cmp rdx,0x1e 21fc: 0f 86 91 fc ff ff jbe 1e93 <utf16_to_utf8+0x713> 2202: e9 74 fc ff ff jmp 1e7b <utf16_to_utf8+0x6fb> 2207: 66 0f 1f 84 00 00 00 nop WORD PTR [rax+rax*1+0x0] 220e: 00 00 2210: 48 83 fa 0e cmp rdx,0xe 2214: 0f 86 e0 fd ff ff jbe 1ffa <utf16_to_utf8+0x87a> 221a: e9 b7 fd ff ff jmp 1fd6 <utf16_to_utf8+0x856> 221f: 90 nop 2220: c5 fd 67 c0 vpackuswb ymm0,ymm0,ymm0 2224: 48 83 c1 20 add rcx,0x20 2228: 48 83 c0 10 add rax,0x10 222c: c4 e3 fd 00 c0 d8 vpermq ymm0,ymm0,0xd8 2232: c5 fa 7f 40 f0 vmovdqu XMMWORD PTR [rax-0x10],xmm0 2237: e9 57 fc ff ff jmp 1e93 <utf16_to_utf8+0x713> 223c: 44 8b 01 mov r8d,DWORD PTR [rcx] 223f: 48 83 c0 04 add rax,0x4 2243: 48 83 c1 04 add rcx,0x4 2247: 44 89 c2 mov edx,r8d 224a: 41 c1 e0 08 shl r8d,0x8 224e: c1 ea 06 shr edx,0x6 2251: 41 81 e0 00 3f 00 3f and r8d,0x3f003f00 2258: 81 e2 1f 00 1f 00 and edx,0x1f001f 225e: 44 09 c2 or edx,r8d 2261: 81 ca c0 80 c0 80 or edx,0x80c080c0 2267: 89 50 fc mov DWORD PTR [rax-0x4],edx 226a: e9 d5 fd ff ff jmp 2044 <utf16_to_utf8+0x8c4> 226f: c5 f9 71 d1 06 vpsrlw xmm0,xmm1,0x6 2274: c5 e1 71 f1 08 vpsllw xmm3,xmm1,0x8 2279: 48 83 c1 10 add rcx,0x10 227d: 48 83 c0 10 add rax,0x10 2281: c5 f9 eb c7 vpor xmm0,xmm0,xmm7 2285: c5 c9 db cb vpand xmm1,xmm6,xmm3 2289: c5 f9 eb c1 vpor xmm0,xmm0,xmm1 228d: c5 fa 7f 40 f0 vmovdqu XMMWORD PTR [rax-0x10],xmm0 2292: e9 63 fd ff ff jmp 1ffa <utf16_to_utf8+0x87a> 2297: 31 c0 xor eax,eax 2299: c5 f8 77 vzeroupper 229c: c3 ret --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"intent": "Validate both units after preceding short kernels advance the input", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n- if ((size_t)(end - in) >= 2 && in[1] < 0x80) {\n+ if ((size_t)(end - in) >= 2 && in[0] < 0x80 && in[1] < 0x80) {\n@@\n- if ((uint32_t)(in[1] - 0x80) < 0x780) {\n+ if ((uint32_t)(in[0] - 0x80) < 0x780 &&\n+ (uint32_t)(in[1] - 0x80) < 0x780) {\n@@\n- if ((size_t)(end - in) >= 2 && in[1] >= 0x800 &&\n- (uint16_t)(in[1] - 0xd800) >= 0x800) {\n+ if ((size_t)(end - in) >= 2 && in[0] >= 0x800 && in[1] >= 0x800 &&\n+ (uint16_t)(in[0] - 0xd800) >= 0x800 &&\n+ (uint16_t)(in[1] - 0xd800) >= 0x800) {\n*** End Patch"}

✓ submission/solve.c: modified (3 hunks) 105- if ((size_t)(end - in) >= 2 && in[1] < 0x80) { 105+ if ((size_t)(end - in) >= 2 && in[0] < 0x80 && in[1] < 0x80) { 165- if ((uint32_t)(in[1] - 0x80) < 0x780) { 165+ if ((uint32_t)(in[0] - 0x80) < 0x780 && 166+ (uint32_t)(in[1] - 0x80) < 0x780) { 247- if ((size_t)(end - in) >= 2 && in[1] >= 0x800 && 248+ if ((size_t)(end - in) >= 2 && in[0] >= 0x800 && in[1] >= 0x800 && 249+ (uint16_t)(in[0] - 0xd800) >= 0x800 &&

{"command": "./grade --seed 48818", "intent": "Verify corrected two-unit kernels and measure net gain", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 2.1s verify 2.6s PASS measure 0.7s 22,917,218 instructions (given: 77,696,233) SCORE +1.7614 (3.390x) --- Command finished with exit code: 0 ---

{"intent": "Adapt SIMD probe sizes to observed record regime", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n const uint16_t *const end = in + n;\n uint8_t *const out_begin = out;\n+ unsigned mode = 0; // 0 unknown/ASCII, 1 Latin, 2 wide BMP, 3 surrogate pairs\n@@\n if (c < 0x80) {\n // Long ASCII runs dominate the corpus. Convert 32 units per test.\n- while ((size_t)(end - in) >= 32) {\n- __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in);\n- __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16));\n- if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break;\n- __m256i bytes = _mm256_packus_epi16(a, b);\n- bytes = _mm256_permute4x64_epi64(bytes, 0xd8);\n- _mm256_storeu_si256((__m256i *)(void *)out, bytes);\n- in += 32;\n- out += 32;\n- }\n- if ((size_t)(end - in) >= 16) {\n- __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n- if (_mm256_testz_si256(v, ascii_mask)) {\n- v = _mm256_packus_epi16(v, v);\n- v = _mm256_permute4x64_epi64(v, 0xd8);\n- _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v));\n- in += 16;\n- out += 16;\n+ if (mode == 0) {\n+ while ((size_t)(end - in) >= 32) {\n+ __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in);\n+ __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16));\n+ if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break;\n+ __m256i bytes = _mm256_packus_epi16(a, b);\n+ bytes = _mm256_permute4x64_epi64(bytes, 0xd8);\n+ _mm256_storeu_si256((__m256i *)(void *)out, bytes);\n+ in += 32;\n+ out += 32;\n+ }\n+ if ((size_t)(end - in) >= 16) {\n+ __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n+ if (_mm256_testz_si256(v, ascii_mask)) {\n+ v = _mm256_packus_epi16(v, v);\n+ v = _mm256_permute4x64_epi64(v, 0xd8);\n+ _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v));\n+ in += 16;\n+ out += 16;\n+ }\n }\n }\n- if ((size_t)(end - in) >= 8) {\n+ if (mode <= 1 && (size_t)(end - in) >= 8) {\n@@\n if (c < 0x800) {\n+ if (mode == 0) mode = 1;\n // Sixteen two-byte characters become sixteen packed 16-bit words.\n- while ((size_t)(end - in) >= 16) {\n- __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n- __m256i ge80 = _mm256_cmpgt_epi16(v, lo7);\n- __m256i lt800 = _mm256_cmpgt_epi16(lim800, v);\n- if (_mm256_movemask_epi8(_mm256_and_si256(ge80, lt800)) != -1) break;\n- __m256i x = _mm256_or_si256(_mm256_srli_epi16(v, 6),\n- _mm256_and_si256(_mm256_slli_epi16(v, 8), mask3f00));\n- x = _mm256_or_si256(x, base2);\n- _mm256_storeu_si256((__m256i *)(void *)out, x);\n- in += 16;\n- out += 32;\n+ if (mode != 1) {\n+ while ((size_t)(end - in) >= 16) {\n+ __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n+ __m256i ge80 = _mm256_cmpgt_epi16(v, lo7);\n+ __m256i lt800 = _mm256_cmpgt_epi16(lim800, v);\n+ if (_mm256_movemask_epi8(_mm256_and_si256(ge80, lt800)) != -1) break;\n+ __m25 ... [726 characters truncated for page size]

✓ submission/solve.c: modified (5 hunks) 35+ unsigned mode = 0; // 0 unknown/ASCII, 1 Latin, 2 wide BMP, 3 surrogate pairs 66- while ((size_t)(end - in) >= 32) { 67- __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in); 68- __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16)); 69- if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break; 70- __m256i bytes = _mm256_packus_epi16(a, b); 71- bytes = _mm256_permute4x64_epi64(bytes, 0xd8); 72- _mm256_storeu_si256((__m256i *)(void *)out, bytes); 73- in += 32; 74- out += 32; 75- } 76- if ((size_t)(end - in) >= 16) { 77- __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); 78- if (_mm256_testz_si256(v, ascii_mask)) { 79- v = _mm256_packus_epi16(v, v); 80- v = _mm256_permute4x64_epi64(v, 0xd8); 81- _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v)); 82- in += 16; 83- out += 16; 67+ if (mode == 0) { 68+ while ((size_t)(end - in) >= 32) { 69+ __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in); 70+ __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16)); 71+ if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break; 72+ __m256i bytes = _mm256_packus_epi16(a, b); 73+ bytes = _mm256_permute4x64_epi64(bytes, 0xd8); 74+ _mm256_storeu_si256((__m256i *)(void *)out, bytes); 75+ in += 32; 76+ out += 32; 77+ } ... (diff truncated)

{"command": "./grade --seed 48818", "intent": "Verify adaptive probing and measure instruction reduction", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 2.2s verify 2.6s PASS measure 0.7s 28,108,753 instructions (given: 77,696,233) SCORE +1.4668 (2.764x) --- Command finished with exit code: 0 ---

{"file_path": "submission/solve.c", "intent": "Inspect adaptive changes for targeted rollback", "limit": 150, "start_line": 30}

30 __attribute__((target("avx2,bmi2"))) 31 size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 32 const uint16_t *const begin = in; 33 const uint16_t *const end = in + n; 34 uint8_t *const out_begin = out; 35 unsigned mode = 0; // 0 unknown/ASCII, 1 Latin, 2 wide BMP, 3 surrogate pairs 36 37 const __m256i ascii_mask = _mm256_set1_epi16((short)0xff80); 38 const __m256i lo7 = _mm256_set1_epi16(0x007f); 39 const __m256i lim800 = _mm256_set1_epi16(0x0800); 40 const __m256i base2 = _mm256_set1_epi16((short)0x80c0); 41 const __m256i mask3f00 = _mm256_set1_epi16(0x3f00); 42 const __m256i hi5mask = _mm256_set1_epi16((short)0xf800); 43 const __m256i surbits = _mm256_set1_epi16((short)0xd800); 44 const __m256i zero = _mm256_setzero_si256(); 45 const __m256i pairmask = _mm256_set1_epi16((short)0xfc00); 46 const __m256i pairexpect = _mm256_setr_epi16( 47 (short)0xd800, (short)0xdc00, (short)0xd800, (short)0xdc00, 48 (short)0xd800, (short)0xdc00, (short)0xd800, (short)0xdc00, 49 (short)0xd800, (short)0xdc00, (short)0xd800, (short)0xdc00, 50 (short)0xd800, (short)0xdc00, (short)0xd800, (short)0xdc00); 51 const __m256i low10 = _mm256_set1_epi32(0x3ff); 52 const __m256i cpbase = _mm256_set1_epi32(0x10000); 53 const __m256i utf4base = _mm256_set1_epi32((int)0x808080f0u); 54 const __m256i m3f00_32 = _mm256_set1_epi32(0x00003f00); 55 const __m256i m3f0000 = _mm256_set1_epi32(0x003f0000); 56 const __m256i m3f000000 = _mm256_set1_epi32(0x3f000000); 57 const __m256i utf3base = _mm256_set1_epi32(0x008080e0); 58 const __m256i compress3 = _mm256_setr_epi8( 59 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1, 60 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1); 61 62 while (in < end) { 63 uint32_t c = *in; 64 65 if (c < 0x80) { 66 // Long ASCII runs dominate the corpus. Convert 32 units per test. 67 if (mode == 0) { 68 while ((size_t)(end - in) >= 32) { 69 __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in); 70 __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16)); 71 if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break; 72 __m256i bytes = _mm256_packus_epi16(a, b); 73 bytes = _mm256_permute4x64_epi64(bytes, 0xd8); 74 _mm256_storeu_si256((__m256i *)(void *)out, bytes); 75 in += 32; 76 out += 32; 77 } 78 if ((size_t)(end - in) >= 16) { 79 __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); 80 if (_mm256_testz_si256(v, ascii_mask)) { 81 v = _mm256_packus_epi16(v, v); 82 v = _mm256_permute4x64_epi64(v, 0xd8); 83 _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v)); 84 in += 16; 85 out += 16; 86 } 87 } 88 } 89 if (mode <= 1 && (size_t)(end - in) >= 8) { 90 __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); 91 if (_mm_testz_si128(v, _mm256_castsi256_si128(ascii_mask))) { 92 v = _mm_packus_epi16(v, v); 93 _mm_storel_epi64((__m128i *)(void *)out, v); 94 in += 8; 95 out += 8; 96 } 97 } 98 if ((size_t)(end - in) >= 4) { 99 uint64_t v; 100 memcpy(&v, in, sizeof(v)); 101 if (!(v & UINT64_C(0xff80ff80ff80ff80))) { 102 uint32_t x = (uint32_t)_pext_u64(v, UINT64_C(0x00ff00ff00ff00ff)); 103 memcpy(out, &x, sizeof(x)); 104 in += 4; 105 out += 4; 106 } 107 } 108 if ((size_t)(end - in) >= 2 && in[0] < 0x80 && in[1] < 0x80) { 109 uint32_t v; 110 memcpy(&v, in, sizeof(v)); 111 uint16_t x = (uint16_t)_pext_u32(v, 0x00ff00ffu); 112 memcpy(out, &x, sizeof(x)); 113 in += 2; 114 out += 2; 115 } 116 while (in < end && (c = *in) < 0x80) { 117 *out++ = (uint8_t)c; 118 ++in; 119 } 120 continue; 121 } 122 123 if (c < 0x800) { 124 if (mode == 0) mode = 1; 125 // Sixteen two-byte characters become sixteen packed 16-bit words. 126 if (mode != 1) { 127 while ((size_t)(end - in) >= 16) { 128 __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); 129 __m256i ge80 = _mm256_cmpgt_epi16(v, lo7); 130 __m256i lt800 = _mm256_cmpgt_epi16(lim800, v); 131 if (_mm256_movemask_epi8(_mm256_and_si256(ge80, lt800)) != -1) break; 132 __m256i x = _mm256_or_si256(_mm256_srli_epi16(v, 6), 133 _mm256_and_si256(_mm256_slli_epi16(v, 8), mask3f00)); 134 x = _mm256_or_si256(x, base2); 135 _mm256_storeu_si256((__m256i *)(void *)out, x); 136 in += 16; 137 out += 32; 138 } 139 } 140 if ((size_t)(end - in) >= 8) { 141 __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); 142 __m128i ge80 = _mm_cmpgt_epi16(v, _mm256_castsi256_si128(lo7)); 143 __m128i lt800 = _mm_cmpgt_epi16(_mm256_castsi256_si128(lim800), v); 144 if (_mm_movemask_epi8(_mm_and_si128(ge80, lt800)) == 0xffff) { 145 __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6), 146 _mm_and_si128(_mm_slli_epi16(v, 8), 147 _mm256_castsi256_si128(mask3f00))); 148 x = _mm_or_si128(x, _mm256_castsi256_si128(base2)); 149 _mm_storeu_si128((__m128i *)(void *)out, x); 150 in += 8; 151 out += 16; 152 } 153 } 154 if ((size_t)(end - in) >= 4) { 155 __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in); 156 __m128i ge80 = _mm_cmpgt_epi16(v, _mm256_castsi256_si128(lo7)); 157 __m128i lt800 = _mm_cmpgt_epi16(_mm256_castsi256_si128(lim800), v); 158 if ((_mm_movemask_epi8(_mm_and_si128(ge80, lt800)) & 0xff) == 0xff) { 159 __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6), 160 _mm_and_si128(_mm_slli_epi16(v, 8), 161 _mm256_castsi256_si128(mask3f00))); 162 x = _mm_or_si128(x, _mm256_castsi256_si128(base2)); 163 _mm_storel_epi64((__m128i *)(void *)out, x); 164 in += 4; 165 out += 8; 166 } 167 } 168 if ((size_t)(end - in) >= 2) { 169 uint32_t v; 170 memcpy(&v, in, sizeof(v)); 171 if ((uint32_t)(in[0] - 0x80) < 0x780 && 172 (uint32_t)(in[1] - 0x80) < 0x780) { 173 uint32_t x = 0x80c080c0u | ((v >> 6) & 0x001f001fu) | 174 ((v << 8) & 0x3f003f00u); 175 memcpy(out, &x, sizeof(x)); 176 in += 2; 177 out += 4; 178 } 179 } ... 191 more lines (use start_line=180 to continue)

{"intent": "Rollback counterproductive adaptive probe experiment", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n- unsigned mode = 0; // 0 unknown/ASCII, 1 Latin, 2 wide BMP, 3 surrogate pairs\n@@\n- if (mode == 0) {\n- while ((size_t)(end - in) >= 32) {\n- __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in);\n- __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16));\n- if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break;\n- __m256i bytes = _mm256_packus_epi16(a, b);\n- bytes = _mm256_permute4x64_epi64(bytes, 0xd8);\n- _mm256_storeu_si256((__m256i *)(void *)out, bytes);\n- in += 32;\n- out += 32;\n- }\n- if ((size_t)(end - in) >= 16) {\n- __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n- if (_mm256_testz_si256(v, ascii_mask)) {\n- v = _mm256_packus_epi16(v, v);\n- v = _mm256_permute4x64_epi64(v, 0xd8);\n- _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v));\n- in += 16;\n- out += 16;\n- }\n+ while ((size_t)(end - in) >= 32) {\n+ __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in);\n+ __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16));\n+ if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break;\n+ __m256i bytes = _mm256_packus_epi16(a, b);\n+ bytes = _mm256_permute4x64_epi64(bytes, 0xd8);\n+ _mm256_storeu_si256((__m256i *)(void *)out, bytes);\n+ in += 32;\n+ out += 32;\n+ }\n+ if ((size_t)(end - in) >= 16) {\n+ __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n+ if (_mm256_testz_si256(v, ascii_mask)) {\n+ v = _mm256_packus_epi16(v, v);\n+ v = _mm256_permute4x64_epi64(v, 0xd8);\n+ _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v));\n+ in += 16;\n+ out += 16;\n }\n }\n- if (mode <= 1 && (size_t)(end - in) >= 8) {\n+ if ((size_t)(end - in) >= 8) {\n@@\n- if (mode == 0) mode = 1;\n // Sixteen two-byte characters become sixteen packed 16-bit words.\n- if (mode != 1) {\n- while ((size_t)(end - in) >= 16) {\n- __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n- __m256i ge80 = _mm256_cmpgt_epi16(v, lo7);\n- __m256i lt800 = _mm256_cmpgt_epi16(lim800, v);\n- if (_mm256_movemask_epi8(_mm256_and_si256(ge80, lt800)) != -1) break;\n- __m256i x = _mm256_or_si256(_mm256_srli_epi16(v, 6),\n- _mm256_and_si256(_mm256_slli_epi16(v, 8), mask3f00));\n- x = _mm256_or_si256(x, base2);\n- _mm256_storeu_si256((__m256i *)(void *)out, x);\n- in += 16;\n- out += 32;\n- }\n+ while ((size_t)(end - in) >= 16) {\n+ __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n+ __m256i ge80 = _mm256_cmpgt_epi16(v, lo7);\n+ __m256i lt800 = _mm256_cmpgt_epi16(lim800, v);\n+ if (_mm256_movemask_epi8(_mm256_and_si256(ge80, lt800)) != -1) break;\n+ __m256i x = _mm256_or_si256(_mm256_srli_epi16(v, 6),\n+ _mm256_and_si256(_mm256_slli_epi16(v, 8), mask3f00));\n+ x = _mm256_or_si256(x, base2 ... [424 characters truncated for page size]

✓ submission/solve.c: modified (5 hunks) 35- unsigned mode = 0; // 0 unknown/ASCII, 1 Latin, 2 wide BMP, 3 surrogate pairs 67- if (mode == 0) { 68- while ((size_t)(end - in) >= 32) { 69- __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in); 70- __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16)); 71- if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break; 72- __m256i bytes = _mm256_packus_epi16(a, b); 73- bytes = _mm256_permute4x64_epi64(bytes, 0xd8); 74- _mm256_storeu_si256((__m256i *)(void *)out, bytes); 75- in += 32; 76- out += 32; 77- } 78- if ((size_t)(end - in) >= 16) { 79- __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); 80- if (_mm256_testz_si256(v, ascii_mask)) { 81- v = _mm256_packus_epi16(v, v); 82- v = _mm256_permute4x64_epi64(v, 0xd8); 83- _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v)); 84- in += 16; 85- out += 16; 86- } 66+ while ((size_t)(end - in) >= 32) { 67+ __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in); 68+ __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16)); 69+ if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break; 70+ __m256i bytes = _mm256_packus_epi16(a, b); 71+ bytes = _mm256_permute4x64_epi64(bytes, 0xd8); 72+ _mm256_storeu_si256((__m256i *)(void *)out, bytes); 73+ in += 32; 74+ out += 32; ... (diff truncated)

{"intent": "Reuse failed wide ASCII probes to emit exact known prefixes", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n static inline void put4(uint8_t *p, uint32_t cp) {\n@@\n memcpy(p, &x, sizeof(x));\n }\n+\n+__attribute__((always_inline, target(\"avx2,bmi2\")))\n+static inline void put_ascii_prefix(const uint16_t **pin, uint8_t **pout,\n+ unsigned count) {\n+ const uint16_t *in = *pin;\n+ uint8_t *out = *pout;\n+ if (count >= 16) {\n+ __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n+ v = _mm256_packus_epi16(v, v);\n+ v = _mm256_permute4x64_epi64(v, 0xd8);\n+ _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v));\n+ in += 16; out += 16; count -= 16;\n+ }\n+ if (count >= 8) {\n+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in);\n+ v = _mm_packus_epi16(v, v);\n+ _mm_storel_epi64((__m128i *)(void *)out, v);\n+ in += 8; out += 8; count -= 8;\n+ }\n+ if (count >= 4) {\n+ uint64_t v;\n+ memcpy(&v, in, sizeof(v));\n+ uint32_t x = (uint32_t)_pext_u64(v, UINT64_C(0x00ff00ff00ff00ff));\n+ memcpy(out, &x, sizeof(x));\n+ in += 4; out += 4; count -= 4;\n+ }\n+ if (count >= 2) {\n+ uint32_t v;\n+ memcpy(&v, in, sizeof(v));\n+ uint16_t x = (uint16_t)_pext_u32(v, 0x00ff00ffu);\n+ memcpy(out, &x, sizeof(x));\n+ in += 2; out += 2; count -= 2;\n+ }\n+ if (count) *out++ = (uint8_t)*in++;\n+ *pin = in;\n+ *pout = out;\n+}\n@@\n while ((size_t)(end - in) >= 32) {\n __m256i a = _mm256_loadu_si256((const __m256i *)(const void *)in);\n __m256i b = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16));\n- if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) break;\n+ if (!_mm256_testz_si256(_mm256_or_si256(a, b), ascii_mask)) {\n+ int ga = _mm256_movemask_epi8(_mm256_cmpeq_epi16(\n+ _mm256_and_si256(a, ascii_mask), zero));\n+ unsigned count;\n+ if (ga != -1) {\n+ count = (unsigned)__builtin_ctz((unsigned)~ga) >> 1;\n+ } else {\n+ int gb = _mm256_movemask_epi8(_mm256_cmpeq_epi16(\n+ _mm256_and_si256(b, ascii_mask), zero));\n+ count = 16 + ((unsigned)__builtin_ctz((unsigned)~gb) >> 1);\n+ }\n+ put_ascii_prefix(&in, &out, count);\n+ goto ascii_done;\n+ }\n __m256i bytes = _mm256_packus_epi16(a, b);\n@@\n if ((size_t)(end - in) >= 16) {\n __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n- if (_mm256_testz_si256(v, ascii_mask)) {\n+ if (_mm256_testz_si256(v, ascii_mask)) {\n v = _mm256_packus_epi16(v, v);\n@@\n in += 16;\n out += 16;\n+ } else {\n+ int good = _mm256_movemask_epi8(_mm256_cmpeq_epi16(\n+ _mm256_and_si256(v, ascii_mask), zero));\n+ unsigned count = (unsigned)__builtin_ctz((unsigned)~good) >> 1;\n+ put_ascii_prefix(&in, &out, count);\n+ goto ascii_done;\n }\n }\n if ((size_t)(end - in) >= 8) {\n __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in);\n if (_mm_testz_si128(v, _mm256_castsi256_si128(ascii_mask))) {\n@@\n in += 8;\n out += 8;\n+ } else {\n+ __m128i goodv = _mm_cmpeq_epi16(\n+ _mm_and_si128(v, _mm256_castsi256_si128(ascii_mask)),\n+ _mm_setz ... [499 characters truncated for page size]

✓ submission/solve.c: modified (7 hunks) 30+ __attribute__((always_inline, target("avx2,bmi2"))) 31+ static inline void put_ascii_prefix(const uint16_t **pin, uint8_t **pout, 32+ unsigned count) { 33+ const uint16_t *in = *pin; 34+ uint8_t *out = *pout; 35+ if (count >= 16) { 36+ __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); 37+ v = _mm256_packus_epi16(v, v); 38+ v = _mm256_permute4x64_epi64(v, 0xd8); 39+ _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v)); 40+ in += 16; out += 16; count -= 16; 41+ } 42+ if (count >= 8) { 43+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); 44+ v = _mm_packus_epi16(v, v); 45+ _mm_storel_epi64((__m128i *)(void *)out, v); 46+ in += 8; out += 8; count -= 8; 47+ } 48+ if (count >= 4) { 49+ uint64_t v; 50+ memcpy(&v, in, sizeof(v)); 51+ uint32_t x = (uint32_t)_pext_u64(v, UINT64_C(0x00ff00ff00ff00ff)); 52+ memcpy(out, &x, sizeof(x)); 53+ in += 4; out += 4; count -= 4; 54+ } 55+ if (count >= 2) { 56+ uint32_t v; 57+ memcpy(&v, in, sizeof(v)); 58+ uint16_t x = (uint16_t)_pext_u32(v, 0x00ff00ffu); 59+ memcpy(out, &x, sizeof(x)); ... (diff truncated)

{"command": "./grade --seed 48818", "intent": "Verify exact-prefix ASCII optimization and measure its effect", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 2.5s verify 2.6s PASS measure 0.7s 21,646,190 instructions (given: 77,696,233) SCORE +1.8437 (3.589x) --- Command finished with exit code: 0 ---

{"intent": "Reuse failed two-byte probes to emit exact known prefixes", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n static inline void put_ascii_prefix(const uint16_t **pin, uint8_t **pout,\n@@\n *pout = out;\n }\n+\n+__attribute__((always_inline, target(\"avx2\")))\n+static inline void put_two_prefix(const uint16_t **pin, uint8_t **pout,\n+ unsigned count) {\n+ const uint16_t *in = *pin;\n+ uint8_t *out = *pout;\n+ const __m128i m = _mm_set1_epi16(0x3f00);\n+ const __m128i b = _mm_set1_epi16((short)0x80c0);\n+ if (count >= 8) {\n+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in);\n+ __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6),\n+ _mm_and_si128(_mm_slli_epi16(v, 8), m));\n+ _mm_storeu_si128((__m128i *)(void *)out, _mm_or_si128(x, b));\n+ in += 8; out += 16; count -= 8;\n+ }\n+ if (count >= 4) {\n+ __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in);\n+ __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6),\n+ _mm_and_si128(_mm_slli_epi16(v, 8), m));\n+ _mm_storel_epi64((__m128i *)(void *)out, _mm_or_si128(x, b));\n+ in += 4; out += 8; count -= 4;\n+ }\n+ if (count >= 2) {\n+ uint32_t v;\n+ memcpy(&v, in, sizeof(v));\n+ uint32_t x = 0x80c080c0u | ((v >> 6) & 0x001f001fu) |\n+ ((v << 8) & 0x3f003f00u);\n+ memcpy(out, &x, sizeof(x));\n+ in += 2; out += 4; count -= 2;\n+ }\n+ if (count) { put2(out, *in); ++in; out += 2; }\n+ *pin = in;\n+ *pout = out;\n+}\n@@\n __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n __m256i ge80 = _mm256_cmpgt_epi16(v, lo7);\n __m256i lt800 = _mm256_cmpgt_epi16(lim800, v);\n- if (_mm256_movemask_epi8(_mm256_and_si256(ge80, lt800)) != -1) break;\n+ int valid = _mm256_movemask_epi8(_mm256_and_si256(ge80, lt800));\n+ if (valid != -1) {\n+ unsigned count = (unsigned)__builtin_ctz((unsigned)~valid) >> 1;\n+ put_two_prefix(&in, &out, count);\n+ goto two_done;\n+ }\n@@\n if ((size_t)(end - in) >= 8) {\n __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in);\n __m128i ge80 = _mm_cmpgt_epi16(v, _mm256_castsi256_si128(lo7));\n __m128i lt800 = _mm_cmpgt_epi16(_mm256_castsi256_si128(lim800), v);\n- if (_mm_movemask_epi8(_mm_and_si128(ge80, lt800)) == 0xffff) {\n+ unsigned valid = (unsigned)_mm_movemask_epi8(_mm_and_si128(ge80, lt800));\n+ if (valid == 0xffff) {\n@@\n in += 8;\n out += 16;\n+ } else {\n+ unsigned count = (unsigned)__builtin_ctz((~valid) & 0xffffu) >> 1;\n+ put_two_prefix(&in, &out, count);\n+ goto two_done;\n }\n@@\n while (in < end && (c = *in) >= 0x80 && c < 0x800) {\n@@\n ++in;\n }\n+two_done:\n continue;\n*** End Patch"}

✓ submission/solve.c: modified (7 hunks) 67+ __attribute__((always_inline, target("avx2"))) 68+ static inline void put_two_prefix(const uint16_t **pin, uint8_t **pout, 69+ unsigned count) { 70+ const uint16_t *in = *pin; 71+ uint8_t *out = *pout; 72+ const __m128i m = _mm_set1_epi16(0x3f00); 73+ const __m128i b = _mm_set1_epi16((short)0x80c0); 74+ if (count >= 8) { 75+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); 76+ __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6), 77+ _mm_and_si128(_mm_slli_epi16(v, 8), m)); 78+ _mm_storeu_si128((__m128i *)(void *)out, _mm_or_si128(x, b)); 79+ in += 8; out += 16; count -= 8; 80+ } 81+ if (count >= 4) { 82+ __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in); 83+ __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6), 84+ _mm_and_si128(_mm_slli_epi16(v, 8), m)); 85+ _mm_storel_epi64((__m128i *)(void *)out, _mm_or_si128(x, b)); 86+ in += 4; out += 8; count -= 4; 87+ } 88+ if (count >= 2) { 89+ uint32_t v; 90+ memcpy(&v, in, sizeof(v)); 91+ uint32_t x = 0x80c080c0u | ((v >> 6) & 0x001f001fu) | 92+ ((v << 8) & 0x3f003f00u); 93+ memcpy(out, &x, sizeof(x)); 94+ in += 2; out += 4; count -= 2; 95+ } 96+ if (count) { put2(out, *in); ++in; out += 2; } ... (diff truncated)

{"command": "./grade --seed 48818", "intent": "Verify exact-prefix two-byte optimization and measure gain", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 2.4s verify 2.5s PASS measure 0.7s 20,303,617 instructions (given: 77,696,233) SCORE +1.9361 (3.827x) --- Command finished with exit code: 0 ---

{"intent": "Reuse failed three-byte probes to emit exact known prefixes", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n static inline void put_two_prefix(const uint16_t **pin, uint8_t **pout,\n@@\n *pout = out;\n }\n+\n+__attribute__((always_inline, target(\"avx2\")))\n+static inline void put_three_prefix(const uint16_t **pin, uint8_t **pout,\n+ unsigned count) {\n+ const uint16_t *in = *pin;\n+ uint8_t *out = *pout;\n+ const __m256i m1 = _mm256_set1_epi32(0x00003f00);\n+ const __m256i m2 = _mm256_set1_epi32(0x003f0000);\n+ const __m256i base = _mm256_set1_epi32(0x008080e0);\n+ const __m256i shuf = _mm256_setr_epi8(\n+ 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1,\n+ 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1);\n+ if (count >= 8) {\n+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in);\n+ __m256i a = _mm256_cvtepu16_epi32(v);\n+ __m256i a1 = _mm256_and_si256(_mm256_slli_epi32(a, 2), m1);\n+ __m256i a2 = _mm256_and_si256(_mm256_slli_epi32(a, 16), m2);\n+ a = _mm256_or_si256(base, _mm256_or_si256(_mm256_srli_epi32(a, 12),\n+ _mm256_or_si256(a1, a2)));\n+ a = _mm256_shuffle_epi8(a, shuf);\n+ _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(a));\n+ _mm_storeu_si128((__m128i *)(void *)(out + 12), _mm256_extracti128_si256(a, 1));\n+ in += 8; out += 24; count -= 8;\n+ }\n+ if (count >= 4) {\n+ __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in);\n+ __m128i a = _mm_cvtepu16_epi32(v);\n+ __m128i a1 = _mm_and_si128(_mm_slli_epi32(a, 2), _mm256_castsi256_si128(m1));\n+ __m128i a2 = _mm_and_si128(_mm_slli_epi32(a, 16), _mm256_castsi256_si128(m2));\n+ a = _mm_or_si128(_mm256_castsi256_si128(base),\n+ _mm_or_si128(_mm_srli_epi32(a, 12), _mm_or_si128(a1, a2)));\n+ a = _mm_shuffle_epi8(a, _mm256_castsi256_si128(shuf));\n+ _mm_storeu_si128((__m128i *)(void *)out, a);\n+ in += 4; out += 12; count -= 4;\n+ }\n+ if (count >= 2) {\n+ put3(out, in[0]);\n+ put3(out + 3, in[1]);\n+ in += 2; out += 6; count -= 2;\n+ }\n+ if (count) { put3(out, *in); ++in; out += 3; }\n+ *pin = in;\n+ *pout = out;\n+}\n@@\n __m256i high = _mm256_and_si256(v, hi5mask);\n __m256i small = _mm256_cmpeq_epi16(high, zero);\n __m256i sur = _mm256_cmpeq_epi16(high, surbits);\n- if (_mm256_movemask_epi8(_mm256_or_si256(small, sur))) break;\n+ unsigned bad = (unsigned)_mm256_movemask_epi8(_mm256_or_si256(small, sur));\n+ if (bad) {\n+ unsigned count = (unsigned)__builtin_ctz(bad) >> 1;\n+ put_three_prefix(&in, &out, count);\n+ goto three_done;\n+ }\n@@\n __m128i high = _mm_and_si128(v, _mm256_castsi256_si128(hi5mask));\n __m128i bad = _mm_or_si128(_mm_cmpeq_epi16(high, _mm_setzero_si128()),\n _mm_cmpeq_epi16(high, _mm256_castsi256_si128(surbits)));\n- if (!_mm_movemask_epi8(bad)) {\n+ unsigned badmask = (unsigned)_mm_movemask_epi8(bad);\n+ if (!badmask) {\n@@\n in += 8;\n out += 24;\n+ } else {\n+ unsigned count = (unsigned)__builtin_ctz(badmask) >> 1;\n+ put_three_prefix(&in, &out, count);\n+ goto three_done;\n }\n@@\n while (in < end && (c = *in) >= 0x800 &&\n@@\n ++in;\n }\n+three_done:\n continue;\n*** End Patch"}

✓ submission/solve.c: modified (7 hunks) 101+ __attribute__((always_inline, target("avx2"))) 102+ static inline void put_three_prefix(const uint16_t **pin, uint8_t **pout, 103+ unsigned count) { 104+ const uint16_t *in = *pin; 105+ uint8_t *out = *pout; 106+ const __m256i m1 = _mm256_set1_epi32(0x00003f00); 107+ const __m256i m2 = _mm256_set1_epi32(0x003f0000); 108+ const __m256i base = _mm256_set1_epi32(0x008080e0); 109+ const __m256i shuf = _mm256_setr_epi8( 110+ 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1, 111+ 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1); 112+ if (count >= 8) { 113+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); 114+ __m256i a = _mm256_cvtepu16_epi32(v); 115+ __m256i a1 = _mm256_and_si256(_mm256_slli_epi32(a, 2), m1); 116+ __m256i a2 = _mm256_and_si256(_mm256_slli_epi32(a, 16), m2); 117+ a = _mm256_or_si256(base, _mm256_or_si256(_mm256_srli_epi32(a, 12), 118+ _mm256_or_si256(a1, a2))); 119+ a = _mm256_shuffle_epi8(a, shuf); 120+ _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(a)); 121+ _mm_storeu_si128((__m128i *)(void *)(out + 12), _mm256_extracti128_si256(a, 1)); 122+ in += 8; out += 24; count -= 8; 123+ } 124+ if (count >= 4) { 125+ __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in); 126+ __m128i a = _mm_cvtepu16_epi32(v); 127+ __m128i a1 = _mm_and_si128(_mm_slli_epi32(a, 2), _mm256_castsi256_si128(m1)); 128+ __m128i a2 = _mm_and_si128(_mm_slli_epi32(a, 16), _mm256_castsi256_si128(m2)); 129+ a = _mm_or_si128(_mm256_castsi256_si128(base), 130+ _mm_or_si128(_mm_srli_epi32(a, 12), _mm_or_si128(a1, a2))); ... (diff truncated)

{"command": "./grade --seed 48818", "intent": "Verify exact-prefix three-byte optimization and measure gain", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 2.5s verify 2.6s PASS measure 0.6s 19,655,577 instructions (given: 77,696,233) SCORE +1.9829 (3.953x) --- Command finished with exit code: 0 ---

{"intent": "Reuse failed surrogate probes to emit complete valid pair prefixes", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n static inline void put_three_prefix(const uint16_t **pin, uint8_t **pout,\n@@\n *pout = out;\n }\n+\n+__attribute__((always_inline, target(\"avx2\")))\n+static inline void put_pair_prefix(const uint16_t **pin, uint8_t **pout,\n+ unsigned count) {\n+ const uint16_t *in = *pin;\n+ uint8_t *out = *pout;\n+ const __m128i low10 = _mm_set1_epi32(0x3ff);\n+ const __m128i cpbase = _mm_set1_epi32(0x10000);\n+ const __m128i base = _mm_set1_epi32((int)0x808080f0u);\n+ const __m128i m1 = _mm_set1_epi32(0x00003f00);\n+ const __m128i m2 = _mm_set1_epi32(0x003f0000);\n+ const __m128i m3 = _mm_set1_epi32(0x3f000000);\n+ if (count >= 4) {\n+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in);\n+ __m128i hi = _mm_and_si128(v, low10);\n+ __m128i lo = _mm_and_si128(_mm_srli_epi32(v, 16), low10);\n+ __m128i cp = _mm_add_epi32(cpbase, _mm_add_epi32(_mm_slli_epi32(hi, 10), lo));\n+ __m128i x = _mm_or_si128(base, _mm_srli_epi32(cp, 18));\n+ x = _mm_or_si128(x, _mm_and_si128(_mm_srli_epi32(cp, 4), m1));\n+ x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 10), m2));\n+ x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 24), m3));\n+ _mm_storeu_si128((__m128i *)(void *)out, x);\n+ in += 8; out += 16; count -= 4;\n+ }\n+ if (count >= 2) {\n+ __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in);\n+ __m128i hi = _mm_and_si128(v, low10);\n+ __m128i lo = _mm_and_si128(_mm_srli_epi32(v, 16), low10);\n+ __m128i cp = _mm_add_epi32(cpbase, _mm_add_epi32(_mm_slli_epi32(hi, 10), lo));\n+ __m128i x = _mm_or_si128(base, _mm_srli_epi32(cp, 18));\n+ x = _mm_or_si128(x, _mm_and_si128(_mm_srli_epi32(cp, 4), m1));\n+ x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 10), m2));\n+ x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 24), m3));\n+ _mm_storel_epi64((__m128i *)(void *)out, x);\n+ in += 4; out += 8; count -= 2;\n+ }\n+ if (count) {\n+ uint32_t cp = 0x10000u + (((uint32_t)in[0] - 0xd800u) << 10) +\n+ ((uint32_t)in[1] - 0xdc00u);\n+ put4(out, cp);\n+ in += 2; out += 4;\n+ }\n+ *pin = in;\n+ *pout = out;\n+}\n@@\n __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in);\n __m256i tags = _mm256_cmpeq_epi16(_mm256_and_si256(v, pairmask), pairexpect);\n- if (_mm256_movemask_epi8(tags) != -1) break;\n+ int valid = _mm256_movemask_epi8(tags);\n+ if (valid != -1) {\n+ unsigned units = (unsigned)__builtin_ctz((unsigned)~valid) >> 1;\n+ put_pair_prefix(&in, &out, units >> 1);\n+ goto pair_scalar;\n+ }\n@@\n __m128i tags = _mm_cmpeq_epi16(\n _mm_and_si128(v, _mm256_castsi256_si128(pairmask)),\n _mm256_castsi256_si128(pairexpect));\n- if (_mm_movemask_epi8(tags) == 0xffff) {\n+ unsigned valid = (unsigned)_mm_movemask_epi8(tags);\n+ if (valid == 0xffff) {\n@@\n in += 8;\n out += 16;\n+ } else {\n+ unsigned units = (unsigned)__builtin_ctz((~valid) & 0xffffu) >> 1;\n+ put_pair_prefix(&in, &out, units >> 1);\n+ goto pair_scalar;\n }\n@@\n- while (in < end && (c = *in) >= 0xd800 && c < 0xdc00) {\n+pair_scalar:\n+ while (in < end && (c = *in) >= 0xd800 && c < 0xdc00) {\n*** End Patch"}

✓ submission/solve.c: modified (6 hunks) 145+ __attribute__((always_inline, target("avx2"))) 146+ static inline void put_pair_prefix(const uint16_t **pin, uint8_t **pout, 147+ unsigned count) { 148+ const uint16_t *in = *pin; 149+ uint8_t *out = *pout; 150+ const __m128i low10 = _mm_set1_epi32(0x3ff); 151+ const __m128i cpbase = _mm_set1_epi32(0x10000); 152+ const __m128i base = _mm_set1_epi32((int)0x808080f0u); 153+ const __m128i m1 = _mm_set1_epi32(0x00003f00); 154+ const __m128i m2 = _mm_set1_epi32(0x003f0000); 155+ const __m128i m3 = _mm_set1_epi32(0x3f000000); 156+ if (count >= 4) { 157+ __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); 158+ __m128i hi = _mm_and_si128(v, low10); 159+ __m128i lo = _mm_and_si128(_mm_srli_epi32(v, 16), low10); 160+ __m128i cp = _mm_add_epi32(cpbase, _mm_add_epi32(_mm_slli_epi32(hi, 10), lo)); 161+ __m128i x = _mm_or_si128(base, _mm_srli_epi32(cp, 18)); 162+ x = _mm_or_si128(x, _mm_and_si128(_mm_srli_epi32(cp, 4), m1)); 163+ x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 10), m2)); 164+ x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 24), m3)); 165+ _mm_storeu_si128((__m128i *)(void *)out, x); 166+ in += 8; out += 16; count -= 4; 167+ } 168+ if (count >= 2) { 169+ __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in); 170+ __m128i hi = _mm_and_si128(v, low10); 171+ __m128i lo = _mm_and_si128(_mm_srli_epi32(v, 16), low10); 172+ __m128i cp = _mm_add_epi32(cpbase, _mm_add_epi32(_mm_slli_epi32(hi, 10), lo)); 173+ __m128i x = _mm_or_si128(base, _mm_srli_epi32(cp, 18)); 174+ x = _mm_or_si128(x, _mm_and_si128(_mm_srli_epi32(cp, 4), m1)); ... (diff truncated)

{"command": "./grade --seed 48818", "intent": "Verify exact-prefix surrogate optimization and measure gain", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 2.6s verify 2.6s PASS measure 0.6s 18,913,591 instructions (given: 77,696,233) SCORE +2.0384 (4.108x) --- Command finished with exit code: 0 ---

{"intent": "Profile exact-prefix implementation for final refinements", "tool_calls": [{"tool": "bash", "command": "callgrind_annotate --auto=yes --inclusive=no --threshold=0.15 .build/callgrind.runner.out submission/solve.c 2>/dev/null | sed -n '1,420p'", "timeout": 10000, "intent": "Identify remaining hot paths after exact-prefix optimizations"}, {"tool": "bash", "command": "objdump -d -Mintel --disassemble=utf16_to_utf8 .build/runner | wc -l; size .build/runner; tail -n 10 scores.jsonl", "timeout": 10000, "intent": "Review code size and score progression"}]}

--- [1] bash --- -------------------------------------------------------------------------------- Profile data file '.build/callgrind.runner.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 594724 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner /tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/corpus_48818.bin (PID 931, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 0.15 Include dirs: User annotated: submission/solve.c Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 3,443,438 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 2,117,607 (61.50%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T081317Z-jcode-solo-gpt-5.6-sol-utf16-transcode/tasks/utf16-transcode/.build/runner] -------------------------------------------------------------------------------- -- User-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir -- line 2 ---------------------------------------- . #include <stdint.h> . #include <stddef.h> . #include <string.h> . #include <immintrin.h> . . #define INVALID ((size_t)-1) . . static inline void put2(uint8_t *p, uint32_t c) { 36,757 ( 1.07%) uint16_t x = (uint16_t)(0x80c0u | (c >> 6) | ((c & 63u) << 8)); . memcpy(p, &x, sizeof(x)); . } . . // The fourth byte is harmless: the contract provides four bytes of slop and . // the next output overwrites it. . static inline void put3(uint8_t *p, uint32_t c) { 5,929 ( 0.17%) uint32_t x = 0x008080e0u | (c >> 12) | 53,361 ( 1.55%) ((c << 2) & 0x00003f00u) | ((c << 16) & 0x003f0000u); . memcpy(p, &x, sizeof(x)); . } . . static inline void put4(uint8_t *p, uint32_t cp) { 7,342 ( 0.21%) uint32_t x = 0x808080f0u | (cp >> 18) | 11,013 ( 0.32%) ((cp >> 4) & 0x00003f00u) | 25,697 ( 0.75%) ((cp << 10) & 0x003f0000u) | 11,013 ( 0.32%) ((cp << 24) & 0x3f000000u); . memcpy(p, &x, sizeof(x)); . } . . __attribute__((always_inline, target("avx2,bmi2"))) . static inline void put_ascii_prefix(const uint16_t **pin, uint8_t **pout, . unsigned count) { . const uint16_t *in = *pin; . uint8_t *out = *pout; . if (count >= 16) { . __m256i v = _mm256_loadu_si256((const __m256i *)(const void *)in); . v = _mm256_packus_epi16(v, v); . v = _mm256_permute4x64_epi64(v, 0xd8); . _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(v)); 6,951 ( 0.20%) in += 16; out += 16; count -= 16; . } 42,432 ( 1.23%) if (count >= 8) { . __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); . v = _mm_packus_epi16(v, v); . _mm_storel_epi64((__m128i *)(void *)out, v); 19,419 ( 0.56%) in += 8; out += 8; count -= 8; . } 42,658 ( 1.24%) if (count >= 4) { . uint64_t v; . memcpy(&v, in, sizeof(v)); 10,649 ( 0.31%) uint32_t x = (uint32_t)_pext_u64(v, UINT64_C(0x00ff00ff00ff00ff)); . memcpy(out, &x, sizeof(x)); 31,947 ( 0.93%) in += 4; out += 4; count -= 4; . } 64,058 ( 1.86%) if (count >= 2) { . uint32_t v; . memcpy(&v, in, sizeof(v)); 10,747 ( 0.31%) uint16_t x = (uint16_t)_pext_u32(v, 0x00ff00ffu); . memcpy(out, &x, sizeof(x)); 32,241 ( 0.94%) in += 2; out += 2; count -= 2; . } 87,691 ( 2.55%) if (count) *out++ = (uint8_t)*in++; . *pin = in; . *pout = out; . } . . __attribute__((always_inline, target("avx2"))) . static inline void put_two_prefix(const uint16_t **pin, uint8_t **pout, . unsigned count) { . const uint16_t *in = *pin; . uint8_t *out = *pout; . const __m128i m = _mm_set1_epi16(0x3f00); . const __m128i b = _mm_set1_epi16((short)0x80c0); 20,802 ( 0.60%) if (count >= 8) { . __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); . __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6), . _mm_and_si128(_mm_slli_epi16(v, 8), m)); . _mm_storeu_si128((__m128i *)(void *)out, _mm_or_si128(x, b)); 14,490 ( 0.42%) in += 8; out += 16; count -= 8; . } 20,866 ( 0.61%) if (count >= 4) { . __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in); . __m128i x = _mm_or_si128(_mm_srli_epi16(v, 6), . _mm_and_si128(_mm_slli_epi16(v, 8), m)); . _mm_storel_epi64((__m128i *)(void *)out, _mm_or_si128(x, b)); 19,340 ( 0.56%) in += 4; out += 8; count -= 4; . } 20,866 ( 0.61%) if (count >= 2) { . uint32_t v; 5,745 ( 0.17%) memcpy(&v, in, sizeof(v)); 34,470 ( 1.00%) uint32_t x = 0x80c080c0u | ((v >> 6) & 0x001f001fu) | 11,490 ( 0.33%) ((v << 8) & 0x3f003f00u); . memcpy(out, &x, sizeof(x)); 17,235 ( 0.50%) in += 2; out += 4; count -= 2; . } 36,442 ( 1.06%) if (count) { put2(out, *in); ++in; out += 2; } . *pin = in; . *pout = out; . } . . __attribute__((always_inline, target("avx2"))) . static inline void put_three_prefix(const uint16_t **pin, uint8_t **pout, . unsigned count) { . const uint16_t *in = *pin; . uint8_t *out = *pout; . const __m256i m1 = _mm256_set1_epi32(0x00003f00); . const __m256i m2 = _mm256_set1_epi32(0x003f0000); . const __m256i base = _mm256_set1_epi32(0x008080e0); . const __m256i shuf = _mm256_setr_epi8( . 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1, . 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1); 7,946 ( 0.23%) if (count >= 8) { . __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); . __m256i a = _mm256_cvtepu16_epi32(v); . __m256i a1 = _mm256_and_si256(_mm256_slli_epi32(a, 2), m1); . __m256i a2 = _mm256_and_si256(_mm256_slli_epi32(a, 16), m2); . a = _mm256_or_si256(base, _mm256_or_si256(_mm256_srli_epi32(a, 12), . _mm256_or_si256(a1, a2))); . a = _mm256_shuffle_epi8(a, shuf); . _mm_storeu_si128((__m128i *)(void *)out, _mm256_castsi256_si128(a)); . _mm_storeu_si128((__m128i *)(void *)(out + 12), _mm256_extracti128_si256(a, 1)); 5,901 ( 0.17%) in += 8; out += 24; count -= 8; . } 7,946 ( 0.23%) if (count >= 4) { . __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in); . __m128i a = _mm_cvtepu16_epi32(v); . __m128i a1 = _mm_and_si128(_mm_slli_epi32(a, 2), _mm256_castsi256_si128(m1)); . __m128i a2 = _mm_and_si128(_mm_slli_epi32(a, 16), _mm256_castsi256_si128(m2)); . a = _mm_or_si128(_mm256_castsi256_si128(base), . _mm_or_si128(_mm_srli_epi32(a, 12), _mm_or_si128(a1, a2))); . a = _mm_shuffle_epi8(a, _mm256_castsi256_si128(shuf)); . _mm_storeu_si128((__m128i *)(void *)out, a); 5,904 ( 0.17%) in += 4; out += 12; count -= 4; . } 7,946 ( 0.23%) if (count >= 2) { 1,982 ( 0.06%) put3(out, in[0]); 1,982 ( 0.06%) put3(out + 3, in[1]); 5,946 ( 0.17%) in += 2; out += 6; count -= 2; . } 13,670 ( 0.40%) if (count) { put3(out, *in); ++in; out += 3; } . *pin = in; . *pout = out; . } . . __attribute__((always_inline, target("avx2"))) . static inline void put_pair_prefix(const uint16_t **pin, uint8_t **pout, . unsigned count) { . const uint16_t *in = *pin; . uint8_t *out = *pout; . const __m128i low10 = _mm_set1_epi32(0x3ff); . const __m128i cpbase = _mm_set1_epi32(0x10000); . const __m128i base = _mm_set1_epi32((int)0x808080f0u); . const __m128i m1 = _mm_set1_epi32(0x00003f00); . const __m128i m2 = _mm_set1_epi32(0x003f0000); . const __m128i m3 = _mm_set1_epi32(0x3f000000); 13,684 ( 0.40%) if (count >= 4) { . __m128i v = _mm_loadu_si128((const __m128i *)(const void *)in); . __m128i hi = _mm_and_si128(v, low10); . __m128i lo = _mm_and_si128(_mm_srli_epi32(v, 16), low10); . __m128i cp = _mm_add_epi32(cpbase, _mm_add_epi32(_mm_slli_epi32(hi, 10), lo)); . __m128i x = _mm_or_si128(base, _mm_srli_epi32(cp, 18)); . x = _mm_or_si128(x, _mm_and_si128(_mm_srli_epi32(cp, 4), m1)); . x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 10), m2)); . x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(cp, 24), m3)); . _mm_storeu_si128((__m128i *)(void *)out, x); 9,972 ( 0.29%) in += 8; out += 16; count -= 4; . } 13,716 ( 0.40%) if (count >= 2) { . __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in); . __m128i hi = _mm_and_si128(v, low10); . __m128i lo = _mm_and_si128(_mm_srli_epi32(v, 16), low10); . __m128i cp = _mm_add_epi32(cpbase, _mm_add_epi32(_mm_slli_epi32(hi, 10), lo)); . __m128i x = _mm_or_si128(base, _mm_srli_epi32(cp, 18)); . x = _mm_or_si128(x, _mm_and_si128(_mm_srli_epi32(cp, 4), m1)); . x = _mm_or_si128(x, _mm_and_si128(_mm_slli_epi32(c ... [14485 characters truncated for page size]

{"edits": [{"new_string": " const uint16_t *const end = in + n;\n uint8_t *const out_begin = out;\n const uintptr_t lim32 = n >= 32 ? (uintptr_t)(end - 32) : 0;\n const uintptr_t lim16 = n >= 16 ? (uintptr_t)(end - 16) : 0;\n const uintptr_t lim8 = n >= 8 ? (uintptr_t)(end - 8) : 0;\n const uintptr_t lim4 = n >= 4 ? (uintptr_t)(end - 4) : 0;\n const uintptr_t lim2 = n >= 2 ? (uintptr_t)(end - 2) : 0;\n", "old_string": " const uint16_t *const end = in + n;\n uint8_t *const out_begin = out;\n", "replace_all": false}, {"new_string": "while ((uintptr_t)in <= lim32)", "old_string": "while ((size_t)(end - in) >= 32)", "replace_all": true}, {"new_string": "if ((uintptr_t)in <= lim16)", "old_string": "if ((size_t)(end - in) >= 16)", "replace_all": true}, {"new_string": "while ((uintptr_t)in <= lim16)", "old_string": "while ((size_t)(end - in) >= 16)", "replace_all": true}, {"new_string": "if ((uintptr_t)in <= lim8)", "old_string": "if ((size_t)(end - in) >= 8)", "replace_all": true}, {"new_string": "if ((uintptr_t)in <= lim4)", "old_string": "if ((size_t)(end - in) >= 4)", "replace_all": true}, {"new_string": "if ((uintptr_t)in <= lim2 &&", "old_string": "if ((size_t)(end - in) >= 2 &&", "replace_all": true}, {"new_string": "if ((uintptr_t)in <= lim2)", "old_string": "if ((size_t)(end - in) >= 2)", "replace_all": true}, {"new_string": "if ((uintptr_t)in > lim2) return INVALID;", "old_string": "if (end - in < 2) return INVALID;", "replace_all": true}], "file_path": "submission/solve.c", "intent": "Hoist SIMD boundary limits out of hot loops"}

Edited submission/solve.c Applied: ✓ Edit 1: replaced 1 occurrence ✓ Edit 2: replaced 1 occurrences ✓ Edit 3: replaced 1 occurrences ✓ Edit 4: replaced 3 occurrences ✓ Edit 5: replaced 4 occurrences ✓ Edit 6: replaced 4 occurrences ✓ Edit 7: replaced 2 occurrences ✓ Edit 8: replaced 1 occurrences ✓ Edit 9: replaced 1 occurrences Total: 9 applied, 0 failed Diff: 195+ const uintptr_t lim32 = n >= 32 ? (uintptr_t)(end - 32) : 0; 196+ const uintptr_t lim16 = n >= 16 ? (uintptr_t)(end - 16) : 0; 197+ const uintptr_t lim8 = n >= 8 ? (uintptr_t)(end - 8) : 0; 198+ const uintptr_t lim4 = n >= 4 ? (uintptr_t)(end - 4) : 0; 199+ const uintptr_t lim2 = n >= 2 ? (uintptr_t)(end - 2) : 0; 226- while ((size_t)(end - in) >= 32) { 231+ while ((uintptr_t)in <= lim32) { 249- if ((size_t)(end - in) >= 16) { 254+ if ((uintptr_t)in <= lim16) { 265- if ((size_t)(end - in) >= 8) { 270+ if ((uintptr_t)in <= lim8) { 282- if ((size_t)(end - in) >= 4) { 287+ if ((uintptr_t)in <= lim4) { 292- if ((size_t)(end - in) >= 2 && in[0] < 0x80 && in[1] < 0x80) { 297+ if ((uintptr_t)in <= lim2 && in[0] < 0x80 && in[1] < 0x80) { 310- while ((size_t)(end - in) >= 16) { 315+ while ((uintptr_t)in <= lim16) { 327- if ((size_t)(end - in) >= 8) { 332+ if ((uintptr_t)in <= lim8) { 346- if ((size_t)(end - in) >= 4) { 351+ if ((uintptr_t)in <= lim4) { 360- if ((size_t)(end - in) >= 2) { 365+ if ((uintptr_t)in <= lim2) { 384- while ((size_t)(end - in) >= 16) { 389+ while ((uintptr_t)in <= lim16) { 415- if ((size_t)(end - in) >= 8) { 420+ if ((uintptr_t)in <= lim8) { 438- if ((size_t)(end - in) >= 4) { 443+ if ((uintptr_t)in <= lim4) { 457- if ((size_t)(end - in) >= 2 && in[0] >= 0x800 && in[1] >= 0x800 && ...

{"intent": "Verify hoisted limit optimization", "tool_calls": [{"tool": "bash", "command": "./grade --seed 48818", "timeout": 600000, "intent": "Check correctness and score of hoisted boundary comparisons"}, {"tool": "bash", "command": "grep -n 'end - in\\|lim[0-9]' submission/solve.c", "timeout": 10000, "intent": "Audit all boundary checks after replacement"}]}

--- [1] bash --- build 2.6s verify 2.5s PASS measure 0.6s 18,156,151 instructions (given: 77,696,233) SCORE +2.0974 (4.279x) --- Command finished with exit code: 0 --- --- [2] bash --- 195: const uintptr_t lim32 = n >= 32 ? (uintptr_t)(end - 32) : 0; 196: const uintptr_t lim16 = n >= 16 ? (uintptr_t)(end - 16) : 0; 197: const uintptr_t lim8 = n >= 8 ? (uintptr_t)(end - 8) : 0; 198: const uintptr_t lim4 = n >= 4 ? (uintptr_t)(end - 4) : 0; 199: const uintptr_t lim2 = n >= 2 ? (uintptr_t)(end - 2) : 0; 203: const __m256i lim800 = _mm256_set1_epi16(0x0800); 231: while ((uintptr_t)in <= lim32) { 254: if ((uintptr_t)in <= lim16) { 270: if ((uintptr_t)in <= lim8) { 287: if ((uintptr_t)in <= lim4) { 297: if ((uintptr_t)in <= lim2 && in[0] < 0x80 && in[1] < 0x80) { 315: while ((uintptr_t)in <= lim16) { 318: __m256i lt800 = _mm256_cmpgt_epi16(lim800, v); 332: if ((uintptr_t)in <= lim8) { 335: __m128i lt800 = _mm_cmpgt_epi16(_mm256_castsi256_si128(lim800), v); 351: if ((uintptr_t)in <= lim4) { 354: __m128i lt800 = _mm_cmpgt_epi16(_mm256_castsi256_si128(lim800), v); 365: if ((uintptr_t)in <= lim2) { 389: while ((uintptr_t)in <= lim16) { 420: if ((uintptr_t)in <= lim8) { 443: if ((uintptr_t)in <= lim4) { 462: if ((uintptr_t)in <= lim2 && in[0] >= 0x800 && in[1] >= 0x800 && 491: while ((uintptr_t)in <= lim16) { 515: if ((uintptr_t)in <= lim8) { 544: if ((uintptr_t)in <= lim4) { 570: if ((uintptr_t)in > lim2) return INVALID; --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"intent": "Reuse four-unit surrogate probe for a leading complete pair", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n if ((uintptr_t)in <= lim4) {\n __m128i v = _mm_loadl_epi64((const __m128i *)(const void *)in);\n __m128i tags = _mm_cmpeq_epi16(\n _mm_and_si128(v, _mm256_castsi256_si128(pairmask)),\n _mm256_castsi256_si128(pairexpect));\n- if ((_mm_movemask_epi8(tags) & 0xff) == 0xff) {\n+ unsigned valid = (unsigned)_mm_movemask_epi8(tags) & 0xffu;\n+ if (valid == 0xff) {\n@@\n in += 4;\n out += 8;\n+ } else {\n+ unsigned units = (unsigned)__builtin_ctz((~valid) & 0xffu) >> 1;\n+ if (units >= 2) {\n+ uint32_t cp = 0x10000u + (((uint32_t)in[0] - 0xd800u) << 10) +\n+ ((uint32_t)in[1] - 0xdc00u);\n+ put4(out, cp);\n+ in += 2;\n+ out += 4;\n+ }\n+ goto pair_scalar;\n }\n }\n*** End Patch"}

✓ submission/solve.c: modified (2 hunks) 549- if ((_mm_movemask_epi8(tags) & 0xff) == 0xff) { 549+ unsigned valid = (unsigned)_mm_movemask_epi8(tags) & 0xffu; 550+ if (valid == 0xff) { 567+ } else { 568+ unsigned units = (unsigned)__builtin_ctz((~valid) & 0xffu) >> 1; 569+ if (units >= 2) { 570+ uint32_t cp = 0x10000u + (((uint32_t)in[0] - 0xd800u) << 10) + 571+ ((uint32_t)in[1] - 0xdc00u); 572+ put4(out, cp); 573+ in += 2; 574+ out += 4; 575+ } 576+ goto pair_scalar;

{"command": "./grade --seed 48818", "intent": "Measure four-unit surrogate prefix reuse", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 2.7s verify 2.6s PASS measure 0.7s 18,183,940 instructions (given: 77,696,233) SCORE +2.0952 (4.273x) --- Command finished with exit code: 0 ---

{"intent": "Revert unhelpful four-unit surrogate prefix branch", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n- unsigned valid = (unsigned)_mm_movemask_epi8(tags) & 0xffu;\n- if (valid == 0xff) {\n+ if ((_mm_movemask_epi8(tags) & 0xff) == 0xff) {\n@@\n- } else {\n- unsigned units = (unsigned)__builtin_ctz((~valid) & 0xffu) >> 1;\n- if (units >= 2) {\n- uint32_t cp = 0x10000u + (((uint32_t)in[0] - 0xd800u) << 10) +\n- ((uint32_t)in[1] - 0xdc00u);\n- put4(out, cp);\n- in += 2;\n- out += 4;\n- }\n- goto pair_scalar;\n }\n*** End Patch"}

✓ submission/solve.c: modified (2 hunks) 549- unsigned valid = (unsigned)_mm_movemask_epi8(tags) & 0xffu; 550- if (valid == 0xff) { 549+ if ((_mm_movemask_epi8(tags) & 0xff) == 0xff) { 567- } else { 568- unsigned units = (unsigned)__builtin_ctz((~valid) & 0xffu) >> 1; 569- if (units >= 2) { 570- uint32_t cp = 0x10000u + (((uint32_t)in[0] - 0xd800u) << 10) + 571- ((uint32_t)in[1] - 0xdc00u); 572- put4(out, cp); 573- in += 2; 574- out += 4; 575- } 576- goto pair_scalar;

{"file_path": "submission/solve.c", "intent": "Test higher per-function compiler optimization level", "new_string": "__attribute__((target(\"avx2,bmi2\"), optimize(\"O3\")))\nsize_t utf16_to_utf8", "old_string": "__attribute__((target(\"avx2,bmi2\")))\nsize_t utf16_to_utf8", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 190- __attribute__((target("avx2,bmi2"))) 190+ __attribute__((target("avx2,bmi2"), optimize("O3"))) Context after edit (lines 187-194): 187│ *pout = out; 188│ } 189│ 190│ __attribute__((target("avx2,bmi2"), optimize("O3"))) 191│ size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 192│ const uint16_t *const begin = in; 193│ const uint16_t *const end = in + n; 194│ uint8_t *const out_begin = out;

{"command": "./grade --seed 48818", "intent": "Measure per-function O3 code generation", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 2.7s verify 2.6s PASS measure 0.6s 18,389,710 instructions (given: 77,696,233) SCORE +2.0789 (4.225x) --- Command finished with exit code: 0 ---

{"intent": "Add a 128-unit initial ASCII fast path and restore O2", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n-__attribute__((target(\"avx2,bmi2\"), optimize(\"O3\")))\n+__attribute__((target(\"avx2,bmi2\")))\n size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) {\n@@\n uint8_t *const out_begin = out;\n+ const uintptr_t lim128 = n >= 128 ? (uintptr_t)(end - 128) : 0;\n@@\n const __m256i compress3 = _mm256_setr_epi8(\n@@\n 0,1,2, 4,5,6, 8,9,10, 12,13,14, -1,-1,-1,-1);\n+\n+ // A one-time wide probe targets records from the all-ASCII regime. It is\n+ // deliberately not retried after mixed text has been observed.\n+ while ((uintptr_t)in <= lim128) {\n+ __m256i v0 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 0));\n+ __m256i v1 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16));\n+ __m256i v2 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 32));\n+ __m256i v3 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 48));\n+ __m256i v4 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 64));\n+ __m256i v5 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 80));\n+ __m256i v6 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 96));\n+ __m256i v7 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 112));\n+ __m256i any = _mm256_or_si256(_mm256_or_si256(v0, v1),\n+ _mm256_or_si256(_mm256_or_si256(v2, v3),\n+ _mm256_or_si256(_mm256_or_si256(v4, v5),\n+ _mm256_or_si256(v6, v7))));\n+ if (!_mm256_testz_si256(any, ascii_mask)) break;\n+ __m256i x0 = _mm256_permute4x64_epi64(_mm256_packus_epi16(v0, v1), 0xd8);\n+ __m256i x1 = _mm256_permute4x64_epi64(_mm256_packus_epi16(v2, v3), 0xd8);\n+ __m256i x2 = _mm256_permute4x64_epi64(_mm256_packus_epi16(v4, v5), 0xd8);\n+ __m256i x3 = _mm256_permute4x64_epi64(_mm256_packus_epi16(v6, v7), 0xd8);\n+ _mm256_storeu_si256((__m256i *)(void *)(out + 0), x0);\n+ _mm256_storeu_si256((__m256i *)(void *)(out + 32), x1);\n+ _mm256_storeu_si256((__m256i *)(void *)(out + 64), x2);\n+ _mm256_storeu_si256((__m256i *)(void *)(out + 96), x3);\n+ in += 128;\n+ out += 128;\n+ }\n \n while (in < end) {\n*** End Patch"}

✓ submission/solve.c: modified (4 hunks) 190- __attribute__((target("avx2,bmi2"), optimize("O3"))) 190+ __attribute__((target("avx2,bmi2"))) 195+ const uintptr_t lim128 = n >= 128 ? (uintptr_t)(end - 128) : 0; 227+ // A one-time wide probe targets records from the all-ASCII regime. It is 228+ // deliberately not retried after mixed text has been observed. 229+ while ((uintptr_t)in <= lim128) { 230+ __m256i v0 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 0)); 231+ __m256i v1 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 16)); 232+ __m256i v2 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 32)); 233+ __m256i v3 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 48)); 234+ __m256i v4 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 64)); 235+ __m256i v5 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 80)); 236+ __m256i v6 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 96)); 237+ __m256i v7 = _mm256_loadu_si256((const __m256i *)(const void *)(in + 112)); 238+ __m256i any = _mm256_or_si256(_mm256_or_si256(v0, v1), 239+ _mm256_or_si256(_mm256_or_si256(v2, v3), 240+ _mm256_or_si256(_mm256_or_si256(v4, v5), 241+ _mm256_or_si256(v6, v7)))); 242+ if (!_mm256_testz_si256(any, ascii_mask)) break; 243+ __m256i x0 = _mm256_permute4x64_epi64(_mm256_packus_epi16(v0, v1), 0xd8); 244+ __m256i x1 = _mm256_permute4x64_epi64(_mm256_packus_epi16(v2, v3), 0xd8); 245+ __m256i x2 = _mm256_permute4x64_epi64(_mm256_packus_epi16(v4, v5), 0xd8); 246+ __m256i x3 = _mm256_permute4x64_epi64(_mm256_packus_epi16(v6, v7), 0xd8); 247+ _mm256_storeu_si256((__m256i *)(void *)(out + 0), x0); 248+ _mm256_storeu_si256((__m256i *)(void *)(out + 32), x1); 249+ _mm256_storeu_si256((__m256i *)(void *)(out + 64), x2); 250+ _mm256_storeu_si256((__m256i *)(void *)(out + 96), x3); 251+ in += 128; 252+ out += 128; 253+ } ... (diff truncated)

{"command": "./grade --seed 48818", "intent": "Verify and measure 128-unit ASCII front end", "notify": false, "run_in_background": false, "timeout": 600000, "wake": false}

build 2.6s verify 2.6s PASS measure 0.6s 17,946,318 instructions (given: 77,696,233) SCORE +2.1142 (4.329x) --- Command finished with exit code: 0 ---

{"intent": "Validate final candidate across independent corpus seeds", "tool_calls": [{"tool": "bash", "command": "./grade --seed 12345", "timeout": 600000, "intent": "Cross-check correctness and performance on a different corpus"}, {"tool": "bash", "command": "./grade --seed 77777", "timeout": 600000, "intent": "Cross-check correctness and performance on another corpus"}]}

--- [1] bash --- build 2.7s verify 2.6s PASS measure 1.8s 18,048,295 instructions (given: 77,792,209) SCORE +2.1078 (4.310x) --- Command finished with exit code: 0 --- --- [2] bash --- build 2.3s verify 2.5s PASS measure 1.9s 18,071,952 instructions (given: 78,211,638) SCORE +2.1136 (4.328x) --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"tool_calls": [{"tool": "agentgrep", "path": "submission/solve.c", "query": "*(const int", "intent": "Find unsafe typed loads"}, {"tool": "bash", "command": "git status --short && git diff --stat && cc -O2 -std=c17 -Wall -Wextra -Wpedantic -c submission/solve.c -o \"$JCODE_SCRATCH_DIR/solve.o\"", "timeout": 10000, "intent": "Audit changes and compiler warnings"}], "intent": "Audit final code safety and repository state"}

--- [1] agentgrep --- query: *(const int matches: 1 in 1 files solve.c symbols: no structural items detected - <file scope> - @ 494 __m128i v = _mm_cvtsi32_si128(*(const int *)(const void *)in); --- [2] bash --- fatal: not a git repository (or any of the parent directories): .git --- Command finished with exit code: 128 --- Exit code: 128 Completed: 2 succeeded, 0 failed

{"intent": "Remove strict-aliasing and alignment undefined behavior from short load", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n if ((uintptr_t)in <= lim2 && in[0] >= 0x800 && in[1] >= 0x800 &&\n (uint16_t)(in[0] - 0xd800) >= 0x800 &&\n (uint16_t)(in[1] - 0xd800) >= 0x800) {\n- __m128i v = _mm_cvtsi32_si128(*(const int *)(const void *)in);\n+ uint32_t packed;\n+ memcpy(&packed, in, sizeof(packed));\n+ __m128i v = _mm_cvtsi32_si128((int)packed);\n*** End Patch"}

✓ submission/solve.c: modified (1 hunks) 494- __m128i v = _mm_cvtsi32_si128(*(const int *)(const void *)in); 494+ uint32_t packed; 495+ memcpy(&packed, in, sizeof(packed)); 496+ __m128i v = _mm_cvtsi32_si128((int)packed);

{"intent": "Run final warning audit and benchmark gate", "tool_calls": [{"tool": "bash", "command": "cc -O2 -std=c17 -Wall -Wextra -Wpedantic -c submission/solve.c -o \"$JCODE_SCRATCH_DIR/solve.o\"", "timeout": 10000, "intent": "Compile final source with strict warnings"}, {"tool": "bash", "command": "./grade --seed 48818", "timeout": 600000, "intent": "Run final exhaustive correctness gate and deterministic score"}]}

--- [1] bash --- --- Command finished with exit code: 0 --- --- [2] bash --- build 2.3s verify 2.6s PASS measure 0.6s 17,946,318 instructions (given: 77,696,233) SCORE +2.1142 (4.329x) --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"goals": [{"end_to_end_ownership": 100, "feedback_loop": "Repeated ./grade with fixed and independent seeds, compared instruction scores, reverted regressions, and compiled with strict warnings.", "group": "optimize", "hill_climbability": 98, "objective": "Maximize instruction-count improvement while passing every correctness case.", "user_intention": "Produce the fastest correct C17 UTF-16 transcoder implementation under the benchmark constraints.", "user_intention_alignment": 100}], "intent": "Mark optimization benchmark complete", "todos": [{"completion_confidence": 100, "confidence": 100, "content": "Read spec and baseline implementation", "group": "optimize", "id": "inspect", "priority": "high", "status": "completed"}, {"completion_confidence": 98, "confidence": 98, "content": "Identify hot paths and implement optimized transcoding", "group": "optimize", "id": "optimize", "priority": "high", "status": "completed"}, {"completion_confidence": 98, "confidence": 98, "content": "Grade repeatedly and refine instruction count", "group": "optimize", "id": "iterate", "priority": "high", "status": "completed"}, {"completion_confidence": 100, "confidence": 100, "content": "Verify final correctness and report score", "group": "optimize", "id": "final", "priority": "high", "status": "completed"}]}

[ { "content": "Read spec and baseline implementation", "status": "completed", "priority": "high", "id": "inspect", "group": "optimize", "confidence": 100, "completion_confidence": 100, "confidence_history": [ 95, 100 ] }, { "content": "Identify hot paths and implement optimized transcoding", "status": "completed", "priority": "high", "id": "optimize", "group": "optimize", "confidence": 98, "completion_confidence": 98, "confidence_history": [ 85, 98 ] }, { "content": "Grade repeatedly and refine instruction count", "status": "completed", "priority": "high", "id": "iterate", "group": "optimize", "confidence": 98, "completion_confidence": 98, "confidence_history": [ 90, 98 ] }, { "content": "Verify final correctness and report score", "status": "completed", "priority": "high", "id": "final", "group": "optimize", "confidence": 100, "completion_confidence": 100, "confidence_history": [ 95, 100 ] } ] Goals: [ { "group": "optimize", "user_intention": "Produce the fastest correct C17 UTF-16 transcoder implementation under the benchmark constraints.", "user_intention_alignment": 100, "hill_climbability": 98, "objective": "Maximize instruction-count improvement while passing every correctness case.", "feedback_loop": "Repeated ./grade with fixed and independent seeds, compared instruction scores, reverted regressions, and compiled with strict warnings.", "end_to_end_ownership": 100 } ]