jcode + GPT-5.4 on utf16-transcode

{"goals": [{"end_to_end_ownership": null, "feedback_loop": "Run ./grade after each meaningful optimization and use score plus correctness to guide next changes.", "group": "utf16-transcode optimization", "hill_climbability": 95, "objective": "Increase deterministic callgrind score while preserving correctness on all grader inputs.", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100}], "intent": "Track benchmark optimization work", "todos": [{"completion_confidence": null, "confidence": 90, "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "group": "utf16-transcode optimization", "id": "t1", "priority": "high", "status": "in_progress"}, {"completion_confidence": null, "confidence": 80, "content": "Implement targeted performance optimizations under submission/ only", "group": "utf16-transcode optimization", "id": "t2", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 85, "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "group": "utf16-transcode optimization", "id": "t3", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 70, "content": "Iterate until no further meaningful gains are found and report final score", "group": "utf16-transcode optimization", "id": "t4", "priority": "medium", "status": "pending"}]}

[ { "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "status": "in_progress", "priority": "high", "id": "t1", "group": "utf16-transcode optimization", "confidence": 90, "confidence_history": [ 90 ] }, { "content": "Implement targeted performance optimizations under submission/ only", "status": "pending", "priority": "high", "id": "t2", "group": "utf16-transcode optimization", "confidence": 80, "confidence_history": [ 80 ] }, { "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "status": "pending", "priority": "high", "id": "t3", "group": "utf16-transcode optimization", "confidence": 85, "confidence_history": [ 85 ] }, { "content": "Iterate until no further meaningful gains are found and report final score", "status": "pending", "priority": "medium", "id": "t4", "group": "utf16-transcode optimization", "confidence": 70, "confidence_history": [ 70 ] } ] Goals: [ { "group": "utf16-transcode optimization", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100, "hill_climbability": 95, "objective": "Increase deterministic callgrind score while preserving correctness on all grader inputs.", "feedback_loop": "Run ./grade after each meaningful optimization and use score plus correctness to guide next changes." } ] Your hill-climbability is not high enough. First, improve the goal's objective and feedback loop so progress can be measured across iterations. Then call the todo tool again with the revised goal before continuing the task. The goal is to create a strong feedback loop you can iterate against.

{"goals": [{"end_to_end_ownership": null, "feedback_loop": "After each code change, run ./grade, record the latest score from its output or scores.jsonl, and compare against the previous best. Keep only changes that preserve correctness and improve or meaningfully explain score movement.", "group": "utf16-transcode optimization", "hill_climbability": 98, "objective": "Maximize the grader's deterministic callgrind score for submission/solve.c, measured as log2 instruction-count improvement over baseline, while keeping 100% correctness on every graded input.", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100}], "intent": "Strengthen measurable optimization feedback loop", "todos": [{"completion_confidence": null, "confidence": 90, "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "group": "utf16-transcode optimization", "id": "t1", "priority": "high", "status": "in_progress"}, {"completion_confidence": null, "confidence": 80, "content": "Implement targeted performance optimizations under submission/ only", "group": "utf16-transcode optimization", "id": "t2", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 85, "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "group": "utf16-transcode optimization", "id": "t3", "priority": "high", "status": "pending"}, {"completion_confidence": null, "confidence": 70, "content": "Iterate until no further meaningful gains are found and report final score", "group": "utf16-transcode optimization", "id": "t4", "priority": "medium", "status": "pending"}]}

[ { "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "status": "in_progress", "priority": "high", "id": "t1", "group": "utf16-transcode optimization", "confidence": 90, "confidence_history": [ 90 ] }, { "content": "Implement targeted performance optimizations under submission/ only", "status": "pending", "priority": "high", "id": "t2", "group": "utf16-transcode optimization", "confidence": 80, "confidence_history": [ 80 ] }, { "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "status": "pending", "priority": "high", "id": "t3", "group": "utf16-transcode optimization", "confidence": 85, "confidence_history": [ 85 ] }, { "content": "Iterate until no further meaningful gains are found and report final score", "status": "pending", "priority": "medium", "id": "t4", "group": "utf16-transcode optimization", "confidence": 70, "confidence_history": [ 70 ] } ] Goals: [ { "group": "utf16-transcode optimization", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100, "hill_climbability": 98, "objective": "Maximize the grader's deterministic callgrind score for submission/solve.c, measured as log2 instruction-count improvement over baseline, while keeping 100% correctness on every graded input.", "feedback_loop": "After each code change, run ./grade, record the latest score from its output or scores.jsonl, and compare against the previous best. Keep only changes that preserve correctness and improve or meaningfully explain score movement." } ] Goal updates: [ { "before": { "group": "utf16-transcode optimization", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100, "hill_climbability": 95, "objective": "Increase deterministic callgrind score while preserving correctness on all grader inputs.", "feedback_loop": "Run ./grade after each meaningful optimization and use score plus correctness to guide next changes." }, "after": { "group": "utf16-transcode optimization", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100, "hill_climbability": 98, "objective": "Maximize the grader's deterministic callgrind score for submission/solve.c, measured as log2 instruction-count improvement over baseline, while keeping 100% correctness on every graded input.", "feedback_loop": "After each code change, run ./grade, record the latest score from its output or scores.jsonl, and compare against the previous best. Keep only changes that preserve correctness and improve or meaningfully explain score movement." }, "fields": [ "hill_climbability", "objective", "feedback_loop" ] } ]

{"intent": "Read spec and baseline files", "tool_calls": [{"tool": "ls", "path": ".", "ignore": [".git", "node_modules", "target", "build"], "intent": "List task files"}, {"tool": "read", "file_path": "spec.md", "start_line": 1, "limit": 400, "intent": "Read benchmark spec"}, {"tool": "read", "file_path": "submission/solve.c", "start_line": 1, "limit": 400, "intent": "Read baseline solve implementation"}]}

--- [1] 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 --- [2] 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. --- [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 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 } Completed: 3 succeeded, 0 failed

{"intent": "Inspect reference and grading behavior", "tool_calls": [{"tool": "read", "file_path": "verify/reference.c", "start_line": 1, "limit": 300, "intent": "Read reference implementation"}, {"tool": "read", "file_path": "grade", "start_line": 1, "limit": 300, "intent": "Read grader script"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Run baseline grade"}]}

--- [1] read --- 1 // reference.c — oracle for utf16-transcode. Defines the semantics. 2 #include <stdint.h> 3 #include <stddef.h> 4 5 #define INVALID ((size_t)-1) 6 7 size_t ref_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { 8 size_t o = 0, i = 0; 9 while (i < n) { 10 uint32_t cu = in[i]; 11 uint32_t cp; 12 if (cu >= 0xD800 && cu <= 0xDBFF) { 13 if (i + 1 >= n) return INVALID; 14 uint32_t lo = in[i + 1]; 15 if (!(lo >= 0xDC00 && lo <= 0xDFFF)) return INVALID; 16 cp = 0x10000u + ((cu - 0xD800u) * 0x400u) + (lo - 0xDC00u); 17 i += 2; 18 } else if (cu >= 0xDC00 && cu <= 0xDFFF) { 19 return INVALID; 20 } else { 21 cp = cu; 22 i += 1; 23 } 24 if (cp <= 0x7F) { 25 out[o++] = (uint8_t)cp; 26 } else if (cp <= 0x7FF) { 27 out[o++] = (uint8_t)(0xC0u | (cp >> 6)); 28 out[o++] = (uint8_t)(0x80u | (cp & 0x3Fu)); 29 } else if (cp <= 0xFFFF) { 30 out[o++] = (uint8_t)(0xE0u | (cp >> 12)); 31 out[o++] = (uint8_t)(0x80u | ((cp >> 6) & 0x3Fu)); 32 out[o++] = (uint8_t)(0x80u | (cp & 0x3Fu)); 33 } else { 34 out[o++] = (uint8_t)(0xF0u | (cp >> 18)); 35 out[o++] = (uint8_t)(0x80u | ((cp >> 12) & 0x3Fu)); 36 out[o++] = (uint8_t)(0x80u | ((cp >> 6) & 0x3Fu)); 37 out[o++] = (uint8_t)(0x80u | (cp & 0x3Fu)); 38 } 39 } 40 return o; 41 } --- [2] 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") --- [3] bash --- build 0.5s verify 2.0s PASS measure 6.8s 79,109,690 instructions (given: 77,949,142) SCORE -0.0213 (0.985x) --- Command finished with exit code: 0 --- Completed: 3 succeeded, 0 failed

{"intent": "Inspect benchmark driver and corpus characteristics", "tool_calls": [{"tool": "read", "file_path": "verify/runner.c", "start_line": 1, "limit": 300, "intent": "Read measurement runner"}, {"tool": "read", "file_path": "verify/gen_corpus.py", "start_line": 1, "limit": 400, "intent": "Read corpus generator"}, {"tool": "read", "file_path": "verify/verify.c", "start_line": 1, "limit": 300, "intent": "Read verifier harness"}]}

--- [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 #!/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] 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 } Completed: 3 succeeded, 0 failed

{"intent": "Replace baseline transcoder with optimized pointer-based implementation and ASCII fast path", "patch_text": "*** Begin Patch\n*** Delete File: submission/solve.c\n*** Add File: submission/solve.c\n+#include <stddef.h>\n+#include <stdint.h>\n+#include <string.h>\n+\n+#define INVALID ((size_t)-1)\n+\n+#if defined(__GNUC__) || defined(__clang__)\n+#define LIKELY(x) __builtin_expect(!!(x), 1)\n+#define UNLIKELY(x) __builtin_expect(!!(x), 0)\n+#else\n+#define LIKELY(x) (x)\n+#define UNLIKELY(x) (x)\n+#endif\n+\n+static inline uint64_t load64(const void *src) {\n+ uint64_t v;\n+ memcpy(&v, src, sizeof(v));\n+ return v;\n+}\n+\n+static inline void store32(void *dst, uint32_t v) {\n+ memcpy(dst, &v, sizeof(v));\n+}\n+\n+static inline void store64(void *dst, uint64_t v) {\n+ memcpy(dst, &v, sizeof(v));\n+}\n+\n+static inline uint32_t pack4_ascii(uint64_t x) {\n+ return (uint32_t)((x & 0x00000000000000FFULL)\n+ | ((x >> 8) & 0x000000000000FF00ULL)\n+ | ((x >> 16) & 0x0000000000FF0000ULL)\n+ | ((x >> 24) & 0x00000000FF000000ULL));\n+}\n+\n+static inline uint32_t pack2(uint32_t c) {\n+ return (0xC0u | (c >> 6))\n+ | ((0x80u | (c & 0x3Fu)) << 8);\n+}\n+\n+static inline uint32_t pack3(uint32_t c) {\n+ return (0xE0u | (c >> 12))\n+ | ((0x80u | ((c >> 6) & 0x3Fu)) << 8)\n+ | ((0x80u | (c & 0x3Fu)) << 16);\n+}\n+\n+static inline uint32_t pack4(uint32_t cp) {\n+ return (0xF0u | (cp >> 18))\n+ | ((0x80u | ((cp >> 12) & 0x3Fu)) << 8)\n+ | ((0x80u | ((cp >> 6) & 0x3Fu)) << 16)\n+ | ((0x80u | (cp & 0x3Fu)) << 24);\n+}\n+\n+size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) {\n+ const uint16_t *p = in;\n+ const uint16_t *const end = in + n;\n+ uint8_t *q = out;\n+\n+ while (p < end) {\n+ while (LIKELY((size_t)(end - p) >= 8)) {\n+ uint64_t x0 = load64(p);\n+ uint64_t x1 = load64(p + 4);\n+ if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break;\n+ store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32));\n+ p += 8;\n+ q += 8;\n+ }\n+\n+ if (LIKELY((size_t)(end - p) >= 4)) {\n+ uint64_t x = load64(p);\n+ if ((x & 0xFF80FF80FF80FF80ULL) == 0) {\n+ store32(q, pack4_ascii(x));\n+ p += 4;\n+ q += 4;\n+ continue;\n+ }\n+ }\n+\n+ uint32_t c = *p++;\n+ if (c < 0x80u) {\n+ *q++ = (uint8_t)c;\n+ continue;\n+ }\n+\n+ if (c < 0x800u) {\n+ do {\n+ store32(q, pack2(c));\n+ q += 2;\n+ if (p == end) return (size_t)(q - out);\n+ c = *p;\n+ if (c - 0x80u >= 0x780u) break;\n+ p++;\n+ } while (1);\n+ continue;\n+ }\n+\n+ if ((c & 0xF800u) != 0xD800u) {\n+ do {\n+ store32(q, pack3(c));\n+ q += 3;\n+ if (p == end) return (size_t)(q - out);\n+ c = *p;\n+ if (c < 0x800u || (c & 0xF800u) == 0xD800u) break;\n+ p++;\n+ } while (1);\n+ continue;\n+ }\n+\n+ if (c >= 0xDC00u || UNLIKELY(p == end)) return INVALID;\n+ uint32_t lo = *p;\n+ if (UNLIKELY((lo & 0xFC00u) != 0xDC00u)) return INVALID;\n+ p++;\n+ store32(q, pack4(0x10000u + ((c - 0xD800u) << 10) + (lo - 0xDC00u)));\n+ q += 4;\n+ }\n+\n+ return (size_t)(q - out);\n+}\n*** End Patch"}

✓ submission/solve.c: deleted 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> 7- #define INVALID ((size_t)-1) 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)); ... (diff truncated) ✓ submission/solve.c: created 1+ #include <stddef.h> 2+ #include <stdint.h> 3+ #include <string.h> 5+ #define INVALID ((size_t)-1) 7+ #if defined(__GNUC__) || defined(__clang__) 8+ #define LIKELY(x) __builtin_expect(!!(x), 1) 9+ #define UNLIKELY(x) __builtin_expect(!!(x), 0) 10+ #else 11+ #define LIKELY(x) (x) 12+ #define UNLIKELY(x) (x) 13+ #endif 15+ static inline uint64_t load64(const void *src) { 16+ uint64_t v; 17+ memcpy(&v, src, sizeof(v)); 18+ return v; 19+ } 21+ static inline void store32(void *dst, uint32_t v) { 22+ memcpy(dst, &v, sizeof(v)); 23+ } 25+ static inline void store64(void *dst, uint64_t v) { 26+ memcpy(dst, &v, sizeof(v)); 27+ } 29+ static inline uint32_t pack4_ascii(uint64_t x) { 30+ return (uint32_t)((x & 0x00000000000000FFULL) 31+ | ((x >> 8) & 0x000000000000FF00ULL) 32+ | ((x >> 16) & 0x0000000000FF0000ULL) 33+ | ((x >> 24) & 0x00000000FF000000ULL)); 34+ } 36+ static inline uint32_t pack2(uint32_t c) { 37+ return (0xC0u | (c >> 6)) ... (diff truncated)

{"command": "./grade", "intent": "Grade first optimized implementation", "notify": false, "run_in_background": false, "timeout": 1200000, "wake": false}

MISMATCH (random) on 34 units: d99b df16 0644 0029 02e1 da03 df95 8108 07d5 db3e decf d833 dfaa 01c9 043c 5d64 d90f df35 dac2 dd02 001c 0726 0c72 05da grade: FAIL (verification) --- Command finished with exit code: 1 --- Exit code: 1

{"command": "cat > $JCODE_SCRATCH_DIR/debug_utf16.c <<'EOF'\n#include <stdio.h>\n#include <stdint.h>\n#include <stddef.h>\n#include <string.h>\nsize_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out);\nsize_t ref_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out);\nint main(){\n uint16_t in[] = {0xd99b,0xdf16,0x0644,0x0029,0x02e1,0xda03,0xdf95,0x8108,0x07d5,0xdb3e,0xdecf,0xd833,0xdfaa,0x01c9,0x043c,0x5d64,0xd90f,0xdf35,0xdac2,0xdd02,0x001c,0x0726,0x0c72,0x05da};\n size_t n = sizeof(in)/sizeof(in[0]);\n uint8_t a[256], b[256];\n memset(a,0xaa,sizeof(a)); memset(b,0x55,sizeof(b));\n size_t ra = utf16_to_utf8(in,n,a); size_t rb = ref_utf16_to_utf8(in,n,b);\n printf(\"ra=%zu rb=%zu\\n\",ra,rb);\n size_t m = ra<rb?ra:rb;\n for(size_t i=0;i<m;i++) if(a[i]!=b[i]) { printf(\"diff at %zu: %02x %02x\\n\",i,a[i],b[i]); break; }\n for(size_t i=0;i<rb;i++) printf(\"%02x\",b[i]); printf(\"\\n\");\n for(size_t i=0;i<ra && i<rb;i++) printf(\"%02x\",a[i]); printf(\"\\n\");\n return 0;\n}\nEOF\ncc -O3 -std=c17 -I. $JCODE_SCRATCH_DIR/debug_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/debug_utf16 && $JCODE_SCRATCH_DIR/debug_utf16", "intent": "Reproduce mismatch on failing random case", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

ra=49 rb=49 f1b6bc96d98429cba1f290be95e88488df95f39fab8ff09cbeaac789d0bce5b5a4f193bcb5f380a4821cdca6e0b1b2d79a f1b6bc96d98429cba1f290be95e88488df95f39fab8ff09cbeaac789d0bce5b5a4f193bcb5f380a4821cdca6e0b1b2d79a --- Command finished with exit code: 0 ---

{"command": "cat > $JCODE_SCRATCH_DIR/fuzz_utf16.c <<'EOF'\n#include <stdio.h>\n#include <stdint.h>\n#include <stddef.h>\n#include <string.h>\n#include <stdlib.h>\nsize_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out);\nsize_t ref_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out);\nstatic uint64_t state = 0x6a636f6465ULL;\nstatic uint64_t rng_next(void) {\n uint64_t z = (state += 0x9E3779B97F4A7C15ULL);\n z = (z ^ (z >> 30)) * 0xBF58476D1CE4E5B9ULL;\n z = (z ^ (z >> 27)) * 0x94D049BB133111EBULL;\n return z ^ (z >> 31);\n}\nint main() {\n uint16_t s[64];\n uint8_t a[64*3+16], b[64*3+16];\n for (unsigned long long t = 0; t < 5000000ULL; t++) {\n size_t n = (size_t)(rng_next() % 40);\n for (size_t i = 0; i < n; i++) {\n unsigned r = (unsigned)(rng_next() % 100);\n if (r < 40) s[i] = (uint16_t)(rng_next() % 0x80);\n else if (r < 60) s[i] = (uint16_t)(0x80 + rng_next() % 0x780);\n else if (r < 80) { uint16_t v; do { v = (uint16_t)(0x800 + rng_next() % 0xF800); } while (v >= 0xD800 && v < 0xE000); s[i] = v; }\n else if (r < 95 && i + 1 < n) { s[i] = (uint16_t)(0xD800 + rng_next() % 0x400); s[++i] = (uint16_t)(0xDC00 + rng_next() % 0x400); }\n else s[i] = (uint16_t)(0xD800 + rng_next() % 0x800);\n }\n memset(a, 0xaa, sizeof(a)); memset(b, 0x55, sizeof(b));\n size_t ra = utf16_to_utf8(s, n, a);\n size_t rb = ref_utf16_to_utf8(s, n, b);\n if (ra != rb || (rb != (size_t)-1 && memcmp(a, b, rb) != 0)) {\n printf(\"mismatch t=%llu n=%zu ra=%zu rb=%zu\\n\", t, n, ra, rb);\n for (size_t i = 0; i < n; i++) printf(\"%04x \", s[i]);\n printf(\"\\n\");\n if (ra == rb && rb != (size_t)-1) {\n for (size_t i = 0; i < rb; i++) if (a[i] != b[i]) { printf(\"diff at %zu got=%02x exp=%02x\\n\", i, a[i], b[i]); break; }\n }\n return 1;\n }\n }\n puts(\"ok\");\n return 0;\n}\nEOF\ncc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "intent": "Fuzz optimized transcoder against reference", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

mismatch t=4701 n=15 ra=22 rb=21 04a7 0017 0553 0a34 000e 0050 3c10 000b 007b 0021 0012 0072 003f 0018 0032 --- Command finished with exit code: 1 --- Exit code: 1

{"command": "cat > $JCODE_SCRATCH_DIR/case_utf16.c <<'EOF'\n#include <stdio.h>\n#include <stdint.h>\n#include <stddef.h>\n#include <string.h>\nsize_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out);\nsize_t ref_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out);\nint main(){\n uint16_t s[] = {0x04a7,0x0017,0x0553,0x0a34,0x000e,0x0050,0x3c10,0x000b,0x007b,0x0021,0x0012,0x0072,0x003f,0x0018,0x0032};\n uint8_t a[128], b[128];\n memset(a,0xaa,sizeof(a)); memset(b,0x55,sizeof(b));\n size_t ra = utf16_to_utf8(s, 15, a), rb = ref_utf16_to_utf8(s, 15, b);\n printf(\"ra=%zu rb=%zu\\n\", ra, rb);\n for(size_t i=0;i<ra;i++) printf(\"%02x\", a[i]); puts(\"\");\n for(size_t i=0;i<rb;i++) printf(\"%02x\", b[i]); puts(\"\");\n return 0;\n}\nEOF\ncc -O3 -std=c17 $JCODE_SCRATCH_DIR/case_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/case_utf16 && $JCODE_SCRATCH_DIR/case_utf16", "intent": "Inspect exact failing case output", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

ra=22 rb=21 d2a717d593e0a8b40e50e3b0900b7b2112723f183200 d2a717d593e0a8b40e50e3b0900b7b2112723f1832 --- Command finished with exit code: 0 ---

{"command": "cat > $JCODE_SCRATCH_DIR/debug_logic.c <<'EOF'\n#include <stddef.h>\n#include <stdint.h>\n#include <stdio.h>\n#include <string.h>\n\n#define INVALID ((size_t)-1)\nstatic inline uint64_t load64(const void *src) { uint64_t v; memcpy(&v, src, sizeof(v)); return v; }\nstatic inline void store32(void *dst, uint32_t v) { memcpy(dst, &v, sizeof(v)); }\nstatic inline void store64(void *dst, uint64_t v) { memcpy(dst, &v, sizeof(v)); }\nstatic inline uint32_t pack4_ascii(uint64_t x) {\n return (uint32_t)((x & 0x00000000000000FFULL)\n | ((x >> 8) & 0x000000000000FF00ULL)\n | ((x >> 16) & 0x0000000000FF0000ULL)\n | ((x >> 24) & 0x00000000FF000000ULL));\n}\nstatic inline uint32_t pack2(uint32_t c) { return (0xC0u | (c >> 6)) | ((0x80u | (c & 0x3Fu)) << 8); }\nstatic inline uint32_t pack3(uint32_t c) { return (0xE0u | (c >> 12)) | ((0x80u | ((c >> 6) & 0x3Fu)) << 8) | ((0x80u | (c & 0x3Fu)) << 16); }\nstatic inline uint32_t pack4(uint32_t cp) { return (0xF0u | (cp >> 18)) | ((0x80u | ((cp >> 12) & 0x3Fu)) << 8) | ((0x80u | ((cp >> 6) & 0x3Fu)) << 16) | ((0x80u | (cp & 0x3Fu)) << 24); }\nsize_t test(const uint16_t *in, size_t n, uint8_t *out) {\n const uint16_t *p = in;\n const uint16_t *const end = in + n;\n uint8_t *q = out;\n while (p < end) {\n while ((size_t)(end - p) >= 8) {\n uint64_t x0 = load64(p);\n uint64_t x1 = load64(p + 4);\n if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break;\n printf(\"ascii8 at i=%td q=%td\\n\", p-in, q-out);\n store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32));\n p += 8;\n q += 8;\n }\n if ((size_t)(end - p) >= 4) {\n uint64_t x = load64(p);\n if ((x & 0xFF80FF80FF80FF80ULL) == 0) {\n printf(\"ascii4 at i=%td q=%td\\n\", p-in, q-out);\n store32(q, pack4_ascii(x));\n p += 4;\n q += 4;\n continue;\n }\n }\n uint32_t c = *p++;\n if (c < 0x80u) {\n printf(\"ascii1 %04x at i=%td q=%td\\n\", c, p-in-1, q-out);\n *q++ = (uint8_t)c;\n continue;\n }\n if (c < 0x800u) {\n do {\n printf(\"two %04x at i=%td q=%td\\n\", c, p-in-1, q-out);\n store32(q, pack2(c));\n q += 2;\n if (p == end) return (size_t)(q - out);\n c = *p;\n if (c - 0x80u >= 0x780u) break;\n p++;\n } while (1);\n continue;\n }\n if ((c & 0xF800u) != 0xD800u) {\n do {\n printf(\"three %04x at i=%td q=%td\\n\", c, p-in-1, q-out);\n store32(q, pack3(c));\n q += 3;\n if (p == end) return (size_t)(q - out);\n c = *p;\n if (c < 0x800u || (c & 0xF800u) == 0xD800u) break;\n p++;\n } while (1);\n continue;\n }\n if (c >= 0xDC00u || p == end) return INVALID;\n uint32_t lo = *p;\n if ((lo & 0xFC00u) != 0xDC00u) return INVALID;\n p++;\n printf(\"four %04x %04x at i=%td q=%td\\n\", c, lo, p-in-1, q-out);\n store32(q, pack4(0x10000u + ((c - 0xD800u) << 10) + (lo - 0xDC00u)));\n q += 4;\n }\n return (size_t)(q - out);\n}\nint main(){\n uint16_t s[] = {0x04a7,0x0017,0x0553,0x0a34,0x000e,0x0050,0x3c10,0x000b,0x007b,0x0021,0x0012,0x0072,0x003f,0x0018,0x0032};\n uint8_t a[128]; memset(a,0xaa,sizeof(a));\n size_t ra = test(s, 15, a);\n printf(\"ra=%zu\\n\", ra);\n for(size_t i=0;i<ra;i++) printf(\"%02x\", a[i]); puts(\"\");\n}\nEOF\ncc -O0 -std=c17 $JCODE_SCRATCH_DIR/debug_logic.c -o $JCODE_SCRATCH_DIR/debug_logic && $JCODE_SCRATCH_DIR/debug_logic", "intent": "Trace pointer and length behavior on failing case", "notify": false, "run_in_b ... [52 characters truncated for page size]

two 04a7 at i=0 q=0 ascii1 0017 at i=1 q=2 two 0553 at i=2 q=3 three 0a34 at i=3 q=5 ascii1 000e at i=4 q=8 ascii1 0050 at i=5 q=9 three 3c10 at i=6 q=10 ascii8 at i=7 q=13 ascii1 0000 at i=15 q=21 ra=22 d2a717d593e0a8b40e50e3b0900b7b2112723f183200 --- Command finished with exit code: 0 ---

{"file_path": "submission/solve.c", "intent": "Fix end-of-input bug after ASCII fast path", "new_string": " while (LIKELY((size_t)(end - p) >= 8)) {\n uint64_t x0 = load64(p);\n uint64_t x1 = load64(p + 4);\n if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break;\n store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32));\n p += 8;\n q += 8;\n }\n\n if (p == end) break;\n\n if (LIKELY((size_t)(end - p) >= 4)) {\n", "old_string": " while (LIKELY((size_t)(end - p) >= 8)) {\n uint64_t x0 = load64(p);\n uint64_t x1 = load64(p + 4);\n if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break;\n store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32));\n p += 8;\n q += 8;\n }\n\n if (LIKELY((size_t)(end - p) >= 4)) {\n", "replace_all": false}

Edited submission/solve.c: replaced 1 occurrence(s) 69+ if (p == end) break; Context after edit (lines 57-74): 57│ uint8_t *q = out; 58│ 59│ while (p < end) { 60│ while (LIKELY((size_t)(end - p) >= 8)) { 61│ uint64_t x0 = load64(p); 62│ uint64_t x1 = load64(p + 4); 63│ if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break; 64│ store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32)); 65│ p += 8; 66│ q += 8; 67│ } 68│ 69│ if (p == end) break; 70│ 71│ if (LIKELY((size_t)(end - p) >= 4)) { 72│ uint64_t x = load64(p); 73│ if ((x & 0xFF80FF80FF80FF80ULL) == 0) { 74│ store32(q, pack4_ascii(x));

{"intent": "Validate corrected optimized implementation", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Re-run fuzz test after bug fix"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade corrected optimized implementation"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 0.7s verify 2.1s PASS measure 1.5s 67,356,088 instructions (given: 77,969,614) SCORE +0.2111 (1.158x) --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"intent": "Inspect optimized codegen and score history", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 -S submission/solve.c -o $JCODE_SCRATCH_DIR/solve.s && sed -n '1,260p' $JCODE_SCRATCH_DIR/solve.s", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Inspect generated assembly for hot loop"}, {"tool": "read", "file_path": "scores.jsonl", "start_line": 1, "limit": 200, "intent": "Read score history"}]}

--- [1] bash --- .file "solve.c" .text .p2align 4 .globl utf16_to_utf8 .type utf16_to_utf8, @function utf16_to_utf8: .LFB7: .cfi_startproc leaq (%rdi,%rsi,2), %rsi movq %rdx, %r9 cmpq %rsi, %rdi jnb .L38 movabsq $-35747867511423104, %r8 movq %rdx, %rax jmp .L30 .p2align 4,,10 .p2align 3 .L5: movq 8(%rdi), %rcx movq (%rdi), %rdx movq %rcx, %r10 orq %rdx, %r10 testq %r8, %r10 jne .L4 movq %rcx, %r10 movq %rcx, %r11 addq $16, %rdi addq $8, %rax shrq $8, %r10 shrq $16, %r11 andl $16711680, %r11d andl $65280, %r10d orl %r11d, %r10d movzbl %cl, %r11d shrq $24, %rcx orl %r11d, %r10d andl $-16777216, %ecx movq %rdx, %r11 orl %r10d, %ecx shrq $16, %r11 salq $32, %rcx andl $16711680, %r11d movq %rcx, %r10 movq %rdx, %rcx shrq $8, %rcx andl $65280, %ecx orl %r11d, %ecx movzbl %dl, %r11d shrq $24, %rdx orl %r11d, %ecx andl $-16777216, %edx orl %ecx, %edx movq %r10, %rcx orq %rdx, %rcx movq %rcx, -8(%rax) .L30: movq %rsi, %rdx subq %rdi, %rdx cmpq $14, %rdx ja .L5 cmpq %rdi, %rsi je .L35 cmpq $6, %rdx jbe .L7 movq (%rdi), %rdx testq %r8, %rdx je .L39 .L7: movzwl (%rdi), %edx leaq 2(%rdi), %r10 movl %edx, %ecx cmpw $127, %dx jbe .L40 cmpl $2047, %edx jbe .L41 andw $-2048, %cx cmpw $-10240, %cx jne .L42 cmpl $56319, %edx ja .L18 cmpq %r10, %rsi je .L18 movzwl 2(%rdi), %ecx movl %ecx, %r10d andw $-1024, %r10w cmpw $-9216, %r10w jne .L18 subl $55296, %edx addq $4, %rdi addq $4, %rax sall $10, %edx addl %ecx, %edx leal 9216(%rdx), %ecx shrl $6, %edx addl $144, %edx movl %ecx, %r10d sall $16, %edx shrl $18, %r10d andl $4128768, %edx orl %r10d, %edx movl %ecx, %r10d shrl $4, %ecx sall $24, %r10d andl $16128, %ecx andl $1056964608, %r10d orl %r10d, %edx orl %ecx, %edx orl $-2139062032, %edx movl %edx, -4(%rax) .p2align 4 .p2align 3 .L8: cmpq %rsi, %rdi jb .L30 .L35: subq %r9, %rax ret .p2align 4,,10 .p2align 3 .L4: cmpq %rdi, %rsi je .L35 movq (%rdi), %rdx testq %r8, %rdx jne .L7 .L39: movq %rdx, %rcx movq %rdx, %r10 addq $8, %rdi addq $4, %rax shrq $8, %rcx shrq $16, %r10 andl $16711680, %r10d andl $65280, %ecx orl %r10d, %ecx movzbl %dl, %r10d shrq $24, %rdx orl %r10d, %ecx andl $-16777216, %edx orl %ecx, %edx movl %edx, -4(%rax) jmp .L8 .p2align 4,,10 .p2align 3 .L40: movb %dl, (%rax) movq %r10, %rdi addq $1, %rax jmp .L8 .p2align 4,,10 .p2align 3 .L42: leal 0(,%rdx,4), %ecx movl %edx, %edi sall $16, %edx andl $16128, %ecx shrl $12, %edi andl $4128768, %edx orl %edi, %ecx .L34: orl %ecx, %edx addq $3, %rax orl $8421600, %edx movl %edx, -3(%rax) cmpq %r10, %rsi je .L35 movzwl (%r10), %ecx movl %ecx, %edx cmpw $2047, %cx jbe .L23 andw $-2048, %dx cmpw $-10240, %dx je .L23 leal 0(,%rcx,4), %edx movl %ecx, %edi sall $16, %ecx addq $2, %r10 andl $16128, %edx shrl $12, %edi andl $4128768, %ecx orl %edi, %edx jmp .L34 .p2align 4,,10 .p2align 3 .L23: movq %r10, %rdi jmp .L8 .p2align 4,,10 .p2align 3 .L41: sall $8, %ecx shrl $6, %edx andl $16128, %ecx .L32: orl %ecx, %edx addq $2, %rax orl $32960, %edx movl %edx, -2(%rax) cmpq %r10, %rsi je .L35 movzwl (%r10), %ecx leal -128(%rcx), %edx cmpl $1919, %edx ja .L23 movl %ecx, %edx addq $2, %r10 shrl $6, %ecx sall $8, %edx andl $16128, %edx jmp .L32 .L18: movq $-1, %rax ret .L38: xorl %eax, %eax ret .cfi_endproc .LFE7: .size utf16_to_utf8, .-utf16_to_utf8 .ident "GCC: (GNU) 16.1.1 20260625" .section .note.GNU-stack,"",@progbits --- Command finished with exit code: 0 --- --- [2] read --- 1 {"ts": "2026-07-19T02:36:41Z", "seed": 28596, "cost": 77863475, "given_cost": 77863475, "score": 0.0, "full_gate": false} 2 {"ts": "2026-07-19T02:37:04Z", "seed": 28615, "cost": 79109690, "given_cost": 77949142, "score": -0.0213, "full_gate": false} 3 {"ts": "2026-07-19T02:39:02Z", "seed": 28738, "cost": 67356088, "given_cost": 77969614, "score": 0.2111, "full_gate": false} Completed: 2 succeeded, 0 failed

{"intent": "Use SSE2 for wider ASCII fast path on x86_64", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n #include <stddef.h>\n #include <stdint.h>\n #include <string.h>\n+\n+#if defined(__x86_64__) || defined(_M_X64) || defined(__SSE2__)\n+#include <emmintrin.h>\n+#define HAVE_SSE2 1\n+#else\n+#define HAVE_SSE2 0\n+#endif\n@@\n static inline void store64(void *dst, uint64_t v) {\n memcpy(dst, &v, sizeof(v));\n }\n+\n+#if HAVE_SSE2\n+static inline int copy_ascii16(const uint16_t *src, uint8_t *dst) {\n+ const __m128i mask = _mm_set1_epi16((short)0xFF80u);\n+ const __m128i zero = _mm_setzero_si128();\n+ __m128i x0 = _mm_loadu_si128((const __m128i *)src);\n+ __m128i x1 = _mm_loadu_si128((const __m128i *)(src + 8));\n+ __m128i high = _mm_or_si128(_mm_and_si128(x0, mask), _mm_and_si128(x1, mask));\n+ if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0;\n+ _mm_storeu_si128((__m128i *)dst, _mm_packus_epi16(x0, x1));\n+ return 1;\n+}\n+\n+static inline int copy_ascii8(const uint16_t *src, uint8_t *dst) {\n+ const __m128i mask = _mm_set1_epi16((short)0xFF80u);\n+ const __m128i zero = _mm_setzero_si128();\n+ __m128i x = _mm_loadu_si128((const __m128i *)src);\n+ __m128i high = _mm_and_si128(x, mask);\n+ if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0;\n+ _mm_storel_epi64((__m128i *)dst, _mm_packus_epi16(x, zero));\n+ return 1;\n+}\n+#endif\n@@\n uint8_t *q = out;\n \n while (p < end) {\n- while (LIKELY((size_t)(end - p) >= 8)) {\n- uint64_t x0 = load64(p);\n- uint64_t x1 = load64(p + 4);\n- if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break;\n- store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32));\n- p += 8;\n- q += 8;\n- }\n+#if HAVE_SSE2\n+ while (LIKELY((size_t)(end - p) >= 16)) {\n+ if (!copy_ascii16(p, q)) break;\n+ p += 16;\n+ q += 16;\n+ }\n+\n+ while (LIKELY((size_t)(end - p) >= 8)) {\n+ if (!copy_ascii8(p, q)) break;\n+ p += 8;\n+ q += 8;\n+ }\n+#else\n+ while (LIKELY((size_t)(end - p) >= 8)) {\n+ uint64_t x0 = load64(p);\n+ uint64_t x1 = load64(p + 4);\n+ if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break;\n+ store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32));\n+ p += 8;\n+ q += 8;\n+ }\n+#endif\n*** End Patch"}

✓ submission/solve.c: modified (3 hunks) 5+ #if defined(__x86_64__) || defined(_M_X64) || defined(__SSE2__) 6+ #include <emmintrin.h> 7+ #define HAVE_SSE2 1 8+ #else 9+ #define HAVE_SSE2 0 10+ #endif 36+ #if HAVE_SSE2 37+ static inline int copy_ascii16(const uint16_t *src, uint8_t *dst) { 38+ const __m128i mask = _mm_set1_epi16((short)0xFF80u); 39+ const __m128i zero = _mm_setzero_si128(); 40+ __m128i x0 = _mm_loadu_si128((const __m128i *)src); 41+ __m128i x1 = _mm_loadu_si128((const __m128i *)(src + 8)); 42+ __m128i high = _mm_or_si128(_mm_and_si128(x0, mask), _mm_and_si128(x1, mask)); 43+ if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0; 44+ _mm_storeu_si128((__m128i *)dst, _mm_packus_epi16(x0, x1)); 45+ return 1; 46+ } 48+ static inline int copy_ascii8(const uint16_t *src, uint8_t *dst) { 49+ const __m128i mask = _mm_set1_epi16((short)0xFF80u); 50+ const __m128i zero = _mm_setzero_si128(); 51+ __m128i x = _mm_loadu_si128((const __m128i *)src); 52+ __m128i high = _mm_and_si128(x, mask); 53+ if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0; 54+ _mm_storel_epi64((__m128i *)dst, _mm_packus_epi16(x, zero)); 55+ return 1; 56+ } 57+ #endif 90+ #if HAVE_SSE2 91+ while (LIKELY((size_t)(end - p) >= 16)) { 92+ if (!copy_ascii16(p, q)) break; ... (diff truncated)

{"intent": "Validate SSE2 ASCII fast path", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz SSE2 implementation"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade SSE2 implementation"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 0.7s verify 2.1s PASS measure 1.5s 67,117,067 instructions (given: 77,806,196) SCORE +0.2132 (1.159x) --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"intent": "Optimize surrogate pair encoding and loop over consecutive pairs", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n-static inline uint32_t pack4(uint32_t cp) {\n- return (0xF0u | (cp >> 18))\n- | ((0x80u | ((cp >> 12) & 0x3Fu)) << 8)\n- | ((0x80u | ((cp >> 6) & 0x3Fu)) << 16)\n- | ((0x80u | (cp & 0x3Fu)) << 24);\n+static inline uint32_t pack4_pair(uint32_t hi, uint32_t lo) {\n+ uint32_t c = hi - 0xD800u;\n+ uint32_t d = lo - 0xDC00u;\n+ return (0xF0u | ((c + 0x40u) >> 8))\n+ | ((0x80u | (((c >> 2) + 0x10u) & 0x3Fu)) << 8)\n+ | ((0x80u | (((c & 0x03u) << 4) | (d >> 6))) << 16)\n+ | ((0x80u | (d & 0x3Fu)) << 24);\n }\n@@\n- if (c >= 0xDC00u || UNLIKELY(p == end)) return INVALID;\n- uint32_t lo = *p;\n- if (UNLIKELY((lo & 0xFC00u) != 0xDC00u)) return INVALID;\n- p++;\n- store32(q, pack4(0x10000u + ((c - 0xD800u) << 10) + (lo - 0xDC00u)));\n- q += 4;\n+ do {\n+ if (c >= 0xDC00u || UNLIKELY(p == end)) return INVALID;\n+ uint32_t lo = *p;\n+ if (UNLIKELY((lo & 0xFC00u) != 0xDC00u)) return INVALID;\n+ p++;\n+ store32(q, pack4_pair(c, lo));\n+ q += 4;\n+ if (p == end) return (size_t)(q - out);\n+ c = *p;\n+ if ((c & 0xFC00u) != 0xD800u) break;\n+ p++;\n+ } while (1);\n }\n*** End Patch"}

✓ submission/solve.c: modified (2 hunks) 77- static inline uint32_t pack4(uint32_t cp) { 78- return (0xF0u | (cp >> 18)) 79- | ((0x80u | ((cp >> 12) & 0x3Fu)) << 8) 80- | ((0x80u | ((cp >> 6) & 0x3Fu)) << 16) 81- | ((0x80u | (cp & 0x3Fu)) << 24); 77+ static inline uint32_t pack4_pair(uint32_t hi, uint32_t lo) { 78+ uint32_t c = hi - 0xD800u; 79+ uint32_t d = lo - 0xDC00u; 80+ return (0xF0u | ((c + 0x40u) >> 8)) 81+ | ((0x80u | (((c >> 2) + 0x10u) & 0x3Fu)) << 8) 82+ | ((0x80u | (((c & 0x03u) << 4) | (d >> 6))) << 16) 83+ | ((0x80u | (d & 0x3Fu)) << 24); 155- if (c >= 0xDC00u || UNLIKELY(p == end)) return INVALID; 156- uint32_t lo = *p; 157- if (UNLIKELY((lo & 0xFC00u) != 0xDC00u)) return INVALID; 158- p++; 159- store32(q, pack4(0x10000u + ((c - 0xD800u) << 10) + (lo - 0xDC00u))); 160- q += 4; 157+ do { 158+ if (c >= 0xDC00u || UNLIKELY(p == end)) return INVALID; 159+ uint32_t lo = *p; 160+ if (UNLIKELY((lo & 0xFC00u) != 0xDC00u)) return INVALID; 161+ p++; 162+ store32(q, pack4_pair(c, lo)); 163+ q += 4; 164+ if (p == end) return (size_t)(q - out); 165+ c = *p; 166+ if ((c & 0xFC00u) != 0xD800u) break; 167+ p++; 168+ } while (1); ... (diff truncated)

{"intent": "Validate surrogate-pair loop optimization", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz after surrogate optimization"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade after surrogate optimization"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 0.7s verify 2.1s PASS measure 1.5s 58,842,845 instructions (given: 77,781,251) SCORE +0.4026 (1.322x) --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"command": "set -e\npython3 verify/gen_corpus.py 12345 $JCODE_SCRATCH_DIR/corpus.bin >/dev/null\ncc -O3 -std=c17 verify/runner.c submission/solve.c -o $JCODE_SCRATCH_DIR/runner\nvalgrind --tool=callgrind --callgrind-out-file=$JCODE_SCRATCH_DIR/callgrind.out --toggle-collect=utf16_to_utf8 $JCODE_SCRATCH_DIR/runner $JCODE_SCRATCH_DIR/corpus.bin >/dev/null 2>&1\ncallgrind_annotate --inclusive=yes $JCODE_SCRATCH_DIR/callgrind.out submission/solve.c | sed -n '1,220p'", "intent": "Profile current implementation with callgrind line attribution", "notify": false, "run_in_background": false, "timeout": 1200000, "wake": false}

-------------------------------------------------------------------------------- Profile data file '/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/callgrind.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 2062496 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/corpus.bin (PID 544, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 99 Include dirs: User annotated: submission/solve.c Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 11,524,240 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 11,524,240 (100.0%) /usr/src/debug/glibc/glibc/csu/../csu/libc-start.c:__libc_start_main@@GLIBC_2.34 [/usr/lib/libc.so.6] 11,524,240 (100.0%) /usr/src/debug/glibc/glibc/csu/../sysdeps/nptl/libc_start_call_main.h:(below main) [/usr/lib/libc.so.6] 11,524,240 (100.0%) ???:(below main) [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner] 11,524,240 (100.0%) ???:0x000000000001f100 [/usr/lib/ld-linux-x86-64.so.2] 11,524,240 (100.0%) ???:main [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner] 11,524,240 (100.0%) ???:utf16_to_utf8 [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner] -------------------------------------------------------------------------------- -- User-annotated source: submission/solve.c -------------------------------------------------------------------------------- No information has been collected for submission/solve.c -------------------------------------------------------------------------------- The following files chosen for auto-annotation could not be found: -------------------------------------------------------------------------------- /usr/src/debug/glibc/glibc/csu/../csu/libc-start.c /usr/src/debug/glibc/glibc/csu/../sysdeps/nptl/libc_start_call_main.h --- Command finished with exit code: 0 ---

{"command": "set -e\npython3 verify/gen_corpus.py 12345 $JCODE_SCRATCH_DIR/corpus.bin >/dev/null\ncc -O3 -g -std=c17 verify/runner.c submission/solve.c -o $JCODE_SCRATCH_DIR/runner_g\nvalgrind --tool=callgrind --callgrind-out-file=$JCODE_SCRATCH_DIR/callgrind_g.out --toggle-collect=utf16_to_utf8 $JCODE_SCRATCH_DIR/runner_g $JCODE_SCRATCH_DIR/corpus.bin >/dev/null 2>&1\ncallgrind_annotate --inclusive=yes $JCODE_SCRATCH_DIR/callgrind_g.out $JCODE_SCRATCH_DIR/runner_g | sed -n '1,260p'", "intent": "Get line-level callgrind annotation with debug info", "notify": false, "run_in_background": false, "timeout": 1200000, "wake": false}

-------------------------------------------------------------------------------- Profile data file '/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/callgrind_g.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 2062494 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/corpus.bin (PID 574, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 99 Include dirs: User annotated: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 11,524,240 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 11,524,240 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c:utf16_to_utf8 11,524,240 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c:main 11,524,240 (100.0%) /usr/src/debug/glibc/glibc/csu/../csu/libc-start.c:__libc_start_main@@GLIBC_2.34 [/usr/lib/libc.so.6] 11,524,240 (100.0%) /usr/src/debug/glibc/glibc/csu/../sysdeps/nptl/libc_start_call_main.h:(below main) [/usr/lib/libc.so.6] 11,524,240 (100.0%) ???:(below main) [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 11,524,240 (100.0%) ???:0x000000000001f100 [/usr/lib/ld-linux-x86-64.so.2] 11,524,240 (100.0%) verify/runner.c:main [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 10,442,551 (90.61%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 1,081,689 ( 9.39%) /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h:utf16_to_utf8 -------------------------------------------------------------------------------- -- Auto-annotated source: /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h -------------------------------------------------------------------------------- Ir -- line 699 ---------------------------------------- . _mm_load_si128 (__m128i const *__P) . { . return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadu_si128 (__m128i_u const *__P) . { 257,676 ( 2.24%) return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadl_epi64 (__m128i_u const *__P) . { . return _mm_set_epi64 ((__m64)0LL, *(__m64_u *)__P); . } . -- line 715 ---------------------------------------- -- line 735 ---------------------------------------- . _mm_store_si128 (__m128i *__P, __m128i __B) . { . *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storeu_si128 (__m128i_u *__P, __m128i __B) . { 28,015 ( 0.24%) *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mUse 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. m_storel_epi64 (__m128i_u *__P, __m128i __B) . { 6,624 ( 0.06%) *(__m64_u *)__P = (__m64) ((__v2di)__B)[0]; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storeu_si64 (void *__P, __m128i __B) . { . _mm_storel_epi64 ((__m128i_u *)__P, __B); . } . -- line 757 ---------------------------------------- -- line 999 ---------------------------------------- . _mm_packs_epi32 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_packssdw128 ((__v4si)__A, (__v4si)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_packus_epi16 (__m128i __A, __m128i __B) . { 34,639 ( 0.30%) return (__m128i)__builtin_ia32_packuswb128 ((__v8hi)__A, (__v8hi)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_unpackhi_epi8 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_punpckhbw128 ((__v16qi)__A, (__v16qi)__B); . } . -- line 1015 ---------------------------------------- -- line 1310 ---------------------------------------- . _mm_srl_epi64 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_psrlq128 ((__v2di)__A, (__v2di)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_and_si128 (__m128i __A, __m128i __B) . { 143,640 ( 1.25%) return (__m128i) ((__v2du)__A & (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_andnot_si128 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pandn128 ((__v2di)__A, (__v2di)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_or_si128 (__m128i __A, __m128i __B) . { 281,036 ( 2.44%) return (__m128i) ((__v2du)__A | (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_xor_si128 (__m128i __A, __m128i __B) . { . return (__m128i) ((__v2du)__A ^ (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_cmpeq_epi8 (__m128i __A, __m128i __B) . { 165,311 ( 1.43%) return (__m128i) ((__v16qi)__A == (__v16qi)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_cmpeq_epi16 (__m128i __A, __m128i __B) . { . return (__m128i) ((__v8hi)__A == (__v8hi)__B); . } . -- line 1350 ---------------------------------------- -- line 1454 ---------------------------------------- . _mm_min_epu8 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pminub128 ((__v16qi)__A, (__v16qi)__B); . } . . extern __inline int __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_movemask_epi8 (__m128i __A) . { 164,748 ( 1.43%) return __builtin_ia32_pmovmskb128 ((__v16qi)__A); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_mulhi_epu16 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pmulhuw128 ((__v8hi)__A, (__v8hi)__B); . } . -- line 1470 ---------------------------------------- -------------------------------------------------------------------------------- -- Auto-annotated source: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c -------------------------------------------------------------------------------- No information has been collected for /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c -------------------------------------------------------------------------------- -- Auto-annotated source: verify/runner.c -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- -- User-annotated source: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g -------------------------------------------------------------------------------- No information has been collected for /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g -------------------------------------------------------------------------------- -- Auto-annotated source: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c -------------------------------------------------------------------------------- No information has been collected for /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c -------------------------------------------------------------------------------- -- Auto-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir -- line 16 ---------------------------------------- . #define UNLIKELY(x) __builtin_expect(!!(x), 0) . #else . #define LIKELY(x) (x) . #define UNLIKELY(x) (x) . #endif . . static inline uint64_t load64(const void *src) { . uint64_t v; 65,493 ( 0.57%) memcpy(&v, src, sizeof(v)); . return v; . } . . static inline void store32(void *dst, uint32_t v) { . memcpy(dst, &v, sizeof(v)); . } . . static inline void store64(void *dst, uint64_t v) { -- line 32 ---------------------------------------- -- line 35 ---------------------------------------- . . #if HAVE_SSE2 . static inline int copy_ascii16(const uint16_t *src, uint8_t *dst) { . const __m128i mask = _mm_set1_epi16((short)0xFF80u); . const __m128i zero = _mm_setzero_si128(); . __m128i x0 = _mm_loadu_si128((const __m128i *)src); . __m128i x1 = _mm_loadu_si128((const __m128i *)(src + 8)); . __m128i high = _mm_or_si128(_mm_and_si128(x0, mask), _mm_and_si128(x1, mask)); 185,856 ( ... [2185 characters truncated for page size]

{"command": "python3 - <<'PY'\nfrom pathlib import Path\npath = Path('submission/utf16_table.h')\nwith path.open('w') as f:\n f.write('#ifndef UTF16_TABLE_H\\n#define UTF16_TABLE_H\\n#include <stdint.h>\\n\\n')\n f.write('static const uint32_t utf16_unit_table[65536] = {\\n')\n for base in range(0, 65536, 8):\n vals = []\n for c in range(base, base + 8):\n if c < 0x80:\n v = c | (1 << 24)\n elif c < 0x800:\n b0 = 0xC0 | (c >> 6)\n b1 = 0x80 | (c & 0x3F)\n v = b0 | (b1 << 8) | (2 << 24)\n elif c < 0xD800 or c >= 0xE000:\n b0 = 0xE0 | (c >> 12)\n b1 = 0x80 | ((c >> 6) & 0x3F)\n b2 = 0x80 | (c & 0x3F)\n v = b0 | (b1 << 8) | (b2 << 16) | (3 << 24)\n elif c < 0xDC00:\n v = 4 << 24\n else:\n v = 5 << 24\n vals.append(f'0x{v:08x}u')\n f.write(' ' + ', '.join(vals) + ',\\n')\n f.write('};\\n\\n#endif\\n')\nPY\nwc -c submission/utf16_table.h | sed 's/^/utf16_table.h bytes: /'", "intent": "Generate static UTF-16 unit lookup table under submission", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

utf16_table.h bytes: 884862 submission/utf16_table.h --- Command finished with exit code: 0 ---

{"intent": "Replace scalar BMP packing with table lookups", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n #include <stddef.h>\n #include <stdint.h>\n #include <string.h>\n+#include \"utf16_table.h\"\n@@\n static inline uint32_t pack4_ascii(uint64_t x) {\n return (uint32_t)((x & 0x00000000000000FFULL)\n | ((x >> 8) & 0x000000000000FF00ULL)\n | ((x >> 16) & 0x0000000000FF0000ULL)\n | ((x >> 24) & 0x00000000FF000000ULL));\n }\n-\n-static inline uint32_t pack2(uint32_t c) {\n- return (0xC0u | (c >> 6))\n- | ((0x80u | (c & 0x3Fu)) << 8);\n-}\n-\n-static inline uint32_t pack3(uint32_t c) {\n- return (0xE0u | (c >> 12))\n- | ((0x80u | ((c >> 6) & 0x3Fu)) << 8)\n- | ((0x80u | (c & 0x3Fu)) << 16);\n-}\n@@\n- uint32_t c = *p++;\n- if (c < 0x80u) {\n- *q++ = (uint8_t)c;\n- continue;\n- }\n-\n- if (c < 0x800u) {\n- do {\n- store32(q, pack2(c));\n- q += 2;\n- if (p == end) return (size_t)(q - out);\n- c = *p;\n- if (c - 0x80u >= 0x780u) break;\n- p++;\n- } while (1);\n- continue;\n- }\n-\n- if ((c & 0xF800u) != 0xD800u) {\n- do {\n- store32(q, pack3(c));\n- q += 3;\n- if (p == end) return (size_t)(q - out);\n- c = *p;\n- if (c < 0x800u || (c & 0xF800u) == 0xD800u) break;\n- p++;\n- } while (1);\n- continue;\n- }\n+ uint32_t c = *p++;\n+ uint32_t e = utf16_unit_table[c];\n+ uint32_t tag = e >> 24;\n+\n+ if (tag == 1u) {\n+ *q++ = (uint8_t)e;\n+ continue;\n+ }\n+\n+ if (tag == 2u) {\n+ do {\n+ store32(q, e);\n+ q += 2;\n+ if (p == end) return (size_t)(q - out);\n+ e = utf16_unit_table[*p];\n+ if ((e >> 24) != 2u) break;\n+ p++;\n+ } while (1);\n+ continue;\n+ }\n+\n+ if (tag == 3u) {\n+ do {\n+ store32(q, e);\n+ q += 3;\n+ if (p == end) return (size_t)(q - out);\n+ e = utf16_unit_table[*p];\n+ if ((e >> 24) != 3u) break;\n+ p++;\n+ } while (1);\n+ continue;\n+ }\n \n do {\n- if (c >= 0xDC00u || UNLIKELY(p == end)) return INVALID;\n+ if (tag != 4u || UNLIKELY(p == end)) return INVALID;\n uint32_t lo = *p;\n if (UNLIKELY((lo & 0xFC00u) != 0xDC00u)) return INVALID;\n p++;\n store32(q, pack4_pair(c, lo));\n q += 4;\n if (p == end) return (size_t)(q - out);\n c = *p;\n- if ((c & 0xFC00u) != 0xD800u) break;\n+ e = utf16_unit_table[c];\n+ tag = e >> 24;\n+ if (tag != 4u) break;\n p++;\n } while (1);\n*** End Patch"}

✓ submission/solve.c: modified (3 hunks) 4+ #include "utf16_table.h" 64- } 66- static inline uint32_t pack2(uint32_t c) { 67- return (0xC0u | (c >> 6)) 68- | ((0x80u | (c & 0x3Fu)) << 8); 71- static inline uint32_t pack3(uint32_t c) { 72- return (0xE0u | (c >> 12)) 73- | ((0x80u | ((c >> 6) & 0x3Fu)) << 8) 74- | ((0x80u | (c & 0x3Fu)) << 16); 75- } 128- if (c < 0x80u) { 129- *q++ = (uint8_t)c; 118+ uint32_t e = utf16_unit_table[c]; 119+ uint32_t tag = e >> 24; 121+ if (tag == 1u) { 122+ *q++ = (uint8_t)e; 133- if (c < 0x800u) { 126+ if (tag == 2u) { 135- store32(q, pack2(c)); 128+ store32(q, e); 138- c = *p; 139- if (c - 0x80u >= 0x780u) break; 131+ e = utf16_unit_table[*p]; 132+ if ((e >> 24) != 2u) break; 145- if ((c & 0xF800u) != 0xD800u) { 138+ if (tag == 3u) { 147- store32(q, pack3(c)); 140+ store32(q, e); 150- c = *p; 151- if (c < 0x800u || (c & 0xF800u) == 0xD800u) break; ... (diff truncated)

{"intent": "Validate lookup-table BMP encoding variant", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz lookup-table implementation"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade lookup-table implementation"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 0.8s verify 2.1s PASS measure 1.6s 47,134,033 instructions (given: 77,716,308) SCORE +0.7214 (1.649x) --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"command": "set -e\npython3 verify/gen_corpus.py 12345 $JCODE_SCRATCH_DIR/corpus.bin >/dev/null\ncc -O3 -g -std=c17 verify/runner.c submission/solve.c -o $JCODE_SCRATCH_DIR/runner_g\nvalgrind --tool=callgrind --callgrind-out-file=$JCODE_SCRATCH_DIR/callgrind_g.out --toggle-collect=utf16_to_utf8 $JCODE_SCRATCH_DIR/runner_g $JCODE_SCRATCH_DIR/corpus.bin >/dev/null 2>&1\ncallgrind_annotate --inclusive=yes $JCODE_SCRATCH_DIR/callgrind_g.out submission/solve.c | sed -n '1,260p'", "intent": "Re-profile lookup-table implementation", "notify": false, "run_in_background": false, "timeout": 1200000, "wake": false}

-------------------------------------------------------------------------------- Profile data file '/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/callgrind_g.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 1587370 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/corpus.bin (PID 692, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 99 Include dirs: User annotated: submission/solve.c Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 9,041,175 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 9,041,175 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c:utf16_to_utf8 9,041,175 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c:main 9,041,175 (100.0%) /usr/src/debug/glibc/glibc/csu/../csu/libc-start.c:__libc_start_main@@GLIBC_2.34 [/usr/lib/libc.so.6] 9,041,175 (100.0%) /usr/src/debug/glibc/glibc/csu/../sysdeps/nptl/libc_start_call_main.h:(below main) [/usr/lib/libc.so.6] 9,041,175 (100.0%) ???:(below main) [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 9,041,175 (100.0%) ???:0x000000000001f100 [/usr/lib/ld-linux-x86-64.so.2] 9,041,175 (100.0%) verify/runner.c:main [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 7,960,049 (88.04%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 1,081,126 (11.96%) /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h:utf16_to_utf8 -------------------------------------------------------------------------------- -- Auto-annotated source: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c -------------------------------------------------------------------------------- No information has been collected for /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c -------------------------------------------------------------------------------- -- User-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir -- line 17 ---------------------------------------- . #define UNLIKELY(x) __builtin_expect(!!(x), 0) . #else . #define LIKELY(x) (x) . #define UNLIKELY(x) (x) . #endif . . static inline uint64_t load64(const void *src) { . uint64_t v; 65,493 ( 0.72%) memcpy(&v, src, sizeof(v)); . return v; . } . . static inline void store32(void *dst, uint32_t v) { 320,524 ( 3.55%) memcpy(dst, &v, sizeof(v)); . } . . static inline void store64(void *dst, uint64_t v) { . memcpy(dst, &v, sizeof(v)); . } . . #if HAVE_SSE2 . static inline int copy_ascii16(const uint16_t *src, uint8_t *dst) { . const __m128i mask = _mm_set1_epi16((short)0xFF80u); . const __m128i zero = _mm_setzero_si128(); . __m128i x0 = _mm_loadu_si128((const __m128i *)src); . __m128i x1 = _mm_loadu_si128((const __m128i *)(src + 8)); . __m128i high = _mm_or_si128(_mm_and_si128(x0, mask), _mm_and_si128(x1, mask)); 185,856 ( 2.06%) if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0; . _mm_storeu_si128((__m128i *)dst, _mm_packus_epi16(x0, x1)); . return 1; . } . . static inline int copy_ascii8(const uint16_t *src, uint8_t *dst) { . const __m128i mask = _mm_set1_epi16((short)0xFF80u); . const __m128i zero = _mm_setzero_si128(); . __m128i x = _mm_loadu_si128((const __m128i *)src); . __m128i high = _mm_and_si128(x, mask); 143,640 ( 1.59%) if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0; . _mm_storel_epi64((__m128i *)dst, _mm_packus_epi16(x, zero)); . return 1; . } . #endif . . static inline uint32_t pack4_ascii(uint64_t x) { 32,784 ( 0.36%) return (uint32_t)((x & 0x00000000000000FFULL) 32,784 ( 0.36%) | ((x >> 8) & 0x000000000000FF00ULL) 54,640 ( 0.60%) | ((x >> 16) & 0x0000000000FF0000ULL) 21,856 ( 0.24%) | ((x >> 24) & 0x00000000FF000000ULL)); . } . . static inline uint32_t pack4_pair(uint32_t hi, uint32_t lo) { 51,980 ( 0.57%) uint32_t c = hi - 0xD800u; . uint32_t d = lo - 0xDC00u; 103,960 ( 1.15%) return (0xF0u | ((c + 0x40u) >> 8)) 207,920 ( 2.30%) | ((0x80u | (((c >> 2) + 0x10u) & 0x3Fu)) << 8) 519,800 ( 5.75%) | ((0x80u | (((c & 0x03u) << 4) | (d >> 6))) << 16) 259,900 ( 2.87%) | ((0x80u | (d & 0x3Fu)) << 24); . } . 2,252 ( 0.02%) size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { . const uint16_t *p = in; 563 ( 0.01%) const uint16_t *const end = in + n; 563 ( 0.01%) uint8_t *q = out; . 132,696 ( 1.47%) while (p < end) { . #if HAVE_SSE2 320,510 ( 3.55%) while (LIKELY((size_t)(end - p) >= 16)) { . if (!copy_ascii16(p, q)) break; 56,030 ( 0.62%) p += 16; 56,030 ( 0.62%) q += 16; . } . 275,186 ( 3.04%) while (LIKELY((size_t)(end - p) >= 8)) { . if (!copy_ascii8(p, q)) break; 13,248 ( 0.15%) p += 8; 13,248 ( 0.15%) q += 8; . } . #else . while (LIKELY((size_t)(end - p) >= 8)) { . uint64_t x0 = load64(p); . uint64_t x1 = load64(p + 4); . if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break; . store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32)); . p += 8; . q += 8; . } . #endif . 132,112 ( 1.46%) if (p == end) break; . 1,959 ( 0.02%) if (LIKELY((size_t)(end - p) >= 4)) { . uint64_t x = load64(p); 131,549 ( 1.45%) if ((x & 0xFF80FF80FF80FF80ULL) == 0) { . store32(q, pack4_ascii(x)); 10,928 ( 0.12%) p += 4; 10,928 ( 0.12%) q += 4; . continue; . } . } . 198,681 ( 2.20%) uint32_t c = *p++; 55,662 ( 0.62%) uint32_t e = utf16_unit_table[c]; 110,198 ( 1.22%) uint32_t tag = e >> 24; . 110,198 ( 1.22%) if (tag == 1u) { 66,768 ( 0.74%) *q++ = (uint8_t)e; 33,384 ( 0.37%) continue; . } . 43,430 ( 0.48%) if (tag == 2u) { . do { . store32(q, e); 136,006 ( 1.50%) q += 2; 272,082 ( 3.01%) if (p == end) return (size_t)(q - out); 271,854 ( 3.01%) e = utf16_unit_table[*p]; 543,708 ( 6.01%) if ((e >> 24) != 2u) break; 125,466 ( 1.39%) p++; . } while (1); . continue; . } . 22,350 ( 0.25%) if (tag == 3u) { . do { . store32(q, e); 184,518 ( 2.04%) q += 3; 369,134 ( 4.08%) if (p == end) return (size_t)(q - out); 368,834 ( 4.08%) e = utf16_unit_table[*p]; 766,694 ( 8.48%) if ((e >> 24) != 3u) break; 180,365 ( 1.99%) p++; . } while (1); . continue; . } . . do { 191,050 ( 2.11%) if (tag != 4u || UNLIKELY(p == end)) return INVALID; 51,980 ( 0.57%) uint32_t lo = *p; 259,900 ( 2.87%) if (UNLIKELY((lo & 0xFC00u) != 0xDC00u)) return INVALID; . p++; . store32(q, pack4_pair(c, lo)); 51,980 ( 0.57%) q += 4; 104,208 ( 1.15%) if (p == end) return (size_t)(q - out); 103,836 ( 1.15%) c = *p; . e = utf16_unit_table[c]; . tag = e >> 24; 176,634 ( 1.95%) if (tag != 4u) break; . p++; . } while (1); . } . 501 ( 0.01%) return (size_t)(q - out); 1,689 ( 0.02%) } -------------------------------------------------------------------------------- -- Auto-annotated source: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c -------------------------------------------------------------------------------- No information has been collected for /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c -------------------------------------------------------------------------------- -- Auto-annotated source: /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h -------------------------------------------------------------------------------- Ir -- line 699 ---------------------------------------- . _mm_load_si128 (__m128i const *__P) . { . return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadu_si128 (__m128i_u const *__P) . { 257,676 ( 2.85%) return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadl_epi64 (__m128i_u const *__P) . { . return _mm_set_epi64 ((__m64)0LL, *(__m64_u *)__P); . } . -- line 715 ---------------------------------------- -- line 735 ---------------------------------------- . _mm_store_si128 (__m128i *__P, __m128i __B) . { . *__P = __B; . } . . extern __inline void __attribute__((__g ... [1612 characters truncated for page size]

{"intent": "Batch adjacent 2-byte and 3-byte BMP runs after first code unit", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n if (tag == 2u) {\n- do {\n- store32(q, e);\n- q += 2;\n- if (p == end) return (size_t)(q - out);\n- e = utf16_unit_table[*p];\n- if ((e >> 24) != 2u) break;\n- p++;\n- } while (1);\n+ store32(q, e);\n+ q += 2;\n+\n+ while (LIKELY((size_t)(end - p) >= 2)) {\n+ uint32_t e0 = utf16_unit_table[p[0]];\n+ uint32_t e1 = utf16_unit_table[p[1]];\n+ if ((e0 >> 24) != 2u || (e1 >> 24) != 2u) break;\n+ store32(q, (e0 & 0xFFFFu) | (e1 << 16));\n+ q += 4;\n+ p += 2;\n+ }\n+\n+ while (p < end) {\n+ e = utf16_unit_table[*p];\n+ if ((e >> 24) != 2u) break;\n+ store32(q, e);\n+ q += 2;\n+ p++;\n+ }\n continue;\n }\n \n if (tag == 3u) {\n- do {\n- store32(q, e);\n- q += 3;\n- if (p == end) return (size_t)(q - out);\n- e = utf16_unit_table[*p];\n- if ((e >> 24) != 3u) break;\n- p++;\n- } while (1);\n+ store32(q, e);\n+ q += 3;\n+\n+ while (LIKELY((size_t)(end - p) >= 2)) {\n+ uint32_t e0 = utf16_unit_table[p[0]];\n+ uint32_t e1 = utf16_unit_table[p[1]];\n+ if ((e0 >> 24) != 3u || (e1 >> 24) != 3u) break;\n+ store64(q, (uint64_t)(e0 & 0x00FFFFFFu) | ((uint64_t)(e1 & 0x00FFFFFFu) << 24));\n+ q += 6;\n+ p += 2;\n+ }\n+\n+ while (p < end) {\n+ e = utf16_unit_table[*p];\n+ if ((e >> 24) != 3u) break;\n+ store32(q, e);\n+ q += 3;\n+ p++;\n+ }\n continue;\n }\n*** End Patch"}

✓ submission/solve.c: modified (1 hunks) 127- do { 128- store32(q, e); 129- q += 2; 130- if (p == end) return (size_t)(q - out); 127+ store32(q, e); 128+ q += 2; 130+ while (LIKELY((size_t)(end - p) >= 2)) { 131+ uint32_t e0 = utf16_unit_table[p[0]]; 132+ uint32_t e1 = utf16_unit_table[p[1]]; 133+ if ((e0 >> 24) != 2u || (e1 >> 24) != 2u) break; 134+ store32(q, (e0 & 0xFFFFu) | (e1 << 16)); 135+ q += 4; 136+ p += 2; 137+ } 139+ while (p < end) { 142+ store32(q, e); 143+ q += 2; 134- } while (1); 145+ } 139- do { 140- store32(q, e); 141- q += 3; 142- if (p == end) return (size_t)(q - out); 150+ store32(q, e); 151+ q += 3; 153+ while (LIKELY((size_t)(end - p) >= 2)) { 154+ uint32_t e0 = utf16_unit_table[p[0]]; 155+ uint32_t e1 = utf16_unit_table[p[1]]; 156+ if ((e0 >> 24) != 3u || (e1 >> 24) != 3u) break; 157+ store64(q, (uint64_t)(e0 & 0x00FFFFFFu) | ((uint64_t)(e1 & 0x00FFFFFFu) << 24)); ... (diff truncated)

{"intent": "Validate batched 2-byte and 3-byte run handling", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz batched run implementation"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade batched run implementation"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 1.1s verify 2.1s PASS measure 1.6s 48,485,571 instructions (given: 77,879,774) SCORE +0.6837 (1.606x) --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"intent": "Revert regressive batched 2-byte and 3-byte run handling", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n if (tag == 2u) {\n- store32(q, e);\n- q += 2;\n-\n- while (LIKELY((size_t)(end - p) >= 2)) {\n- uint32_t e0 = utf16_unit_table[p[0]];\n- uint32_t e1 = utf16_unit_table[p[1]];\n- if ((e0 >> 24) != 2u || (e1 >> 24) != 2u) break;\n- store32(q, (e0 & 0xFFFFu) | (e1 << 16));\n- q += 4;\n- p += 2;\n- }\n-\n- while (p < end) {\n- e = utf16_unit_table[*p];\n- if ((e >> 24) != 2u) break;\n- store32(q, e);\n- q += 2;\n- p++;\n- }\n+ do {\n+ store32(q, e);\n+ q += 2;\n+ if (p == end) return (size_t)(q - out);\n+ e = utf16_unit_table[*p];\n+ if ((e >> 24) != 2u) break;\n+ p++;\n+ } while (1);\n continue;\n }\n \n if (tag == 3u) {\n- store32(q, e);\n- q += 3;\n-\n- while (LIKELY((size_t)(end - p) >= 2)) {\n- uint32_t e0 = utf16_unit_table[p[0]];\n- uint32_t e1 = utf16_unit_table[p[1]];\n- if ((e0 >> 24) != 3u || (e1 >> 24) != 3u) break;\n- store64(q, (uint64_t)(e0 & 0x00FFFFFFu) | ((uint64_t)(e1 & 0x00FFFFFFu) << 24));\n- q += 6;\n- p += 2;\n- }\n-\n- while (p < end) {\n- e = utf16_unit_table[*p];\n- if ((e >> 24) != 3u) break;\n- store32(q, e);\n- q += 3;\n- p++;\n- }\n+ do {\n+ store32(q, e);\n+ q += 3;\n+ if (p == end) return (size_t)(q - out);\n+ e = utf16_unit_table[*p];\n+ if ((e >> 24) != 3u) break;\n+ p++;\n+ } while (1);\n continue;\n }\n*** End Patch"}

✓ submission/solve.c: modified (1 hunks) 127- store32(q, e); 128- q += 2; 130- while (LIKELY((size_t)(end - p) >= 2)) { 131- uint32_t e0 = utf16_unit_table[p[0]]; 132- uint32_t e1 = utf16_unit_table[p[1]]; 133- if ((e0 >> 24) != 2u || (e1 >> 24) != 2u) break; 134- store32(q, (e0 & 0xFFFFu) | (e1 << 16)); 135- q += 4; 136- p += 2; 137- } 139- while (p < end) { 127+ do { 128+ store32(q, e); 129+ q += 2; 130+ if (p == end) return (size_t)(q - out); 142- store32(q, e); 143- q += 2; 145- } 134+ } while (1); 150- store32(q, e); 151- q += 3; 153- while (LIKELY((size_t)(end - p) >= 2)) { 154- uint32_t e0 = utf16_unit_table[p[0]]; 155- uint32_t e1 = utf16_unit_table[p[1]]; 156- if ((e0 >> 24) != 3u || (e1 >> 24) != 3u) break; 157- store64(q, (uint64_t)(e0 & 0x00FFFFFFu) | ((uint64_t)(e1 & 0x00FFFFFFu) << 24)); 158- q += 6; 159- p += 2; 160- } 162- while (p < end) { ... (diff truncated)

{"intent": "Replace memcpy-based unaligned scalar loads and stores with may_alias accesses on GCC/Clang", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n #if defined(__GNUC__) || defined(__clang__)\n #define LIKELY(x) __builtin_expect(!!(x), 1)\n #define UNLIKELY(x) __builtin_expect(!!(x), 0)\n+typedef uint32_t u32_alias __attribute__((__may_alias__));\n+typedef uint64_t u64_alias __attribute__((__may_alias__));\n #else\n #define LIKELY(x) (x)\n #define UNLIKELY(x) (x)\n #endif\n \n static inline uint64_t load64(const void *src) {\n- uint64_t v;\n- memcpy(&v, src, sizeof(v));\n- return v;\n+#if defined(__GNUC__) || defined(__clang__)\n+ return *(const u64_alias *)src;\n+#else\n+ uint64_t v;\n+ memcpy(&v, src, sizeof(v));\n+ return v;\n+#endif\n }\n \n static inline void store32(void *dst, uint32_t v) {\n- memcpy(dst, &v, sizeof(v));\n+#if defined(__GNUC__) || defined(__clang__)\n+ *(u32_alias *)dst = v;\n+#else\n+ memcpy(dst, &v, sizeof(v));\n+#endif\n }\n \n static inline void store64(void *dst, uint64_t v) {\n- memcpy(dst, &v, sizeof(v));\n+#if defined(__GNUC__) || defined(__clang__)\n+ *(u64_alias *)dst = v;\n+#else\n+ memcpy(dst, &v, sizeof(v));\n+#endif\n }\n*** End Patch"}

✓ submission/solve.c: modified (1 hunks) 18+ typedef uint32_t u32_alias __attribute__((__may_alias__)); 19+ typedef uint64_t u64_alias __attribute__((__may_alias__)); 26+ #if defined(__GNUC__) || defined(__clang__) 27+ return *(const u64_alias *)src; 28+ #else 32+ #endif 36+ #if defined(__GNUC__) || defined(__clang__) 37+ *(u32_alias *)dst = v; 38+ #else 40+ #endif 44+ #if defined(__GNUC__) || defined(__clang__) 45+ *(u64_alias *)dst = v; 46+ #else 48+ #endif

{"intent": "Validate may_alias load/store optimization", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz may_alias implementation"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade may_alias implementation"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 1.0s verify 2.1s PASS measure 1.5s 47,590,701 instructions (given: 78,189,687) SCORE +0.7163 (1.643x) --- Command finished with exit code: 0 --- Completed: 2 succeeded, 0 failed

{"file_path": "scores.jsonl", "intent": "Inspect recent scores and seeds", "limit": 20, "start_line": 1}

1 {"ts": "2026-07-19T02:36:41Z", "seed": 28596, "cost": 77863475, "given_cost": 77863475, "score": 0.0, "full_gate": false} 2 {"ts": "2026-07-19T02:37:04Z", "seed": 28615, "cost": 79109690, "given_cost": 77949142, "score": -0.0213, "full_gate": false} 3 {"ts": "2026-07-19T02:39:02Z", "seed": 28738, "cost": 67356088, "given_cost": 77969614, "score": 0.2111, "full_gate": false} 4 {"ts": "2026-07-19T02:39:31Z", "seed": 28767, "cost": 67117067, "given_cost": 77806196, "score": 0.2132, "full_gate": false} 5 {"ts": "2026-07-19T02:40:05Z", "seed": 28800, "cost": 58842845, "given_cost": 77781251, "score": 0.4026, "full_gate": false} 6 {"ts": "2026-07-19T02:40:43Z", "seed": 28838, "cost": 47134033, "given_cost": 77716308, "score": 0.7214, "full_gate": false} 7 {"ts": "2026-07-19T02:41:28Z", "seed": 28883, "cost": 48485571, "given_cost": 77879774, "score": 0.6837, "full_gate": false} 8 {"ts": "2026-07-19T02:41:52Z", "seed": 28907, "cost": 47590701, "given_cost": 78189687, "score": 0.7163, "full_gate": false}

{"command": "./grade --seed 28838", "intent": "Compare current implementation against best known seed", "notify": false, "run_in_background": false, "timeout": 1200000, "wake": false}

build 0.9s verify 2.1s PASS measure 0.5s 47,154,991 instructions (given: 77,716,308) SCORE +0.7208 (1.648x) --- Command finished with exit code: 0 ---

{"command": "python3 - <<'PY'\nfrom pathlib import Path\npath = Path('submission/surrogate_table.h')\nwith path.open('w') as f:\n f.write('#ifndef SURROGATE_TABLE_H\\n#define SURROGATE_TABLE_H\\n#include <stdint.h>\\n\\n')\n f.write('static const uint32_t surrogate_hi_table[1024] = {\\n')\n for base in range(0, 1024, 8):\n vals = []\n for c in range(base, base+8):\n v = (0xF0 | ((c + 0x40) >> 8)) | ((0x80 | (((c >> 2) + 0x10) & 0x3F)) << 8) | ((0x80 | ((c & 0x03) << 4)) << 16)\n vals.append(f'0x{v:08x}u')\n f.write(' ' + ', '.join(vals) + ',\\n')\n f.write('};\\n\\n')\n f.write('static const uint32_t surrogate_lo_table[1024] = {\\n')\n for base in range(0, 1024, 8):\n vals = []\n for d in range(base, base+8):\n v = ((d >> 6) << 16) | ((0x80 | (d & 0x3F)) << 24)\n vals.append(f'0x{v:08x}u')\n f.write(' ' + ', '.join(vals) + ',\\n')\n f.write('};\\n\\n#endif\\n')\nPY\nwc -c submission/surrogate_table.h | sed 's/^/surrogate_table.h bytes: /'", "intent": "Generate small surrogate lookup tables", "notify": false, "run_in_background": false, "timeout": 120000, "wake": false}

surrogate_table.h bytes: 27838 submission/surrogate_table.h --- Command finished with exit code: 0 ---

{"intent": "Replace surrogate arithmetic with small lookup tables", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n #include <stddef.h>\n #include <stdint.h>\n #include <string.h>\n+#include \"surrogate_table.h\"\n #include \"utf16_table.h\"\n@@\n static inline uint32_t pack4_pair(uint32_t hi, uint32_t lo) {\n- uint32_t c = hi - 0xD800u;\n- uint32_t d = lo - 0xDC00u;\n- return (0xF0u | ((c + 0x40u) >> 8))\n- | ((0x80u | (((c >> 2) + 0x10u) & 0x3Fu)) << 8)\n- | ((0x80u | (((c & 0x03u) << 4) | (d >> 6))) << 16)\n- | ((0x80u | (d & 0x3Fu)) << 24);\n+ return surrogate_hi_table[hi - 0xD800u] | surrogate_lo_table[lo - 0xDC00u];\n }\n*** End Patch"}

✓ submission/solve.c: modified (2 hunks) 4+ #include "surrogate_table.h" 82- uint32_t c = hi - 0xD800u; 83- uint32_t d = lo - 0xDC00u; 84- return (0xF0u | ((c + 0x40u) >> 8)) 85- | ((0x80u | (((c >> 2) + 0x10u) & 0x3Fu)) << 8) 86- | ((0x80u | (((c & 0x03u) << 4) | (d >> 6))) << 16) 87- | ((0x80u | (d & 0x3Fu)) << 24); 83+ return surrogate_hi_table[hi - 0xD800u] | surrogate_lo_table[lo - 0xDC00u];

{"intent": "Validate surrogate-table optimization", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz surrogate-table implementation"}, {"tool": "bash", "command": "./grade --seed 28838", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Compare surrogate-table implementation on best-known seed"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade surrogate-table implementation"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 1.0s verify 2.1s PASS measure 0.5s 42,876,068 instructions (given: 77,716,308) SCORE +0.8580 (1.813x) --- Command finished with exit code: 0 --- --- [3] bash --- build 1.0s verify 2.1s PASS measure 1.6s 42,952,147 instructions (given: 77,862,553) SCORE +0.8582 (1.813x) --- Command finished with exit code: 0 --- Completed: 3 succeeded, 0 failed

{"command": "set -e\npython3 verify/gen_corpus.py 12345 $JCODE_SCRATCH_DIR/corpus.bin >/dev/null\ncc -O3 -g -std=c17 verify/runner.c submission/solve.c -o $JCODE_SCRATCH_DIR/runner_g\nvalgrind --tool=callgrind --callgrind-out-file=$JCODE_SCRATCH_DIR/callgrind_g.out --toggle-collect=utf16_to_utf8 $JCODE_SCRATCH_DIR/runner_g $JCODE_SCRATCH_DIR/corpus.bin >/dev/null 2>&1\ncallgrind_annotate --inclusive=yes $JCODE_SCRATCH_DIR/callgrind_g.out submission/solve.c | sed -n '1,260p'", "intent": "Profile current best implementation after surrogate-table optimization", "notify": false, "run_in_background": false, "timeout": 1200000, "wake": false}

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 '/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/callgrind_g.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 1587370 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/corpus.bin (PID 1065, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 99 Include dirs: User annotated: submission/solve.c Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 8,171,559 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 8,171,559 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c:utf16_to_utf8 8,171,559 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c:main 8,171,559 (100.0%) /usr/src/debug/glibc/glibc/csu/../csu/libc-start.c:__libc_start_main@@GLIBC_2.34 [/usr/lib/libc.so.6] 8,171,559 (100.0%) /usr/src/debug/glibc/glibc/csu/../sysdeps/nptl/libc_start_call_main.h:(below main) [/usr/lib/libc.so.6] 8,171,559 (100.0%) ???:(below main) [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 8,171,559 (100.0%) ???:0x000000000001f100 [/usr/lib/ld-linux-x86-64.so.2] 8,171,559 (100.0%) verify/runner.c:main [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 7,090,433 (86.77%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 1,081,126 (13.23%) /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/emmintrin.h -------------------------------------------------------------------------------- Ir -- line 699 ---------------------------------------- . _mm_load_si128 (__m128i const *__P) . { . return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadu_si128 (__m128i_u const *__P) . { 257,676 ( 3.15%) return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadl_epi64 (__m128i_u const *__P) . { . return _mm_set_epi64 ((__m64)0LL, *(__m64_u *)__P); . } . -- line 715 ---------------------------------------- -- line 735 ---------------------------------------- . _mm_store_si128 (__m128i *__P, __m128i __B) . { . *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storeu_si128 (__m128i_u *__P, __m128i __B) . { 28,015 ( 0.34%) *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storel_epi64 (__m128i_u *__P, __m128i __B) . { 6,624 ( 0.08%) *(__m64_u *)__P = (__m64) ((__v2di)__B)[0]; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storeu_si64 (void *__P, __m128i __B) . { . _mm_storel_epi64 ((__m128i_u *)__P, __B); . } . -- line 757 ---------------------------------------- -- line 999 ---------------------------------------- . _mm_packs_epi32 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_packssdw128 ((__v4si)__A, (__v4si)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_packus_epi16 (__m128i __A, __m128i __B) . { 34,639 ( 0.42%) return (__m128i)__builtin_ia32_packuswb128 ((__v8hi)__A, (__v8hi)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_unpackhi_epi8 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_punpckhbw128 ((__v16qi)__A, (__v16qi)__B); . } . -- line 1015 ---------------------------------------- -- line 1310 ---------------------------------------- . _mm_srl_epi64 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_psrlq128 ((__v2di)__A, (__v2di)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_and_si128 (__m128i __A, __m128i __B) . { 143,640 ( 1.76%) return (__m128i) ((__v2du)__A & (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_andnot_si128 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pandn128 ((__v2di)__A, (__v2di)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_or_si128 (__m128i __A, __m128i __B) . { 280,473 ( 3.43%) return (__m128i) ((__v2du)__A | (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_xor_si128 (__m128i __A, __m128i __B) . { . return (__m128i) ((__v2du)__A ^ (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_cmpeq_epi8 (__m128i __A, __m128i __B) . { 165,311 ( 2.02%) return (__m128i) ((__v16qi)__A == (__v16qi)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_cmpeq_epi16 (__m128i __A, __m128i __B) . { . return (__m128i) ((__v8hi)__A == (__v8hi)__B); . } . -- line 1350 ---------------------------------------- -- line 1454 ---------------------------------------- . _mm_min_epu8 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pminub128 ((__v16qi)__A, (__v16qi)__B); . } . . extern __inline int __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_movemask_epi8 (__m128i __A) . { 164,748 ( 2.02%) return __builtin_ia32_pmovmskb128 ((__v16qi)__A); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_mulhi_epu16 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pmulhuw128 ((__v8hi)__A, (__v8hi)__B); . } . -- line 1470 ---------------------------------------- -------------------------------------------------------------------------------- -- User-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir -- line 20 ---------------------------------------- . typedef uint64_t u64_alias __attribute__((__may_alias__)); . #else . #define LIKELY(x) (x) . #define UNLIKELY(x) (x) . #endif . . static inline uint64_t load64(const void *src) { . #if defined(__GNUC__) || defined(__clang__) 65,493 ( 0.80%) return *(const u64_alias *)src; . #else . uint64_t v; . memcpy(&v, src, sizeof(v)); . return v; . #endif . } . . static inline void store32(void *dst, uint32_t v) { . #if defined(__GNUC__) || defined(__clang__) 372,504 ( 4.56%) *(u32_alias *)dst = v; . #else . memcpy(dst, &v, sizeof(v)); . #endif . } . . static inline void store64(void *dst, uint64_t v) { . #if defined(__GNUC__) || defined(__clang__) . *(u64_alias *)dst = v; -- line 46 ---------------------------------------- -- line 51 ---------------------------------------- . . #if HAVE_SSE2 . static inline int copy_ascii16(const uint16_t *src, uint8_t *dst) { . const __m128i mask = _mm_set1_epi16((short)0xFF80u); . const __m128i zero = _mm_setzero_si128(); . __m128i x0 = _mm_loadu_si128((const __m128i *)src); . __m128i x1 = _mm_loadu_si128((const __m128i *)(src + 8)); . __m128i high = _mm_or_si128(_mm_and_si128(x0, mask), _mm_and_si128(x1, mask)); 185,856 ( 2.27%) if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0; . _mm_storeu_si128((__m128i *)dst, _mm_packus_epi16(x0, x1)); . return 1; . } . . static inline int copy_ascii8(const uint16_t *src, uint8_t *dst) { . const __m128i mask = _mm_set1_epi16((short)0xFF80u); . const __m128i zero = _mm_setzero_si128(); . __m128i x = _mm_loadu_si128((const __m128i *)src); . __m128i high = _mm_and_si128(x, mask); 143,640 ( 1.76%) if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0; . _mm_storel_epi64((__m128i *)dst, _mm_packus_epi16(x, zero)); . return 1; . } . #endif . . static inline uint32_t pack4_ascii(uint64_t x) { 32,784 ( 0.40%) return (uin ... [1371 characters truncated for page size]

{"intent": "Avoid failed SIMD ASCII probes when the next code unit is already non-ASCII", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n uint8_t *q = out;\n \n while (p < end) {\n+ if (LIKELY(*p < 0x80u)) {\n #if HAVE_SSE2\n- while (LIKELY((size_t)(end - p) >= 16)) {\n- if (!copy_ascii16(p, q)) break;\n- p += 16;\n- q += 16;\n- }\n+ while (LIKELY((size_t)(end - p) >= 16)) {\n+ if (!copy_ascii16(p, q)) break;\n+ p += 16;\n+ q += 16;\n+ }\n \n- while (LIKELY((size_t)(end - p) >= 8)) {\n- if (!copy_ascii8(p, q)) break;\n- p += 8;\n- q += 8;\n- }\n+ while (LIKELY((size_t)(end - p) >= 8)) {\n+ if (!copy_ascii8(p, q)) break;\n+ p += 8;\n+ q += 8;\n+ }\n #else\n- while (LIKELY((size_t)(end - p) >= 8)) {\n- uint64_t x0 = load64(p);\n- uint64_t x1 = load64(p + 4);\n- if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break;\n- store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32));\n- p += 8;\n- q += 8;\n- }\n+ while (LIKELY((size_t)(end - p) >= 8)) {\n+ uint64_t x0 = load64(p);\n+ uint64_t x1 = load64(p + 4);\n+ if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break;\n+ store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32));\n+ p += 8;\n+ q += 8;\n+ }\n #endif\n \n- if (p == end) break;\n+ if (p == end) break;\n \n- if (LIKELY((size_t)(end - p) >= 4)) {\n- uint64_t x = load64(p);\n- if ((x & 0xFF80FF80FF80FF80ULL) == 0) {\n- store32(q, pack4_ascii(x));\n- p += 4;\n- q += 4;\n+ if (LIKELY((size_t)(end - p) >= 4)) {\n+ uint64_t x = load64(p);\n+ if ((x & 0xFF80FF80FF80FF80ULL) == 0) {\n+ store32(q, pack4_ascii(x));\n+ p += 4;\n+ q += 4;\n+ continue;\n+ }\n+ }\n+\n+ if (*p < 0x80u) {\n+ *q++ = (uint8_t)*p++;\n continue;\n }\n }\n \n uint32_t c = *p++;\n*** End Patch"}

✓ submission/solve.c: modified (1 hunks) 92+ if (LIKELY(*p < 0x80u)) { 93- while (LIKELY((size_t)(end - p) >= 16)) { 94- if (!copy_ascii16(p, q)) break; 95- p += 16; 96- q += 16; 97- } 94+ while (LIKELY((size_t)(end - p) >= 16)) { 95+ if (!copy_ascii16(p, q)) break; 96+ p += 16; 97+ q += 16; 98+ } 99- while (LIKELY((size_t)(end - p) >= 8)) { 100- if (!copy_ascii8(p, q)) break; 101- p += 8; 102- q += 8; 103- } 100+ while (LIKELY((size_t)(end - p) >= 8)) { 101+ if (!copy_ascii8(p, q)) break; 102+ p += 8; 103+ q += 8; 104+ } 105- while (LIKELY((size_t)(end - p) >= 8)) { 106- uint64_t x0 = load64(p); 107- uint64_t x1 = load64(p + 4); 108- if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break; 109- store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32)); 110- p += 8; 111- q += 8; 112- } 106+ while (LIKELY((size_t)(end - p) >= 8)) { ... (diff truncated)

{"intent": "Validate ASCII fast-path gating optimization", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz ASCII-gated implementation"}, {"tool": "bash", "command": "./grade --seed 28838", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Compare ASCII-gated implementation on best-known seed"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade ASCII-gated implementation"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 1.1s verify 2.1s PASS measure 0.6s 39,825,985 instructions (given: 77,716,308) SCORE +0.9645 (1.951x) --- Command finished with exit code: 0 --- --- [3] bash --- build 1.1s verify 2.1s PASS measure 1.5s 40,081,294 instructions (given: 78,064,849) SCORE +0.9617 (1.948x) --- Command finished with exit code: 0 --- Completed: 3 succeeded, 0 failed

{"command": "set -e\npython3 verify/gen_corpus.py 12345 $JCODE_SCRATCH_DIR/corpus.bin >/dev/null\ncc -O3 -g -std=c17 verify/runner.c submission/solve.c -o $JCODE_SCRATCH_DIR/runner_g\nvalgrind --tool=callgrind --callgrind-out-file=$JCODE_SCRATCH_DIR/callgrind_g.out --toggle-collect=utf16_to_utf8 $JCODE_SCRATCH_DIR/runner_g $JCODE_SCRATCH_DIR/corpus.bin >/dev/null 2>&1\ncallgrind_annotate --inclusive=yes $JCODE_SCRATCH_DIR/callgrind_g.out submission/solve.c | sed -n '1,260p'", "intent": "Profile current near-2x implementation", "notify": false, "run_in_background": false, "timeout": 1200000, "wake": false}

-------------------------------------------------------------------------------- Profile data file '/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/callgrind_g.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 1535529 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/corpus.bin (PID 1219, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 99 Include dirs: User annotated: submission/solve.c Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 7,611,042 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 7,611,042 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c:utf16_to_utf8 7,611,042 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c:main 7,611,042 (100.0%) /usr/src/debug/glibc/glibc/csu/../csu/libc-start.c:__libc_start_main@@GLIBC_2.34 [/usr/lib/libc.so.6] 7,611,042 (100.0%) /usr/src/debug/glibc/glibc/csu/../sysdeps/nptl/libc_start_call_main.h:(below main) [/usr/lib/libc.so.6] 7,611,042 (100.0%) ???:(below main) [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 7,611,042 (100.0%) ???:0x000000000001f100 [/usr/lib/ld-linux-x86-64.so.2] 7,611,042 (100.0%) verify/runner.c:main [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 6,767,476 (88.92%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 843,566 (11.08%) /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h:utf16_to_utf8 -------------------------------------------------------------------------------- -- Auto-annotated source: /usr/lib/gcc/x86_64-pc-linux-gnu/16/include/emmintrin.h -------------------------------------------------------------------------------- Ir -- line 699 ---------------------------------------- . _mm_load_si128 (__m128i const *__P) . { . return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadu_si128 (__m128i_u const *__P) . { 198,311 ( 2.61%) return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadl_epi64 (__m128i_u const *__P) . { . return _mm_set_epi64 ((__m64)0LL, *(__m64_u *)__P); . } . -- line 715 ---------------------------------------- -- line 735 ---------------------------------------- . _mm_store_si128 (__m128i *__P, __m128i __B) . { . *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storeu_si128 (__m128i_u *__P, __m128i __B) . { 28,015 ( 0.37%) *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storel_epi64 (__m128i_u *__P, __m128i __B) . { 6,624 ( 0.09%) *(__m64_u *)__P = (__m64) ((__v2di)__B)[0]; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storeu_si64 (void *__P, __m128i __B) . { . _mm_storel_epi64 ((__m128i_u *)__P, __B); . } . -- line 757 ---------------------------------------- -- line 999 ---------------------------------------- . _mm_packs_epi32 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_packssdw128 ((__v4si)__A, (__v4si)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_packus_epi16 (__m128i __A, __m128i __B) . { 34,639 ( 0.46%) return (__m128i)__builtin_ia32_packuswb128 ((__v8hi)__A, (__v8hi)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_unpackhi_epi8 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_punpckhbw128 ((__v16qi)__A, (__v16qi)__B); . } . -- line 1015 ---------------------------------------- -- line 1310 ---------------------------------------- . _mm_srl_epi64 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_psrlq128 ((__v2di)__A, (__v2di)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_and_si128 (__m128i __A, __m128i __B) . { 103,930 ( 1.37%) return (__m128i) ((__v2du)__A & (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_andnot_si128 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pandn128 ((__v2di)__A, (__v2di)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_or_si128 (__m128i __A, __m128i __B) . { 221,208 ( 2.91%) return (__m128i) ((__v2du)__A | (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_xor_si128 (__m128i __A, __m128i __B) . { . return (__m128i) ((__v2du)__A ^ (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_cmpeq_epi8 (__m128i __A, __m128i __B) . { 125,701 ( 1.65%) return (__m128i) ((__v16qi)__A == (__v16qi)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_cmpeq_epi16 (__m128i __A, __m128i __B) . { . return (__m128i) ((__v8hi)__A == (__v8hi)__B); . } . -- line 1350 ---------------------------------------- -- line 1454 ---------------------------------------- . _mm_min_epu8 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pminub128 ((__v16qi)__A, (__v16qi)__B); . } . . extern __inline int __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_movemask_epi8 (__m128i __A) . { 125,138 ( 1.64%) return __builtin_ia32_pmovmskb128 ((__v16qi)__A); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_mulhi_epu16 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pmulhuw128 ((__v8hi)__A, (__v8hi)__B); . } . -- line 1470 ---------------------------------------- -------------------------------------------------------------------------------- -- Auto-annotated source: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c -------------------------------------------------------------------------------- No information has been collected for /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c -------------------------------------------------------------------------------- -- Auto-annotated source: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c -------------------------------------------------------------------------------- No information has been collected for /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c -------------------------------------------------------------------------------- -- User-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir -- line 20 ---------------------------------------- . typedef uint64_t u64_alias __attribute__((__may_alias__)); . #else . #define LIKELY(x) (x) . #define UNLIKELY(x) (x) . #endif . . static inline uint64_t load64(const void *src) { . #if defined(__GNUC__) || defined(__clang__) 45,593 ( 0.60%) return *(const u64_alias *)src; . #else . uint64_t v; . memcpy(&v, src, sizeof(v)); . return v; . #endif . } . . static inline void store32(void *dst, uint32_t v) { . #if defined(__GNUC__) || defined(__clang__) 372,504 ( 4.89%) *(u32_alias *)dst = v; . #else . memcpy(dst, &v, sizeof(v)); . #endif . } . . static inline void store64(void *dst, uint64_t v) { . #if defined(__GNUC__) || defined(__clang__) . *(u64_alias *)dst = v; -- line 46 ---------------------------------------- -- line 51 ---------------------------------------- . . #if HAVE_SSE2 . static inline int copy_ascii16(const uint16_t *src, uint8_t *dst) { . const __m128i mask = _mm_set1_epi16((short)0xFF80u); . const __m128i zero = _mm_setzero_si128(); . __m128i x0 = _mm_loadu_si128((const __m128i *)src); . __m128i x1 = _mm_loadu_si128((const __m128i *)(src + 8)); . __m128i high = _mm_or_si128(_mm_and_si128(x0, mask), _mm_and_si128(x1, mask)); 146,346 ( 1.92%) if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0; . _mm_storeu_si128((__m128i *)dst, _mm_packus_epi16(x0, x1)); . return 1; . } . . static inline int copy_ascii8(const uint16_t *src, uint8_t *dst) { . const __m128i mask = _mm_set1_epi16((short)0xFF80u); . const __m128i zero = _mm_setzero_si128(); . __m128i x = _mm_loadu_si128((const __m128i *)src); . __m128i high = _mm_and_s ... [1893 characters truncated for page size]

{"intent": "Revert may_alias scalar load/store helpers to memcpy-based versions for comparison", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n #if defined(__GNUC__) || defined(__clang__)\n #define LIKELY(x) __builtin_expect(!!(x), 1)\n #define UNLIKELY(x) __builtin_expect(!!(x), 0)\n-typedef uint32_t u32_alias __attribute__((__may_alias__));\n-typedef uint64_t u64_alias __attribute__((__may_alias__));\n #else\n #define LIKELY(x) (x)\n #define UNLIKELY(x) (x)\n #endif\n \n static inline uint64_t load64(const void *src) {\n-#if defined(__GNUC__) || defined(__clang__)\n- return *(const u64_alias *)src;\n-#else\n uint64_t v;\n memcpy(&v, src, sizeof(v));\n return v;\n-#endif\n }\n \n static inline void store32(void *dst, uint32_t v) {\n-#if defined(__GNUC__) || defined(__clang__)\n- *(u32_alias *)dst = v;\n-#else\n memcpy(dst, &v, sizeof(v));\n-#endif\n }\n \n static inline void store64(void *dst, uint64_t v) {\n-#if defined(__GNUC__) || defined(__clang__)\n- *(u64_alias *)dst = v;\n-#else\n memcpy(dst, &v, sizeof(v));\n-#endif\n }\n*** End Patch"}

✓ submission/solve.c: modified (1 hunks) 19- typedef uint32_t u32_alias __attribute__((__may_alias__)); 20- typedef uint64_t u64_alias __attribute__((__may_alias__)); 27- #if defined(__GNUC__) || defined(__clang__) 28- return *(const u64_alias *)src; 29- #else 33- #endif 37- #if defined(__GNUC__) || defined(__clang__) 38- *(u32_alias *)dst = v; 39- #else 41- #endif 45- #if defined(__GNUC__) || defined(__clang__) 46- *(u64_alias *)dst = v; 47- #else 49- #endif

{"intent": "Compare memcpy scalar helpers against may_alias variant", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz memcpy-helper variant"}, {"tool": "bash", "command": "./grade --seed 28838", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Measure memcpy-helper variant on best-known seed"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade memcpy-helper variant"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 0.9s verify 2.1s PASS measure 0.5s 39,825,985 instructions (given: 77,716,308) SCORE +0.9645 (1.951x) --- Command finished with exit code: 0 --- --- [3] bash --- build 0.9s verify 2.1s PASS measure 1.5s 39,933,584 instructions (given: 77,944,158) SCORE +0.9648 (1.952x) --- Command finished with exit code: 0 --- Completed: 3 succeeded, 0 failed

{"intent": "Simplify ASCII handling to 16-wide SIMD bulk plus repeated 4-code-unit scalar tail", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n static inline int copy_ascii16(const uint16_t *src, uint8_t *dst) {\n const __m128i mask = _mm_set1_epi16((short)0xFF80u);\n const __m128i zero = _mm_setzero_si128();\n __m128i x0 = _mm_loadu_si128((const __m128i *)src);\n __m128i x1 = _mm_loadu_si128((const __m128i *)(src + 8));\n __m128i high = _mm_or_si128(_mm_and_si128(x0, mask), _mm_and_si128(x1, mask));\n if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0;\n _mm_storeu_si128((__m128i *)dst, _mm_packus_epi16(x0, x1));\n return 1;\n }\n-\n-static inline int copy_ascii8(const uint16_t *src, uint8_t *dst) {\n- const __m128i mask = _mm_set1_epi16((short)0xFF80u);\n- const __m128i zero = _mm_setzero_si128();\n- __m128i x = _mm_loadu_si128((const __m128i *)src);\n- __m128i high = _mm_and_si128(x, mask);\n- if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0;\n- _mm_storel_epi64((__m128i *)dst, _mm_packus_epi16(x, zero));\n- return 1;\n-}\n #endif\n@@\n if (LIKELY(*p < 0x80u)) {\n #if HAVE_SSE2\n while (LIKELY((size_t)(end - p) >= 16)) {\n if (!copy_ascii16(p, q)) break;\n p += 16;\n q += 16;\n }\n-\n- while (LIKELY((size_t)(end - p) >= 8)) {\n- if (!copy_ascii8(p, q)) break;\n- p += 8;\n- q += 8;\n- }\n #else\n while (LIKELY((size_t)(end - p) >= 8)) {\n uint64_t x0 = load64(p);\n uint64_t x1 = load64(p + 4);\n if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break;\n@@\n \n if (p == end) break;\n \n- if (LIKELY((size_t)(end - p) >= 4)) {\n+ while (LIKELY((size_t)(end - p) >= 4)) {\n uint64_t x = load64(p);\n- if ((x & 0xFF80FF80FF80FF80ULL) == 0) {\n- store32(q, pack4_ascii(x));\n- p += 4;\n- q += 4;\n- continue;\n- }\n- }\n-\n- if (*p < 0x80u) {\n- *q++ = (uint8_t)*p++;\n- continue;\n+ if ((x & 0xFF80FF80FF80FF80ULL) != 0) break;\n+ store32(q, pack4_ascii(x));\n+ p += 4;\n+ q += 4;\n }\n+\n+ if (p == end) break;\n+\n+ *q++ = (uint8_t)*p++;\n+ continue;\n }\n*** End Patch"}

✓ submission/solve.c: modified (3 hunks) 50- static inline int copy_ascii8(const uint16_t *src, uint8_t *dst) { 51- const __m128i mask = _mm_set1_epi16((short)0xFF80u); 52- const __m128i zero = _mm_setzero_si128(); 53- __m128i x = _mm_loadu_si128((const __m128i *)src); 54- __m128i high = _mm_and_si128(x, mask); 55- if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0; 56- _mm_storel_epi64((__m128i *)dst, _mm_packus_epi16(x, zero)); 57- return 1; 58- } 86- while (LIKELY((size_t)(end - p) >= 8)) { 87- if (!copy_ascii8(p, q)) break; 88- p += 8; 89- q += 8; 90- } 104- if (LIKELY((size_t)(end - p) >= 4)) { 88+ while (LIKELY((size_t)(end - p) >= 4)) { 106- if ((x & 0xFF80FF80FF80FF80ULL) == 0) { 107- store32(q, pack4_ascii(x)); 108- p += 4; 109- q += 4; 110- continue; 111- } 90+ if ((x & 0xFF80FF80FF80FF80ULL) != 0) break; 91+ store32(q, pack4_ascii(x)); 92+ p += 4; 93+ q += 4; 114- if (*p < 0x80u) { 115- *q++ = (uint8_t)*p++; 116- continue; 117- } ... (diff truncated)

{"intent": "Validate simplified ASCII bulk-plus-tail strategy", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz simplified ASCII strategy"}, {"tool": "bash", "command": "./grade --seed 28838", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Measure simplified ASCII strategy on best-known seed"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade simplified ASCII strategy"}]}

--- [1] bash --- mismatch t=2 n=10 ra=12 rb=18446744073709551615 0617 0001 0005 0014 01a6 0007 000b 003b 0060 d9db --- Command finished with exit code: 1 --- Exit code: 1 --- [2] bash --- MISMATCH (random) on 45 units: 05b1 4ad4 0003 005f 0027 0067 279e 0015 3856 0053 04e4 278b db3b de75 9f38 037f 7527 10f7 101e 0427 07bc 04ac 0051 039d grade: FAIL (verification) --- Command finished with exit code: 1 --- Exit code: 1 --- [3] bash --- MISMATCH (random) on 41 units: 0024 0079 0046 0071 00d3 3fdd 7851 a326 0304 0603 fdc8 07b9 d849 de27 d990 dcfb 004a 0047 a28e 006d 0057 0052 078a 078d grade: FAIL (verification) --- Command finished with exit code: 1 --- Exit code: 1 Completed: 3 succeeded, 0 failed

{"intent": "Fix correctness bug in simplified ASCII handoff after bulk loops", "patch_text": "*** Begin Patch\n*** Update File: submission/solve.c\n@@\n while (LIKELY((size_t)(end - p) >= 4)) {\n uint64_t x = load64(p);\n if ((x & 0xFF80FF80FF80FF80ULL) != 0) break;\n store32(q, pack4_ascii(x));\n p += 4;\n q += 4;\n }\n \n if (p == end) break;\n \n- *q++ = (uint8_t)*p++;\n- continue;\n+ if (*p < 0x80u) {\n+ *q++ = (uint8_t)*p++;\n+ continue;\n+ }\n }\n*** End Patch"}

✓ submission/solve.c: modified (1 hunks) 98- *q++ = (uint8_t)*p++; 99- continue; 98+ if (*p < 0x80u) { 99+ *q++ = (uint8_t)*p++; 100+ continue; 101+ }

{"intent": "Validate corrected simplified ASCII bulk-plus-tail strategy", "tool_calls": [{"tool": "bash", "command": "cc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16 && $JCODE_SCRATCH_DIR/fuzz_utf16", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Fuzz corrected simplified ASCII strategy"}, {"tool": "bash", "command": "./grade --seed 28838", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Measure corrected simplified ASCII strategy on best-known seed"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Grade corrected simplified ASCII strategy"}]}

--- [1] bash --- ok --- Command finished with exit code: 0 --- --- [2] bash --- build 1.1s verify 2.1s PASS measure 0.7s 38,014,318 instructions (given: 77,716,308) SCORE +1.0317 (2.044x) --- Command finished with exit code: 0 --- --- [3] bash --- build 1.1s verify 2.1s PASS measure 1.7s 38,171,814 instructions (given: 77,873,521) SCORE +1.0286 (2.040x) --- Command finished with exit code: 0 --- Completed: 3 succeeded, 0 failed

{"command": "set -e\npython3 verify/gen_corpus.py 12345 $JCODE_SCRATCH_DIR/corpus.bin >/dev/null\ncc -O3 -g -std=c17 verify/runner.c submission/solve.c -o $JCODE_SCRATCH_DIR/runner_g\nvalgrind --tool=callgrind --callgrind-out-file=$JCODE_SCRATCH_DIR/callgrind_g.out --toggle-collect=utf16_to_utf8 $JCODE_SCRATCH_DIR/runner_g $JCODE_SCRATCH_DIR/corpus.bin >/dev/null 2>&1\ncallgrind_annotate --inclusive=yes $JCODE_SCRATCH_DIR/callgrind_g.out submission/solve.c | sed -n '1,240p'", "intent": "Profile current >2x implementation for any remaining obvious win", "notify": false, "run_in_background": false, "timeout": 1200000, "wake": false}

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 '/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/callgrind_g.out' (creator: callgrind-3.25.1) -------------------------------------------------------------------------------- I1 cache: D1 cache: LL cache: Timerange: Basic block 0 - 1470652 Trigger: Program termination Profiled target: /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/corpus.bin (PID 1611, part 1) Events recorded: Ir Events shown: Ir Event sort order: Ir Thresholds: 99 Include dirs: User annotated: submission/solve.c Auto-annotation: on -------------------------------------------------------------------------------- Ir -------------------------------------------------------------------------------- 7,423,873 (100.0%) PROGRAM TOTALS -------------------------------------------------------------------------------- Ir file:function -------------------------------------------------------------------------------- 7,423,873 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/submission/solve.c:utf16_to_utf8 7,423,873 (100.0%) /tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/tasks/utf16-transcode/verify/runner.c:main 7,423,873 (100.0%) /usr/src/debug/glibc/glibc/csu/../csu/libc-start.c:__libc_start_main@@GLIBC_2.34 [/usr/lib/libc.so.6] 7,423,873 (100.0%) /usr/src/debug/glibc/glibc/csu/../sysdeps/nptl/libc_start_call_main.h:(below main) [/usr/lib/libc.so.6] 7,423,873 (100.0%) ???:(below main) [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 7,423,873 (100.0%) ???:0x000000000001f100 [/usr/lib/ld-linux-x86-64.so.2] 7,423,873 (100.0%) verify/runner.c:main [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 6,907,441 (93.04%) submission/solve.c:utf16_to_utf8 [/tmp/jcode-bench/20260719T023554Z-jcode-solo-gpt-5.4-utf16-transcode/home/.jcode/scratch/runner_g] 516,432 ( 6.96%) /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/emmintrin.h -------------------------------------------------------------------------------- Ir -- line 699 ---------------------------------------- . _mm_load_si128 (__m128i const *__P) . { . return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadu_si128 (__m128i_u const *__P) . { 130,900 ( 1.76%) return *__P; . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_loadl_epi64 (__m128i_u const *__P) . { . return _mm_set_epi64 ((__m64)0LL, *(__m64_u *)__P); . } . -- line 715 ---------------------------------------- -- line 735 ---------------------------------------- . _mm_store_si128 (__m128i *__P, __m128i __B) . { . *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storeu_si128 (__m128i_u *__P, __m128i __B) . { 28,015 ( 0.38%) *__P = __B; . } . . extern __inline void __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_storel_epi64 (__m128i_u *__P, __m128i __B) . { . *(__m64_u *)__P = (__m64) ((__v2di)__B)[0]; . } . -- line 751 ---------------------------------------- -- line 999 ---------------------------------------- . _mm_packs_epi32 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_packssdw128 ((__v4si)__A, (__v4si)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_packus_epi16 (__m128i __A, __m128i __B) . { 28,015 ( 0.38%) return (__m128i)__builtin_ia32_packuswb128 ((__v8hi)__A, (__v8hi)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_unpackhi_epi8 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_punpckhbw128 ((__v16qi)__A, (__v16qi)__B); . } . -- line 1015 ---------------------------------------- -- line 1322 ---------------------------------------- . _mm_andnot_si128 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pandn128 ((__v2di)__A, (__v2di)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_or_si128 (__m128i __A, __m128i __B) . { 198,039 ( 2.67%) return (__m128i) ((__v2du)__A | (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_xor_si128 (__m128i __A, __m128i __B) . { . return (__m128i) ((__v2du)__A ^ (__v2du)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_cmpeq_epi8 (__m128i __A, __m128i __B) . { 66,013 ( 0.89%) return (__m128i) ((__v16qi)__A == (__v16qi)__B); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_cmpeq_epi16 (__m128i __A, __m128i __B) . { . return (__m128i) ((__v8hi)__A == (__v8hi)__B); . } . -- line 1350 ---------------------------------------- -- line 1454 ---------------------------------------- . _mm_min_epu8 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pminub128 ((__v16qi)__A, (__v16qi)__B); . } . . extern __inline int __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_movemask_epi8 (__m128i __A) . { 65,450 ( 0.88%) return __builtin_ia32_pmovmskb128 ((__v16qi)__A); . } . . extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__, __artificial__)) . _mm_mulhi_epu16 (__m128i __A, __m128i __B) . { . return (__m128i)__builtin_ia32_pmulhuw128 ((__v8hi)__A, (__v8hi)__B); . } . -- line 1470 ---------------------------------------- -------------------------------------------------------------------------------- -- User-annotated source: submission/solve.c -------------------------------------------------------------------------------- Ir -- line 18 ---------------------------------------- . #define UNLIKELY(x) __builtin_expect(!!(x), 0) . #else . #define LIKELY(x) (x) . #define UNLIKELY(x) (x) . #endif . . static inline uint64_t load64(const void *src) { . uint64_t v; 61,836 ( 0.83%) memcpy(&v, src, sizeof(v)); . return v; . } . . static inline void store32(void *dst, uint32_t v) { 372,504 ( 5.02%) memcpy(dst, &v, sizeof(v)); . } . . static inline void store64(void *dst, uint64_t v) { . memcpy(dst, &v, sizeof(v)); . } . . #if HAVE_SSE2 . static inline int copy_ascii16(const uint16_t *src, uint8_t *dst) { . const __m128i mask = _mm_set1_epi16((short)0xFF80u); . const __m128i zero = _mm_setzero_si128(); . __m128i x0 = _mm_loadu_si128((const __m128i *)src); . __m128i x1 = _mm_loadu_si128((const __m128i *)(src + 8)); . __m128i high = _mm_or_si128(_mm_and_si128(x0, mask), _mm_and_si128(x1, mask)); 130,900 ( 1.76%) if (_mm_movemask_epi8(_mm_cmpeq_epi8(high, zero)) != 0xFFFF) return 0; . _mm_storeu_si128((__m128i *)dst, _mm_packus_epi16(x0, x1)); . return 1; . } . #endif . . static inline uint32_t pack4_ascii(uint64_t x) { 72,528 ( 0.98%) return (uint32_t)((x & 0x00000000000000FFULL) 72,528 ( 0.98%) | ((x >> 8) & 0x000000000000FF00ULL) 120,880 ( 1.63%) | ((x >> 16) & 0x0000000000FF0000ULL) 48,352 ( 0.65%) | ((x >> 24) & 0x00000000FF000000ULL)); . } . . static inline uint32_t pack4_pair(uint32_t hi, uint32_t lo) { 228,986 ( 3.08%) return surrogate_hi_table[hi - 0xD800u] | surrogate_lo_table[lo - 0xDC00u]; . } . 1,126 ( 0.02%) size_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out) { . const uint16_t *p = in; 563 ( 0.01%) const uint16_t *const end = in + n; 563 ( 0.01%) uint8_t *q = out; . 110,840 ( 1.49%) while (p < end) { 165,522 ( 2.23%) if (LIKELY(*p < 0x80u)) { . #if HAVE_SSE2 265,532 ( 3.58%) while (LIKELY((size_t)(end - p) >= 16)) { . if (!copy_ascii16(p, q)) break; 28,015 ( 0.38%) p += 16; 28,015 ( 0.38%) q += 16; . } . #else . while (LIKELY((size_t)(end - p) >= 8)) { . uint64_t x0 = load64(p); . uint64_t x1 = load64(p + 4); . if (((x0 | x1) & 0xFF80FF80FF80FF80ULL) != 0) break; . store64(q, (uint64_t)pack4_ascii(x0) | ((uint64_t)pack4_ascii(x1) << 32)); . p += 8; . q += 8; . } . #endif . 76,480 ( 1.03%) if (p == end) break; . 287,496 ( 3.87%) while (LIKELY((size_t)(end - p) >= 4)) { . uint64_t x = load64(p); 124,235 ( 1.67%) if ((x & 0xFF80FF80 ... [337 characters truncated for page size]

{"intent": "Check repo status and finalize todo state", "tool_calls": [{"tool": "bash", "command": "git status --short", "timeout": 120000, "notify": false, "wake": false, "run_in_background": false, "intent": "Check git status for benchmark task"}, {"tool": "todo", "todos": [{"completion_confidence": 97, "confidence": 97, "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "group": "utf16-transcode optimization", "id": "t1", "priority": "high", "status": "completed"}, {"completion_confidence": 95, "confidence": 95, "content": "Implement targeted performance optimizations under submission/ only", "group": "utf16-transcode optimization", "id": "t2", "priority": "high", "status": "completed"}, {"completion_confidence": 98, "confidence": 98, "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "group": "utf16-transcode optimization", "id": "t3", "priority": "high", "status": "completed"}, {"completion_confidence": 90, "confidence": 90, "content": "Iterate until no further meaningful gains are found and report final score", "group": "utf16-transcode optimization", "id": "t4", "priority": "medium", "status": "completed"}], "goals": [{"end_to_end_ownership": 92, "feedback_loop": "After each code change, run ./grade, record the latest score from its output or scores.jsonl, and compare against the previous best. Keep only changes that preserve correctness and improve or meaningfully explain score movement.", "group": "utf16-transcode optimization", "hill_climbability": 98, "objective": "Maximize the grader's deterministic callgrind score for submission/solve.c, measured as log2 instruction-count improvement over baseline, while keeping 100% correctness on every graded input.", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100}], "intent": "Mark benchmark optimization work complete"}]}

--- [1] bash --- fatal: not a git repository (or any of the parent directories): .git --- Command finished with exit code: 128 --- Exit code: 128 --- [2] todo --- [ { "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "status": "in_progress", "priority": "high", "id": "t1", "group": "utf16-transcode optimization", "confidence": 90, "confidence_history": [ 90 ] }, { "content": "Implement targeted performance optimizations under submission/ only", "status": "pending", "priority": "high", "id": "t2", "group": "utf16-transcode optimization", "confidence": 80, "confidence_history": [ 80 ] }, { "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "status": "pending", "priority": "high", "id": "t3", "group": "utf16-transcode optimization", "confidence": 85, "confidence_history": [ 85 ] }, { "content": "Iterate until no further meaningful gains are found and report final score", "status": "pending", "priority": "medium", "id": "t4", "group": "utf16-transcode optimization", "confidence": 70, "confidence_history": [ 70 ] } ] Goals: [ { "group": "utf16-transcode optimization", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100, "hill_climbability": 98, "objective": "Maximize the grader's deterministic callgrind score for submission/solve.c, measured as log2 instruction-count improvement over baseline, while keeping 100% correctness on every graded input.", "feedback_loop": "After each code change, run ./grade, record the latest score from its output or scores.jsonl, and compare against the previous best. Keep only changes that preserve correctness and improve or meaningfully explain score movement." } ] Your end-to-end ownership is not high enough to complete this goal. Take ownership of the full user outcome, not just the immediate implementation. Follow the work through every relevant integration and runtime path, resolve consequential gaps, validate the complete workflow, and finish the necessary follow-through. Completed: 2 succeeded, 0 failed

{"goals": [{"end_to_end_ownership": 100, "feedback_loop": "After each code change, run ./grade, record the latest score from its output or scores.jsonl, and compare against the previous best. Keep only changes that preserve correctness and improve or meaningfully explain score movement.", "group": "utf16-transcode optimization", "hill_climbability": 98, "objective": "Maximize the grader's deterministic callgrind score for submission/solve.c, measured as log2 instruction-count improvement over baseline, while keeping 100% correctness on every graded input.", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100}], "intent": "Finalize benchmark task ownership and completion", "todos": [{"completion_confidence": 97, "confidence": 97, "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "group": "utf16-transcode optimization", "id": "t1", "priority": "high", "status": "completed"}, {"completion_confidence": 95, "confidence": 95, "content": "Implement targeted performance optimizations under submission/ only", "group": "utf16-transcode optimization", "id": "t2", "priority": "high", "status": "completed"}, {"completion_confidence": 98, "confidence": 98, "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "group": "utf16-transcode optimization", "id": "t3", "priority": "high", "status": "completed"}, {"completion_confidence": 90, "confidence": 90, "content": "Iterate until no further meaningful gains are found and report final score", "group": "utf16-transcode optimization", "id": "t4", "priority": "medium", "status": "completed"}]}

[ { "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "status": "completed", "priority": "high", "id": "t1", "group": "utf16-transcode optimization", "confidence": 97, "completion_confidence": 97, "confidence_history": [ 90, 97 ] }, { "content": "Implement targeted performance optimizations under submission/ only", "status": "completed", "priority": "high", "id": "t2", "group": "utf16-transcode optimization", "confidence": 95, "completion_confidence": 95, "confidence_history": [ 80, 95 ] }, { "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "status": "completed", "priority": "high", "id": "t3", "group": "utf16-transcode optimization", "confidence": 98, "completion_confidence": 98, "confidence_history": [ 85, 98 ] }, { "content": "Iterate until no further meaningful gains are found and report final score", "status": "completed", "priority": "medium", "id": "t4", "group": "utf16-transcode optimization", "confidence": 90, "completion_confidence": 90, "confidence_history": [ 70, 90 ] } ] Goals: [ { "group": "utf16-transcode optimization", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100, "hill_climbability": 98, "objective": "Maximize the grader's deterministic callgrind score for submission/solve.c, measured as log2 instruction-count improvement over baseline, while keeping 100% correctness on every graded input.", "feedback_loop": "After each code change, run ./grade, record the latest score from its output or scores.jsonl, and compare against the previous best. Keep only changes that preserve correctness and improve or meaningfully explain score movement.", "end_to_end_ownership": 100 } ]

{"goals": [{"end_to_end_ownership": 100, "feedback_loop": "After each code change or finalization check, run ./grade and targeted independent validations such as extra fuzzing and fixed-seed reruns, then compare scores and correctness against prior evidence before finalizing.", "group": "utf16-transcode optimization", "hill_climbability": 98, "objective": "Maximize deterministic callgrind score for submission/solve.c while preserving 100% correctness on every graded input, and independently validate the final result before declaring completion.", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100}], "intent": "Track independent final validation work", "todos": [{"completion_confidence": 97, "confidence": 97, "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "group": "utf16-transcode optimization", "id": "t1", "priority": "high", "status": "completed"}, {"completion_confidence": 95, "confidence": 95, "content": "Implement targeted performance optimizations under submission/ only", "group": "utf16-transcode optimization", "id": "t2", "priority": "high", "status": "completed"}, {"completion_confidence": 98, "confidence": 98, "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "group": "utf16-transcode optimization", "id": "t3", "priority": "high", "status": "completed"}, {"completion_confidence": 90, "confidence": 90, "content": "Iterate until no further meaningful gains are found and report final score", "group": "utf16-transcode optimization", "id": "t4", "priority": "medium", "status": "completed"}, {"completion_confidence": null, "confidence": 95, "content": "Independently revalidate the final implementation with extra fuzzing and multiple fixed-seed grade runs before finalizing", "group": "utf16-transcode optimization", "id": "t5", "priority": "high", "status": "in_progress"}]}

[ { "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "status": "completed", "priority": "high", "id": "t1", "group": "utf16-transcode optimization", "confidence": 97, "completion_confidence": 97, "confidence_history": [ 90, 97 ] }, { "content": "Implement targeted performance optimizations under submission/ only", "status": "completed", "priority": "high", "id": "t2", "group": "utf16-transcode optimization", "confidence": 95, "completion_confidence": 95, "confidence_history": [ 80, 95 ] }, { "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "status": "completed", "priority": "high", "id": "t3", "group": "utf16-transcode optimization", "confidence": 98, "completion_confidence": 98, "confidence_history": [ 85, 98 ] }, { "content": "Iterate until no further meaningful gains are found and report final score", "status": "completed", "priority": "medium", "id": "t4", "group": "utf16-transcode optimization", "confidence": 90, "completion_confidence": 90, "confidence_history": [ 70, 90 ] }, { "content": "Independently revalidate the final implementation with extra fuzzing and multiple fixed-seed grade runs before finalizing", "status": "in_progress", "priority": "high", "id": "t5", "group": "utf16-transcode optimization", "confidence": 95, "confidence_history": [ 95 ] } ] Goals: [ { "group": "utf16-transcode optimization", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100, "hill_climbability": 98, "objective": "Maximize deterministic callgrind score for submission/solve.c while preserving 100% correctness on every graded input, and independently validate the final result before declaring completion.", "feedback_loop": "After each code change or finalization check, run ./grade and targeted independent validations such as extra fuzzing and fixed-seed reruns, then compare scores and correctness against prior evidence before finalizing.", "end_to_end_ownership": 100 } ]

{"intent": "Independently validate final implementation with fuzzing and fixed-seed grades", "tool_calls": [{"tool": "bash", "command": "cat > $JCODE_SCRATCH_DIR/fuzz_utf16_final.c <<'EOF'\n#include <stdio.h>\n#include <stdint.h>\n#include <stddef.h>\n#include <string.h>\n#include <stdlib.h>\nsize_t utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out);\nsize_t ref_utf16_to_utf8(const uint16_t *in, size_t n, uint8_t *out);\nstatic uint64_t state = 0x123456789abcdef0ULL;\nstatic uint64_t rng_next(void) {\n uint64_t z = (state += 0x9E3779B97F4A7C15ULL);\n z = (z ^ (z >> 30)) * 0xBF58476D1CE4E5B9ULL;\n z = (z ^ (z >> 27)) * 0x94D049BB133111EBULL;\n return z ^ (z >> 31);\n}\nint main(void) {\n uint16_t s[128];\n uint8_t a[128 * 3 + 32], b[128 * 3 + 32];\n for (unsigned long long t = 0; t < 8000000ULL; t++) {\n size_t n = (size_t)(rng_next() % 96);\n for (size_t i = 0; i < n; i++) {\n unsigned r = (unsigned)(rng_next() % 100);\n if (r < 45) s[i] = (uint16_t)(rng_next() % 0x80);\n else if (r < 62) s[i] = (uint16_t)(0x80 + rng_next() % 0x780);\n else if (r < 82) {\n uint16_t v;\n do { v = (uint16_t)(0x800 + rng_next() % 0xF800); } while (v >= 0xD800 && v < 0xE000);\n s[i] = v;\n } else if (r < 95 && i + 1 < n) {\n s[i] = (uint16_t)(0xD800 + rng_next() % 0x400);\n s[++i] = (uint16_t)(0xDC00 + rng_next() % 0x400);\n } else {\n s[i] = (uint16_t)(0xD800 + rng_next() % 0x800);\n }\n }\n memset(a, 0xaa, sizeof(a));\n memset(b, 0x55, sizeof(b));\n size_t ra = utf16_to_utf8(s, n, a);\n size_t rb = ref_utf16_to_utf8(s, n, b);\n if (ra != rb || (rb != (size_t)-1 && memcmp(a, b, rb) != 0)) {\n printf(\"mismatch t=%llu n=%zu ra=%zu rb=%zu\\n\", t, n, ra, rb);\n for (size_t i = 0; i < n; i++) printf(\"%04x \", s[i]);\n printf(\"\\n\");\n if (ra == rb && rb != (size_t)-1) {\n for (size_t i = 0; i < rb; i++) if (a[i] != b[i]) { printf(\"diff at %zu got=%02x exp=%02x\\n\", i, a[i], b[i]); break; }\n }\n return 1;\n }\n }\n puts(\"extra fuzz ok\");\n return 0;\n}\nEOF\ncc -O3 -std=c17 $JCODE_SCRATCH_DIR/fuzz_utf16_final.c submission/solve.c verify/reference.c -o $JCODE_SCRATCH_DIR/fuzz_utf16_final && $JCODE_SCRATCH_DIR/fuzz_utf16_final", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Run independent extra fuzz validation"}, {"tool": "bash", "command": "./grade --seed 28838", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Validate final implementation on prior best seed"}, {"tool": "bash", "command": "./grade --seed 12345", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Validate final implementation on independent fixed seed 12345"}, {"tool": "bash", "command": "./grade --seed 424242", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Validate final implementation on independent fixed seed 424242"}, {"tool": "bash", "command": "./grade", "timeout": 1200000, "notify": false, "wake": false, "run_in_background": false, "intent": "Validate final implementation on fresh default seed"}]}

--- [1] bash --- extra fuzz ok --- Command finished with exit code: 0 --- --- [2] bash --- build 1.3s verify 2.1s PASS measure 0.6s 38,014,318 instructions (given: 77,716,308) SCORE +1.0317 (2.044x) --- Command finished with exit code: 0 --- --- [3] bash --- build 1.3s verify 2.1s PASS measure 1.7s 38,085,948 instructions (given: 77,792,209) SCORE +1.0304 (2.043x) --- Command finished with exit code: 0 --- --- [4] bash --- build 1.3s verify 2.1s PASS measure 1.8s 38,172,458 instructions (given: 78,061,999) SCORE +1.0321 (2.045x) --- Command finished with exit code: 0 --- --- [5] bash --- build 1.2s verify 2.1s PASS measure 1.7s 38,019,474 instructions (given: 77,802,205) SCORE +1.0331 (2.046x) --- Command finished with exit code: 0 --- Completed: 5 succeeded, 0 failed

{"goals": [{"end_to_end_ownership": 100, "feedback_loop": "After each code change or finalization check, run ./grade and targeted independent validations such as extra fuzzing and fixed-seed reruns, then compare scores and correctness against prior evidence before finalizing.", "group": "utf16-transcode optimization", "hill_climbability": 98, "objective": "Maximize deterministic callgrind score for submission/solve.c while preserving 100% correctness on every graded input, and independently validate the final result before declaring completion.", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100}], "intent": "Mark independent validation complete", "todos": [{"completion_confidence": 97, "confidence": 97, "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "group": "utf16-transcode optimization", "id": "t1", "priority": "high", "status": "completed"}, {"completion_confidence": 95, "confidence": 95, "content": "Implement targeted performance optimizations under submission/ only", "group": "utf16-transcode optimization", "id": "t2", "priority": "high", "status": "completed"}, {"completion_confidence": 98, "confidence": 98, "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "group": "utf16-transcode optimization", "id": "t3", "priority": "high", "status": "completed"}, {"completion_confidence": 90, "confidence": 90, "content": "Iterate until no further meaningful gains are found and report final score", "group": "utf16-transcode optimization", "id": "t4", "priority": "medium", "status": "completed"}, {"completion_confidence": 96, "confidence": 96, "content": "Independently revalidate the final implementation with extra fuzzing and multiple fixed-seed grade runs before finalizing", "group": "utf16-transcode optimization", "id": "t5", "priority": "high", "status": "completed"}]}

[ { "content": "Read spec and baseline implementation to understand exact correctness and hot paths", "status": "completed", "priority": "high", "id": "t1", "group": "utf16-transcode optimization", "confidence": 97, "completion_confidence": 97, "confidence_history": [ 90, 97 ] }, { "content": "Implement targeted performance optimizations under submission/ only", "status": "completed", "priority": "high", "id": "t2", "group": "utf16-transcode optimization", "confidence": 95, "completion_confidence": 95, "confidence_history": [ 80, 95 ] }, { "content": "Run ./grade repeatedly to validate correctness and measure score improvements", "status": "completed", "priority": "high", "id": "t3", "group": "utf16-transcode optimization", "confidence": 98, "completion_confidence": 98, "confidence_history": [ 85, 98 ] }, { "content": "Iterate until no further meaningful gains are found and report final score", "status": "completed", "priority": "medium", "id": "t4", "group": "utf16-transcode optimization", "confidence": 90, "completion_confidence": 90, "confidence_history": [ 70, 90 ] }, { "content": "Independently revalidate the final implementation with extra fuzzing and multiple fixed-seed grade runs before finalizing", "status": "completed", "priority": "high", "id": "t5", "group": "utf16-transcode optimization", "confidence": 96, "completion_confidence": 96, "confidence_history": [ 95, 96 ] } ] Goals: [ { "group": "utf16-transcode optimization", "user_intention": "Make submission/solve.c faster than baseline without touching non-submission files.", "user_intention_alignment": 100, "hill_climbability": 98, "objective": "Maximize deterministic callgrind score for submission/solve.c while preserving 100% correctness on every graded input, and independently validate the final result before declaring completion.", "feedback_loop": "After each code change or finalization check, run ./grade and targeted independent validations such as extra fuzzing and fixed-seed reruns, then compare scores and correctness against prior evidence before finalizing.", "end_to_end_ownership": 100 } ]