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Optimize str_repeat #23128

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Optimize str_repeat #23128

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e72c582
Optimize str_repeat
divinity76 Aug 8, 2026
5f64b3c
comment pinning the non-overlap invariant
divinity76 Sep 19, 2026
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3 changes: 2 additions & 1 deletion ext/standard/string.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5524,7 +5524,8 @@ PHP_FUNCTION(str_repeat)

while (e<ee) {
l = (e-s) < (ee-e) ? (e-s) : (ee-e);
memmove(e, s, l);

@divinity76 divinity76 Sep 18, 2026

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can you try using ```suggestion
like the codeblock language is "suggestion" ?

@laruence laruence Sep 18, 2026

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Aha, thx！I didn't know this trick! First time I've seen this. It's been ages since I used GitHub much. :)

@divinity76 divinity76 Sep 18, 2026

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very close! the last line got 3 indentation levels too many

@divinity76 divinity76 Sep 19, 2026

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hmm, your comment was created is on the deleted memmove line, can you re-create the comment on the added memcpy line?

/* src [s, s+l) and dst [e, e+l) cannot overlap: l <= e-s */
memcpy(e, s, l);
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e += l;
}
}
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