Re: RFR: 8271732: Regression in StringBuilder.charAt bounds checking [v4]
On Wed, 11 Aug 2021 21:40:52 GMT, Claes Redestad wrote: >> In #4738 we removed the `checkIndex(value, count)` call in `ASB.charAt` to >> avoid potentially getting two bounds checks in the UTF-16 case. Problem is >> this optimization cause a regression since `StringUTF16.charAt(..)` checks >> `index` against the length of the `value` array and not `count`. >> >> A correct fix that still maintain the possible performance advantage >> reported by #4738 is to reinstate the `checkIndex(value, count)` and call >> `StringUTF16.getChar` instead of `charAt`. > > Claes Redestad has updated the pull request incrementally with one additional > commit since the last revision: > > Fix copy-paste error Marked as reviewed by alanb (Reviewer). - PR: https://git.openjdk.java.net/jdk/pull/5086
Re: RFR: 8271732: Regression in StringBuilder.charAt bounds checking [v4]
On Wed, 11 Aug 2021 21:40:52 GMT, Claes Redestad wrote: >> In #4738 we removed the `checkIndex(value, count)` call in `ASB.charAt` to >> avoid potentially getting two bounds checks in the UTF-16 case. Problem is >> this optimization cause a regression since `StringUTF16.charAt(..)` checks >> `index` against the length of the `value` array and not `count`. >> >> A correct fix that still maintain the possible performance advantage >> reported by #4738 is to reinstate the `checkIndex(value, count)` and call >> `StringUTF16.getChar` instead of `charAt`. > > Claes Redestad has updated the pull request incrementally with one additional > commit since the last revision: > > Fix copy-paste error Marked as reviewed by naoto (Reviewer). - PR: https://git.openjdk.java.net/jdk/pull/5086
Re: RFR: 8271732: Regression in StringBuilder.charAt bounds checking [v4]
> In #4738 we removed the `checkIndex(value, count)` call in `ASB.charAt` to > avoid potentially getting two bounds checks in the UTF-16 case. Problem is > this optimization cause a regression since `StringUTF16.charAt(..)` checks > `index` against the length of the `value` array and not `count`. > > A correct fix that still maintain the possible performance advantage reported > by #4738 is to reinstate the `checkIndex(value, count)` and call > `StringUTF16.getChar` instead of `charAt`. Claes Redestad has updated the pull request incrementally with one additional commit since the last revision: Fix copy-paste error - Changes: - all: https://git.openjdk.java.net/jdk/pull/5086/files - new: https://git.openjdk.java.net/jdk/pull/5086/files/4ef9ccbc..83a64828 Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk=5086=03 - incr: https://webrevs.openjdk.java.net/?repo=jdk=5086=02-03 Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod Patch: https://git.openjdk.java.net/jdk/pull/5086.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/5086/head:pull/5086 PR: https://git.openjdk.java.net/jdk/pull/5086
