[Webkit-unassigned] [Bug 152578] New: RegExp with anchor negation and grouping performance

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=152578

            Bug ID: 152578
           Summary: RegExp with anchor negation and grouping performance
    Classification: Unclassified
           Product: WebKit
           Version: Safari 9
          Hardware: Macintosh
                OS: Mac OS X 10.10
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: JavaScriptCore
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: shahar.soel at gmail.com

reproduced here:

https://jsperf.com/regexp-negation-in-group/5

Expected: 
* Similar performance for these two regExps
* Performance for these RegExp.test should be independent of input size as they anchor to the start of the input. 
var noGroup = /^"[^\\"]+"/;
var oneGroup = /^"(:?[^\\"])+"/;

Actual:
* for oneGroup regExp the performance is much worse.
anywhere from x30 slower for a single line input
to 5 orders of magnitude for a 10000 lines input.

When running the benchmark on other browsers (chrome/firefox)
The input size does not affect the performance.

Thanks.
Shahar.

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