Display execution time required to find all matches

[GoogleCodeExporter]

I'd like to see the amount of time the regex engine spent processing my test 
regex on the test text. it doesn't need to be anything precise, just a means of 
comparing the performance of one regular expression in relation to another. 
Perhaps it could be displayed in the yellow bar in bold.

Something like this,

Execution Time : (~12ms for 100 runs) 

Original issue reported on code.google.com by [email protected] on 19 Oct 2011 at 6:12

[GoogleCodeExporter]

This is generally a bad idea because comparing regexes against each other is 
more difficult than most people realize. You have to account for various 
lengths of subject text that match, don't match, and nearly match. Also, 
internal regex engine optimizations can change between browsers and browser 
versions. I'm not ruling out a feature like this, but it sounds like a footgun 
that would mostly be used to spread misinformation about regex performance.

Original comment by [email protected] on 30 Aug 2012 at 8:07