JIT optimizer does not perform loop top alignment - by Edward D. Brey

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ID 742527 Comments
Status Active Workarounds
Type Bug Repros 2
Opened 5/17/2012 9:03:31 AM
Access Restriction Public
Moderator Decision Sent to Engineering Team for consideration

Description

For x86 instructions generated from looping constructs, the instructions are not aligned on word boundaries. This can cause performance to degrade substantially, depending on the nature of the loop. The performance penalty can be difficult to profile because the alignment can change based on the structure of an assembly or even the order in which methods are JIT compiled.

A related question on stackoverflow is here:
http://stackoverflow.com/questions/10406796/why-does-jit-order-affect-performance
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Posted by MS-Moderator10 [Feedback Moderator] on 5/17/2012 at 11:03 PM
Thanks for your feedback.

We are rerouting this issue to the appropriate group within the Visual Studio Product Team for triage and resolution. These specialized experts will follow-up with your issue.
Posted by MS-Moderator01 on 5/17/2012 at 10:46 PM
Thank you for your feedback, we are currently reviewing the issue you have submitted. If this issue is urgent, please contact support directly(http://support.microsoft.com)