Last Comment Bug 452576 - Improve CSE to recognize commutative instructions
: Improve CSE to recognize commutative instructions
Status: VERIFIED WONTFIX
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Product: Tamarin Graveyard
Classification: Graveyard
Component: Tracing Virtual Machine (show other bugs)
: unspecified
: x86 Linux
-- enhancement (vote)
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Assigned To: Nobody; OK to take it and work on it
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Mentors:
Depends on:
Blocks:
  Show dependency treegraph
 
Reported: 2008-08-28 01:23 PDT by Peter Varga
Modified: 2011-03-11 08:14 PST (History)
5 users (show)
cpeyer: in‑testsuite-
cpeyer: flashplayer‑triage+
See Also:
QA Whiteboard:
Iteration: ---
Points: ---


Attachments
Commutative instructions (594 bytes, patch)
2008-08-28 01:24 PDT, Peter Varga
edwsmith: review-
Details | Diff | Splinter Review

Description User image Peter Varga 2008-08-28 01:23:03 PDT
User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; hu; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1
Build Identifier: tamarin-tracing/5f35ec56a98a

This patch modifies the CSE filter to be able to eliminate commutative instructions with different ordered operands. It is a small modification and does not show any measurable difference on the sunspider tests but it helps the CSE filter to remove some unnecessary instructions. In the performance tests it can eliminate 7 LIR instructions in 3 files. It is not so much, but more than nothing.

Reproducible: Always

Steps to Reproduce:
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Comment 1 User image Peter Varga 2008-08-28 01:24:35 PDT
Created attachment 335852 [details] [diff] [review]
Commutative instructions
Comment 2 User image Edwin Smith 2009-02-05 08:34:02 PST
Comment on attachment 335852 [details] [diff] [review]
Commutative instructions

Needs testing and rebasing (R-), but this is a good change that we do want so lets keep it near the top of our lists.
Comment 3 User image Edwin Smith 2009-02-13 12:31:22 PST
rebasing & testing has been done, the improvements are so minor it doesn't seem worthwhile.  reopen if a more comprehensive patch with better results comes to light.

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