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<div class="moz-cite-prefix">Dear Chao,<br>
<br>
Yes, you can use LLVM to transform code to improve its Worse Case
Execution Time (WCET). I was involved in the PREM project that
used a combination of LLVM and special hardware to reduce WCET by
storing the data needed by a computation in the cache so that the
bus could be used exclusively for I/O
(<a class="moz-txt-link-freetext" href="http://dl.acm.org/citation.cfm?id=1989765.1990504&coll=DL&dl=GUIDE">http://dl.acm.org/citation.cfm?id=1989765.1990504&coll=DL&dl=GUIDE</a>).
I suspect there are other transforms that can improve WCET, but
since I know nothing about them, you'll have to read up on them on
your own.<br>
<br>
As for including your changes into the LLVM distribution, that has
a higher bar for entry. Whatever transforms you write to improve
WCET will need to be usable by others, and you'll need someone
committed to maintaining the transforms long term (which usually
means having enough users interested in using your transforms that
it's worth making a long term maintenance commitment).<br>
<br>
Regards,<br>
<br>
John Criswell<br>
<br>
On 9/9/14, 8:16 AM, Chao Peng wrote:<br>
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<p class="MsoNormal"><span lang="EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I want to add some WCET
optimizations into LLVM. Is it possible? Is there any
existing work to follow? Or some advices?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Thanks<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Chao.<o:p></o:p></span></p>
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