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<div class="moz-cite-prefix">On 03/14/2017 05:56 AM, Andreas
Scherman via llvm-dev wrote:<br>
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cite="mid:CAFRBxJdH4sBbrTyekQaOXgKxE+4Oh5qo_xE8Upp5vM+LqhZiOg@mail.gmail.com"
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<div dir="ltr">Hi!
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<div>The example in the docs[1] states that the LLVM concurrency
model does not allow the hoisting of loads and introduction of
local variables due to another thread potentially altering the
value whilst running the function. Given that I have analysis
which shows that the memory location of variable <i>x </i>can
not be concurrently accessed -- how would I inform the LLVM
transformation passes of this information?</div>
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<br>
You'll need to modify the LICM code to use this information (look
for calls to isSimple()).<br>
<br>
Can you describe what your analysis does?<br>
<br>
-Hal<br>
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cite="mid:CAFRBxJdH4sBbrTyekQaOXgKxE+4Oh5qo_xE8Upp5vM+LqhZiOg@mail.gmail.com"
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<div>I tried injecting this information in to the AliasAnalysis
under getModRefInfo() by returning NoModref for the memory
locations I knew not to be accessed concurrently. However, it
seemed that the usages of the variables was not respected in
that case, such that we could reorder variables and change the
semantics of the program.</div>
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<div>Thanks in advance,</div>
</div>
<div><br>
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<div>Andreas</div>
<div><br>
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<div>[1]: <a moz-do-not-send="true"
href="http://llvm.org/docs/Atomics.html#optimization-outside-atomic">http://llvm.org/docs/Atomics.html#optimization-outside-atomic</a></div>
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<br>
<pre class="moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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