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For AA-based memory-dependency analysis, this makes sense to me. read/read aliasing doesn't affect anything.</div>
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My only questions is: is there any concern that this might confuse instrumentation passes, or similar, which might do something even for read/read cases? Does anyone know of any other use cases that might be affected by this?</div>
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-Hal</div>
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<div class="PlainText">Hal Finkel<br>
Lead, Compiler Technology and Programming Languages<br>
Leadership Computing Facility<br>
Argonne National Laboratory</div>
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<b>From:</b> Johannes Doerfert<br>
<b>Sent:</b> Thursday, February 20, 2020 5:46 PM<br>
<b>To:</b> LLVM-Dev<br>
<b>Cc:</b> Finkel, Hal J.<br>
<b>Subject:</b> [RFC][LangRef][AliasAnalysis] Clarify `noalias` affects only modified objects
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<div class="PlainText">I would like to clarify that `noalias` on arguments matches `restrict`<br>
in C99. In particular, objects need to be modified for the `noalias` to<br>
be "effective". We basically apply this reasoning already in various<br>
parts but I want to make it explicit now.<br>
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The wording change and the reasons are explained in<br>
<a href="https://reviews.llvm.org/D74935" target="_blank" rel="noopener noreferrer" data-auth="NotApplicable">
https://reviews.llvm.org/D74935</a><br>
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Please let me know if there are concerns.<br>
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Thanks,<br>
Johannes<br>
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