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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">|
</span>(canonicalizeOperands swaps arguments of an and and then ReassociateExpression swaps them back).<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></a></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">That feels like its own bug, canonicalize and reassociate having different opinions of canonical order. Just saying.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">--paulr<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> llvm-dev [mailto:llvm-dev-bounces@lists.llvm.org]
<b>On Behalf Of </b>Artur Pilipenko via llvm-dev<br>
<b>Sent:</b> Monday, December 21, 2015 9:11 AM<br>
<b>To:</b> Russell Wallace<br>
<b>Cc:</b> llvm-dev<br>
<b>Subject:</b> Re: [llvm-dev] Hash of a module<o:p></o:p></span></p>
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<p class="MsoNormal">There is a caveat here. I was experimenting with something similar and found that this status is not always trustworthy. I fixed one bug in prune-eh. These is also a bug in reassociate pass. It returns true with no change made on the following
instruction: <o:p></o:p></p>
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<p class="MsoNormal"> %0 = and i64 %b, %a<o:p></o:p></p>
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<p class="MsoNormal">It happens because it performs two distinct transformations which nullify each other (canonicalizeOperands swaps arguments of an and and then ReassociateExpression swaps them back).<o:p></o:p></p>
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<p class="MsoNormal">This approach might work for your set of passes, but beware of the problem.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Artur<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On 21 Dec 2015, at 19:59, Russell Wallace <<a href="mailto:russell.wallace@gmail.com">russell.wallace@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Yes, I'm running all the existing passes that I know how to run. I didn't know they returned change-made. Thanks!<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Mon, Dec 21, 2015 at 12:36 PM, Artur Pilipenko <<a href="mailto:apilipenko@azulsystems.com" target="_blank">apilipenko@azulsystems.com</a>> wrote:<o:p></o:p></p>
<p class="MsoNormal">Are you going to run some of the existing passes? Why can’t you just use the returned change-made value from the passes?<br>
<span style="color:#888888"><br>
<span class="hoenzb">Artur</span></span><o:p></o:p></p>
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<p class="MsoNormal"><br>
> On 20 Dec 2015, at 15:43, Russell Wallace via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<br>
><br>
> I want to run a bunch of optimizations, iteratively, that is keep running until things stop changing (to make sure all optimization opportunities are taken). As far as I know, there is no way to copy a module or compare modules by value, so it occurs to me
that a practical solution might be to take the hash code of the module and see if that changes.<br>
><br>
> A problem is that hash algorithms are designed to work on streams of bytes, not compound objects.<br>
><br>
> First attempt at a solution: iterate through all instructions in all functions and hash the instruction kinds. I can think of some possible changes that would fail to be captured by that.<br>
><br>
> Is there any already known solution?<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">> _______________________________________________<br>
> LLVM Developers mailing list<br>
> <a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a><br>
> <a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev" target="_blank">
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev</a><o:p></o:p></p>
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