<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">On a side note: The printing is also disabled when the runOnXXX() functions return false, as passes indicate that they did not do any changes that way.<div class="">I certainly have seen some passes getting this wrong and reporting false even though they did some small changes to the MIR, but because the return value only affects the debug printing it's no really an important bug and we may still have some around...</div><div class=""><br class=""></div><div class="">- Matthias</div><div class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Nov 8, 2018, at 10:03 AM, Fedor Sergeev via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="auto" class=""><div class=""><div class="gmail_quote"><div dir="ltr" class="">чт, 8 нояб. 2018 г., 14:45 Markus Lavin <a href="mailto:markus.lavin@ericsson.com" class="">markus.lavin@ericsson.com</a>:<br class=""></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div class="m_829352630815205055WordSection1"><p class="MsoNormal">Fedor,<u class=""></u><u class=""></u></p><p class="MsoNormal"><u class=""></u> <u class=""></u></p><p class="MsoNormal">Yes that is what happens in my case that the loop is fully unrolled and hence ‘removed’.<u class=""></u><u class=""></u></p><p class="MsoNormal"><u class=""></u> <u class=""></u></p><p class="MsoNormal">My objection though is that there is still IR that could be dumped (i.e. the function containing the loop that was removed or the entire module) and that is what I want to have dumped after each pass when I specify -print-after-all. Of
course there may be certain implementation details that could make this hard to achieve but ideally I would like to have a reliable option that dumps the entire IR (complete enough to import into opt and run additional passes on) after each individual pass
(module, function, loop or whatever).<u class=""></u><u class=""></u></p><p class="MsoNormal"><u class=""></u> <u class=""></u></p><p class="MsoNormal">Doesn’t that make sense?</p></div></div></blockquote></div></div><div dir="auto" class="">It does not agree with the semantics of plain - print-before-all, which intends to prints only the IRunit pass works on. </div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">It does however makes perfect sense for the combo with -print-module-scope.</div><div dir="auto" class="">In fact I was going to try doing that for new-pass-manager implementation.</div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">Legacy one is technically doable as well, though there is a catch that you can't get module out of invalidated Loop, so there needs to be some hackstery employed...</div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">Patches welcome! :) </div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">regards,</div><div dir="auto" class=""> Fedor. </div><div dir="auto" class=""><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="EN-US" link="blue" vlink="purple" class=""><div class="m_829352630815205055WordSection1"><p class="MsoNormal"><u class=""></u><u class=""></u></p><p class="MsoNormal"><u class=""></u> <u class=""></u></p><p class="MsoNormal">Regards,<u class=""></u><u class=""></u></p><p class="MsoNormal">Markus<u class=""></u><u class=""></u></p><p class="MsoNormal"><u class=""></u> <u class=""></u></p><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
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<div style="border:none;border-top:solid #e1e1e1 1.0pt;padding:3.0pt 0in 0in 0in" class=""><p class="MsoNormal"><b class="">From:</b> Fedor Sergeev <<a href="mailto:fedor.v.sergeev@gmail.com" target="_blank" rel="noreferrer" class="">fedor.v.sergeev@gmail.com</a>> <br class="">
<b class="">Sent:</b> Thursday, November 8, 2018 11:06 AM<br class="">
<b class="">To:</b> Markus Lavin <<a href="mailto:markus.lavin@ericsson.com" target="_blank" rel="noreferrer" class="">markus.lavin@ericsson.com</a>><br class="">
<b class="">Cc:</b> <a href="mailto:llvm-dev@lists.llvm.org" target="_blank" rel="noreferrer" class="">llvm-dev@lists.llvm.org</a><br class="">
<b class="">Subject:</b> Re: [llvm-dev] Completeness of -print-after-all<u class=""></u><u class=""></u></p>
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<div class=""><p class="MsoNormal">Markus,<u class=""></u><u class=""></u></p>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
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<div class=""><p class="MsoNormal">Loop passes are kinda unique compared to func/module passes in that they could destroy the loop they worked on. And there might be no loop to print after that (btw, there is a known bug in new pass manager where it tries to print deleted
loop in this situation - nothing good happens!).<u class=""></u><u class=""></u></p>
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<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
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<div class=""><p class="MsoNormal">In your case loop unroll can fully uroll the loop, essentially removing the Loop. <u class=""></u><u class=""></u></p>
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<div class=""><p class="MsoNormal">If you have suggestions on how to improve behavior in such cases I would be happy to discuss this further. <u class=""></u><u class=""></u></p>
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<div class=""><p class="MsoNormal">regards, <u class=""></u><u class=""></u></p>
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<div class=""><p class="MsoNormal">Fedor <u class=""></u><u class=""></u></p>
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<div class=""><p class="MsoNormal">8 нояб. 2018 г. 12:38 пользователь "Markus Lavin via llvm-dev" <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank" rel="noreferrer" class="">llvm-dev@lists.llvm.org</a>> написал:<u class=""></u><u class=""></u></p>
<blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in" class=""><p class="MsoNormal">Hi,<br class="">
<br class="">
I recently worked on an issue where I realized that -print-after-all does not<br class="">
cover all passes run by the pass manager. E.g. it seems that loop passes are<br class="">
not fully covered and I could find that loop transformations showed up in the<br class="">
dump of the next non-loop pass (which happened to be 'Combine redundant<br class="">
instructions' and that was rather confusing).<br class="">
<br class="">
Specifying both -print-before-all and -print-after-all and doing some grepping<br class="">
gives me the following where we see two back-to-back 'Before' dumps which<br class="">
should not be possible.<br class="">
<br class="">
*** IR Dump Before LCSSA Verifier ***<br class="">
*** IR Dump After LCSSA Verifier ***<br class="">
*** IR Dump Before Loop-Closed SSA Form Pass ***<br class="">
*** IR Dump After Loop-Closed SSA Form Pass ***<br class="">
*** IR Dump Before Unroll loops ***<br class="">
*** IR Dump Before Combine redundant instructions ***<br class="">
*** IR Dump After Combine redundant instructions ***<br class="">
<br class="">
Maybe there are good reasons for making this hard to fix but to me it seems<br class="">
like a rather severe deficiency so I wonder if this is widely known and if there<br class="">
are any plans to improve it?<br class="">
<br class="">
-Markus<br class="">
<br class="">
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