<div dir="ltr">There still is nothing like bugpoint's pass list reduce for the new PM.<div><br><div>The issue is that ideally we'd be able to map a pass pipeline to the string version of it. But we can't really do that right now. We could attempt to do that, but a generated argument list won't be exact since passes added via code (e.g. PassManagerBuilder/PassBuilder.cpp) often have parameters that can't be represented via opt arguments. Maybe getting an approximate textual representation of the pipeline is good enough for some cases? But that doesn't seem ideal.</div><div>We could also go down the route of making all pipelines representable via text, but that's a non-trivial project.</div><div><br></div><div>Note that even the legacy PM has this problem, and I've heard that this has bitten people in the past.</div><div><br></div><div>Perhaps as a short term hack, we could get an approximation of the pipeline by hacking PrintPassInstrumentation to print the textual name of each pass that's run via `PIC->getPassNameForClassName(PassID)` (like PrintIRInstrumentation). Then run `opt -debug-pass-manager with that hacked up version of PrintPassInstrumentation. We'd also need another version of -debug-pass-manager that prints adaptors/pass managers but doesn't print analyses. We'd run `opt` over a file with one function that contains one loop, e.g. the IR in new-pm-defaults.ll. Then cleanup the output of -debug-pass-manager with proper pass nesting.</div><div><br></div><div>Or of course you could attempt to manually recreate the proper textual representation by looking at PassBuilder.cpp.</div><div><br></div><div>Then we'd need something that reduces the textual pass pipeline.</div><div><br></div><div>Let me know if you'd like more details.</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jul 30, 2021 at 12:25 AM Markus Lavin via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div lang="SV">
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<p class="MsoNormal"><span lang="EN-US">Hi,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Right now I am trying to analyze a bug that appears with new PM pipeline as follows<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">$ opt -enable-new-pm=1 -disable-basic-aa -tbaa -O1 -o /dev/null reduced.ll<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">the crashing pass is LICM but simply exporting IR before that pass and then running just that pass does not seem to capture enough state to reproduce the problem.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">So here one would either want bugpoint to help automatically reduce the pass list or simply use -debug-pass=Arguments and do it manually but as I understand it neither of those options work with the new PM.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">This has already been brought up in </span>
<a href="https://lists.llvm.org/pipermail/llvm-dev/2021-March/148994.html" target="_blank"><span lang="EN-US">[llvm-dev] How to get from "opt -O3" to "opt <a-single-pass>" with the new PM?</span></a>
<span lang="EN-US"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Has there been any progress since then?<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">br<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Markus<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
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