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<p class="MsoNormal">Worth mentioning is perhaps that machine optimizations such as BranchFolding and IfConversion probably only handle simple cases with one or two successors (possibly depending on your analyzeBranch implementation for your backend). See
<a href="https://llvm.org/docs/WritingAnLLVMBackend.html#branch-folding-and-if-conversion">
https://llvm.org/docs/WritingAnLLVMBackend.html#branch-folding-and-if-conversion</a><o:p></o:p></p>
<p class="MsoNormal">So while there is no restriction to the number of successors, there might be implications when it comes to the amount of optimizations done if you have more than two successors.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">/Björn<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> llvm-dev <llvm-dev-bounces@lists.llvm.org> <b>On Behalf Of
</b>Krzysztof Parzyszek via llvm-dev<br>
<b>Sent:</b> den 20 april 2021 18:25<br>
<b>To:</b> Svetlana Getmanskaya <Svetlana.Getmanskaya@mir.dev><br>
<b>Cc:</b> llvm-dev <llvm-dev@lists.llvm.org><br>
<b>Subject:</b> Re: [llvm-dev] Successors of MBB<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">There is no restriction. For example, indirect branches can have multiple (more than two) targets.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:Consolas">-- <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Consolas">Krzysztof Parzyszek
<a href="mailto:kparzysz@quicinc.com">kparzysz@quicinc.com</a> AI tools development<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> llvm-dev <<a href="mailto:llvm-dev-bounces@lists.llvm.org">llvm-dev-bounces@lists.llvm.org</a>>
<b>On Behalf Of </b>Svetlana Getmanskaya via llvm-dev<br>
<b>Sent:</b> Monday, April 19, 2021 6:52 AM<br>
<b>To:</b> <a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a><br>
<b>Subject:</b> [EXT] [llvm-dev] Successors of MBB<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hello All,<o:p></o:p></p>
<p class="MsoNormal">In my implementation of EmitInstrWithCustomInserter I have two branches in machine basic block so this MBB has 3 successors (two from branches and one fallthrough) but I’ve not found such a solution in other targets. I wonder if there is
any restriction for the number of successors for MBB?<o:p></o:p></p>
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