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<p class="MsoNormal"><span style="color:#1F497D">MachineInstr prints “UNKNOWN” only when “TII” in invalid.
<a href="https://llvm.org/doxygen/MachineInstr_8cpp_source.html#l01669">https://llvm.org/doxygen/MachineInstr_8cpp_source.html#l01669</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">It’s a bit strange that you generate IR using aarch64 while using X86 as backend. I think some target specific builtins won’t work, as well as many function attributes are not available.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Pengfei<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> llvm-dev <llvm-dev-bounces@lists.llvm.org> <b>On Behalf Of
</b>Zhang via llvm-dev<br>
<b>Sent:</b> Friday, August 20, 2021 11:05 AM<br>
<b>To:</b> llvm-dev <llvm-dev@lists.llvm.org><br>
<b>Subject:</b> [llvm-dev] Hints needed for debugging an X86 backend bug.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi:<o:p></o:p></p>
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<p class="MsoNormal">I have a IR file which has been reduced by bugpoint, the IR is originally compiled for X86_64 and has custom transforms applied.<o:p></o:p></p>
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<p class="MsoNormal">It compiles fine if I set the triple to aarch64-arm-none-eabi, but crashes when using the X86 backend , results in the following stack trace:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">```<o:p></o:p></p>
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<p class="MsoNormal">Assertion failed: (itr != mi2iMap.end() && "Instruction not found in maps."), function getInstructionIndex, file LLVM/llvm/include/llvm/CodeGen/SlotIndexes.h, line 399.<o:p></o:p></p>
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<p class="MsoNormal">PLEASE submit a bug report to <a href="https://bugs.llvm.org/">
https://bugs.llvm.org/</a> and include the crash backtrace.<o:p></o:p></p>
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<p class="MsoNormal">Stack dump:<o:p></o:p></p>
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<p class="MsoNormal">0.<span class="apple-tab-span"> </span>Program arguments: bin/llc LLCCrash.bc -debug <o:p></o:p></p>
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<p class="MsoNormal">1.<span class="apple-tab-span"> </span>Running pass 'Function Pass Manager' on module 'LLCCrash.bc'.<o:p></o:p></p>
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<p class="MsoNormal">2.<span class="apple-tab-span"> </span>Running pass 'Simple Register Coalescing' on function '@_ZNK8CryptoPP15DL_VerifierBaseINS_8ECPPointEE17RecoverAndRestartEPhRNS_21PK_MessageAccumulatorE'<o:p></o:p></p>
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<p class="MsoNormal">0 llc 0x0000000103289eca llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 58<o:p></o:p></p>
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<p class="MsoNormal">1 llc 0x000000010328a459 PrintStackTraceSignalHandler(void*) + 25<o:p></o:p></p>
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<p class="MsoNormal">2 llc 0x000000010328832b llvm::sys::RunSignalHandlers() + 123<o:p></o:p></p>
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<p class="MsoNormal">3 llc 0x000000010328c209 SignalHandler(int) + 249<o:p></o:p></p>
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<p class="MsoNormal">4 libsystem_platform.dylib 0x00007fff2052bd7d _sigtramp + 29<o:p></o:p></p>
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<p class="MsoNormal">5 libdyld.dylib 0x00007fff20501473 dyldGlobalLockRelease() + 0<o:p></o:p></p>
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<p class="MsoNormal">6 libsystem_c.dylib 0x00007fff2043a720 abort + 120<o:p></o:p></p>
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<p class="MsoNormal">7 libsystem_c.dylib 0x00007fff204399d6 err + 0<o:p></o:p></p>
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<p class="MsoNormal">8 llc 0x0000000101e67066 llvm::SlotIndexes::getInstructionIndex(llvm::MachineInstr const&, bool) const + 470<o:p></o:p></p>
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<p class="MsoNormal">9 llc 0x0000000101e66e06 llvm::LiveIntervals::getInstructionIndex(llvm::MachineInstr const&) const + 38<o:p></o:p></p>
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<p class="MsoNormal">10 llc 0x0000000101ec5da5 (anonymous namespace)::RegisterCoalescer::joinCopy(llvm::MachineInstr*, bool&) + 149<o:p></o:p></p>
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<p class="MsoNormal">11 llc 0x0000000101ec2e5c (anonymous namespace)::RegisterCoalescer::copyCoalesceWorkList(llvm::MutableArrayRef<llvm::MachineInstr*>) + 204<o:p></o:p></p>
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<p class="MsoNormal">12 llc 0x0000000101ebdc34 (anonymous namespace)::RegisterCoalescer::joinAllIntervals() + 740<o:p></o:p></p>
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<p class="MsoNormal">13 llc 0x0000000101ebad54 (anonymous namespace)::RegisterCoalescer::runOnMachineFunction(llvm::MachineFunction&) + 804<o:p></o:p></p>
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<p class="MsoNormal">```<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The IR passes``opt -verify``, and given AArch64 backend works fine, I assume it's a bug in the X86 backend, thus I modified SlotIndexes::getInstructionIndex to print the MachineInstr:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">```<o:p></o:p></p>
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<p class="MsoNormal"> errs()<<"SlotIndex:\n";<o:p></o:p></p>
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<p class="MsoNormal"> BundleNonDebug.dump();<o:p></o:p></p>
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<p class="MsoNormal">```<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">which gives me:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">```<o:p></o:p></p>
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<p style="margin:0in;font-stretch: normal"><span style="font-size:8.5pt;font-family:"Menlo",serif">SlotIndex:<o:p></o:p></span></p>
<p style="margin:0in;font-stretch: normal"><span style="font-size:8.5pt;font-family:"Menlo",serif"> UNKNOWN , %59<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"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I'm now absolutely lost on where this "UNKNOWN" comes from.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Zhang<o:p></o:p></p>
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