| Issue |
164663
|
| Summary |
typed load hits assert and `Do not know how to promote this operator!`
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
folkertdev
|
This issue was reported in https://github.com/rust-lang/rust/issues/124093, but I have reduced the LLVM IR a bit and diagnosed that the issue is a typed load that rust emits. It seems like this is an oversight in a `switch`. The error occurs at least for x86_64 and aarch64, so I think it's not target-specific.
---
Firstly, I reduced the program just looking for any crash. With debug assertions the inputs hit an assertion in a cast. Here is a minimal example:
https://godbolt.org/z/K9d1qTerb
```llvm
define void @a(ptr %b) {
call { ptr, i1 } @llvm.type.checked.load(ptr %b, i32 4, metadata !"")
ret void
}
```
```
# | llc: /home/folkertdev/c/llvm-project/llvm/include/llvm/Support/Casting.h:573: decltype(auto) llvm::cast(From*) [with To = MDNode; From = Metadata]: Assertion `isa<To>(Val) && "cast<Ty>() argument of incompatible type!"' failed.
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
# | Stack dump:
# | 0. Program arguments: /home/folkertdev/c/llvm-project/build/bin/llc -print-before=isel -print-after=isel
# | 1. Running pass 'Function Pass Manager' on module '<stdin>'.
```
---
Next I turned that debug assertion off and minimized the two rust examples. The LLVM IR is kind of ill-formed because it uses identifiers that are not defined. Specifically the `call i1 %40()` and similar are apparently needed to inhibit some transformation/optimization.
https://godbolt.org/z/6YYEs3Msc
https://godbolt.org/z/71hd8EYd1
Based on the error location, maybe a typed load needs some special handling here?
https://github.com/llvm/llvm-project/blob/866879f80342b857a8b911c804189c43ac4fc334/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp#L42-L58
Here is a local backtrace with some more helpful line numbers.
```
PromoteIntegerResult #1: t9: i64,i1 = llvm.type.checked.load TargetConstant:i64<363>, t5, Constant:i32<0>, MDNode:ch<0x5aaad8feae88>
LLVM ERROR: Do not know how to promote this operator!
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0. Program arguments: /home/folkertdev/c/llvm-project/build/bin/llc
1. Running pass 'Function Pass Manager' on module '<stdin>'.
2. Running pass 'X86 DAG->DAG Instruction Selection' on function '@foo'
#0 0x00005aaad4fa4af2 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/folkertdev/c/llvm-project/llvm/lib/Support/Unix/Signals.inc:834:22
#1 0x00005aaad4fa4f65 PrintStackTraceSignalHandler(void*) /home/folkertdev/c/llvm-project/llvm/lib/Support/Unix/Signals.inc:916:1
#2 0x00005aaad4fa20dd llvm::sys::RunSignalHandlers() /home/folkertdev/c/llvm-project/llvm/lib/Support/Signals.cpp:104:20
#3 0x00005aaad4fa432f SignalHandler(int, siginfo_t*, void*) /home/folkertdev/c/llvm-project/llvm/lib/Support/Unix/Signals.inc:426:14
#4 0x000077dbbaa45320 (/lib/x86_64-linux-gnu/libc.so.6+0x45320)
#5 0x000077dbbaa9eb1c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
#6 0x000077dbbaa9eb1c __pthread_kill_internal ./nptl/pthread_kill.c:78:10
#7 0x000077dbbaa9eb1c pthread_kill ./nptl/pthread_kill.c:89:10
#8 0x000077dbbaa4526e raise ./signal/../sysdeps/posix/raise.c:27:6
#9 0x000077dbbaa288ff abort ./stdlib/abort.c:81:7
#10 0x00005aaad4ea995e llvm::report_fatal_error(llvm::Twine const&, bool) /home/folkertdev/c/llvm-project/llvm/lib/Support/ErrorHandling.cpp:137:9
#11 0x00005aaad4ea9735 llvm::report_fatal_error(llvm::StringRef, bool) /home/folkertdev/c/llvm-project/llvm/lib/Support/ErrorHandling.cpp:99:68
#12 0x00005aaad4cf2094 llvm::DAGTypeLegalizer::PromoteIntegerResult(llvm::SDNode*, unsigned int) /home/folkertdev/c/llvm-project/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:59:58
#13 0x00005aaad4ce6624 llvm::DAGTypeLegalizer::run() /home/folkertdev/c/llvm-project/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp:265:17
#14 0x00005aaad4ceac90 llvm::SelectionDAG::LegalizeTypes() /home/folkertdev/c/llvm-project/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp:1054:37
#15 0x00005aaad4cc192c llvm::SelectionDAGISel::CodeGenAndEmitDAG() /home/folkertdev/c/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:992:36
#16 0x00005aaad4cc0e23 llvm::SelectionDAGISel::SelectBasicBlock(llvm::ilist_iterator_w_bits<llvm::ilist_detail::node_options<llvm::Instruction, true, false, void, true, llvm::BasicBlock>, false, true>, llvm::ilist_iterator_w_bits<llvm::ilist_detail::node_options<llvm::Instruction, true, false, void, true, llvm::BasicBlock>, false, true>, bool&) /home/folkertdev/c/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:890:1
#17 0x00005aaad4cc7152 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) /home/folkertdev/c/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1922:33
#18 0x00005aaad4cbf4ac llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) /home/folkertdev/c/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:628:7
#19 0x00005aaad2461193 (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) /home/folkertdev/c/llvm-project/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp:188:0
#20 0x00005aaad4cbe11c llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) /home/folkertdev/c/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:390:40
#21 0x00005aaad3585d95 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /home/folkertdev/c/llvm-project/llvm/lib/CodeGen/MachineFunctionPass.cpp:108:30
#22 0x00005aaad3ef1e4c llvm::FPPassManager::runOnFunction(llvm::Function&) /home/folkertdev/c/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1398:20
#23 0x00005aaad3ef2122 llvm::FPPassManager::runOnModule(llvm::Module&) /home/folkertdev/c/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1444:13
#24 0x00005aaad3ef2581 (anonymous namespace)::MPPassManager::runOnModule(llvm::Module&) /home/folkertdev/c/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1513:20
#25 0x00005aaad3eed548 llvm::legacy::PassManagerImpl::run(llvm::Module&) /home/folkertdev/c/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:531:13
#26 0x00005aaad3ef2e77 llvm::legacy::PassManager::run(llvm::Module&) /home/folkertdev/c/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1641:1
#27 0x00005aaad1594d0d compileModule(char**, llvm::LLVMContext&) /home/folkertdev/c/llvm-project/llvm/tools/llc/llc.cpp:833:34
#28 0x00005aaad15921dd main /home/folkertdev/c/llvm-project/llvm/tools/llc/llc.cpp:446:35
#29 0x000077dbbaa2a1ca __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#30 0x000077dbbaa2a28b call_init ./csu/../csu/libc-start.c:128:20
#31 0x000077dbbaa2a28b __libc_start_main ./csu/../csu/libc-start.c:347:5
#32 0x00005aaad1590a25 _start (/home/folkertdev/c/llvm-project/build/bin/llc+0x528aa25)
fish: Job 1, '/home/folkertdev/c/llvm-project…' terminated by signal SIGABRT (Abort)
```
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