[LoongArch] `Assertion '(!UseGPRForFloat || LocVT == GRLenVT) && "Expected an GRLenVT at this stage"' failed.`

[alexrp]

❯ llc --version | head -n2
LLVM (http://llvm.org/):
  LLVM version 21.1.0

We have two repros for this one:

target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "loongarch64-unknown-linux5.19.0-gnu2.36.0"

define fastcc <64 x i32> @behavior.math.expectVectorsEqual__anon_63531(<64 x i32> %0) {
Entry:
  ret <64 x i32> %0
}

❯ llc reduced_behavior.ll
llc: /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6848: bool CC_LoongArch(const llvm::DataLayout&, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&, bool, bool, llvm::Type*): Assertion `(!UseGPRForFloat || LocVT == GRLenVT) && "Expected an GRLenVT at this stage"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: llc reduced_behavior.ll
1.      Running pass 'Function Pass Manager' on module 'reduced_behavior.ll'.
2.      Running pass 'LoongArch DAG->DAG Pattern Instruction Selection' on function '@behavior.math.expectVectorsEqual__anon_63531'
 #0 0x00007d2e67d91af0 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/alexrp/Source/llvm-project/llvm/lib/Support/Unix/Signals.inc:838:3
 #1 0x00007d2e67d8e9b4 llvm::sys::RunSignalHandlers() /home/alexrp/Source/llvm-project/llvm/lib/Support/Signals.cpp:104:20
 #2 0x00007d2e67d8f1e9 SignalHandler(int, siginfo_t*, void*) /home/alexrp/Source/llvm-project/llvm/lib/Support/Unix/Signals.inc:426:14
 #3 0x00007d2e666458d0 (/lib/x86_64-linux-gnu/libc.so.6+0x458d0)
 #4 0x00007d2e666a49bc __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #5 0x00007d2e666a49bc __pthread_kill_internal ./nptl/pthread_kill.c:89:10
 #6 0x00007d2e666a49bc pthread_kill ./nptl/pthread_kill.c:100:10
 #7 0x00007d2e6664579e raise ./signal/../sysdeps/posix/raise.c:27:6
 #8 0x00007d2e666288cd internal_signal_block_all ./stdlib/../sysdeps/unix/sysv/linux/internal-signals.h:81:3
 #9 0x00007d2e666288cd __abort_lock_wrlock ./stdlib/abort.c:58:3
#10 0x00007d2e666288cd abort ./stdlib/abort.c:81:3
#11 0x00007d2e66628830 __assert_perror_fail ./assert/assert-perr.c:31:1
#12 0x00007d2e679a61e8 CC_LoongArch(llvm::DataLayout const&, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&, bool, bool, llvm::Type*) (.cold) /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6836:5
#13 0x00007d2e6b9300ae llvm::LoongArchTargetLowering::analyzeInputArgs(llvm::MachineFunction&, llvm::CCState&, llvm::SmallVectorImpl<llvm::ISD::InputArg> const&, bool, bool (*)(llvm::DataLayout const&, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&, bool, bool, llvm::Type*)) const /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6880:5
#14 0x00007d2e6b947771 llvm::SmallVectorBase<unsigned int>::size() const /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/SmallVector.h:79:32
#15 0x00007d2e6b947771 llvm::LoongArchTargetLowering::LowerFormalArguments(llvm::SDValue, unsigned int, bool, llvm::SmallVectorImpl<llvm::ISD::InputArg> const&, llvm::SDLoc const&, llvm::SelectionDAG&, llvm::SmallVectorImpl<llvm::SDValue>&) const /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:7114:40
#16 0x00007d2e688d1890 llvm::SelectionDAGISel::LowerArguments(llvm::Function const&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:11768:46
#17 0x00007d2e6898d9d1 std::__uniq_ptr_impl<llvm::SwiftErrorValueTracking, std::default_delete<llvm::SwiftErrorValueTracking>>::_M_ptr() const /usr/include/c++/14/bits/unique_ptr.h:193:18
#18 0x00007d2e6898d9d1 std::unique_ptr<llvm::SwiftErrorValueTracking, std::default_delete<llvm::SwiftErrorValueTracking>>::get() const /usr/include/c++/14/bits/unique_ptr.h:465:27
#19 0x00007d2e6898d9d1 std::unique_ptr<llvm::SwiftErrorValueTracking, std::default_delete<llvm::SwiftErrorValueTracking>>::operator->() const /usr/include/c++/14/bits/unique_ptr.h:458:12
#20 0x00007d2e6898d9d1 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1670:56
#21 0x00007d2e6898e3d9 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:605:22
#22 0x00007d2e68985137 llvm::OptLevelChanger::~OptLevelChanger() /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:267:11
#23 0x00007d2e68985137 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:373:1
#24 0x00007d2e68985137 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:345:6
#25 0x00007d2e682d947b llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/MachineFunctionPass.cpp:108:30
#26 0x00007d2e67f4cd34 llvm::FPPassManager::runOnFunction(llvm::Function&) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1408:7
#27 0x00007d2e67f4cf45 llvm::ilist_detail::node_base_prevnext<llvm::ilist_node_base<true, void>, true>::getNext() const /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_node_base.h:42:38
#28 0x00007d2e67f4cf45 llvm::ilist_node_impl<llvm::ilist_detail::node_options<llvm::Function, true, false, void, false, void>>::getNext() /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_node.h:119:66
#29 0x00007d2e67f4cf45 llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Function, true, false, void, false, void>, false, false>::operator++() /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_iterator.h:187:25
#30 0x00007d2e67f4cf45 llvm::FPPassManager::runOnModule(llvm::Module&) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1443:22
#31 0x00007d2e67f4d75b runOnModule /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1520:7
#32 0x00007d2e67f4d75b llvm::legacy::PassManagerImpl::run(llvm::Module&) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:531:55
#33 0x00005aa6e4dca16d compileModule(char**, llvm::LLVMContext&) /home/alexrp/Source/llvm-project/llvm/tools/llc/llc.cpp:761:34
#34 0x00005aa6e4dbe4cf main /home/alexrp/Source/llvm-project/llvm/tools/llc/llc.cpp:404:35
#35 0x00007d2e6662a578 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#36 0x00007d2e6662a63b call_init ./csu/../csu/libc-start.c:128:20
#37 0x00007d2e6662a63b __libc_start_main ./csu/../csu/libc-start.c:347:5
#38 0x00005aa6e4dbfaa5 _start (/opt/llvm-21/bin/llc+0x14aa5)
fish: Job 1, 'llc reduced_behavior.ll' terminated by signal SIGABRT (Abort)

---

target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "loongarch64-unknown-linux5.19.0-musl"

define fastcc <16 x double> @testing.expectEqualInner__anon_1383779(<16 x double> %0, <16 x double> %1) {
Entry:
  ret <16 x double> %0
}

❯ llc reduced_std.ll
llc: /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6848: bool CC_LoongArch(const llvm::DataLayout&, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&, bool, bool, llvm::Type*): Assertion `(!UseGPRForFloat || LocVT == GRLenVT) && "Expected an GRLenVT at this stage"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: llc reduced_std.ll
1.      Running pass 'Function Pass Manager' on module 'reduced_std.ll'.
2.      Running pass 'LoongArch DAG->DAG Pattern Instruction Selection' on function '@testing.expectEqualInner__anon_1383779'
 #0 0x00007e6a7e991af0 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/alexrp/Source/llvm-project/llvm/lib/Support/Unix/Signals.inc:838:3
 #1 0x00007e6a7e98e9b4 llvm::sys::RunSignalHandlers() /home/alexrp/Source/llvm-project/llvm/lib/Support/Signals.cpp:104:20
 #2 0x00007e6a7e98f1e9 SignalHandler(int, siginfo_t*, void*) /home/alexrp/Source/llvm-project/llvm/lib/Support/Unix/Signals.inc:426:14
 #3 0x00007e6a7d2458d0 (/lib/x86_64-linux-gnu/libc.so.6+0x458d0)
 #4 0x00007e6a7d2a49bc __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #5 0x00007e6a7d2a49bc __pthread_kill_internal ./nptl/pthread_kill.c:89:10
 #6 0x00007e6a7d2a49bc pthread_kill ./nptl/pthread_kill.c:100:10
 #7 0x00007e6a7d24579e raise ./signal/../sysdeps/posix/raise.c:27:6
 #8 0x00007e6a7d2288cd internal_signal_block_all ./stdlib/../sysdeps/unix/sysv/linux/internal-signals.h:81:3
 #9 0x00007e6a7d2288cd __abort_lock_wrlock ./stdlib/abort.c:58:3
#10 0x00007e6a7d2288cd abort ./stdlib/abort.c:81:3
#11 0x00007e6a7d228830 __assert_perror_fail ./assert/assert-perr.c:31:1
#12 0x00007e6a7e5a61e8 CC_LoongArch(llvm::DataLayout const&, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&, bool, bool, llvm::Type*) (.cold) /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6836:5
#13 0x00007e6a825300ae llvm::LoongArchTargetLowering::analyzeInputArgs(llvm::MachineFunction&, llvm::CCState&, llvm::SmallVectorImpl<llvm::ISD::InputArg> const&, bool, bool (*)(llvm::DataLayout const&, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&, bool, bool, llvm::Type*)) const /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6880:5
#14 0x00007e6a82547771 llvm::SmallVectorBase<unsigned int>::size() const /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/SmallVector.h:79:32
#15 0x00007e6a82547771 llvm::LoongArchTargetLowering::LowerFormalArguments(llvm::SDValue, unsigned int, bool, llvm::SmallVectorImpl<llvm::ISD::InputArg> const&, llvm::SDLoc const&, llvm::SelectionDAG&, llvm::SmallVectorImpl<llvm::SDValue>&) const /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:7114:40
#16 0x00007e6a7f4d1890 llvm::SelectionDAGISel::LowerArguments(llvm::Function const&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:11768:46
#17 0x00007e6a7f58d9d1 std::__uniq_ptr_impl<llvm::SwiftErrorValueTracking, std::default_delete<llvm::SwiftErrorValueTracking>>::_M_ptr() const /usr/include/c++/14/bits/unique_ptr.h:193:18
#18 0x00007e6a7f58d9d1 std::unique_ptr<llvm::SwiftErrorValueTracking, std::default_delete<llvm::SwiftErrorValueTracking>>::get() const /usr/include/c++/14/bits/unique_ptr.h:465:27
#19 0x00007e6a7f58d9d1 std::unique_ptr<llvm::SwiftErrorValueTracking, std::default_delete<llvm::SwiftErrorValueTracking>>::operator->() const /usr/include/c++/14/bits/unique_ptr.h:458:12
#20 0x00007e6a7f58d9d1 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1670:56
#21 0x00007e6a7f58e3d9 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:605:22
#22 0x00007e6a7f585137 llvm::OptLevelChanger::~OptLevelChanger() /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:267:11
#23 0x00007e6a7f585137 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:373:1
#24 0x00007e6a7f585137 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:345:6
#25 0x00007e6a7eed947b llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/MachineFunctionPass.cpp:108:30
#26 0x00007e6a7eb4cd34 llvm::FPPassManager::runOnFunction(llvm::Function&) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1408:7
#27 0x00007e6a7eb4cf45 llvm::ilist_detail::node_base_prevnext<llvm::ilist_node_base<true, void>, true>::getNext() const /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_node_base.h:42:38
#28 0x00007e6a7eb4cf45 llvm::ilist_node_impl<llvm::ilist_detail::node_options<llvm::Function, true, false, void, false, void>>::getNext() /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_node.h:119:66
#29 0x00007e6a7eb4cf45 llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Function, true, false, void, false, void>, false, false>::operator++() /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_iterator.h:187:25
#30 0x00007e6a7eb4cf45 llvm::FPPassManager::runOnModule(llvm::Module&) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1443:22
#31 0x00007e6a7eb4d75b runOnModule /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1520:7
#32 0x00007e6a7eb4d75b llvm::legacy::PassManagerImpl::run(llvm::Module&) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:531:55
#33 0x000062fde5cb116d compileModule(char**, llvm::LLVMContext&) /home/alexrp/Source/llvm-project/llvm/tools/llc/llc.cpp:761:34
#34 0x000062fde5ca54cf main /home/alexrp/Source/llvm-project/llvm/tools/llc/llc.cpp:404:35
#35 0x00007e6a7d22a578 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#36 0x00007e6a7d22a63b call_init ./csu/../csu/libc-start.c:128:20
#37 0x00007e6a7d22a63b __libc_start_main ./csu/../csu/libc-start.c:347:5
#38 0x000062fde5ca6aa5 _start (/opt/llvm-21/bin/llc+0x14aa5)
fish: Job 1, 'llc reduced_std.ll' terminated by signal SIGABRT (Abort)

[llvmbot]

@llvm/issue-subscribers-backend-loongarch

Author: Alex Rønne Petersen (alexrp)

``` ❯ llc --version | head -n2 LLVM (http://llvm.org/): LLVM version 21.1.0 ```

We have two repros for this one:

target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "loongarch64-unknown-linux5.19.0-gnu2.36.0"

define fastcc &lt;64 x i32&gt; @<!-- -->behavior.math.expectVectorsEqual__anon_63531(&lt;64 x i32&gt; %0) {
Entry:
  ret &lt;64 x i32&gt; %0
}

❯ llc reduced_behavior.ll
llc: /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6848: bool CC_LoongArch(const llvm::DataLayout&, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&, bool, bool, llvm::Type*): Assertion `(!UseGPRForFloat || LocVT == GRLenVT) && "Expected an GRLenVT at this stage"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: llc reduced_behavior.ll
1.      Running pass 'Function Pass Manager' on module 'reduced_behavior.ll'.
2.      Running pass 'LoongArch DAG-&gt;DAG Pattern Instruction Selection' on function '@<!-- -->behavior.math.expectVectorsEqual__anon_63531'
 #<!-- -->0 0x00007d2e67d91af0 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) /home/alexrp/Source/llvm-project/llvm/lib/Support/Unix/Signals.inc:838:3
 #<!-- -->1 0x00007d2e67d8e9b4 llvm::sys::RunSignalHandlers() /home/alexrp/Source/llvm-project/llvm/lib/Support/Signals.cpp:104:20
 #<!-- -->2 0x00007d2e67d8f1e9 SignalHandler(int, siginfo_t*, void*) /home/alexrp/Source/llvm-project/llvm/lib/Support/Unix/Signals.inc:426:14
 #<!-- -->3 0x00007d2e666458d0 (/lib/x86_64-linux-gnu/libc.so.6+0x458d0)
 #<!-- -->4 0x00007d2e666a49bc __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #<!-- -->5 0x00007d2e666a49bc __pthread_kill_internal ./nptl/pthread_kill.c:89:10
 #<!-- -->6 0x00007d2e666a49bc pthread_kill ./nptl/pthread_kill.c:100:10
 #<!-- -->7 0x00007d2e6664579e raise ./signal/../sysdeps/posix/raise.c:27:6
 #<!-- -->8 0x00007d2e666288cd internal_signal_block_all ./stdlib/../sysdeps/unix/sysv/linux/internal-signals.h:81:3
 #<!-- -->9 0x00007d2e666288cd __abort_lock_wrlock ./stdlib/abort.c:58:3
#<!-- -->10 0x00007d2e666288cd abort ./stdlib/abort.c:81:3
#<!-- -->11 0x00007d2e66628830 __assert_perror_fail ./assert/assert-perr.c:31:1
#<!-- -->12 0x00007d2e679a61e8 CC_LoongArch(llvm::DataLayout const&amp;, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&amp;, bool, bool, llvm::Type*) (.cold) /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6836:5
#<!-- -->13 0x00007d2e6b9300ae llvm::LoongArchTargetLowering::analyzeInputArgs(llvm::MachineFunction&amp;, llvm::CCState&amp;, llvm::SmallVectorImpl&lt;llvm::ISD::InputArg&gt; const&amp;, bool, bool (*)(llvm::DataLayout const&amp;, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&amp;, bool, bool, llvm::Type*)) const /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6880:5
#<!-- -->14 0x00007d2e6b947771 llvm::SmallVectorBase&lt;unsigned int&gt;::size() const /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/SmallVector.h:79:32
#<!-- -->15 0x00007d2e6b947771 llvm::LoongArchTargetLowering::LowerFormalArguments(llvm::SDValue, unsigned int, bool, llvm::SmallVectorImpl&lt;llvm::ISD::InputArg&gt; const&amp;, llvm::SDLoc const&amp;, llvm::SelectionDAG&amp;, llvm::SmallVectorImpl&lt;llvm::SDValue&gt;&amp;) const /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:7114:40
#<!-- -->16 0x00007d2e688d1890 llvm::SelectionDAGISel::LowerArguments(llvm::Function const&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:11768:46
#<!-- -->17 0x00007d2e6898d9d1 std::__uniq_ptr_impl&lt;llvm::SwiftErrorValueTracking, std::default_delete&lt;llvm::SwiftErrorValueTracking&gt;&gt;::_M_ptr() const /usr/include/c++/14/bits/unique_ptr.h:193:18
#<!-- -->18 0x00007d2e6898d9d1 std::unique_ptr&lt;llvm::SwiftErrorValueTracking, std::default_delete&lt;llvm::SwiftErrorValueTracking&gt;&gt;::get() const /usr/include/c++/14/bits/unique_ptr.h:465:27
#<!-- -->19 0x00007d2e6898d9d1 std::unique_ptr&lt;llvm::SwiftErrorValueTracking, std::default_delete&lt;llvm::SwiftErrorValueTracking&gt;&gt;::operator-&gt;() const /usr/include/c++/14/bits/unique_ptr.h:458:12
#<!-- -->20 0x00007d2e6898d9d1 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1670:56
#<!-- -->21 0x00007d2e6898e3d9 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:605:22
#<!-- -->22 0x00007d2e68985137 llvm::OptLevelChanger::~OptLevelChanger() /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:267:11
#<!-- -->23 0x00007d2e68985137 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:373:1
#<!-- -->24 0x00007d2e68985137 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:345:6
#<!-- -->25 0x00007d2e682d947b llvm::MachineFunctionPass::runOnFunction(llvm::Function&amp;) (.part.0) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/MachineFunctionPass.cpp:108:30
#<!-- -->26 0x00007d2e67f4cd34 llvm::FPPassManager::runOnFunction(llvm::Function&amp;) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1408:7
#<!-- -->27 0x00007d2e67f4cf45 llvm::ilist_detail::node_base_prevnext&lt;llvm::ilist_node_base&lt;true, void&gt;, true&gt;::getNext() const /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_node_base.h:42:38
#<!-- -->28 0x00007d2e67f4cf45 llvm::ilist_node_impl&lt;llvm::ilist_detail::node_options&lt;llvm::Function, true, false, void, false, void&gt;&gt;::getNext() /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_node.h:119:66
#<!-- -->29 0x00007d2e67f4cf45 llvm::ilist_iterator&lt;llvm::ilist_detail::node_options&lt;llvm::Function, true, false, void, false, void&gt;, false, false&gt;::operator++() /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_iterator.h:187:25
#<!-- -->30 0x00007d2e67f4cf45 llvm::FPPassManager::runOnModule(llvm::Module&amp;) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1443:22
#<!-- -->31 0x00007d2e67f4d75b runOnModule /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1520:7
#<!-- -->32 0x00007d2e67f4d75b llvm::legacy::PassManagerImpl::run(llvm::Module&amp;) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:531:55
#<!-- -->33 0x00005aa6e4dca16d compileModule(char**, llvm::LLVMContext&amp;) /home/alexrp/Source/llvm-project/llvm/tools/llc/llc.cpp:761:34
#<!-- -->34 0x00005aa6e4dbe4cf main /home/alexrp/Source/llvm-project/llvm/tools/llc/llc.cpp:404:35
#<!-- -->35 0x00007d2e6662a578 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#<!-- -->36 0x00007d2e6662a63b call_init ./csu/../csu/libc-start.c:128:20
#<!-- -->37 0x00007d2e6662a63b __libc_start_main ./csu/../csu/libc-start.c:347:5
#<!-- -->38 0x00005aa6e4dbfaa5 _start (/opt/llvm-21/bin/llc+0x14aa5)
fish: Job 1, 'llc reduced_behavior.ll' terminated by signal SIGABRT (Abort)

---

target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "loongarch64-unknown-linux5.19.0-musl"

define fastcc &lt;16 x double&gt; @<!-- -->testing.expectEqualInner__anon_1383779(&lt;16 x double&gt; %0, &lt;16 x double&gt; %1) {
Entry:
  ret &lt;16 x double&gt; %0
}

❯ llc reduced_std.ll
llc: /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6848: bool CC_LoongArch(const llvm::DataLayout&, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&, bool, bool, llvm::Type*): Assertion `(!UseGPRForFloat || LocVT == GRLenVT) && "Expected an GRLenVT at this stage"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: llc reduced_std.ll
1.      Running pass 'Function Pass Manager' on module 'reduced_std.ll'.
2.      Running pass 'LoongArch DAG-&gt;DAG Pattern Instruction Selection' on function '@<!-- -->testing.expectEqualInner__anon_1383779'
 #<!-- -->0 0x00007e6a7e991af0 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) /home/alexrp/Source/llvm-project/llvm/lib/Support/Unix/Signals.inc:838:3
 #<!-- -->1 0x00007e6a7e98e9b4 llvm::sys::RunSignalHandlers() /home/alexrp/Source/llvm-project/llvm/lib/Support/Signals.cpp:104:20
 #<!-- -->2 0x00007e6a7e98f1e9 SignalHandler(int, siginfo_t*, void*) /home/alexrp/Source/llvm-project/llvm/lib/Support/Unix/Signals.inc:426:14
 #<!-- -->3 0x00007e6a7d2458d0 (/lib/x86_64-linux-gnu/libc.so.6+0x458d0)
 #<!-- -->4 0x00007e6a7d2a49bc __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #<!-- -->5 0x00007e6a7d2a49bc __pthread_kill_internal ./nptl/pthread_kill.c:89:10
 #<!-- -->6 0x00007e6a7d2a49bc pthread_kill ./nptl/pthread_kill.c:100:10
 #<!-- -->7 0x00007e6a7d24579e raise ./signal/../sysdeps/posix/raise.c:27:6
 #<!-- -->8 0x00007e6a7d2288cd internal_signal_block_all ./stdlib/../sysdeps/unix/sysv/linux/internal-signals.h:81:3
 #<!-- -->9 0x00007e6a7d2288cd __abort_lock_wrlock ./stdlib/abort.c:58:3
#<!-- -->10 0x00007e6a7d2288cd abort ./stdlib/abort.c:81:3
#<!-- -->11 0x00007e6a7d228830 __assert_perror_fail ./assert/assert-perr.c:31:1
#<!-- -->12 0x00007e6a7e5a61e8 CC_LoongArch(llvm::DataLayout const&amp;, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&amp;, bool, bool, llvm::Type*) (.cold) /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6836:5
#<!-- -->13 0x00007e6a825300ae llvm::LoongArchTargetLowering::analyzeInputArgs(llvm::MachineFunction&amp;, llvm::CCState&amp;, llvm::SmallVectorImpl&lt;llvm::ISD::InputArg&gt; const&amp;, bool, bool (*)(llvm::DataLayout const&amp;, llvm::LoongArchABI::ABI, unsigned int, llvm::MVT, llvm::CCValAssign::LocInfo, llvm::ISD::ArgFlagsTy, llvm::CCState&amp;, bool, bool, llvm::Type*)) const /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:6880:5
#<!-- -->14 0x00007e6a82547771 llvm::SmallVectorBase&lt;unsigned int&gt;::size() const /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/SmallVector.h:79:32
#<!-- -->15 0x00007e6a82547771 llvm::LoongArchTargetLowering::LowerFormalArguments(llvm::SDValue, unsigned int, bool, llvm::SmallVectorImpl&lt;llvm::ISD::InputArg&gt; const&amp;, llvm::SDLoc const&amp;, llvm::SelectionDAG&amp;, llvm::SmallVectorImpl&lt;llvm::SDValue&gt;&amp;) const /home/alexrp/Source/llvm-project/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp:7114:40
#<!-- -->16 0x00007e6a7f4d1890 llvm::SelectionDAGISel::LowerArguments(llvm::Function const&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:11768:46
#<!-- -->17 0x00007e6a7f58d9d1 std::__uniq_ptr_impl&lt;llvm::SwiftErrorValueTracking, std::default_delete&lt;llvm::SwiftErrorValueTracking&gt;&gt;::_M_ptr() const /usr/include/c++/14/bits/unique_ptr.h:193:18
#<!-- -->18 0x00007e6a7f58d9d1 std::unique_ptr&lt;llvm::SwiftErrorValueTracking, std::default_delete&lt;llvm::SwiftErrorValueTracking&gt;&gt;::get() const /usr/include/c++/14/bits/unique_ptr.h:465:27
#<!-- -->19 0x00007e6a7f58d9d1 std::unique_ptr&lt;llvm::SwiftErrorValueTracking, std::default_delete&lt;llvm::SwiftErrorValueTracking&gt;&gt;::operator-&gt;() const /usr/include/c++/14/bits/unique_ptr.h:458:12
#<!-- -->20 0x00007e6a7f58d9d1 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1670:56
#<!-- -->21 0x00007e6a7f58e3d9 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:605:22
#<!-- -->22 0x00007e6a7f585137 llvm::OptLevelChanger::~OptLevelChanger() /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:267:11
#<!-- -->23 0x00007e6a7f585137 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:373:1
#<!-- -->24 0x00007e6a7f585137 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&amp;) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:345:6
#<!-- -->25 0x00007e6a7eed947b llvm::MachineFunctionPass::runOnFunction(llvm::Function&amp;) (.part.0) /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/MachineFunctionPass.cpp:108:30
#<!-- -->26 0x00007e6a7eb4cd34 llvm::FPPassManager::runOnFunction(llvm::Function&amp;) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1408:7
#<!-- -->27 0x00007e6a7eb4cf45 llvm::ilist_detail::node_base_prevnext&lt;llvm::ilist_node_base&lt;true, void&gt;, true&gt;::getNext() const /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_node_base.h:42:38
#<!-- -->28 0x00007e6a7eb4cf45 llvm::ilist_node_impl&lt;llvm::ilist_detail::node_options&lt;llvm::Function, true, false, void, false, void&gt;&gt;::getNext() /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_node.h:119:66
#<!-- -->29 0x00007e6a7eb4cf45 llvm::ilist_iterator&lt;llvm::ilist_detail::node_options&lt;llvm::Function, true, false, void, false, void&gt;, false, false&gt;::operator++() /home/alexrp/Source/llvm-project/llvm/include/llvm/ADT/ilist_iterator.h:187:25
#<!-- -->30 0x00007e6a7eb4cf45 llvm::FPPassManager::runOnModule(llvm::Module&amp;) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1443:22
#<!-- -->31 0x00007e6a7eb4d75b runOnModule /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1520:7
#<!-- -->32 0x00007e6a7eb4d75b llvm::legacy::PassManagerImpl::run(llvm::Module&amp;) /home/alexrp/Source/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:531:55
#<!-- -->33 0x000062fde5cb116d compileModule(char**, llvm::LLVMContext&amp;) /home/alexrp/Source/llvm-project/llvm/tools/llc/llc.cpp:761:34
#<!-- -->34 0x000062fde5ca54cf main /home/alexrp/Source/llvm-project/llvm/tools/llc/llc.cpp:404:35
#<!-- -->35 0x00007e6a7d22a578 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#<!-- -->36 0x00007e6a7d22a63b call_init ./csu/../csu/libc-start.c:128:20
#<!-- -->37 0x00007e6a7d22a63b __libc_start_main ./csu/../csu/libc-start.c:347:5
#<!-- -->38 0x000062fde5ca6aa5 _start (/opt/llvm-21/bin/llc+0x14aa5)
fish: Job 1, 'llc reduced_std.ll' terminated by signal SIGABRT (Abort)

[heiher]

define fastcc <64 x i32> @behavior.math.expectVectorsEqual__anon_63531(<64 x i32> %0) {
Entry:
  ret <64 x i32> %0
}

In this case, the <64 x i32> argument is split into 16 <4 x i32> parts. The first 8 are passed in vr0–vr7, and the remaining 8 are placed on the stack since no more VR argument registers are available. Is this the expected?

If it is, then we could either remove the assertion or reset UseGPRForFloat once we know the current part will be passed in VRs. If not, then we’ll need to pass some of the parts in GPRs instead.

[alexrp]

Well, it depends on whether the LoongArch backend implements (or wants to implement) fastcc differently from ccc. The former has no stable ABI and the intent is that backends can just do whatever they want to make the code faster, but I believe some backends just treat it as equivalent to ccc for simplicity.

If treating it as equivalent to ccc, I can't really comment since it would then depend on the C vector calling convention for LoongArch, and I don't believe that's publicly documented? (Yet?)

If treating it differently from ccc, then I suppose using GPRs would be better. But I would also say that we (Zig) are mostly just concerned with getting the crash fixed at this stage; extra optimization can always be done later.