crash: Assertion failed: (BestRC && "Couldn't find the register class"), function getCommonMinimalPhysRegClass, file TargetRegisterInfo.cpp

Snippet:

define float @frem_f32() {
  ret float 0.000000e+00
}

Compiler Explorer panes:

Reproduce:

llc -mtriple=riscv32 -mattr=+zfinx -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv32 -mattr=+zfinx -verify-machineinstrs -global-isel=0 snippet.ll -o -

Local llc output:

llc: /home/runner/work/llvm-fuzz/llvm-fuzz/llvm-project/llvm/lib/CodeGen/TargetRegisterInfo.cpp:216: const TargetRegisterClass *getCommonMinimalPhysRegClass(const TargetRegisterInfo *, MCRegister, MCRegister): Assertion `BestRC && "Couldn't find the register class"' 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/runner/work/llvm-fuzz/llvm-fuzz/llvm-project/build/bin/llc -mtriple=riscv32 -mattr=+zfinx -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* -o -
1.	Running pass 'Function Pass Manager' on module '<stdin>'.
2.	Running pass 'Post-RA pseudo instruction expansion pass' on function '@frem_f32'
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  llc       0x00005590932e979b llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 43
1  llc       0x00005590932e6641 llvm::sys::RunSignalHandlers() + 369
2  llc       0x00005590932ea21b
3  libc.so.6 0x00007f25ecc45330
4  libc.so.6 0x00007f25ecc9ec0c pthread_kill + 284
5  libc.so.6 0x00007f25ecc4527e gsignal + 30
6  libc.so.6 0x00007f25ecc288ff abort + 223
7  libc.so.6 0x00007f25ecc2881b
8  libc.so.6 0x00007f25ecc3b517
9  llc       0x00005590933bdea8 llvm::TargetRegisterInfo::getCommonMinimalPhysRegClass(llvm::MCRegister, llvm::MCRegister) const + 248
10 llc       0x0000559094052c9f
11 llc       0x00005590939b7617 llvm::TargetInstrInfo::lowerCopy(llvm::MachineInstr*) const + 359
12 llc       0x0000559093c98998
13 llc       0x0000559093c99143
14 llc       0x00005590938b0d2d llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 653
15 llc       0x0000559093640cd7 llvm::FPPassManager::runOnFunction(llvm::Function&) + 871
16 llc       0x00005590936491d2 llvm::FPPassManager::runOnModule(llvm::Module&) + 50
17 llc       0x0000559093641a80 llvm::legacy::PassManagerImpl::run(llvm::Module&) + 2000
18 llc       0x00005590932f0df8 llcMain + 12056
19 llc       0x000055909322c62f main + 63
20 libc.so.6 0x00007f25ecc2a1ca
21 libc.so.6 0x00007f25ecc2a28b __libc_start_main + 139
22 llc       0x000055909322c525 _start + 37

Occurrences (509) (first 50):

Generated 2026-10-15 08:05 UTC.