rustc LLVM-18 float extension crash (LLVM-404)

[MabezDev]

Checklist

• Checked the issue tracker for similar issues to ensure this is not a duplicate
• Read the documentation to confirm the issue is not addressed there and your configuration is set correctly
• Tested with the latest version to ensure the issue hasn't been fixed

How often does this bug occurs?

always

Expected behavior

Targets with float support to compile

Actual behavior (suspected bug)

It seems float extension i.e compiler support for going from f16 -> f32 is broken and produces the following LLVM error below.

Error logs or terminal output

rustc-LLVM ERROR: Cannot select: 0x7ff58d078ee0: f32 = fp16_to_fp 0x7ff58c609d10
  0x7ff58c609d10: i32,ch = CopyFromReg 0x7ff58caa0fe0, Register:i32 %5
    0x7ff58c07dc10: i32 = Register %5
In function: _ZN17compiler_builtins5float6extend13__extendhfsf217h7e81549493d256faE
error: could not compile `compiler_builtins` (lib)

Steps to reproduce the behavior

1. Download and unzip ll.zip
2. Using LLC from the latest release of llvm 18 run ./llc compiler_builtins-41e65ec39b07922e.compiler_builtins.6ff7e3b67cc0ddd4-cgu.0.rcgu.ll
3. Observe an error like

LLVM ERROR: Cannot select: 0x565015758970: f32 = fp16_to_fp 0x56501563bec0
  0x56501563bec0: i32,ch = CopyFromReg 0x56501462f2c0, Register:i32 %5
    0x56501575ddb0: i32 = Register %5
In function: _ZN17compiler_builtins5float6extend13__extendhfsf217h7e81549493d256faE
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: ./llc /home/mabez/development/rust/embedded/hal/esp-hal/examples/target/xtensa-esp32-none-elf/release/deps/compiler_builtins-41e65ec39b07922e.compiler_builtins.6ff7e3b67cc0ddd4-cgu.0.rcgu.ll
1.      Running pass 'Function Pass Manager' on module '/home/mabez/development/rust/embedded/hal/esp-hal/examples/target/xtensa-esp32-none-elf/release/deps/compiler_builtins-41e65ec39b07922e.compiler_builtins.6ff7e3b67cc0ddd4-cgu.0.rcgu.ll'.
2.      Running pass 'Xtensa DAG->DAG Pattern Instruction Selection' on function '@_ZN17compiler_builtins5float6extend13__extendhfsf217h7e81549493d256faE'
 #0 0x000056500e88d330 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (./llc+0x2d6a330)
 #1 0x000056500e88a77b SignalHandler(int) Signals.cpp:0:0
 #2 0x00007ffb18841960 (/lib64/libc.so.6+0x3c960)
 #3 0x00007ffb1889326c (/lib64/libc.so.6+0x8e26c)
 #4 0x00007ffb188418b6 raise (/lib64/libc.so.6+0x3c8b6)
 #5 0x00007ffb188298b7 abort (/lib64/libc.so.6+0x248b7)
 #6 0x000056500bde0e61 llvm::install_bad_alloc_error_handler(void (*)(void*, char const*, bool), void*) (.cold) ErrorHandling.cpp:0:0
 #7 0x000056500e63b398 llvm::SelectionDAGISel::CannotYetSelect(llvm::SDNode*) (./llc+0x2b18398)
 #8 0x000056500e63fc1b llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*, unsigned int) (./llc+0x2b1cc1b)
 #9 0x000056500d141dcd (anonymous namespace)::XtensaDAGToDAGISel::Select(llvm::SDNode*) XtensaISelDAGToDAG.cpp:0:0
#10 0x000056500e63715c llvm::SelectionDAGISel::DoInstructionSelection() (./llc+0x2b1415c)
#11 0x000056500e642fda llvm::SelectionDAGISel::CodeGenAndEmitDAG() (./llc+0x2b1ffda)
#12 0x000056500e645c6b llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (./llc+0x2b22c6b)
#13 0x000056500e648445 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (.part.0) SelectionDAGISel.cpp:0:0
#14 0x000056500e649c61 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (./llc+0x2b26c61)
#15 0x000056500d8dc87d llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#16 0x000056500de54481 llvm::FPPassManager::runOnFunction(llvm::Function&) (./llc+0x2331481)
#17 0x000056500de54804 llvm::FPPassManager::runOnModule(llvm::Module&) (./llc+0x2331804)
#18 0x000056500de5632e llvm::legacy::PassManagerImpl::run(llvm::Module&) (./llc+0x233332e)
#19 0x000056500bef5e99 compileModule(char**, llvm::LLVMContext&) llc.cpp:0:0
#20 0x000056500bdf61d6 main (./llc+0x2d31d6)
#21 0x00007ffb1882b2e0 (/lib64/libc.so.6+0x262e0)
#22 0x00007ffb1882b399 __libc_start_main (/lib64/libc.so.6+0x26399)
#23 0x000056500beecab5 _start (./llc+0x3c9ab5)
[1]    20664 IOT instruction  ./llc

Project release version

latest 18 release branch

System architecture

Intel/AMD 64-bit (modern PC, older Mac)

Operating system

Linux

Operating system version

Gentoo

Shell

ZSH

Additional context

No response

[gerekon]

Not sure, but it could be related to #91. Or at least it can be fixed with #92. I will check

BTW. I can not even open in editor 13 MB .ll file :-)

[MabezDev]

I can confirm it's fixed with #92