[X86-backend] fptrunc fp128 %x to bfloat failed!

[DigOrDog]

Description

The following code crashes X86 backend with "LLVM ERROR: Unsupported library call operation!"

Minimal Reproduction

https://godbolt.org/z/M6WE541vK

Code

@G.1 = global bfloat 0xR7F80

define void @f(fp128 %x) {
  %CastFPTrunc = fptrunc fp128 %x to bfloat
  store bfloat %CastFPTrunc, ptr @G.1, align 2
  ret void
}

Stack Trace

LLVM ERROR: Unsupported library call operation!
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-trunk/bin/llc -o /app/output.s -x86-asm-syntax=intel -O2 -mtriple=x86_64-linux-android -mattr=+mmx -enable-legalize-types-checking <source>
1.	Running pass 'Function Pass Manager' on module '<source>'.
2.	Running pass 'X86 DAG->DAG Instruction Selection' on function '@f'
 #0 0x000000000391df98 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/llc+0x391df98)
 #1 0x000000000391bb5c SignalHandler(int) Signals.cpp:0:0
 #2 0x000077ce84842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #3 0x000077ce848969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #4 0x000077ce84842476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #5 0x000077ce848287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #6 0x000000000075696c llvm::UniqueStringSaver::save(llvm::Twine const&) (.cold) StringSaver.cpp:0:0
 #7 0x00000000038740b8 (/opt/compiler-explorer/clang-trunk/bin/llc+0x38740b8)
 #8 0x0000000003744e97 llvm::TargetLowering::makeLibCall(llvm::SelectionDAG&, llvm::RTLIB::Libcall, llvm::EVT, llvm::ArrayRef<llvm::SDValue>, llvm::TargetLowering::MakeLibCallOptions, llvm::SDLoc const&, llvm::SDValue) const (/opt/compiler-explorer/clang-trunk/bin/llc+0x3744e97)
 #9 0x0000000001dcab1e llvm::X86TargetLowering::LowerFP_TO_BF16(llvm::SDValue, llvm::SelectionDAG&) const (/opt/compiler-explorer/clang-trunk/bin/llc+0x1dcab1e)
#10 0x0000000001eb8957 llvm::X86TargetLowering::LowerOperation(llvm::SDValue, llvm::SelectionDAG&) const (/opt/compiler-explorer/clang-trunk/bin/llc+0x1eb8957)
#11 0x00000000035d6ca5 (anonymous namespace)::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*) LegalizeDAG.cpp:0:0
#12 0x00000000035db42e llvm::SelectionDAG::Legalize() (/opt/compiler-explorer/clang-trunk/bin/llc+0x35db42e)
#13 0x00000000036db80b llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-trunk/bin/llc+0x36db80b)
#14 0x00000000036de3fc llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x36de3fc)
#15 0x00000000036e005f llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x36e005f)
#16 0x00000000036cc411 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x36cc411)
#17 0x00000000029b498b llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#18 0x0000000002f09492 llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2f09492)
#19 0x0000000002f09721 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2f09721)
#20 0x0000000002f0b0c6 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2f0b0c6)
#21 0x000000000087d334 compileModule(char**, llvm::LLVMContext&) llc.cpp:0:0
#22 0x000000000076aca6 main (/opt/compiler-explorer/clang-trunk/bin/llc+0x76aca6)
#23 0x000077ce84829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#24 0x000077ce84829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#25 0x00000000008750fe _start (/opt/compiler-explorer/clang-trunk/bin/llc+0x8750fe)
Program terminated with signal: SIGSEGV
Compiler returned: 139

[llvmbot]

@llvm/issue-subscribers-backend-x86

Author: None (DigOrDog)

# Description The following code crashes X86 backend with "LLVM ERROR: Unsupported library call operation!"

Minimal Reproduction

https://godbolt.org/z/M6WE541vK

Code

@<!-- -->G.1 = global bfloat 0xR7F80

define void @<!-- -->f(fp128 %x) {
  %CastFPTrunc = fptrunc fp128 %x to bfloat
  store bfloat %CastFPTrunc, ptr @<!-- -->G.1, align 2
  ret void
}

Stack Trace

LLVM ERROR: Unsupported library call operation!
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-trunk/bin/llc -o /app/output.s -x86-asm-syntax=intel -O2 -mtriple=x86_64-linux-android -mattr=+mmx -enable-legalize-types-checking <source>
1.	Running pass 'Function Pass Manager' on module '<source>'.
2.	Running pass 'X86 DAG-&gt;DAG Instruction Selection' on function '@<!-- -->f'
 #<!-- -->0 0x000000000391df98 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/opt/compiler-explorer/clang-trunk/bin/llc+0x391df98)
 #<!-- -->1 0x000000000391bb5c SignalHandler(int) Signals.cpp:0:0
 #<!-- -->2 0x000077ce84842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #<!-- -->3 0x000077ce848969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #<!-- -->4 0x000077ce84842476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #<!-- -->5 0x000077ce848287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #<!-- -->6 0x000000000075696c llvm::UniqueStringSaver::save(llvm::Twine const&amp;) (.cold) StringSaver.cpp:0:0
 #<!-- -->7 0x00000000038740b8 (/opt/compiler-explorer/clang-trunk/bin/llc+0x38740b8)
 #<!-- -->8 0x0000000003744e97 llvm::TargetLowering::makeLibCall(llvm::SelectionDAG&amp;, llvm::RTLIB::Libcall, llvm::EVT, llvm::ArrayRef&lt;llvm::SDValue&gt;, llvm::TargetLowering::MakeLibCallOptions, llvm::SDLoc const&amp;, llvm::SDValue) const (/opt/compiler-explorer/clang-trunk/bin/llc+0x3744e97)
 #<!-- -->9 0x0000000001dcab1e llvm::X86TargetLowering::LowerFP_TO_BF16(llvm::SDValue, llvm::SelectionDAG&amp;) const (/opt/compiler-explorer/clang-trunk/bin/llc+0x1dcab1e)
#<!-- -->10 0x0000000001eb8957 llvm::X86TargetLowering::LowerOperation(llvm::SDValue, llvm::SelectionDAG&amp;) const (/opt/compiler-explorer/clang-trunk/bin/llc+0x1eb8957)
#<!-- -->11 0x00000000035d6ca5 (anonymous namespace)::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*) LegalizeDAG.cpp:0:0
#<!-- -->12 0x00000000035db42e llvm::SelectionDAG::Legalize() (/opt/compiler-explorer/clang-trunk/bin/llc+0x35db42e)
#<!-- -->13 0x00000000036db80b llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-trunk/bin/llc+0x36db80b)
#<!-- -->14 0x00000000036de3fc llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x36de3fc)
#<!-- -->15 0x00000000036e005f llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x36e005f)
#<!-- -->16 0x00000000036cc411 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x36cc411)
#<!-- -->17 0x00000000029b498b llvm::MachineFunctionPass::runOnFunction(llvm::Function&amp;) (.part.0) MachineFunctionPass.cpp:0:0
#<!-- -->18 0x0000000002f09492 llvm::FPPassManager::runOnFunction(llvm::Function&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2f09492)
#<!-- -->19 0x0000000002f09721 llvm::FPPassManager::runOnModule(llvm::Module&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2f09721)
#<!-- -->20 0x0000000002f0b0c6 llvm::legacy::PassManagerImpl::run(llvm::Module&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2f0b0c6)
#<!-- -->21 0x000000000087d334 compileModule(char**, llvm::LLVMContext&amp;) llc.cpp:0:0
#<!-- -->22 0x000000000076aca6 main (/opt/compiler-explorer/clang-trunk/bin/llc+0x76aca6)
#<!-- -->23 0x000077ce84829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#<!-- -->24 0x000077ce84829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#<!-- -->25 0x00000000008750fe _start (/opt/compiler-explorer/clang-trunk/bin/llc+0x8750fe)
Program terminated with signal: SIGSEGV
Compiler returned: 139

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. Check that no other contributor has already been assigned to this issue. If you believe that no one is actually working on it despite an assignment, ping the person. After one week without a response, the assignee may be changed.
2. In the comments of this issue, request for it to be assigned to you, or just create a pull request after following the steps below. Mention this issue in the description of the pull request.
3. Fix the issue locally.
4. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
5. Create a Git commit.
6. Run git clang-format HEAD~1 to format your changes.
7. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation. Mention this issue in the description of the pull request.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: None (DigOrDog)

# Description The following code crashes X86 backend with "LLVM ERROR: Unsupported library call operation!"

Minimal Reproduction

https://godbolt.org/z/M6WE541vK

Code

@<!-- -->G.1 = global bfloat 0xR7F80

define void @<!-- -->f(fp128 %x) {
  %CastFPTrunc = fptrunc fp128 %x to bfloat
  store bfloat %CastFPTrunc, ptr @<!-- -->G.1, align 2
  ret void
}

Stack Trace

LLVM ERROR: Unsupported library call operation!
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-trunk/bin/llc -o /app/output.s -x86-asm-syntax=intel -O2 -mtriple=x86_64-linux-android -mattr=+mmx -enable-legalize-types-checking <source>
1.	Running pass 'Function Pass Manager' on module '<source>'.
2.	Running pass 'X86 DAG-&gt;DAG Instruction Selection' on function '@<!-- -->f'
 #<!-- -->0 0x000000000391df98 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/opt/compiler-explorer/clang-trunk/bin/llc+0x391df98)
 #<!-- -->1 0x000000000391bb5c SignalHandler(int) Signals.cpp:0:0
 #<!-- -->2 0x000077ce84842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #<!-- -->3 0x000077ce848969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #<!-- -->4 0x000077ce84842476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #<!-- -->5 0x000077ce848287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #<!-- -->6 0x000000000075696c llvm::UniqueStringSaver::save(llvm::Twine const&amp;) (.cold) StringSaver.cpp:0:0
 #<!-- -->7 0x00000000038740b8 (/opt/compiler-explorer/clang-trunk/bin/llc+0x38740b8)
 #<!-- -->8 0x0000000003744e97 llvm::TargetLowering::makeLibCall(llvm::SelectionDAG&amp;, llvm::RTLIB::Libcall, llvm::EVT, llvm::ArrayRef&lt;llvm::SDValue&gt;, llvm::TargetLowering::MakeLibCallOptions, llvm::SDLoc const&amp;, llvm::SDValue) const (/opt/compiler-explorer/clang-trunk/bin/llc+0x3744e97)
 #<!-- -->9 0x0000000001dcab1e llvm::X86TargetLowering::LowerFP_TO_BF16(llvm::SDValue, llvm::SelectionDAG&amp;) const (/opt/compiler-explorer/clang-trunk/bin/llc+0x1dcab1e)
#<!-- -->10 0x0000000001eb8957 llvm::X86TargetLowering::LowerOperation(llvm::SDValue, llvm::SelectionDAG&amp;) const (/opt/compiler-explorer/clang-trunk/bin/llc+0x1eb8957)
#<!-- -->11 0x00000000035d6ca5 (anonymous namespace)::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*) LegalizeDAG.cpp:0:0
#<!-- -->12 0x00000000035db42e llvm::SelectionDAG::Legalize() (/opt/compiler-explorer/clang-trunk/bin/llc+0x35db42e)
#<!-- -->13 0x00000000036db80b llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-trunk/bin/llc+0x36db80b)
#<!-- -->14 0x00000000036de3fc llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x36de3fc)
#<!-- -->15 0x00000000036e005f llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x36e005f)
#<!-- -->16 0x00000000036cc411 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x36cc411)
#<!-- -->17 0x00000000029b498b llvm::MachineFunctionPass::runOnFunction(llvm::Function&amp;) (.part.0) MachineFunctionPass.cpp:0:0
#<!-- -->18 0x0000000002f09492 llvm::FPPassManager::runOnFunction(llvm::Function&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2f09492)
#<!-- -->19 0x0000000002f09721 llvm::FPPassManager::runOnModule(llvm::Module&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2f09721)
#<!-- -->20 0x0000000002f0b0c6 llvm::legacy::PassManagerImpl::run(llvm::Module&amp;) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2f0b0c6)
#<!-- -->21 0x000000000087d334 compileModule(char**, llvm::LLVMContext&amp;) llc.cpp:0:0
#<!-- -->22 0x000000000076aca6 main (/opt/compiler-explorer/clang-trunk/bin/llc+0x76aca6)
#<!-- -->23 0x000077ce84829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#<!-- -->24 0x000077ce84829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#<!-- -->25 0x00000000008750fe _start (/opt/compiler-explorer/clang-trunk/bin/llc+0x8750fe)
Program terminated with signal: SIGSEGV
Compiler returned: 139

[phoebewang]

This is very similar to adding support for FP80, just replace truncxfbf2 with trunctfbf2. See #109143

[fzou1]

I'll have a try.