Extended Description

When trying to build https://gitorious.org/arm-neon-tests/arm-neon-tests with clang, clang crashes with assertion failures.

Below are 2 small reproducers, which each trigger a different assert. These snippets use the "X" inline assembly constraint to avoid the inline assembly being reordered with the computations happening later. The technique is explained in detail at http://www.ethernut.de/en/documents/arm-inline-asm.html, under section "C code optimization".

$ cat t2.c
double f2(double f, int pscr_value) {
asm volatile("vmsr fpscr,%1" : "=X" ((f)): "r" (pscr_value));
return f+f;
}
$ cat t3.c
typedef signed char int8_t;
typedef attribute((neon_vector_type(8))) int8_t int8x8_t;
void f (void)
{
int8x8_t vector_res_int8x8;
unsigned int fpscr;
asm volatile ("vmsr fpscr,%1" : "=X" ((vector_res_int8x8)) : "r" (fpscr));
}
$ ~/dev/llvm.org/build/bin/clang -target armv7a-none-eabi -c -mcpu=cortex-a9 -mfloat-abi=hard -S -O -o- t2.c
.text
.syntax unified
.eabi_attribute 67, "2.09" @ Tag_conformance
.cpu cortex-a9
.eabi_attribute 6, 10 @ Tag_CPU_arch
.eabi_attribute 7, 65 @ Tag_CPU_arch_profile
.eabi_attribute 8, 1 @ Tag_ARM_ISA_use
.eabi_attribute 9, 2 @ Tag_THUMB_ISA_use
.fpu neon-fp16
.eabi_attribute 17, 1 @ Tag_ABI_PCS_GOT_use
.eabi_attribute 20, 1 @ Tag_ABI_FP_denormal
.eabi_attribute 21, 1 @ Tag_ABI_FP_exceptions
.eabi_attribute 23, 3 @ Tag_ABI_FP_number_model
.eabi_attribute 34, 0 @ Tag_CPU_unaligned_access
.eabi_attribute 24, 1 @ Tag_ABI_align_needed
.eabi_attribute 25, 1 @ Tag_ABI_align_preserved
.eabi_attribute 28, 1 @ Tag_ABI_VFP_args
.eabi_attribute 36, 1 @ Tag_FP_HP_extension
.eabi_attribute 38, 1 @ Tag_ABI_FP_16bit_format
.eabi_attribute 42, 1 @ Tag_MPextension_use
.eabi_attribute 18, 4 @ Tag_ABI_PCS_wchar_t
.eabi_attribute 26, 2 @ Tag_ABI_enum_size
.eabi_attribute 14, 0 @ Tag_ABI_PCS_R9_use
.eabi_attribute 68, 1 @ Tag_Virtualization_use
.file "t2.c"
Assertion failed: (ConstraintID != InlineAsm::Constraint_Unknown && "Failed to convert memory constraint code to constraint id."), function visitInlineAsm, file /Users/kribey01/dev/llvm.org/llvm-clang-compiler-rt
/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp, line 6401.
0 clang-3.9 0x0000000101f6f96b llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 43
1 clang-3.9 0x0000000101f6ebe6 llvm::sys::RunSignalHandlers() + 70
2 clang-3.9 0x0000000101f70012 SignalHandler(int) + 322
3 libsystem_platform.dylib 0x00007fff8e779f1a _sigtramp + 26
4 clang-3.9 0x0000000104041fd7 clang::Stmt::StatisticsEnabled + 92386
5 clang-3.9 0x0000000101f6fe26 abort + 22
6 clang-3.9 0x0000000101f6fe01 __assert_rtn + 81
7 clang-3.9 0x00000001025e4eff llvm::SelectionDAGBuilder::visitInlineAsm(llvm::ImmutableCallSite) + 15695
8 clang-3.9 0x00000001025cd895 llvm::SelectionDAGBuilder::visit(llvm::Instruction const&) + 69
9 clang-3.9 0x000000010264c2e8 llvm::SelectionDAGISel::SelectBasicBlock(llvm::ilist_iterator<llvm::Instruction const>, llvm::ilist_iterator<llvm::Instruction const>, bool&) + 40
10 clang-3.9 0x000000010264bf74 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) + 6612
11 clang-3.9 0x0000000102649554 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) + 2020
12 clang-3.9 0x000000010108f4f4 (anonymous namespace)::ARMDAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) + 20
13 clang-3.9 0x00000001019b94dc llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 140
14 clang-3.9 0x0000000101b9acd8 llvm::FPPassManager::runOnFunction(llvm::Function&) + 328
15 clang-3.9 0x0000000101b9af2b llvm::FPPassManager::runOnModule(llvm::Module&) + 43
16 clang-3.9 0x0000000101b9b3b6 llvm::legacy::PassManagerImpl::run(llvm::Module&) + 806
17 clang-3.9 0x00000001020cb6be clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Modu
le*, clang::BackendAction, llvm::raw_pwrite_stream*) + 8750
18 clang-3.9 0x000000010223c502 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) + 514
19 clang-3.9 0x000000010290cdd5 clang::ParseAST(clang::Sema&, bool, bool) + 581
20 clang-3.9 0x000000010240c69b clang::FrontendAction::Execute() + 75
21 clang-3.9 0x00000001023d2e81 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 1073
22 clang-3.9 0x000000010244b3bf clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 4047
23 clang-3.9 0x0000000100df7da3 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) + 1491
24 clang-3.9 0x0000000100df67d0 main + 11568
25 libdyld.dylib 0x00007fff9aabd5c9 start + 1
Stack dump:
0. Program arguments: /Users/kribey01/dev/llvm.org/build/bin/clang-3.9 -cc1 -triple armv7-none--eabi -S -disable-free -main-file-name t2.c -mrelocation-model static -mthread-model posix -mdisable-fp-elim -fm
ath-errno -masm-verbose -mconstructor-aliases -target-cpu cortex-a9 -target-feature +strict-align -target-abi aapcs -mfloat-abi hard -target-linker-version 253.6 -dwarf-column-info -debugger-tuning=gdb -coverage-
file /Users/kribey01/dev/triage/android/201602_arm_neon_tests/arm-neon-tests/- -resource-dir /Users/kribey01/dev/llvm.org/build/bin/../lib/clang/3.9.0 -O2 -fdebug-compilation-dir /Users/kribey01/dev/triage/androi
d/201602_arm_neon_tests/arm-neon-tests -ferror-limit 19 -fmessage-length 212 -fallow-half-arguments-and-returns -fno-signed-char -fobjc-runtime=gcc -fdiagnostics-show-option -fcolor-diagnostics -vectorize-loops -
vectorize-slp -o - -x c t2.c

1.  <eof> parser at end of file
   

2.  Code generation
   

3.  Running pass 'Function Pass Manager' on module 't2.c'.
   

4.  Running pass 'ARM Instruction Selection' on function '@f2'
   

clang-3.9: error: unable to execute command: Illegal instruction: 4
clang-3.9: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 3.9.0 (ssh://kribey01@e103606-lin.cambridge.arm.com/work/llvm.org/llvm-clang-compiler-rt/tools/clang da6e53c2620d92ec6ff16c23af69c4e531d23417) (ssh://kribey01@e103606-lin.cambridge.arm.com/work/llvm
.org/llvm-clang-compiler-rt bb152043ce23844ccd348b0cde05f301b1319b70)
Target: armv7a-none--eabi
Thread model: posix
InstalledDir: /Users/kribey01/dev/llvm.org/build/bin
clang-3.9: note: diagnostic msg: PLEASE submit a bug report to http://llvm.org/bugs/ and include the crash backtrace, preprocessed source, and associated run script.
clang-3.9: note: diagnostic msg:

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-3.9: note: diagnostic msg: /var/folders/th/cnt0054d153g3xf5rt87856x_1kq80/T/t2-07d0cb.c
clang-3.9: note: diagnostic msg: /var/folders/th/cnt0054d153g3xf5rt87856x_1kq80/T/t2-07d0cb.sh
clang-3.9: note: diagnostic msg:

$ ~/dev/llvm.org/build/bin/clang -target armv7a-none-eabi -c -mcpu=cortex-a9 -mfloat-abi=hard -S -O -o- t3.c
.text
.syntax unified
.eabi_attribute 67, "2.09" @ Tag_conformance
.cpu cortex-a9
.eabi_attribute 6, 10 @ Tag_CPU_arch
.eabi_attribute 7, 65 @ Tag_CPU_arch_profile
.eabi_attribute 8, 1 @ Tag_ARM_ISA_use
.eabi_attribute 9, 2 @ Tag_THUMB_ISA_use
.fpu neon-fp16
.eabi_attribute 17, 1 @ Tag_ABI_PCS_GOT_use
.eabi_attribute 20, 1 @ Tag_ABI_FP_denormal
.eabi_attribute 21, 1 @ Tag_ABI_FP_exceptions
.eabi_attribute 23, 3 @ Tag_ABI_FP_number_model
.eabi_attribute 34, 0 @ Tag_CPU_unaligned_access
.eabi_attribute 24, 1 @ Tag_ABI_align_needed
.eabi_attribute 25, 1 @ Tag_ABI_align_preserved
.eabi_attribute 28, 1 @ Tag_ABI_VFP_args
.eabi_attribute 36, 1 @ Tag_FP_HP_extension
.eabi_attribute 38, 1 @ Tag_ABI_FP_16bit_format
.eabi_attribute 42, 1 @ Tag_MPextension_use
.eabi_attribute 18, 4 @ Tag_ABI_PCS_wchar_t
.eabi_attribute 26, 2 @ Tag_ABI_enum_size
.eabi_attribute 14, 0 @ Tag_ABI_PCS_R9_use
.eabi_attribute 68, 1 @ Tag_Virtualization_use
.file "t3.c"
Assertion failed: (Val && "isa<> used on a null pointer"), function doit, file /Users/kribey01/dev/llvm.org/llvm-clang-compiler-rt/include/llvm/Support/Casting.h, line 95.
0 clang-3.9 0x000000010721196b llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 43
1 clang-3.9 0x0000000107210be6 llvm::sys::RunSignalHandlers() + 70
2 clang-3.9 0x0000000107212012 SignalHandler(int) + 322
3 libsystem_platform.dylib 0x00007fff8e779f1a _sigtramp + 26
4 clang-3.9 0x00000001092e3fe6 clang::Stmt::StatisticsEnabled + 92401
5 clang-3.9 0x0000000107211e26 abort + 22
6 clang-3.9 0x0000000107211e01 __assert_rtn + 81
7 clang-3.9 0x00000001078a50b7 diagnosePossiblyInvalidConstraint(llvm::LLVMContext&, llvm::Value const*, llvm::Twine const&) + 247
8 clang-3.9 0x000000010786b062 getCopyFromParts(llvm::SelectionDAG&, llvm::SDLoc, llvm::SDValue const*, unsigned int, llvm::MVT, llvm::EVT, llvm::Value const*, llvm::ISD::NodeType) + 2114
9 clang-3.9 0x000000010786a662 llvm::RegsForValue::getCopyFromRegs(llvm::SelectionDAG&, llvm::FunctionLoweringInfo&, llvm::SDLoc, llvm::SDValue&, llvm::SDValue*, llvm::Value const*) const + 2498
10 clang-3.9 0x000000010788605b llvm::SelectionDAGBuilder::visitInlineAsm(llvm::ImmutableCallSite) + 11947
11 clang-3.9 0x000000010786f895 llvm::SelectionDAGBuilder::visit(llvm::Instruction const&) + 69
12 clang-3.9 0x00000001078ee2e8 llvm::SelectionDAGISel::SelectBasicBlock(llvm::ilist_iterator<llvm::Instruction const>, llvm::ilist_iterator<llvm::Instruction const>, bool&) + 40
13 clang-3.9 0x00000001078edf74 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) + 6612
14 clang-3.9 0x00000001078eb554 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) + 2020
15 clang-3.9 0x00000001063314f4 (anonymous namespace)::ARMDAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) + 20
16 clang-3.9 0x0000000106c5b4dc llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 140
17 clang-3.9 0x0000000106e3ccd8 llvm::FPPassManager::runOnFunction(llvm::Function&) + 328
18 clang-3.9 0x0000000106e3cf2b llvm::FPPassManager::runOnModule(llvm::Module&) + 43
19 clang-3.9 0x0000000106e3d3b6 llvm::legacy::PassManagerImpl::run(llvm::Module&) + 806
20 clang-3.9 0x000000010736d6be clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Mod
le*, clang::BackendAction, llvm::raw_pwrite_stream*) + 8750
21 clang-3.9 0x00000001074de502 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) + 514
22 clang-3.9 0x0000000107baedd5 clang::ParseAST(clang::Sema&, bool, bool) + 581
23 clang-3.9 0x00000001076ae69b clang::FrontendAction::Execute() + 75
24 clang-3.9 0x0000000107674e81 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 1073
25 clang-3.9 0x00000001076ed3bf clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 4047
26 clang-3.9 0x0000000106099da3 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) + 1491
27 clang-3.9 0x00000001060987d0 main + 11568
28 libdyld.dylib 0x00007fff9aabd5c9 start + 1
Stack dump:
0. Program arguments: /Users/kribey01/dev/llvm.org/build/bin/clang-3.9 -cc1 -triple armv7-none--eabi -S -disable-free -main-file-name t3.c -mrelocation-model static -mthread-model posix -mdisable-fp-elim -f
ath-errno -masm-verbose -mconstructor-aliases -target-cpu cortex-a9 -target-feature +strict-align -target-abi aapcs -mfloat-abi hard -target-linker-version 253.6 -dwarf-column-info -debugger-tuning=gdb -coverage
file /Users/kribey01/dev/triage/android/201602_arm_neon_tests/arm-neon-tests/- -resource-dir /Users/kribey01/dev/llvm.org/build/bin/../lib/clang/3.9.0 -O2 -fdebug-compilation-dir /Users/kribey01/dev/triage/andro
d/201602_arm_neon_tests/arm-neon-tests -ferror-limit 19 -fmessage-length 212 -fallow-half-arguments-and-returns -fno-signed-char -fobjc-runtime=gcc -fdiagnostics-show-option -fcolor-diagnostics -vectorize-loops
vectorize-slp -o - -x c t3.c

1.  <eof> parser at end of file
   

2.  Code generation
   

3.  Running pass 'Function Pass Manager' on module 't3.c'.
   

4.  Running pass 'ARM Instruction Selection' on function '@f'
   

clang-3.9: error: unable to execute command: Illegal instruction: 4
clang-3.9: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 3.9.0 (ssh://kribey01@e103606-lin.cambridge.arm.com/work/llvm.org/llvm-clang-compiler-rt/tools/clang da6e53c2620d92ec6ff16c23af69c4e531d23417) (ssh://kribey01@e103606-lin.cambridge.arm.com/work/llv
.org/llvm-clang-compiler-rt bb152043ce23844ccd348b0cde05f301b1319b70)
Target: armv7a-none--eabi
Thread model: posix
InstalledDir: /Users/kribey01/dev/llvm.org/build/bin
clang-3.9: note: diagnostic msg: PLEASE submit a bug report to http://llvm.org/bugs/ and include the crash backtrace, preprocessed source, and associated run script.
clang-3.9: note: diagnostic msg:

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-3.9: note: diagnostic msg: /var/folders/th/cnt0054d153g3xf5rt87856x_1kq80/T/t3-c62f0b.c
clang-3.9: note: diagnostic msg: /var/folders/th/cnt0054d153g3xf5rt87856x_1kq80/T/t3-c62f0b.sh
clang-3.9: note: diagnostic msg: