ARM inline assembly causes a crash.

[llvmbot]

Bugzilla Link	25330
Resolution	FIXED
Resolved on	Dec 04, 2017 12:14
Version	trunk
OS	Linux
Blocks	#19300
Attachments	The .ll file.
Reporter	LLVM Bugzilla Contributor
CC	@kbeyls,@rengolin

Extended Description

The attached .ll file, which was generated from a bugpoint reduction of a compiler crash while compiling the Linux kernel, causes llc to crash:

[~] dev% ~/llvm-dir/bin/llc bugpoint-reduced-simplified.ll
llc: /home/rich/llvm/include/llvm/CodeGen/SelectionDAGNodes.h:632: const llvm::SDValue& llvm::SDNode::getOperand(unsigned int) const: Assertion `Num < NumOperands && "Invalid child # of SDNode!"' failed.
#​0 0x19417a5 llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/home/rich/llvm-dir/bin/llc+0x19417a5)
#​1 0x1940886 llvm::sys::RunSignalHandlers() (/home/rich/llvm-dir/bin/llc+0x1940886)
#​2 0x1940aa4 (/home/rich/llvm-dir/bin/llc+0x1940aa4)
#​3 0x37bf6100d0 __restore_rt (/lib64/libpthread.so.0+0x37bf6100d0)
#​4 0x37bea348d7 __GI_raise (/lib64/libc.so.6+0x37bea348d7)
#​5 0x37bea3653a __GI_abort (/lib64/libc.so.6+0x37bea3653a)
#​6 0x37bea2d47d __assert_fail_base (/lib64/libc.so.6+0x37bea2d47d)
#​7 0x37bea2d532 (/lib64/libc.so.6+0x37bea2d532)
#​8 0x5e032c _init (/home/rich/llvm-dir/bin/llc+0x5e032c)
#​9 0xc4bf66 (/home/rich/llvm-dir/bin/llc+0xc4bf66)
#​10 0xc4ff55 (/home/rich/llvm-dir/bin/llc+0xc4ff55)
#​11 0x10d770b llvm::SelectionDAGISel::DoInstructionSelection() (/home/rich/llvm-dir/bin/llc+0x10d770b)
#​12 0x10df839 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/home/rich/llvm-dir/bin/llc+0x10df839)
#​13 0x10e3ffe llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/home/rich/llvm-dir/bin/llc+0x10e3ffe)
#​14 0x10e5ab0 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/home/rich/llvm-dir/bin/llc+0x10e5ab0)
#​15 0xc55564 (/home/rich/llvm-dir/bin/llc+0xc55564)
#​16 0x18b7dd3 llvm::FPPassManager::runOnFunction(llvm::Function&) (/home/rich/llvm-dir/bin/llc+0x18b7dd3)
#​17 0x18b841b llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/rich/llvm-dir/bin/llc+0x18b841b)
#​18 0x69cd66 (/home/rich/llvm-dir/bin/llc+0x69cd66)
#​19 0x661848 main (/home/rich/llvm-dir/bin/llc+0x661848)
#​20 0x37bea1ffe0 __libc_start_main (/lib64/libc.so.6+0x37bea1ffe0)
#​21 0x695417 _start (/home/rich/llvm-dir/bin/llc+0x695417)
Stack dump:
0. Program arguments: /home/rich/llvm-dir/bin/llc bugpoint-reduced-simplified.ll

1.  Running pass 'Function Pass Manager' on module 'bugpoint-reduced-simplified.ll'.
   

2.  Running pass 'ARM Instruction Selection' on function '@optidma_init_one'
   

Abort (core dumped)

[llvmbot]

The following code is now produced and looks correct. Was likely fixed some time since then, so I'm going to resolve. I removed the unreachable and replaced with ret void for clarity.

movw	r0, #​501
movt	r0, #​65248
@APP
ldrb	r0, [r0]
@NO_APP
bx	lr