[LLVMdev] Failure handling half type

[Alessio Giovanni Baroni]

Here there is the dump:

SelectionDAG.cpp:81: static bool
llvm::ConstantFPSDNode::isValueValidForType(llvm::EVT, const llvm::APFloat
&): Assertion `VT.isFloatingPoint() && "Can only convert between FP types"'
failed.
0  libLLVMSupport.so      0x00007f7405022de5
llvm::sys::PrintStackTrace(_IO_FILE*) + 37
1  libLLVMSupport.so      0x00007f74050232e3
2  libpthread.so.0        0x00007f7404960cb0
3  libc.so.6              0x00007f7403bba425 gsignal + 53
4  libc.so.6              0x00007f7403bbdb8b abort + 379
5  libc.so.6              0x00007f7403bb30ee
6  libc.so.6              0x00007f7403bb3192
7  libLLVMSelectionDAG.so 0x00007f7408266500
llvm::ConstantFPSDNode::isValueValidForType(llvm::EVT, llvm::APFloat
const&) + 320
8  libLLVMSelectionDAG.so 0x00007f74081df6cf
9  libLLVMSelectionDAG.so 0x00007f74081d12b1
10 libLLVMSelectionDAG.so 0x00007f74081cff57 llvm::SelectionDAG::Legalize()
+ 375
11 libLLVMSelectionDAG.so 0x00007f74082d6604
llvm::SelectionDAGISel::CodeGenAndEmitDAG() + 3700
12 libLLVMSelectionDAG.so 0x00007f74082d4f07
llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) + 6455
13 libLLVMSelectionDAG.so 0x00007f74082d2876
llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) + 1318
14 libLLVMCodeGen.so      0x00007f74074885dd
llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 125
15 libLLVMCore.so         0x00007f740583e2ac
llvm::FPPassManager::runOnFunction(llvm::Function&) + 364
16 libLLVMCore.so         0x00007f740583e52b
llvm::FPPassManager::runOnModule(llvm::Module&) + 59
17 libLLVMCore.so         0x00007f740583e8d7
llvm::MPPassManager::runOnModule(llvm::Module&) + 519
18 libLLVMCore.so         0x00007f740583ef6b
llvm::PassManagerImpl::run(llvm::Module&) + 539
19 libLLVMCore.so         0x00007f740583f0da
llvm::PassManager::run(llvm::Module&) + 10
20 llc                    0x000000000040839c
21 libc.so.6              0x00007f7403ba576d __libc_start_main + 237
22 llc                    0x0000000000406d7d
Stack dump:
0.    Program arguments: llc -asm-verbose -filetype=asm -o qwe.S qwe.ll
1.    Running pass 'Function Pass Manager' on module 'qwe.ll'.
2.    Running pass 'X86 DAG->DAG Instruction Selection' on function '@foo'


A small note: this is LLVM 3.3 final linked with libc++ on Ubuntu Linux
12.10.


2013/6/17 Jim Grosbach <grosbach at apple.com>

> Make sure you’re running LLVM with assertions enabled. You’ll get more
> information about what’s going wrong that way.
>
> That said, yes, this looks like a bug.
> Specifically, SelectionDAGLegalize::ExpandConstantFP() assumes that f32 is
> the smallest floating point constant type it’ll need to handle, and that
> MVT enum ordering reflects that.
>
>   while (SVT != MVT::f32) {
>
>     SVT = (MVT::SimpleValueType)(SVT.getSimpleVT().SimpleTy - 1);
>     ...
>   }
>
> That function, and possibly others, need to be taught how to handle
> half-floats, it looks like.
>
> -Jim
>
> On Jun 17, 2013, at 6:59 AM, Alessio Giovanni Baroni <
> alessiogiovanni.baroni at gmail.com> wrote:
>
> Hi,
>
> if I write the following simple program:
>
> target datalayout =
> "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
> target triple = "x86_64-unknown-linux-gnu"
>
> define void @foo () {
>     %1 = alloca half
>     store half 0xH42CC, half* %1   ; 0xH42CC = 3.4
>     %2 = load half* %1
>     ret void
> }
>
> llc goes in SIGABRT. In the reference manual says that it's  correct
> syntax.
>
> It's a bug?
>
> Thanks.
> _______________________________________________
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> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
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>
>
>
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