llvm dev - Oct 2015 - [AMDGPU] AMDGPUAsmParser fails to parse several instructions

Dear Developers,

I compile a OpenCL kernel, FFT, in AMDAPP SDK v2.5 using clang 3.8 + libclc
and assembling the code with lld (The LLVM linker). The assembly code
contains the following assembly codes (and lots of other similar format
assembly) that fails to be parsed by AMDGPUAsmParser. It seems to me that
both are valid instructions after looking at the SI instruction spec.

s_mov_b32 s0, 0xfe5163ab
v_mad_f32 v9, 0.5, v5, -v8

To reproduce this, I write this two lines in a text file and run

llvm-mc -arch=amdgcn -mcpu=kaveri input.s

The first line has the following error message:

sop1-playground.s:1:15: error: invalid immediate: only 32-bit values are
legal
s_mov_b32 s0, 0xfe5163ab
                         ^
sop1-playground.s:1:25: error: failed parsing operand.
s_mov_b32 s0, 0xfe5163ab
                                            ^
The part of stack dump:

...
#9 0x4711ee (anonymous namespace)::AMDGPUOperand::setModifiers(unsigned
int)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:185:21
#10 0x46ff6a (anonymous
namespace)::AMDGPUAsmParser::parseOperand(llvm::SmallVectorImpl<std::unique_ptr<llvm::MCParsedAsmOperand,
std::default_delete<llvm::MCParsedAsmOperand> > >&,
llvm::StringRef)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:1040:16
#11 0x46cd46 (anonymous
namespace)::AMDGPUAsmParser::ParseInstruction(llvm::ParseInstructionInfo&,
llvm::StringRef, llvm::SMLoc,
llvm::SmallVectorImpl<std::unique_ptr<llvm::MCParsedAsmOperand,
std::default_delete<llvm::MCParsedAsmOperand> > >&)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:1085:43
...

The second line of the assembly has the assertion fail:

llvm-mc:
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:184:
void (anonymous namespace)::AMDGPUOperand::setModifiers(unsigned int):
Assertion `isReg()' failed.

and reports that 0.5 is "error: invalid operand for instruction"

v_mad_f32 v9, 0.5, v5, -v8
                         ^

Regards,

李弘宇 (Li, Hong-Yu)
Department of Computer Science & Information Engineering
National Taiwan University
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Dear Developers,

I found out the information included in the last mail is incorrect. Sorry
for misleading stack dump information. That information is generated when
AMDGPUAsmParser parsing the following assembly:

v_mad_f32 v9, 0.5, v5, -v8

llvm-mc:
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:184:
void (anonymous namespace)::AMDGPUOperand::setModifiers(unsigned int):
Assertion `isReg()' failed.
#0 0x6608ee llvm::sys::PrintStackTrace(llvm::raw_ostream&)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Support/Unix/Signals.inc:404:15
#1 0x661a29 PrintStackTraceSignalHandler(void*)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Support/Unix/Signals.inc:463:1
#2 0x660463 llvm::sys::RunSignalHandlers()
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Support/Signals.cpp:35:5
#3 0x661c84 SignalHandler(int)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Support/Unix/Signals.inc:211:1
#4 0x7fb282371d60 __restore_rt (/usr/lib/libpthread.so.0+0x10d60)
#5 0x7fb2815445f8 __GI_raise (/usr/lib/libc.so.6+0x335f8)
#6 0x7fb281545a7a __GI_abort (/usr/lib/libc.so.6+0x34a7a)
#7 0x7fb28153d417 __assert_fail_base (/usr/lib/libc.so.6+0x2c417)
#8 0x7fb28153d4c2 (/usr/lib/libc.so.6+0x2c4c2)
#9 0x4711ee (anonymous namespace)::AMDGPUOperand::setModifiers(unsigned
int)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:185:21
#10 0x46ff6a (anonymous
namespace)::AMDGPUAsmParser::parseOperand(llvm::SmallVectorImpl<std::unique_ptr<llvm::MCParsedAsmOperand,
std::default_delete<llvm::MCParsedAsmOperand> > >&,
llvm::StringRef)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:1040:16
#11 0x46cd46 (anonymous
namespace)::AMDGPUAsmParser::ParseInstruction(llvm::ParseInstructionInfo&,
llvm::StringRef, llvm::SMLoc,
llvm::SmallVectorImpl<std::unique_ptr<llvm::MCParsedAsmOperand,
std::default_delete<llvm::MCParsedAsmOperand> > >&)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:1085:43
#12 0x5ae9a7 (anonymous namespace)::AsmParser::parseStatement((anonymous
namespace)::ParseStatementInfo&, llvm::MCAsmParserSemaCallback*)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/MC/MCParser/AsmParser.cpp:1620:8
#13 0x5a4d76 (anonymous namespace)::AsmParser::Run(bool, bool)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/MC/MCParser/AsmParser.cpp:654:9
#14 0x41274c AssembleInput(char const*, llvm::Target const*,
llvm::SourceMgr&, llvm::MCContext&, llvm::MCStreamer&,
llvm::MCAsmInfo&,
llvm::MCSubtargetInfo&, llvm::MCInstrInfo&, llvm::MCTargetOptions&)
/mnt/dm-0/codebase/Compilers/LLVM/llvm/tools/llvm-mc/llvm-mc.cpp:363:13
#15 0x41165a main
/mnt/dm-0/codebase/Compilers/LLVM/llvm/tools/llvm-mc/llvm-mc.cpp:527:9
#16 0x7fb281531610 __libc_start_main (/usr/lib/libc.so.6+0x20610)
#17 0x410009 _start (/usr/local/bin/llvm-mc+0x410009)
Stack dump:
0. Program arguments: llvm-mc -arch=amdgcn -mcpu=SI sop1-playground.s
zsh: abort (core dumped)  llvm-mc -arch=amdgcn -mcpu=SI sop1-playground.s

When the assembly code is s_mov_b32 s0, 0xfe5163ab, the error message is
the following (and the program terminates without the assertion failed)

sop1-playground.s:1:15: error: invalid immediate: only 32-bit values are
legal
s_mov_b32 s0, 0xfe5163ab
                       ^
sop1-playground.s:1:25: error: failed parsing operand.
s_mov_b32 s0, 0xfe5163ab
                                       ^

Regards,

李弘宇 (Li, Hong-Yu)
Department of Computer Science & Information Engineering
National Taiwan University

On Fri, Oct 23, 2015 at 3:36 PM, 李弘宇 <zhenlinospirit at gmail.com> wrote:
> Dear Developers,
>
> I compile a OpenCL kernel, FFT, in AMDAPP SDK v2.5 using clang 3.8 +
> libclc and assembling the code with lld (The LLVM linker). The assembly
> code contains the following assembly codes (and lots of other similar
> format assembly) that fails to be parsed by AMDGPUAsmParser. It seems to me
> that both are valid instructions after looking at the SI instruction spec.
>
> s_mov_b32 s0, 0xfe5163ab
> v_mad_f32 v9, 0.5, v5, -v8
>
> To reproduce this, I write this two lines in a text file and run
>
> llvm-mc -arch=amdgcn -mcpu=kaveri input.s
>
> The first line has the following error message:
>
> sop1-playground.s:1:15: error: invalid immediate: only 32-bit values are
> legal
> s_mov_b32 s0, 0xfe5163ab
>                          ^
> sop1-playground.s:1:25: error: failed parsing operand.
> s_mov_b32 s0, 0xfe5163ab
>                                             ^
> The part of stack dump:
>
> ...
> #9 0x4711ee (anonymous namespace)::AMDGPUOperand::setModifiers(unsigned
> int)
>
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:185:21
> #10 0x46ff6a (anonymous
>
namespace)::AMDGPUAsmParser::parseOperand(llvm::SmallVectorImpl<std::unique_ptr<llvm::MCParsedAsmOperand,
> std::default_delete<llvm::MCParsedAsmOperand> > >&,
llvm::StringRef)
>
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:1040:16
> #11 0x46cd46 (anonymous
>
namespace)::AMDGPUAsmParser::ParseInstruction(llvm::ParseInstructionInfo&,
> llvm::StringRef, llvm::SMLoc,
> llvm::SmallVectorImpl<std::unique_ptr<llvm::MCParsedAsmOperand,
> std::default_delete<llvm::MCParsedAsmOperand> > >&)
>
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:1085:43
> ...
>
> The second line of the assembly has the assertion fail:
>
> llvm-mc:
>
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:184:
> void (anonymous namespace)::AMDGPUOperand::setModifiers(unsigned int):
> Assertion `isReg()' failed.
>
> and reports that 0.5 is "error: invalid operand for instruction"
>
> v_mad_f32 v9, 0.5, v5, -v8
>                          ^
>
> Regards,
>
> 李弘宇 (Li, Hong-Yu)
> Department of Computer Science & Information Engineering
> National Taiwan University
>
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> On Oct 23, 2015, at 3:36 AM, 李弘宇 via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> The first line has the following error message:
> 
> sop1-playground.s:1:15: error: invalid immediate: only 32-bit values are
legal
> s_mov_b32 s0, 0xfe5163ab
I’ve fixed this problem in  r251132.
> 
> The second line of the assembly has the assertion fail:
> 
> llvm-mc:
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:184:
void (anonymous namespace)::AMDGPUOperand::setModifiers(unsigned int): Assertion
`isReg()' failed.
> 
> and reports that 0.5 is "error: invalid operand for instruction"
> 
> v_mad_f32 v9, 0.5, v5, -v8
There is a bug with operand parsing when you have immediate operands and source
modifiers. I haven’t fixed this yet, but you can work around it for now by not
using the source modifier.

-Matt

Thanks you. I'm new to LLVM backend, so the help is much appreciated.

On Sat, Oct 24, 2015 at 2:12 AM, Matt Arsenault <arsenm2 at gmail.com>
wrote:
>
> > On Oct 23, 2015, at 3:36 AM, 李弘宇 via llvm-dev <llvm-dev at
lists.llvm.org>
> wrote:
>
> > The first line has the following error message:
> >
> > sop1-playground.s:1:15: error: invalid immediate: only 32-bit values
are
> legal
> > s_mov_b32 s0, 0xfe5163ab
>
> I’ve fixed this problem in  r251132.
>
Thanks for the reply and the quick fix of negative 32-bit immediate.
> >
> > The second line of the assembly has the assertion fail:
> >
> > llvm-mc:
>
/mnt/dm-0/codebase/Compilers/LLVM/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:184:
> void (anonymous namespace)::AMDGPUOperand::setModifiers(unsigned int):
> Assertion `isReg()' failed.
> >
> > and reports that 0.5 is "error: invalid operand for
instruction"
> >
> > v_mad_f32 v9, 0.5, v5, -v8
>
> There is a bug with operand parsing when you have immediate operands and
> source modifiers. I haven’t fixed this yet, but you can work around it for
> now by not using the source modifier.
>
I have no idea what to do the work-around. To me the modifier is set when
the register has absolute or negate. I traced the code and thought that the
problem occurs in the for loop to empty the modifiers for each source (in
the AMDGPUAsmParser::parseOperand around line 1040). If I add an if
statement like

if(RegOp.isInlineImm()) // because 0.5 is this case
    contiune;

before the statement to empty the modifier (RegOp.setModifiers(0);),

it obvious does not work and cause the other matching fails. Does it mean
to modify other files in other places, such as the VOP3Inst in the
SIInstrInfo.td, or is this nothing to do with the MatchOperandParserImpl
method or the other tablegen'd files.

I'll be grateful for any idea you might give me to work around this.

Regards,

李弘宇 (Li, Hong-Yu)
Department of Computer Science & Information Engineering
National Taiwan University

-Matt
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