Dear colleagues,
I'm looking if we can replace nvopencc with LLVM NVPTX in our project.
It turns NVPTX won't work with the code nvopencc can handle (please
see the log below). So are atomic intrinsics not supported or am I
doing call in a wrong way?
Thanks,
- Dima.
SOURCE
=======
dmikushin at hp2:~> cat kernelgen_monitor.ll
; ModuleID = '/opt/kernelgen/include/kernelgen_monitor.cu'
target datalayout = "e-p:64:64-i64:64:64-f64:64:64-n1:8:16:32:64"
target triple = "ptx64-unknown-unknown"
%struct.kernelgen_callback_t = type { i32, i32,
%"struct.kernelgen::kernel_t"*, i32, i32,
%struct.kernelgen_callback_data_t* }
%"struct.kernelgen::kernel_t" = type opaque
%struct.kernelgen_callback_data_t = type opaque
define ptx_kernel void @_Z17kernelgen_monitorPi(i32* %callback) nounwind {
entry:
%callback.addr = alloca i32*, align 8
store i32* %callback, i32** %callback.addr, align 8
%0 = load i32** %callback.addr, align 8
%1 = bitcast i32* %0 to %struct.kernelgen_callback_t*
%lock = getelementptr inbounds %struct.kernelgen_callback_t* %1, i32 0, i32 0
%call = call ptx_device i32 @_Z12__iAtomicCASPiii(i32* %lock, i32 1, i32 0)
br label %while.cond
while.cond: ; preds = %while.body, %entry
%2 = load i32** %callback.addr, align 8
%3 = bitcast i32* %2 to %struct.kernelgen_callback_t*
%lock1 = getelementptr inbounds %struct.kernelgen_callback_t* %3, i32 0, i32 0
%call2 = call ptx_device i32 @_Z12__iAtomicCASPiii(i32* %lock1, i32 1, i32 1)
%tobool = icmp ne i32 %call2, 0
%lnot = xor i1 %tobool, true
br i1 %lnot, label %while.body, label %while.end
while.body: ; preds = %while.cond
br label %while.cond
while.end: ; preds = %while.cond
ret void
}
declare ptx_device i32 @_Z12__iAtomicCASPiii(i32*, i32, i32)
CODEGEN
========
dmikushin at hp2:~> llc < kernelgen_monitor.ll -march=nvptx -mcpu=sm_20
//
// Generated by LLVM NVPTX Back-End
//
.version 3.0
.target sm_20, texmode_independent
.address_size 32
.func (.param .b32 func_retval0) _Z12__iAtomicCASPiii
(
.param .b32 _Z12__iAtomicCASPiii_param_0,
.param .b32 _Z12__iAtomicCASPiii_param_1,
.param .b32 _Z12__iAtomicCASPiii_param_2
)
;
Not Implemented
UNREACHABLE executed at
/tmp/rpmbuild_debug/BUILD/llvm/build/include/llvm/Target/TargetLowering.h:1249!
0 libLLVM-3.2svn.so 0x00007f47738b8f5f
1 libLLVM-3.2svn.so 0x00007f47738b9525
2 libpthread.so.0 0x00007f47726135d0
3 libc.so.6 0x00007f4771931945 gsignal + 53
4 libc.so.6 0x00007f4771932f21 abort + 385
5 libLLVM-3.2svn.so 0x00007f47738a24c1
llvm::report_fatal_error(llvm::Twine const&) + 0
6 libLLVM-3.2svn.so 0x00007f47735cd390
7 libLLVM-3.2svn.so 0x00007f47737fe2ba
llvm::TargetLowering::LowerCallTo(llvm::SDValue, llvm::Type*, bool,
bool, bool, bool, unsigned int, llvm::CallingConv::ID, bool, bool,
bool, llvm::SDValue, std::vector<llvm::TargetLowering::ArgListEntry,
std::allocator<llvm::TargetLowering::ArgListEntry> >&,
llvm::SelectionDAG&, llvm::DebugLoc) const + 2120
8 libLLVM-3.2svn.so 0x00007f4773807199
llvm::SelectionDAGBuilder::LowerCallTo(llvm::ImmutableCallSite,
llvm::SDValue, bool, llvm::MachineBasicBlock*) + 2913
9 libLLVM-3.2svn.so 0x00007f477381b3af
llvm::SelectionDAGBuilder::visitCall(llvm::CallInst const&) + 9681
10 libLLVM-3.2svn.so 0x00007f477382abee
llvm::SelectionDAGBuilder::visit(unsigned int, llvm::User const&) +
1044
11 libLLVM-3.2svn.so 0x00007f477382ad6d
llvm::SelectionDAGBuilder::visit(llvm::Instruction const&) + 105
12 libLLVM-3.2svn.so 0x00007f4773844925
llvm::SelectionDAGISel::SelectBasicBlock(llvm::ilist_iterator<llvm::Instruction
const>, llvm::ilist_iterator<llvm::Instruction const>, bool&) + 59
13 libLLVM-3.2svn.so 0x00007f477384540c
llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) +
2620
14 libLLVM-3.2svn.so 0x00007f47738459c6
llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) +
896
15 libLLVM-3.2svn.so 0x00007f4773175bfe
llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 82
16 libLLVM-3.2svn.so 0x00007f47733ac299
llvm::FPPassManager::runOnFunction(llvm::Function&) + 331
17 libLLVM-3.2svn.so 0x00007f47733ac474
llvm::FPPassManager::runOnModule(llvm::Module&) + 86
18 libLLVM-3.2svn.so 0x00007f47733abf6d
llvm::MPPassManager::runOnModule(llvm::Module&) + 381
19 libLLVM-3.2svn.so 0x00007f47733ad6eb
llvm::PassManagerImpl::run(llvm::Module&) + 111
20 libLLVM-3.2svn.so 0x00007f47733ad74d
llvm::PassManager::run(llvm::Module&) + 33
21 llc 0x000000000040eed6 main + 2835
22 libc.so.6 0x00007f477191dbc6 __libc_start_main + 230
23 llc 0x000000000040cc09
Stack dump:
0. Program arguments: llc -march=nvptx -mcpu=sm_20
1. Running pass 'Function Pass Manager' on module
'<stdin>'.
2. Running pass 'NVPTX DAG->DAG Pattern Instruction Selection' on
function '@_Z17kernelgen_monitorPi'
Aborted
dmikushin at hp2:~> cd ~/rpmbuild/BUILD/llvm/ && svn info
Path: .
Working Copy Root Path: /tmp/rpmbuild_debug/BUILD/llvm
URL: http://llvm.org/svn/llvm-project/llvm/trunk
Repository Root: http://llvm.org/svn/llvm-project
Repository UUID: 91177308-0d34-0410-b5e6-96231b3b80d8
Revision: 156703
Node Kind: directory
Schedule: normal
Last Changed Author: foad
Last Changed Rev: 156703
Last Changed Date: 2012-05-12 12:30:16 +0400 (Sat, 12 May 2012)
> -----Original Message----- > From: Dmitry N. Mikushin [mailto:maemarcus at gmail.com] > Sent: Wednesday, May 16, 2012 5:44 AM > To: LLVM-Dev > Cc: Justin Holewinski > Subject: NVPTX: __iAtomicCAS support ? > > Dear colleagues, > > I'm looking if we can replace nvopencc with LLVM NVPTX in our project. > It turns NVPTX won't work with the code nvopencc can handle (please > see the log below). So are atomic intrinsics not supported or am I > doing call in a wrong way?There are really two issues here. First, the error you are seeing is because calls are disabled in the back-end until an outstanding LLVM core patch is committed. Hopefully, we'll be able to push that in soon. Second, __iAtomicCAS() is a CUDA-C built-in function; the implementation is provided by a library linked with the LLVM IR before the NVPTX back-end sees it. You will need to provide your own implementations for such functions.> > Thanks, > - Dima. > > SOURCE > =======> > dmikushin at hp2:~> cat kernelgen_monitor.ll > ; ModuleID = '/opt/kernelgen/include/kernelgen_monitor.cu' > target datalayout = "e-p:64:64-i64:64:64-f64:64:64-n1:8:16:32:64" > target triple = "ptx64-unknown-unknown" > > %struct.kernelgen_callback_t = type { i32, i32, > %"struct.kernelgen::kernel_t"*, i32, i32, > %struct.kernelgen_callback_data_t* } > %"struct.kernelgen::kernel_t" = type opaque > %struct.kernelgen_callback_data_t = type opaque > > define ptx_kernel void @_Z17kernelgen_monitorPi(i32* %callback) > nounwind { > entry: > %callback.addr = alloca i32*, align 8 > store i32* %callback, i32** %callback.addr, align 8 > %0 = load i32** %callback.addr, align 8 > %1 = bitcast i32* %0 to %struct.kernelgen_callback_t* > %lock = getelementptr inbounds %struct.kernelgen_callback_t* %1, i32 0, > i32 0 > %call = call ptx_device i32 @_Z12__iAtomicCASPiii(i32* %lock, i32 1, i32 0) > br label %while.cond > > while.cond: ; preds = %while.body, %entry > %2 = load i32** %callback.addr, align 8 > %3 = bitcast i32* %2 to %struct.kernelgen_callback_t* > %lock1 = getelementptr inbounds %struct.kernelgen_callback_t* %3, i32 0, > i32 0 > %call2 = call ptx_device i32 @_Z12__iAtomicCASPiii(i32* %lock1, i32 1, i32 1) > %tobool = icmp ne i32 %call2, 0 > %lnot = xor i1 %tobool, true > br i1 %lnot, label %while.body, label %while.end > > while.body: ; preds = %while.cond > br label %while.cond > > while.end: ; preds = %while.cond > ret void > } > > declare ptx_device i32 @_Z12__iAtomicCASPiii(i32*, i32, i32) > > CODEGEN > ========> > dmikushin at hp2:~> llc < kernelgen_monitor.ll -march=nvptx -mcpu=sm_20 > // > // Generated by LLVM NVPTX Back-End > // > > .version 3.0 > .target sm_20, texmode_independent > .address_size 32 > > .func (.param .b32 func_retval0) _Z12__iAtomicCASPiii > ( > .param .b32 _Z12__iAtomicCASPiii_param_0, > .param .b32 _Z12__iAtomicCASPiii_param_1, > .param .b32 _Z12__iAtomicCASPiii_param_2 > ) > ; > > Not Implemented > UNREACHABLE executed at > /tmp/rpmbuild_debug/BUILD/llvm/build/include/llvm/Target/TargetLowerin > g.h:1249! > 0 libLLVM-3.2svn.so 0x00007f47738b8f5f > 1 libLLVM-3.2svn.so 0x00007f47738b9525 > 2 libpthread.so.0 0x00007f47726135d0 > 3 libc.so.6 0x00007f4771931945 gsignal + 53 > 4 libc.so.6 0x00007f4771932f21 abort + 385 > 5 libLLVM-3.2svn.so 0x00007f47738a24c1 > llvm::report_fatal_error(llvm::Twine const&) + 0 > 6 libLLVM-3.2svn.so 0x00007f47735cd390 > 7 libLLVM-3.2svn.so 0x00007f47737fe2ba > llvm::TargetLowering::LowerCallTo(llvm::SDValue, llvm::Type*, bool, > bool, bool, bool, unsigned int, llvm::CallingConv::ID, bool, bool, > bool, llvm::SDValue, std::vector<llvm::TargetLowering::ArgListEntry, > std::allocator<llvm::TargetLowering::ArgListEntry> >&, > llvm::SelectionDAG&, llvm::DebugLoc) const + 2120 > 8 libLLVM-3.2svn.so 0x00007f4773807199 > llvm::SelectionDAGBuilder::LowerCallTo(llvm::ImmutableCallSite, > llvm::SDValue, bool, llvm::MachineBasicBlock*) + 2913 > 9 libLLVM-3.2svn.so 0x00007f477381b3af > llvm::SelectionDAGBuilder::visitCall(llvm::CallInst const&) + 9681 > 10 libLLVM-3.2svn.so 0x00007f477382abee > llvm::SelectionDAGBuilder::visit(unsigned int, llvm::User const&) + > 1044 > 11 libLLVM-3.2svn.so 0x00007f477382ad6d > llvm::SelectionDAGBuilder::visit(llvm::Instruction const&) + 105 > 12 libLLVM-3.2svn.so 0x00007f4773844925 > llvm::SelectionDAGISel::SelectBasicBlock(llvm::ilist_iterator<llvm::Instruction > const>, llvm::ilist_iterator<llvm::Instruction const>, bool&) + 59 > 13 libLLVM-3.2svn.so 0x00007f477384540c > llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) + > 2620 > 14 libLLVM-3.2svn.so 0x00007f47738459c6 > llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) + > 896 > 15 libLLVM-3.2svn.so 0x00007f4773175bfe > llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 82 > 16 libLLVM-3.2svn.so 0x00007f47733ac299 > llvm::FPPassManager::runOnFunction(llvm::Function&) + 331 > 17 libLLVM-3.2svn.so 0x00007f47733ac474 > llvm::FPPassManager::runOnModule(llvm::Module&) + 86 > 18 libLLVM-3.2svn.so 0x00007f47733abf6d > llvm::MPPassManager::runOnModule(llvm::Module&) + 381 > 19 libLLVM-3.2svn.so 0x00007f47733ad6eb > llvm::PassManagerImpl::run(llvm::Module&) + 111 > 20 libLLVM-3.2svn.so 0x00007f47733ad74d > llvm::PassManager::run(llvm::Module&) + 33 > 21 llc 0x000000000040eed6 main + 2835 > 22 libc.so.6 0x00007f477191dbc6 __libc_start_main + 230 > 23 llc 0x000000000040cc09 > Stack dump: > 0. Program arguments: llc -march=nvptx -mcpu=sm_20 > 1. Running pass 'Function Pass Manager' on module '<stdin>'. > 2. Running pass 'NVPTX DAG->DAG Pattern Instruction Selection' on > function '@_Z17kernelgen_monitorPi' > Aborted > dmikushin at hp2:~> cd ~/rpmbuild/BUILD/llvm/ && svn info > Path: . > Working Copy Root Path: /tmp/rpmbuild_debug/BUILD/llvm > URL: http://llvm.org/svn/llvm-project/llvm/trunk > Repository Root: http://llvm.org/svn/llvm-project > Repository UUID: 91177308-0d34-0410-b5e6-96231b3b80d8 > Revision: 156703 > Node Kind: directory > Schedule: normal > Last Changed Author: foad > Last Changed Rev: 156703 > Last Changed Date: 2012-05-12 12:30:16 +0400 (Sat, 12 May 2012)----------------------------------------------------------------------------------- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. -----------------------------------------------------------------------------------
Thanks, Justin!
Clang does not implement atomic intrinsics, but fortunately supports inline asm:
__inline__ __attribute__((always_inline)) __attribute__((device)) int
__iAtomicCAS(int *p, int compare, int val)
{
int *global, result;
asm(
"cvta.to.global.u64 %0, %1;\n\t"
"atom.global.cas.b32 %2, [%0], %3, %4;"
:: "l"(global), "l"(p),
"r"(result), "r"(compare), "r"(val));
return result;
}
It helped to workaround this particular problem.
- D.
2012/5/16 Justin Holewinski <jholewinski at
nvidia.com>:>> -----Original Message-----
>> From: Dmitry N. Mikushin [mailto:maemarcus at gmail.com]
>> Sent: Wednesday, May 16, 2012 5:44 AM
>> To: LLVM-Dev
>> Cc: Justin Holewinski
>> Subject: NVPTX: __iAtomicCAS support ?
>>
>> Dear colleagues,
>>
>> I'm looking if we can replace nvopencc with LLVM NVPTX in our
project.
>> It turns NVPTX won't work with the code nvopencc can handle (please
>> see the log below). So are atomic intrinsics not supported or am I
>> doing call in a wrong way?
>
> There are really two issues here.
>
> First, the error you are seeing is because calls are disabled in the
back-end until an outstanding LLVM core patch is committed. Hopefully,
we'll be able to push that in soon.
>
> Second, __iAtomicCAS() is a CUDA-C built-in function; the implementation is
provided by a library linked with the LLVM IR before the NVPTX back-end sees it.
You will need to provide your own implementations for such functions.
>
>>
>> Thanks,
>> - Dima.
>>
>> SOURCE
>> =======>>
>> dmikushin at hp2:~> cat kernelgen_monitor.ll
>> ; ModuleID = '/opt/kernelgen/include/kernelgen_monitor.cu'
>> target datalayout =
"e-p:64:64-i64:64:64-f64:64:64-n1:8:16:32:64"
>> target triple = "ptx64-unknown-unknown"
>>
>> %struct.kernelgen_callback_t = type { i32, i32,
>> %"struct.kernelgen::kernel_t"*, i32, i32,
>> %struct.kernelgen_callback_data_t* }
>> %"struct.kernelgen::kernel_t" = type opaque
>> %struct.kernelgen_callback_data_t = type opaque
>>
>> define ptx_kernel void @_Z17kernelgen_monitorPi(i32* %callback)
>> nounwind {
>> entry:
>> %callback.addr = alloca i32*, align 8
>> store i32* %callback, i32** %callback.addr, align 8
>> %0 = load i32** %callback.addr, align 8
>> %1 = bitcast i32* %0 to %struct.kernelgen_callback_t*
>> %lock = getelementptr inbounds %struct.kernelgen_callback_t* %1, i32
0,
>> i32 0
>> %call = call ptx_device i32 @_Z12__iAtomicCASPiii(i32* %lock, i32 1,
i32 0)
>> br label %while.cond
>>
>> while.cond: ; preds =
%while.body, %entry
>> %2 = load i32** %callback.addr, align 8
>> %3 = bitcast i32* %2 to %struct.kernelgen_callback_t*
>> %lock1 = getelementptr inbounds %struct.kernelgen_callback_t* %3, i32
0,
>> i32 0
>> %call2 = call ptx_device i32 @_Z12__iAtomicCASPiii(i32* %lock1, i32
1, i32 1)
>> %tobool = icmp ne i32 %call2, 0
>> %lnot = xor i1 %tobool, true
>> br i1 %lnot, label %while.body, label %while.end
>>
>> while.body: ; preds = %while.cond
>> br label %while.cond
>>
>> while.end: ; preds = %while.cond
>> ret void
>> }
>>
>> declare ptx_device i32 @_Z12__iAtomicCASPiii(i32*, i32, i32)
>>
>> CODEGEN
>> ========>>
>> dmikushin at hp2:~> llc < kernelgen_monitor.ll -march=nvptx
-mcpu=sm_20
>> //
>> // Generated by LLVM NVPTX Back-End
>> //
>>
>> .version 3.0
>> .target sm_20, texmode_independent
>> .address_size 32
>>
>> .func (.param .b32 func_retval0) _Z12__iAtomicCASPiii
>> (
>> .param .b32 _Z12__iAtomicCASPiii_param_0,
>> .param .b32 _Z12__iAtomicCASPiii_param_1,
>> .param .b32 _Z12__iAtomicCASPiii_param_2
>> )
>> ;
>>
>> Not Implemented
>> UNREACHABLE executed at
>> /tmp/rpmbuild_debug/BUILD/llvm/build/include/llvm/Target/TargetLowerin
>> g.h:1249!
>> 0 libLLVM-3.2svn.so 0x00007f47738b8f5f
>> 1 libLLVM-3.2svn.so 0x00007f47738b9525
>> 2 libpthread.so.0 0x00007f47726135d0
>> 3 libc.so.6 0x00007f4771931945 gsignal + 53
>> 4 libc.so.6 0x00007f4771932f21 abort + 385
>> 5 libLLVM-3.2svn.so 0x00007f47738a24c1
>> llvm::report_fatal_error(llvm::Twine const&) + 0
>> 6 libLLVM-3.2svn.so 0x00007f47735cd390
>> 7 libLLVM-3.2svn.so 0x00007f47737fe2ba
>> llvm::TargetLowering::LowerCallTo(llvm::SDValue, llvm::Type*, bool,
>> bool, bool, bool, unsigned int, llvm::CallingConv::ID, bool, bool,
>> bool, llvm::SDValue, std::vector<llvm::TargetLowering::ArgListEntry,
>> std::allocator<llvm::TargetLowering::ArgListEntry> >&,
>> llvm::SelectionDAG&, llvm::DebugLoc) const + 2120
>> 8 libLLVM-3.2svn.so 0x00007f4773807199
>> llvm::SelectionDAGBuilder::LowerCallTo(llvm::ImmutableCallSite,
>> llvm::SDValue, bool, llvm::MachineBasicBlock*) + 2913
>> 9 libLLVM-3.2svn.so 0x00007f477381b3af
>> llvm::SelectionDAGBuilder::visitCall(llvm::CallInst const&) + 9681
>> 10 libLLVM-3.2svn.so 0x00007f477382abee
>> llvm::SelectionDAGBuilder::visit(unsigned int, llvm::User const&) +
>> 1044
>> 11 libLLVM-3.2svn.so 0x00007f477382ad6d
>> llvm::SelectionDAGBuilder::visit(llvm::Instruction const&) + 105
>> 12 libLLVM-3.2svn.so 0x00007f4773844925
>>
llvm::SelectionDAGISel::SelectBasicBlock(llvm::ilist_iterator<llvm::Instruction
>> const>, llvm::ilist_iterator<llvm::Instruction const>,
bool&) + 59
>> 13 libLLVM-3.2svn.so 0x00007f477384540c
>> llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&)
+
>> 2620
>> 14 libLLVM-3.2svn.so 0x00007f47738459c6
>>
llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) +
>> 896
>> 15 libLLVM-3.2svn.so 0x00007f4773175bfe
>> llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 82
>> 16 libLLVM-3.2svn.so 0x00007f47733ac299
>> llvm::FPPassManager::runOnFunction(llvm::Function&) + 331
>> 17 libLLVM-3.2svn.so 0x00007f47733ac474
>> llvm::FPPassManager::runOnModule(llvm::Module&) + 86
>> 18 libLLVM-3.2svn.so 0x00007f47733abf6d
>> llvm::MPPassManager::runOnModule(llvm::Module&) + 381
>> 19 libLLVM-3.2svn.so 0x00007f47733ad6eb
>> llvm::PassManagerImpl::run(llvm::Module&) + 111
>> 20 libLLVM-3.2svn.so 0x00007f47733ad74d
>> llvm::PassManager::run(llvm::Module&) + 33
>> 21 llc 0x000000000040eed6 main + 2835
>> 22 libc.so.6 0x00007f477191dbc6 __libc_start_main + 230
>> 23 llc 0x000000000040cc09
>> Stack dump:
>> 0. Program arguments: llc -march=nvptx -mcpu=sm_20
>> 1. Running pass 'Function Pass Manager' on module
'<stdin>'.
>> 2. Running pass 'NVPTX DAG->DAG Pattern Instruction
Selection' on
>> function '@_Z17kernelgen_monitorPi'
>> Aborted
>> dmikushin at hp2:~> cd ~/rpmbuild/BUILD/llvm/ && svn info
>> Path: .
>> Working Copy Root Path: /tmp/rpmbuild_debug/BUILD/llvm
>> URL: http://llvm.org/svn/llvm-project/llvm/trunk
>> Repository Root: http://llvm.org/svn/llvm-project
>> Repository UUID: 91177308-0d34-0410-b5e6-96231b3b80d8
>> Revision: 156703
>> Node Kind: directory
>> Schedule: normal
>> Last Changed Author: foad
>> Last Changed Rev: 156703
>> Last Changed Date: 2012-05-12 12:30:16 +0400 (Sat, 12 May 2012)
>
-----------------------------------------------------------------------------------
> This email message is for the sole use of the intended recipient(s) and may
contain
> confidential information. Any unauthorized review, use, disclosure or
distribution
> is prohibited. If you are not the intended recipient, please contact the
sender by
> reply email and destroy all copies of the original message.
>
-----------------------------------------------------------------------------------
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