llvm dev - Aug 2010 - [LLVMdev] What does this error mean: psuedo instructions should be removed before code emission?

On 08/27/2010 11:32, Yuri wrote:
> As I understand only one of TCRETURNri64 and RET should be created.
> I have sources of rev.112200.
>
> Here is the stack when TCRETURNri64 instruction is created:
> #1  0x0000000802c8b4e2 in llvm::MachineFunction::CreateMachineInstr
> (this=0x30eb000, TID=@0x803a78940, DL={LineCol = 0, ScopeIdx = 0},
> NoImp=false) at /tmp/llvm-svn/llvm/lib/CodeGen/MachineFunction.cpp:153
> #2  0x00000008028ea45b in llvm::BuildMI (BB=@0x4b69378,
> I={<std::iterator<std::bidirectional_iterator_tag,
llvm::MachineInstr,
> long int, llvm::MachineInstr*, llvm::MachineInstr&>>  = {<No
data
> fields>}, NodePtr = 0x4b69440}, DL={LineCol = 0, ScopeIdx = 0},
> TID=@0x803a78940) at MachineInstrBuilder.h:183
> #3  0x0000000803451825 in llvm::X86RegisterInfo::emitPrologue
> (this=0x1a96220, MF=@0x30eb000) at
> /tmp/llvm-svn/llvm/lib/Target/X86/X86RegisterInfo.cpp:1037
> #4  0x0000000802cdf3e5 in llvm::PEI::insertPrologEpilogCode
> (this=0x3231900, Fn=@0x30eb000) at
> /tmp/llvm-svn/llvm/lib/CodeGen/PrologEpilogInserter.cpp:680
> #5  0x0000000802cdcf04 in llvm::PEI::runOnMachineFunction
> (this=0x3231900, Fn=@0x30eb000) at
> /tmp/llvm-svn/llvm/lib/CodeGen/PrologEpilogInserter.cpp:106
> #6  0x0000000802c92abd in llvm::MachineFunctionPass::runOnFunction
> (this=0x3231900, F=@0x4530c60) at
> /tmp/llvm-svn/llvm/lib/CodeGen/MachineFunctionPass.cpp:33
> #7  0x0000000802e76e77 in llvm::FPPassManager::runOnFunction
> (this=0x235e540, F=@0x4530c60) at
> /tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1443
> #8  0x0000000802e76b3f in llvm::FunctionPassManagerImpl::run
> (this=0x1e1a300, F=@0x4530c60) at
> /tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1394
> #9  0x0000000802e767ef in llvm::FunctionPassManager::run
> (this=0x4b566c0, F=@0x4530c60) at
> /tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1324
> #10 0x0000000802f50500 in llvm::JIT::jitTheFunction (this=0x327a7e0,
> F=0x4530c60, locked=@0x7fffffff9840) at
> /tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:655
> #11 0x0000000802f5037b in llvm::JIT::runJITOnFunctionUnlocked
> (this=0x327a7e0, F=0x4530c60, locked=@0x7fffffff9840) at
> /tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:633
> #12 0x0000000802f507e4 in llvm::JIT::getPointerToFunction
> (this=0x327a7e0, F=0x4530c60) at
> /tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:719
>
>
> Here is the stack when RET instruction is created:
> #1  0x0000000802c8b4e2 in llvm::MachineFunction::CreateMachineInstr
> (this=0x30eb000, TID=@0x803a99240, DL={LineCol = 0, ScopeIdx = 0},
> NoImp=false) at /tmp/llvm-svn/llvm/lib/CodeGen/MachineFunction.cpp:153
> #2  0x00000008028ea45b in llvm::BuildMI (BB=@0x4b69378,
> I={<std::iterator<std::bidirectional_iterator_tag,
llvm::MachineInstr,
> long int, llvm::MachineInstr*, llvm::MachineInstr&>>  = {<No
data
> fields>}, NodePtr = 0x4b69388}, DL={LineCol = 0, ScopeIdx = 0},
> TID=@0x803a99240) at MachineInstrBuilder.h:183
> #3  0x00000008033c7637 in X86SelectRet (this=0x4530bd0, I=0x493fae0) at
> /tmp/llvm-svn/llvm/lib/Target/X86/X86FastISel.cpp:771
> #4  0x00000008033cc4fc in TargetSelectInstruction (this=0x4530bd0,
> I=0x493fae0) at /tmp/llvm-svn/llvm/lib/Target/X86/X86FastISel.cpp:1783
> #5  0x000000080315a64f in llvm::FastISel::SelectInstruction
> (this=0x4530bd0, I=0x493fae0) at
> /tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp:706
> #6  0x0000000803275ee0 in llvm::SelectionDAGISel::SelectAllBasicBlocks
> (this=0x45174d0, Fn=@0x4530c60) at
> /tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:726
> #7  0x00000008032737f7 in llvm::SelectionDAGISel::runOnMachineFunction
> (this=0x45174d0, mf=@0x30eb000) at
> /tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:252
> #8  0x0000000802c92abd in llvm::MachineFunctionPass::runOnFunction
> (this=0x45174d0, F=@0x4530c60) at
> /tmp/llvm-svn/llvm/lib/CodeGen/MachineFunctionPass.cpp:33
> #9  0x0000000802e76e77 in llvm::FPPassManager::runOnFunction
> (this=0x235e540, F=@0x4530c60) at
> /tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1443
> #10 0x0000000802e76b3f in llvm::FunctionPassManagerImpl::run
> (this=0x1e1a300, F=@0x4530c60) at
> /tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1394
> #11 0x0000000802e767ef in llvm::FunctionPassManager::run
> (this=0x4b566c0, F=@0x4530c60) at
> /tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1324
> #12 0x0000000802f50500 in llvm::JIT::jitTheFunction (this=0x327a7e0,
> F=0x4530c60, locked=@0x7fffffff9840) at
> /tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:655
> #13 0x0000000802f5037b in llvm::JIT::runJITOnFunctionUnlocked
> (this=0x327a7e0, F=0x4530c60, locked=@0x7fffffff9840) at
> /tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:633
> #14 0x0000000802f507e4 in llvm::JIT::getPointerToFunction
> (this=0x327a7e0, F=0x4530c60) at
> /tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:719
> ....my code....

It seems wrong that TCRETURNri64 is created in 
X86RegisterInfo::emitPrologue even when RET instruction is already 
there. This seems to be a bug.

Yuri

On Aug 27, 2010, at 11:53 AMPDT, Yuri wrote:
> On 08/27/2010 11:32, Yuri wrote:
>> As I understand only one of TCRETURNri64 and RET should be created.
>> I have sources of rev.112200.
>>
>> Here is the stack when TCRETURNri64 instruction is created:
>> #1  0x0000000802c8b4e2 in llvm::MachineFunction::CreateMachineInstr
>> (this=0x30eb000, TID=@0x803a78940, DL={LineCol = 0, ScopeIdx = 0},
>> NoImp=false) at /tmp/llvm-svn/llvm/lib/CodeGen/MachineFunction.cpp: 
>> 153
>> #2  0x00000008028ea45b in llvm::BuildMI (BB=@0x4b69378,
>> I={<std::iterator<std::bidirectional_iterator_tag,  
>> llvm::MachineInstr,
>> long int, llvm::MachineInstr*, llvm::MachineInstr&>>  =
{<No data
>> fields>}, NodePtr = 0x4b69440}, DL={LineCol = 0, ScopeIdx = 0},
>> TID=@0x803a78940) at MachineInstrBuilder.h:183
>> #3  0x0000000803451825 in llvm::X86RegisterInfo::emitPrologue
>> (this=0x1a96220, MF=@0x30eb000) at
>> /tmp/llvm-svn/llvm/lib/Target/X86/X86RegisterInfo.cpp:1037
>>
> It seems wrong that TCRETURNri64 is created in  
> X86RegisterInfo::emitPrologue even when RET instruction is already  
> there. This seems to be a bug.
I don't think I believe this; emitPrologue should not be generating a  
TCRETURN at all, and line 1037 is generating a PROLOG_LABEL.  Why do  
you say it's a TCRETURN?

The way this is supposed to work:
SelectBasicBlock calls visit on the Call instruction, leading to  
visitCall:
  which winds up in X86TargetLowering::LowerCall:
which generates the TCRETURN and sets the isTailCall argument to True
which causes the loop in SelectBasicBlock to exit early, causing it to  
skip the RET.

It looks like the incoming RET (the Instruction, not the MachineInstr)  
is not getting skipped for some reason.  I suggest stepping through  
the path above to figure out why.

On 08/27/2010 12:13, Dale Johannesen wrote:
> I don't think I believe this; emitPrologue should not be generating a 
> TCRETURN at all, and line 1037 is generating a PROLOG_LABEL.  Why do 
> you say it's a TCRETURN?
Sorry, my bad. I have set breakpoints by MI addresses. But it turns out 
that these addresses were reused and the second MIs created at these 
particular addressed are of interest, not the first ones.

RET creation stack (created first):
#1  0x0000000802c8b4e2 in llvm::MachineFunction::CreateMachineInstr 
(this=0x30eb000, TID=@0x803a99240, DL={LineCol = 0, ScopeIdx = 0}, 
NoImp=false) at /tmp/llvm-svn/llvm/lib/CodeGen/MachineFunction.cpp:153
#2  0x00000008028ea45b in llvm::BuildMI (BB=@0x4b69378, 
I={<std::iterator<std::bidirectional_iterator_tag, llvm::MachineInstr, 
long int, llvm::MachineInstr*, llvm::MachineInstr&>> = {<No data 
fields>}, NodePtr = 0x4b69388}, DL={LineCol = 0, ScopeIdx = 0}, 
TID=@0x803a99240) at MachineInstrBuilder.h:183
#3  0x00000008033c7637 in X86SelectRet (this=0x4530f30, I=0x493f240) at 
/tmp/llvm-svn/llvm/lib/Target/X86/X86FastISel.cpp:771
#4  0x00000008033cc4fc in TargetSelectInstruction (this=0x4530f30, 
I=0x493f240) at /tmp/llvm-svn/llvm/lib/Target/X86/X86FastISel.cpp:1783
#5  0x000000080315a64f in llvm::FastISel::SelectInstruction 
(this=0x4530f30, I=0x493f240) at 
/tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp:706
#6  0x0000000803275ee0 in llvm::SelectionDAGISel::SelectAllBasicBlocks 
(this=0x45174d0, Fn=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:726
#7  0x00000008032737f7 in llvm::SelectionDAGISel::runOnMachineFunction 
(this=0x45174d0, mf=@0x30eb000) at 
/tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:252V
#8  0x0000000802c92abd in llvm::MachineFunctionPass::runOnFunction 
(this=0x45174d0, F=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/CodeGen/MachineFunctionPass.cpp:33
#9  0x0000000802e76e77 in llvm::FPPassManager::runOnFunction 
(this=0x235e540, F=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1443
#10 0x0000000802e76b3f in llvm::FunctionPassManagerImpl::run 
(this=0x1e1a300, F=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1394
#11 0x0000000802e767ef in llvm::FunctionPassManager::run 
(this=0x4b566c0, F=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1324
#12 0x0000000802f50500 in llvm::JIT::jitTheFunction (this=0x327a7e0, 
F=0x4530bd0, locked=@0x7fffffff8b50) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:655
#13 0x0000000802f5037b in llvm::JIT::runJITOnFunctionUnlocked 
(this=0x327a7e0, F=0x4530bd0, locked=@0x7fffffff8b50) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:633
#14 0x0000000802f507e4 in llvm::JIT::getPointerToFunction 
(this=0x327a7e0, F=0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:719
#15 0x0000000802f4f194 in llvm::JIT::runFunction (this=0x327a7e0, 
F=0x4530bd0, ArgValues=@0x7fffffff9230) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:405
#16 0x0000000802f4fe4f in llvm::JIT::runFunction (this=0x327a7e0, 
F=0x4530c60, ArgValues=@0x7fffffff9350) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:561

TCRETURNri64 creation stack (created second):
#1  0x0000000802c8b4e2 in llvm::MachineFunction::CreateMachineInstr 
(this=0x30eb000, TID=@0x803a9f840, DL={LineCol = 0, ScopeIdx = 0}, 
NoImp=false) at /tmp/llvm-svn/llvm/lib/CodeGen/MachineFunction.cpp:153
#2  0x00000008028ea302 in llvm::BuildMI (MF=@0x30eb000, DL={LineCol = 0, 
ScopeIdx = 0}, TID=@0x803a9f840) at MachineInstrBuilder.h:147
#3  0x0000000803164513 in llvm::InstrEmitter::EmitMachineNode 
(this=0x7fffffff7f80, Node=0x4b6c510, IsClone=false, IsCloned=false, 
VRBaseMap=@0x7fffffff8050) at 
/tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp:671
#4  0x00000008031f6bdf in llvm::InstrEmitter::EmitNode 
(this=0x7fffffff7f80, Node=0x4b6c510, IsClone=false, IsCloned=false, 
VRBaseMap=@0x7fffffff8050) at InstrEmitter.h:118
#5  0x00000008031f5781 in llvm::ScheduleDAGSDNodes::EmitSchedule 
(this=0x4b68400) at 
/tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp:602
#6  0x0000000803275459 in llvm::SelectionDAGISel::CodeGenAndEmitDAG 
(this=0x45174d0) at 
/tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:547
#7  0x00000008032740fc in llvm::SelectionDAGISel::SelectBasicBlock 
(this=0x45174d0, Begin={<std::iterator<std::bidirectional_iterator_tag, 
const llvm::Instruction, long int, const llvm::Instruction*, const 
llvm::Instruction&>> = {<No data fields>}, NodePtr = 0x4530ed0},
End={<std::iterator<std::bidirectional_iterator_tag, const 
llvm::Instruction, long int, const llvm::Instruction*, const 
llvm::Instruction&>> = {<No data fields>}, NodePtr = 0x493f240},
HadTailCall=@0x7fffffff853f) at 
/tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:364
#8  0x0000000803276048 in llvm::SelectionDAGISel::SelectAllBasicBlocks 
(this=0x45174d0, Fn=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:744
#9  0x00000008032737f7 in llvm::SelectionDAGISel::runOnMachineFunction 
(this=0x45174d0, mf=@0x30eb000) at 
/tmp/llvm-svn/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:252
#10 0x0000000802c92abd in llvm::MachineFunctionPass::runOnFunction 
(this=0x45174d0, F=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/CodeGen/MachineFunctionPass.cpp:33
#11 0x0000000802e76e77 in llvm::FPPassManager::runOnFunction 
(this=0x235e540, F=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1443
#12 0x0000000802e76b3f in llvm::FunctionPassManagerImpl::run 
(this=0x1e1a300, F=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1394
#13 0x0000000802e767ef in llvm::FunctionPassManager::run 
(this=0x4b566c0, F=@0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/VMCore/PassManager.cpp:1324
#14 0x0000000802f50500 in llvm::JIT::jitTheFunction (this=0x327a7e0, 
F=0x4530bd0, locked=@0x7fffffff8b50) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:655
#15 0x0000000802f5037b in llvm::JIT::runJITOnFunctionUnlocked 
(this=0x327a7e0, F=0x4530bd0, locked=@0x7fffffff8b50) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:633
#16 0x0000000802f507e4 in llvm::JIT::getPointerToFunction 
(this=0x327a7e0, F=0x4530bd0) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:719
#17 0x0000000802f4f194 in llvm::JIT::runFunction (this=0x327a7e0, 
F=0x4530bd0, ArgValues=@0x7fffffff9230) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:405
#18 0x0000000802f4fe4f in llvm::JIT::runFunction (this=0x327a7e0, 
F=0x4530c60, ArgValues=@0x7fffffff9350) at 
/tmp/llvm-svn/llvm/lib/ExecutionEngine/JIT/JIT.cpp:561

> The way this is supposed to work:
> SelectBasicBlock calls visit on the Call instruction, leading to 
> visitCall:
>  which winds up in X86TargetLowering::LowerCall:
> which generates the TCRETURN and sets the isTailCall argument to True
> which causes the loop in SelectBasicBlock to exit early, causing it to 
> skip the RET.
>
> It looks like the incoming RET (the Instruction, not the MachineInstr) 
> is not getting skipped for some reason.  I suggest stepping through 
> the path above to figure out why.
>
Here's what happens:
The first instruction created is RET.
SelectBasicBlock is called.
TCRETURNri64 is created from within it.
HasTailCall is set to true as you mentioned.
Cycle in SelectionDAGISel::SelectBasicBlock skips the rest.

All like you described. But the RET instruction still stays in the end.
RET is skipped by visit but I guess stays in the list. Where should it 
be destroyed?

Yuri