[LLVMdev] TableGen patterns with multiple outputs

[Justin Holewinski]

Are multi-output patterns in TableGen supposed to work, or is that a known
limitation in the current implementation?

If I have TableGen code like the following...

1242 def SDTTestNode : SDTypeProfile<2, 1, [SDTCisSameAs<0, 1>]>;
1243 def TestNode : SDNode<"NVPTXISD::TestNode", SDTTestNode>;
1244
1245 def MyTestNode : NVPTXInst<(outs Int32Regs:$dst0, Int32Regs:$dst1),
1246                            (ins Int32Regs:$a),
1247                            "test $dst0, $dst1, $a;",
1248                            [(set Int32Regs:$dst0, Int32Regs:$dst1,
(TestNode Int32Regs:$a))]>;

... TableGen crashes with the following stack trace:

#0  0x00007fff8f372212 in __pthread_kill ()
#1  0x00007fff8dc0eaf4 in pthread_kill ()
#2  0x00000001003a978b in raise (sig=6) at Signals.inc:345
#3  0x00000001003a9842 in abort () at Signals.inc:362
#4  0x00000001003a9821 in __assert_rtn (func=0x1003d0d14 "operator[]",
file=0x1003b169e
"/Users/jholewinski/projects/llvm/src/llvm/include/llvm/ADT/SmallVector.h",
line=139, expr=0x1003b16e7 "begin() + idx < end()") at Signals.inc:358
#5  0x00000001000ca394 in
llvm::SmallVectorTemplateCommon<llvm::EEVT::TypeSet, void>::operator[]
(this=0x10384fed0, idx=1) at SmallVector.h:139
#6  0x00000001000c965b in llvm::TreePatternNode::getExtType
(this=0x10384fed0, ResNo=1) at CodeGenDAGPatterns.h:349
#7  0x00000001000bd615 in llvm::CodeGenDAGPatterns::ParseInstructions
(this=0x7fff5fbff0b0) at
/Users/jholewinski/projects/llvm/src/llvm/utils/TableGen/CodeGenDAGPatterns.cpp:2782
#8  0x00000001000b7143 in llvm::CodeGenDAGPatterns::CodeGenDAGPatterns
(this=0x7fff5fbff0b0, R=@0x7fff5fbff670) at
/Users/jholewinski/projects/llvm/src/llvm/utils/TableGen/CodeGenDAGPatterns.cpp:2077
#9  0x00000001000b6a3d in llvm::CodeGenDAGPatterns::CodeGenDAGPatterns
(this=0x7fff5fbff0b0, R=@0x7fff5fbff670) at
/Users/jholewinski/projects/llvm/src/llvm/utils/TableGen/CodeGenDAGPatterns.cpp:2091
#10 0x000000010024cd15 in InstrInfoEmitter (this=0x7fff5fbff0a8,
R=@0x7fff5fbff670) at
/Users/jholewinski/projects/llvm/src/llvm/utils/TableGen/InstrInfoEmitter.cpp:39
#11 0x0000000100248e8d in InstrInfoEmitter (this=0x7fff5fbff0a8,
R=@0x7fff5fbff670) at
/Users/jholewinski/projects/llvm/src/llvm/utils/TableGen/InstrInfoEmitter.cpp:39
#12 0x0000000100248e36 in llvm::EmitInstrInfo (RK=@0x7fff5fbff670,
OS=@0x7fff5fbff518) at
/Users/jholewinski/projects/llvm/src/llvm/utils/TableGen/InstrInfoEmitter.cpp:420
#13 0x00000001002d0930 in LLVMTableGenMain (OS=@0x7fff5fbff518,
Records=@0x7fff5fbff670) at
/Users/jholewinski/projects/llvm/src/llvm/utils/TableGen/TableGen.cpp:106
#14 0x00000001002e8385 in llvm::TableGenMain (argv0=0x7fff5fbffa88
"/Users/jholewinski/projects/llvm/build/bin/llvm-tblgen",
MainFn=0x1002d0880 <LLVMTableGenMain>) at
/Users/jholewinski/projects/llvm/src/llvm/lib/TableGen/Main.cpp:117
#15 0x00000001002d0864 in main (argc=11, argv=0x7fff5fbff8f8) at
/Users/jholewinski/projects/llvm/src/llvm/utils/TableGen/TableGen.cpp:181


The fault occurs in CodeGenDAGPatterns.cpp:

2781     for (unsigned i = 0; i != NumResults; ++i)
2782       ResultPattern->setType(i, Res0Node->getExtType(i));

Res0Node has only 1 type, but it is expected to have 2.


Looking at the X86 back-end code, it looks like there do exist multi-output
instructions, but they all use physical (implicit) registers for the second
destination, not arbitrary register types.  And if I change the second
destination to be a certain physical register, this problem goes away in my
code.  Is this just not a supported case currently?  Or am I doing
something wrong?

This is my first time looking into the TableGen internals, so I can't spot
anything obviously wrong with the TableGen tool code.

-- 

Thanks,

Justin Holewinski
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130104/74103044/attachment.html>