[llvm-dev] mysterious assert in SelectionDAGLegalize::LegalizeOp()

[Lawerence, Peter via llvm-dev]

I'm writing a new Target in 3.6.2,  I'm getting this assert

src/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:1166: void {anonymous}::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*): Assertion `TLI.getTypeAction(*DAG.getContext(), Node->getValueType(i)) == TargetLowering::TypeLegal && "Unexpected illegal type!"' failed.

which gdb shows having come from

#4  0x0000000001afce5b in SelectionDAGLegalize::LegalizeOp (this=0x7fffffffd0f0, Node=0x3571be0)

I did my run with -debug-only=isel, so I got the output at the bottom,


the question is, why is Node=0x3571be0 being examined at all ?
in particular that Node got replaced (and deleted ?) a long time ago ?


that node's last appearance in the DAG was in the output titled
     Optimized lowered selection DAG: BB#0 'foobar:entry'
and we are two phases later, in what would be titled
     Legalized selection DAG: BB#2 'foobar:entry'
were we to finished the phase we're in,



0x3571be0: i8 = Constant<1>     original, which got replaced, by CurDAG->LegalizeTypes(), with
0x3571690: i16 = Constant<1>    replacement, but later CurDAG->Legalize() is somehow examining the original ???



TIA, Peter Lawrence.


FYI:

def SLL   : FMT_I3 <0x7200, (outs datareg:$dst), (ins datareg:$rs1, i16imm:$imm),
                "sll   $dst,$rs1,$imm",
                [(set i16:$dst, (shl i16:$rs1, i16:$imm))]>;



int foobar(int A)
{
  return A << 1;
}



Optimized lowered selection DAG: BB#0 'foobar:entry'
SelectionDAG has 11 nodes:
  0x35455b0: ch = EntryToken

    0x35455b0: <multiple use>
    0x3571360: i16 = Register %vreg0

  0x3571470: i16,ch = CopyFromReg 0x35455b0, 0x3571360 [ORD=1]

  0x3571e00: i16 = Register %R0

      0x35455b0: <multiple use>
      0x3571470: <multiple use>
     0x3571580: i16 = FrameIndex<0>

      0x35717a0: i16 = undef

    0x35718b0: ch = store 0x35455b0, 0x3571470, 0x3571580, 0x35717a0 <ST2[%A.addr]> [ORD=3]

    0x3571e00: <multiple use>
      0x3571470: <multiple use>
      0x3571be0: i8 = Constant<1>

    0x3571cf0: i16 = shl 0x3571470, 0x3571be0 [ORD=5]

  0x3571f10: ch,glue = CopyToReg 0x35718b0, 0x3571e00, 0x3571cf0 [ORD=6]

    0x3571f10: <multiple use>
    0x3571e00: <multiple use>
    0x3571f10: <multiple use>
  0x3572020: ch = XmcISD::RET 0x3571f10, 0x3571e00, 0x3571f10:1 [ORD=6]


Type-legalized selection DAG: BB#0 'foobar:entry'
SelectionDAG has 11 nodes:
  0x35455b0: ch = EntryToken [ID=-3]

    0x35455b0: <multiple use>
    0x3571360: i16 = Register %vreg0 [ID=-3]

  0x3571470: i16,ch = CopyFromReg 0x35455b0, 0x3571360 [ORD=1] [ID=-3]

  0x3571e00: i16 = Register %R0 [ID=-3]

      0x35455b0: <multiple use>
      0x3571470: <multiple use>
      0x3571580: i16 = FrameIndex<0> [ID=-3]

      0x35717a0: i16 = undef [ID=-3]

    0x35718b0: ch = store 0x35455b0, 0x3571470, 0x3571580, 0x35717a0 <ST2[%A.addr]> [ORD=3] [ID=-3]

    0x3571e00: <multiple use>
      0x3571470: <multiple use>
      0x3571690: i16 = Constant<1> [ID=-3]

    0x35719c0: i16 = shl 0x3571470, 0x3571690 [ORD=5] [ID=-3]

  0x3571f10: ch,glue = CopyToReg 0x35718b0, 0x3571e00, 0x35719c0 [ORD=6] [ID=-3]

    0x3571f10: <multiple use>
    0x3571e00: <multiple use>
    0x3571f10: <multiple use>
  0x3572020: ch = XmcISD::RET 0x3571f10, 0x3571e00, 0x3571f10:1 [ORD=6] [ID=-3]


Optimized type-legalized selection DAG: BB#0 'foobar:entry'
SelectionDAG has 11 nodes:
  0x35455b0: ch = EntryToken [ID=-3]

    0x35455b0: <multiple use>
    0x3571360: i16 = Register %vreg0 [ID=-3]

  0x3571470: i16,ch = CopyFromReg 0x35455b0, 0x3571360 [ORD=1] [ID=-3]

  0x3571e00: i16 = Register %R0 [ID=-3]

      0x35455b0: <multiple use>
      0x3571470: <multiple use>
      0x3571580: i16 = FrameIndex<0> [ID=-3]

      0x35717a0: i16 = undef [ID=-3]

    0x35718b0: ch = store 0x35455b0, 0x3571470, 0x3571580, 0x35717a0 <ST2[%A.addr]> [ORD=3] [ID=-3]

    0x3571e00: <multiple use>
      0x3571470: <multiple use>
      0x3571690: i16 = Constant<1> [ID=-3]

    0x35719c0: i16 = shl 0x3571470, 0x3571690 [ORD=5] [ID=-3]

  0x3571f10: ch,glue = CopyToReg 0x35718b0, 0x3571e00, 0x35719c0 [ORD=6] [ID=-3]

    0x3571f10: <multiple use>
    0x3571e00: <multiple use>
    0x3571f10: <multiple use>
  0x3572020: ch = XmcISD::RET 0x3571f10, 0x3571e00, 0x3571f10:1 [ORD=6] [ID=-3]


llc: /projects/Firmware/plawrenc/xllvm/llvm-3.6.2.src/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:1166: void {anonymous}::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*): Assertion `TLI.getTypeAction(*DAG.getContext(), Node->getValueType(i)) == TargetLowering::TypeLegal && "Unexpected illegal type!"' failed.

Program received signal SIGABRT, Aborted.
0x0000003d9f035c55 in raise () from /lib64/libc.so.6

(gdb) where
#0  0x0000003d9f035c55 in raise () from /lib64/libc.so.6
#1  0x0000003d9f037408 in abort () from /lib64/libc.so.6
#2  0x0000003d9f02e972 in __assert_fail_base () from /lib64/libc.so.6
#3  0x0000003d9f02ea22 in __assert_fail () from /lib64/libc.so.6
#4  0x0000000001afce5b in (anonymous namespace)::SelectionDAGLegalize::LegalizeOp (this=0x7fffffffd0f0, Node=0x3571be0)
    at /projects/Firmware/plawrenc/xllvm/llvm-3.6.2.src/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:1164
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