llvm dev - Jan 2009 - [LLVMdev] Use two ComplexPatterns (possible bug of TableGen?)

It seems that it's not allowed to two same 'ComplexPattern's  in a
'def',
because TableGen generate the same variable names for the two ComplexPatterns.
If I understand the source code of TableGen correctly, it's not designed to
use more than one ComplexPattern instance (no matter they are the same or not).

In the following example, two 'regsw' are used to match the operands of
mul.

def regsw : Operand<v4i32>,
            ComplexPattern<v4i32, 2, "SelectRegsw", []> {
  let PrintMethod = "printSrcReg";
  let MIOperandInfo = (ops VR128, i8imm);
}

def MUL_1 : FooInst<(outs VR128:$dst),
                    (ins regsw:$src0, regsw:$src1),
                    "mul $dst, $src0, $src1",
                    [(set VR128:$dst, (mul regsw:$src0, regsw:$src1))]>;


The code generate by TableGen is:

SDNode *Select_ISD_MUL_v4i32(const SDValue &N) {
  SDValue N0 = N.getOperand(0);
  SDValue CPTmp0;
  SDValue CPTmp1;
  if (SelectRegsw(N, N0, CPTmp0, CPTmp1)) {
    SDValue N1 = N.getOperand(1);
    SDValue CPTmp0;
    SDValue CPTmp1;
    if (SelectRegsw(N, N1, CPTmp0, CPTmp1)) {
      return Emit_1(N, FooVS::MUL_1, MVT::v4i32, CPTmp0, CPTmp1);
    }
  }

Alex schrieb:
> It seems that it's not allowed to two same 'ComplexPattern's 
in a 'def',
> because TableGen generate the same variable names for the two
ComplexPatterns.
> If I understand the source code of TableGen correctly, it's not
designed to
> use more than one ComplexPattern instance (no matter they are the same or
not).
I've run into this too, the problem is that variables generated for the
ComplexPattern get the same name(s).

I have a patch against llvm 2.4 that fixes this issue, but did not have
the time to post the patch here. I'll do so by tomorrow.

florian

On Wednesday 14 January 2009 18:59:03 Brandner Florian
wrote:
> I have a patch against llvm 2.4 that fixes this issue, but did not have
> the time to post the patch here. I'll do so by tomorrow.
here is the patch, still against llvm 2.4. I had a short look on trunk, but it 
seems that there are several conflicts. Maybe a tablgen expert should have a 
look at this - I also do not know if there are changes needed for the 
FastISelEmitter.

I hope this is a starting point for you,
florian

ps: We have a working compiler here that relies on these changes, so it does 
not seem to break anything, at least for our private backend.


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