[RISCV] Remove traces of Glue from RISCVISD::SELECT_CC

[craig.topper]

Summary

We were creating RISCVISD::SELECT_CC nodes with Glue output that was never being used, and the tablegen SDNode had the SDNPInGlue flag instead of the SDNPOutGlue flag.

Since we don't seem to need the Glue just get rid of it from both places.

[frasercrmck]

LGTM; from a quick look I can't see anything that would need that glue. Do you have an idea why it was added?

[craig.topper]

In D91199#2388012, @frasercrmck wrote:

LGTM; from a quick look I can't see anything that would need that glue. Do you have an idea why it was added?

No. As far as I could tell it had been there but not used since the first patch that added RISCVISD::SELECT_CC.

[asb]

In D91199#2389105, @craig.topper wrote:

In D91199#2388012, @frasercrmck wrote:

LGTM; from a quick look I can't see anything that would need that glue. Do you have an idea why it was added?

No. As far as I could tell it had been there but not used since the first patch that added RISCVISD::SELECT_CC.

I think I'd just copied it across from the equivalent nodes in the Sparc (SPselecticc, SPselectxcc, SPselectfcc) and MSP430 (MSP540selectcc) backends. If it's not required it looks like a similar cleanup could be made there.

[craig.topper]

In D91199#2391113, @asb wrote:

In D91199#2389105, @craig.topper wrote:

In D91199#2388012, @frasercrmck wrote:

LGTM; from a quick look I can't see anything that would need that glue. Do you have an idea why it was added?

No. As far as I could tell it had been there but not used since the first patch that added RISCVISD::SELECT_CC.

I think I'd just copied it across from the equivalent nodes in the Sparc (SPselecticc, SPselectxcc, SPselectfcc) and MSP430 (MSP540selectcc) backends. If it's not required it looks like a similar cleanup could be made there.

It looks like both Sparc and MSP430 do use a Glue input so the td file is correct for them. Sparc does not have a Glue output. MSP430 has an unused Glue output that could be cleaned up.

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

if (Op.getSimpleValueType() == XLenVT && CondV.getOpcode() == ISD::SETCC &&
     SDValue LHS = CondV.getOperand(0);
     SDValue RHS = CondV.getOperand(1);
     auto CC = cast<CondCodeSDNode>(CondV.getOperand(2));
     ISD::CondCode CCVal = CC->get();
 
     normaliseSetCC(LHS, RHS, CCVal);
 
     SDValue TargetCC = DAG.getConstant(CCVal, DL, XLenVT);
-    SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Glue);
     SDValue Ops[] = {LHS, RHS, TargetCC, TrueV, FalseV};
-    return DAG.getNode(RISCVISD::SELECT_CC, DL, VTs, Ops);
+    return DAG.getNode(RISCVISD::SELECT_CC, DL, Op.getValueType(), Ops);
   }
 
   // Otherwise:
   // (select condv, truev, falsev)
   // -> (riscvisd::select_cc condv, zero, setne, truev, falsev)
   SDValue Zero = DAG.getConstant(0, DL, XLenVT);
   SDValue SetNE = DAG.getConstant(ISD::SETNE, DL, XLenVT);
 
-  SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Glue);
   SDValue Ops[] = {CondV, Zero, SetNE, TrueV, FalseV};
 
-  return DAG.getNode(RISCVISD::SELECT_CC, DL, VTs, Ops);
+  return DAG.getNode(RISCVISD::SELECT_CC, DL, Op.getValueType(), Ops);
 }
 
 SDValue RISCVTargetLowering::lowerVASTART(SDValue Op, SelectionDAG &DAG) const {
   MachineFunction &MF = DAG.getMachineFunction();
   RISCVMachineFunctionInfo *FuncInfo = MF.getInfo<RISCVMachineFunctionInfo>();
 
   SDLoc DL(Op);
   SDValue FI = DAG.getFrameIndex(FuncInfo->getVarArgsFrameIndex(),

llvm/lib/Target/RISCV/RISCVInstrInfo.td

 def riscv_ret_flag  : SDNode<"RISCVISD::RET_FLAG", SDTNone,
                              [SDNPHasChain, SDNPOptInGlue, SDNPVariadic]>;
 def riscv_uret_flag : SDNode<"RISCVISD::URET_FLAG", SDTNone,
                              [SDNPHasChain, SDNPOptInGlue]>;
 def riscv_sret_flag : SDNode<"RISCVISD::SRET_FLAG", SDTNone,
                              [SDNPHasChain, SDNPOptInGlue]>;
 def riscv_mret_flag : SDNode<"RISCVISD::MRET_FLAG", SDTNone,
                              [SDNPHasChain, SDNPOptInGlue]>;
-def riscv_selectcc  : SDNode<"RISCVISD::SELECT_CC", SDT_RISCVSelectCC,
-                             [SDNPInGlue]>;
+def riscv_selectcc  : SDNode<"RISCVISD::SELECT_CC", SDT_RISCVSelectCC>;
 def riscv_tail      : SDNode<"RISCVISD::TAIL", SDT_RISCVCall,
                              [SDNPHasChain, SDNPOptInGlue, SDNPOutGlue,
                               SDNPVariadic]>;
 def riscv_sllw      : SDNode<"RISCVISD::SLLW", SDTIntShiftOp>;
 def riscv_sraw      : SDNode<"RISCVISD::SRAW", SDTIntShiftOp>;
 def riscv_srlw      : SDNode<"RISCVISD::SRLW", SDTIntShiftOp>;
 
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