Fix using wrong result type for setcc.

[arsenm]

Summary

When reducing the bitwidth of a comparison against a constant, the
original setcc's result type was used, which was incorrect.

No test since I don't think any other in tree targets change the
bitwidth of the setcc type depending on the bitwidth of the compared type.

[arsenm]

Ping

[arsenm]

Ping

[arsenm]

r208236

include/llvm/CodeGen/SelectionDAG.h

#endif
   /// getZExtOrTrunc - Convert Op, which must be of integer type, to the
   /// integer type VT, by either zero-extending or truncating it.
   SDValue getZExtOrTrunc(SDValue Op, SDLoc DL, EVT VT);
 
   /// getZeroExtendInReg - Return the expression required to zero extend the Op
   /// value assuming it was the smaller SrcTy value.
   SDValue getZeroExtendInReg(SDValue Op, SDLoc DL, EVT SrcTy);
 
+  /// getBoolExtOrTrunc - Convert Op, which must be of integer type, to the
+  /// integer type VT, by using an extension appropriate for the target's
+  /// BooleanContent or truncating it.
+  SDValue getBoolExtOrTrunc(SDValue Op, SDLoc SL, EVT VT);
+
   /// getNOT - Create a bitwise NOT operation as (XOR Val, -1).
   SDValue getNOT(SDLoc DL, SDValue Val, EVT VT);
 
   /// getCALLSEQ_START - Return a new CALLSEQ_START node, which always must have
   /// a glue result (to ensure it's not CSE'd).  CALLSEQ_START does not have a
   /// useful SDLoc.
   SDValue getCALLSEQ_START(SDValue Chain, SDValue Op, SDLoc DL) {
     SDVTList VTs = getVTList(MVT::Other, MVT::Glue);

lib/CodeGen/SelectionDAG/SelectionDAG.cpp

SDValue SelectionDAG::getZeroExtendInReg(SDValue Op, SDLoc DL, EVT VT) {
   if (Op.getValueType() == VT) return Op;
   unsigned BitWidth = Op.getValueType().getScalarType().getSizeInBits();
   APInt Imm = APInt::getLowBitsSet(BitWidth,
                                    VT.getSizeInBits());
   return getNode(ISD::AND, DL, Op.getValueType(), Op,
                  getConstant(Imm, Op.getValueType()));
 }
 
+SDValue SelectionDAG::getBoolExtOrTrunc(SDValue Op, SDLoc SL, EVT VT) {
+  if (VT.bitsLE(Op.getValueType()))
+    return getNode(ISD::TRUNCATE, SL, VT, Op);
+
+  TargetLowering::BooleanContent BType = TLI->getBooleanContents(VT.isVector());
+  return getNode(TLI->getExtendForContent(BType), SL, VT, Op);
+}
+
 /// getNOT - Create a bitwise NOT operation as (XOR Val, -1).
 ///
 SDValue SelectionDAG::getNOT(SDLoc DL, SDValue Val, EVT VT) {
   EVT EltVT = VT.getScalarType();
   SDValue NegOne =
     getConstant(APInt::getAllOnesValue(EltVT.getSizeInBits()), VT);
   return getNode(ISD::XOR, DL, VT, Val, NegOne);
 }

lib/CodeGen/SelectionDAG/TargetLowering.cpp

if (N0.getOpcode() == ISD::ZERO_EXTEND) {
       case ISD::SETNE:
       case ISD::SETUGT:
       case ISD::SETUGE:
       case ISD::SETULT:
       case ISD::SETULE: {
         EVT newVT = N0.getOperand(0).getValueType();
         if (DCI.isBeforeLegalizeOps() ||
             (isOperationLegal(ISD::SETCC, newVT) &&
-             getCondCodeAction(Cond, newVT.getSimpleVT())==Legal))
-          return DAG.getSetCC(dl, VT, N0.getOperand(0),
-                              DAG.getConstant(C1.trunc(InSize), newVT),
-                              Cond);
+             getCondCodeAction(Cond, newVT.getSimpleVT()) == Legal)) {
+          EVT NewSetCCVT = getSetCCResultType(*DAG.getContext(), newVT);
+          SDValue NewConst = DAG.getConstant(C1.trunc(InSize), newVT);
+
+          SDValue NewSetCC = DAG.getSetCC(dl, NewSetCCVT, N0.getOperand(0),
+                                          NewConst, Cond);
+          return DAG.getBoolExtOrTrunc(NewSetCC, dl, VT);
+        }
         break;
       }
       default:
         break;   // todo, be more careful with signed comparisons
       }
     } else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
                (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
       EVT ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();