Fix using wrong result type for setcc.

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.

llvm-svn: 208236

llvm/include/llvm/CodeGen/SelectionDAG.h

@@ -557,6 +557,11 @@ public:
   /// 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);
 

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -963,6 +963,14 @@ SDValue SelectionDAG::getZExtOrTrunc(SDValue Op, SDLoc DL, EVT VT) {
     getNode(ISD::TRUNCATE, DL, VT, Op);
 }
 
+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);
+}
+
 SDValue SelectionDAG::getZeroExtendInReg(SDValue Op, SDLoc DL, EVT VT) {
   assert(!VT.isVector() &&
          "getZeroExtendInReg should use the vector element type instead of "

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -1382,10 +1382,14 @@ TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
         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: