X86: More efficient legalization of wide integer compares

[oota-llvm.git] / lib / CodeGen / SelectionDAG / DAGCombiner.cpp

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 939eb5f54cf028c567605b7ab474d5050d67a807..af73b62546e6591c9a0a7154ad869c7e17aea67e 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -267,6 +267,7 @@ namespace {
     SDValue visitVSELECT(SDNode *N);
     SDValue visitSELECT_CC(SDNode *N);
     SDValue visitSETCC(SDNode *N);
+    SDValue visitSETCCE(SDNode *N);
     SDValue visitSIGN_EXTEND(SDNode *N);
     SDValue visitZERO_EXTEND(SDNode *N);
     SDValue visitANY_EXTEND(SDNode *N);
@@ -1396,6 +1397,7 @@ SDValue DAGCombiner::visit(SDNode *N) {
   case ISD::VSELECT:            return visitVSELECT(N);
   case ISD::SELECT_CC:          return visitSELECT_CC(N);
   case ISD::SETCC:              return visitSETCC(N);
+  case ISD::SETCCE:             return visitSETCCE(N);
   case ISD::SIGN_EXTEND:        return visitSIGN_EXTEND(N);
   case ISD::ZERO_EXTEND:        return visitZERO_EXTEND(N);
   case ISD::ANY_EXTEND:         return visitANY_EXTEND(N);
@@ -5720,6 +5722,19 @@ SDValue DAGCombiner::visitSETCC(SDNode *N) {
                        SDLoc(N));
 }
 
+SDValue DAGCombiner::visitSETCCE(SDNode *N) {
+  SDValue LHS = N->getOperand(0);
+  SDValue RHS = N->getOperand(1);
+  SDValue Carry = N->getOperand(2);
+  SDValue Cond = N->getOperand(3);
+
+  // If Carry is false, fold to a regular SETCC.
+  if (Carry.getOpcode() == ISD::CARRY_FALSE)
+    return DAG.getNode(ISD::SETCC, SDLoc(N), N->getVTList(), LHS, RHS, Cond);
+
+  return SDValue();
+}
+
 /// Try to fold a sext/zext/aext dag node into a ConstantSDNode or
 /// a build_vector of constants.
 /// This function is called by the DAGCombiner when visiting sext/zext/aext