X86: More efficient legalization of wide integer compares

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

diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 8fae6e2dacdf93e8c166a41c86090a77aa6e3504..b465ffb5d1be10bc8360d43db18a2e3242ffeeb5 100644 (file)
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -145,6 +145,7 @@ private:
   SDValue PromoteLegalFP_TO_INT(SDValue LegalOp, EVT DestVT, bool isSigned,
                                 SDLoc dl);
 
+  SDValue ExpandBITREVERSE(SDValue Op, SDLoc dl);
   SDValue ExpandBSWAP(SDValue Op, SDLoc dl);
   SDValue ExpandBitCount(unsigned Opc, SDValue Op, SDLoc dl);
 
@@ -1241,7 +1242,8 @@ void SelectionDAGLegalize::LegalizeOp(SDNode *Node) {
   case ISD::SETCC:
   case ISD::BR_CC: {
     unsigned CCOperand = Node->getOpcode() == ISD::SELECT_CC ? 4 :
-                         Node->getOpcode() == ISD::SETCC ? 2 : 1;
+                         Node->getOpcode() == ISD::SETCC ? 2 :
+                         Node->getOpcode() == ISD::SETCCE ? 3 : 1;
     unsigned CompareOperand = Node->getOpcode() == ISD::BR_CC ? 2 : 0;
     MVT OpVT = Node->getOperand(CompareOperand).getSimpleValueType();
     ISD::CondCode CCCode =
@@ -2775,6 +2777,31 @@ SDValue SelectionDAGLegalize::PromoteLegalFP_TO_INT(SDValue LegalOp,
   return DAG.getNode(ISD::TRUNCATE, dl, DestVT, Operation);
 }
 
+/// Open code the operations for BITREVERSE.
+SDValue SelectionDAGLegalize::ExpandBITREVERSE(SDValue Op, SDLoc dl) {
+  EVT VT = Op.getValueType();
+  EVT SHVT = TLI.getShiftAmountTy(VT, DAG.getDataLayout());
+  unsigned Sz = VT.getScalarSizeInBits();
+  
+  SDValue Tmp, Tmp2;
+  Tmp = DAG.getConstant(0, dl, VT);
+  for (unsigned I = 0, J = Sz-1; I < Sz; ++I, --J) {
+    if (I < J)
+      Tmp2 =
+          DAG.getNode(ISD::SHL, dl, VT, Op, DAG.getConstant(J - I, dl, SHVT));
+    else
+      Tmp2 =
+          DAG.getNode(ISD::SRL, dl, VT, Op, DAG.getConstant(I - J, dl, SHVT));
+    
+    APInt Shift(Sz, 1);
+    Shift = Shift.shl(J);
+    Tmp2 = DAG.getNode(ISD::AND, dl, VT, Tmp2, DAG.getConstant(Shift, dl, VT));
+    Tmp = DAG.getNode(ISD::OR, dl, VT, Tmp, Tmp2);
+  }
+
+  return Tmp;
+}
+
 /// Open code the operations for BSWAP of the specified operation.
 SDValue SelectionDAGLegalize::ExpandBSWAP(SDValue Op, SDLoc dl) {
   EVT VT = Op.getValueType();
@@ -2941,6 +2968,9 @@ bool SelectionDAGLegalize::ExpandNode(SDNode *Node) {
     Tmp1 = ExpandBitCount(Node->getOpcode(), Node->getOperand(0), dl);
     Results.push_back(Tmp1);
     break;
+  case ISD::BITREVERSE:
+    Results.push_back(ExpandBITREVERSE(Node->getOperand(0), dl));
+    break;
   case ISD::BSWAP:
     Results.push_back(ExpandBSWAP(Node->getOperand(0), dl));
     break;