Don't add CFG edges for redundant conditional branches.

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

diff --git a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index d18766a8e9f982e4cf55ff43035c27c0b52d10f3..e8e968aaef31991c65ce573a69779394766901de 100644 (file)
--- a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -588,18 +588,14 @@ SDValue DAGTypeLegalizer::PromoteIntRes_TRUNCATE(SDNode *N) {
     unsigned NumElts = InVT.getVectorNumElements();
     assert(NumElts == NVT.getVectorNumElements() &&
            "Dst and Src must have the same number of elements");
-    EVT EltVT = InVT.getScalarType();
     assert(isPowerOf2_32(NumElts) &&
            "Promoted vector type must be a power of two");
 
-    EVT HalfVT = EVT::getVectorVT(*DAG.getContext(), EltVT, NumElts/2);
+    SDValue EOp1, EOp2;
+    GetSplitVector(InOp, EOp1, EOp2);
+
     EVT HalfNVT = EVT::getVectorVT(*DAG.getContext(), NVT.getScalarType(),
                                    NumElts/2);
-
-    SDValue EOp1 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, HalfVT, InOp,
-                               DAG.getIntPtrConstant(0));
-    SDValue EOp2 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, HalfVT, InOp,
-                               DAG.getIntPtrConstant(NumElts/2));
     EOp1 = DAG.getNode(ISD::TRUNCATE, dl, HalfNVT, EOp1);
     EOp2 = DAG.getNode(ISD::TRUNCATE, dl, HalfNVT, EOp2);
 
@@ -1362,7 +1358,7 @@ ExpandShiftWithKnownAmountBit(SDNode *N, SDValue &Lo, SDValue &Hi) {
 
   APInt HighBitMask = APInt::getHighBitsSet(ShBits, ShBits - Log2_32(NVTBits));
   APInt KnownZero, KnownOne;
-  DAG.ComputeMaskedBits(N->getOperand(1), HighBitMask, KnownZero, KnownOne);
+  DAG.ComputeMaskedBits(N->getOperand(1), KnownZero, KnownOne);
 
   // If we don't know anything about the high bits, exit.
   if (((KnownZero|KnownOne) & HighBitMask) == 0)
@@ -1397,15 +1393,15 @@ ExpandShiftWithKnownAmountBit(SDNode *N, SDValue &Lo, SDValue &Hi) {
     }
   }
 
-#if 0
-  // FIXME: This code is broken for shifts with a zero amount!
   // If we know that all of the high bits of the shift amount are zero, then we
   // can do this as a couple of simple shifts.
   if ((KnownZero & HighBitMask) == HighBitMask) {
-    // Compute 32-amt.
-    SDValue Amt2 = DAG.getNode(ISD::SUB, ShTy,
-                                 DAG.getConstant(NVTBits, ShTy),
-                                 Amt);
+    // Calculate 31-x. 31 is used instead of 32 to avoid creating an undefined
+    // shift if x is zero.  We can use XOR here because x is known to be smaller
+    // than 32.
+    SDValue Amt2 = DAG.getNode(ISD::XOR, dl, ShTy, Amt,
+                               DAG.getConstant(NVTBits-1, ShTy));
+
     unsigned Op1, Op2;
     switch (N->getOpcode()) {
     default: llvm_unreachable("Unknown shift");
@@ -1414,13 +1410,23 @@ ExpandShiftWithKnownAmountBit(SDNode *N, SDValue &Lo, SDValue &Hi) {
     case ISD::SRA:  Op1 = ISD::SRL; Op2 = ISD::SHL; break;
     }
 
-    Lo = DAG.getNode(N->getOpcode(), NVT, InL, Amt);
-    Hi = DAG.getNode(ISD::OR, NVT,
-                     DAG.getNode(Op1, NVT, InH, Amt),
-                     DAG.getNode(Op2, NVT, InL, Amt2));
+    // When shifting right the arithmetic for Lo and Hi is swapped.
+    if (N->getOpcode() != ISD::SHL)
+      std::swap(InL, InH);
+
+    // Use a little trick to get the bits that move from Lo to Hi. First
+    // shift by one bit.
+    SDValue Sh1 = DAG.getNode(Op2, dl, NVT, InL, DAG.getConstant(1, ShTy));
+    // Then compute the remaining shift with amount-1.
+    SDValue Sh2 = DAG.getNode(Op2, dl, NVT, Sh1, Amt2);
+
+    Lo = DAG.getNode(N->getOpcode(), dl, NVT, InL, Amt);
+    Hi = DAG.getNode(ISD::OR, dl, NVT, DAG.getNode(Op1, dl, NVT, InH, Amt),Sh2);
+
+    if (N->getOpcode() != ISD::SHL)
+      std::swap(Hi, Lo);
     return true;
   }
-#endif
 
   return false;
 }
@@ -2263,9 +2269,9 @@ void DAGTypeLegalizer::ExpandIntRes_XMULO(SDNode *N,
     // A divide for UMULO will be faster than a function call. Select to
     // make sure we aren't using 0.
     SDValue isZero = DAG.getSetCC(dl, TLI.getSetCCResultType(VT),
-                                 RHS, DAG.getConstant(0, VT), ISD::SETNE);
+                                  RHS, DAG.getConstant(0, VT), ISD::SETNE);
     SDValue NotZero = DAG.getNode(ISD::SELECT, dl, VT, isZero,
-                                 DAG.getConstant(1, VT), RHS);
+                                  DAG.getConstant(1, VT), RHS);
     SDValue DIV = DAG.getNode(ISD::UDIV, DL, LHS.getValueType(), MUL, NotZero);
     SDValue Overflow;
     Overflow = DAG.getSetCC(DL, N->getValueType(1), DIV, LHS, ISD::SETNE);
@@ -2286,8 +2292,8 @@ void DAGTypeLegalizer::ExpandIntRes_XMULO(SDNode *N,
   SDValue Temp = DAG.CreateStackTemporary(PtrVT);
   // Temporary for the overflow value, default it to zero.
   SDValue Chain = DAG.getStore(DAG.getEntryNode(), dl,
-                              DAG.getConstant(0, PtrVT), Temp,
-                              MachinePointerInfo(), false, false, 0);
+                               DAG.getConstant(0, PtrVT), Temp,
+                               MachinePointerInfo(), false, false, 0);
 
   TargetLowering::ArgListTy Args;
   TargetLowering::ArgListEntry Entry;
@@ -2309,14 +2315,17 @@ void DAGTypeLegalizer::ExpandIntRes_XMULO(SDNode *N,
   Args.push_back(Entry);
 
   SDValue Func = DAG.getExternalSymbol(TLI.getLibcallName(LC), PtrVT);
-  std::pair<SDValue, SDValue> CallInfo =
-    TLI.LowerCallTo(Chain, RetTy, true, false, false, false,
-                   0, TLI.getLibcallCallingConv(LC), false,
-                   true, Func, Args, DAG, dl);
+  TargetLowering::
+  CallLoweringInfo CLI(Chain, RetTy, true, false, false, false,
+                       0, TLI.getLibcallCallingConv(LC),
+                       /*isTailCall=*/false,
+                       /*doesNotReturn=*/false, /*isReturnValueUsed=*/true,
+                       Func, Args, DAG, dl);
+  std::pair<SDValue, SDValue> CallInfo = TLI.LowerCallTo(CLI);
 
   SplitInteger(CallInfo.first, Lo, Hi);
   SDValue Temp2 = DAG.getLoad(PtrVT, dl, CallInfo.second, Temp,
-                             MachinePointerInfo(), false, false, false, 0);
+                              MachinePointerInfo(), false, false, false, 0);
   SDValue Ofl = DAG.getSetCC(dl, N->getValueType(1), Temp2,
                              DAG.getConstant(0, PtrVT),
                              ISD::SETNE);