Always compute all the bits in ComputeMaskedBits.

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

diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index e4a0016435c3962876f40b1ad5bf20ad932fe9e1..eefb9e84b17c779c4c3cf7a0f836ac90c85ceff8 100644 (file)
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1244,7 +1244,7 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
     if (Depth != 0) {
       // If not at the root, Just compute the KnownZero/KnownOne bits to
       // simplify things downstream.
-      TLO.DAG.ComputeMaskedBits(Op, DemandedMask, KnownZero, KnownOne, Depth);
+      TLO.DAG.ComputeMaskedBits(Op, KnownZero, KnownOne, Depth);
       return false;
     }
     // If this is the root being simplified, allow it to have multiple uses,
@@ -1263,8 +1263,8 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
   switch (Op.getOpcode()) {
   case ISD::Constant:
     // We know all of the bits for a constant!
-    KnownOne = cast<ConstantSDNode>(Op)->getAPIntValue() & NewMask;
-    KnownZero = ~KnownOne & NewMask;
+    KnownOne = cast<ConstantSDNode>(Op)->getAPIntValue();
+    KnownZero = ~KnownOne;
     return false;   // Don't fall through, will infinitely loop.
   case ISD::AND:
     // If the RHS is a constant, check to see if the LHS would be zero without
@@ -1274,8 +1274,7 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
     if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
       APInt LHSZero, LHSOne;
       // Do not increment Depth here; that can cause an infinite loop.
-      TLO.DAG.ComputeMaskedBits(Op.getOperand(0), NewMask,
-                                LHSZero, LHSOne, Depth);
+      TLO.DAG.ComputeMaskedBits(Op.getOperand(0), LHSZero, LHSOne, Depth);
       // If the LHS already has zeros where RHSC does, this and is dead.
       if ((LHSZero & NewMask) == (~RHSC->getAPIntValue() & NewMask))
         return TLO.CombineTo(Op, Op.getOperand(0));
@@ -1725,11 +1724,11 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
 
     // If the sign bit is known one, the top bits match.
     if (KnownOne.intersects(InSignBit)) {
-      KnownOne  |= NewBits;
-      KnownZero &= ~NewBits;
+      KnownOne |= NewBits;
+      assert((KnownZero & NewBits) == 0);
     } else {   // Otherwise, top bits aren't known.
-      KnownOne  &= ~NewBits;
-      KnownZero &= ~NewBits;
+      assert((KnownOne & NewBits) == 0);
+      assert((KnownZero & NewBits) == 0);
     }
     break;
   }
@@ -1863,7 +1862,7 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
   // FALL THROUGH
   default:
     // Just use ComputeMaskedBits to compute output bits.
-    TLO.DAG.ComputeMaskedBits(Op, NewMask, KnownZero, KnownOne, Depth);
+    TLO.DAG.ComputeMaskedBits(Op, KnownZero, KnownOne, Depth);
     break;
   }
 
@@ -1879,7 +1878,6 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
 /// in Mask are known to be either zero or one and return them in the
 /// KnownZero/KnownOne bitsets.
 void TargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
-                                                    const APInt &Mask,
                                                     APInt &KnownZero,
                                                     APInt &KnownOne,
                                                     const SelectionDAG &DAG,
@@ -1890,7 +1888,7 @@ void TargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
           Op.getOpcode() == ISD::INTRINSIC_VOID) &&
          "Should use MaskedValueIsZero if you don't know whether Op"
          " is a target node!");
-  KnownZero = KnownOne = APInt(Mask.getBitWidth(), 0);
+  KnownZero = KnownOne = APInt(KnownOne.getBitWidth(), 0);
 }
 
 /// ComputeNumSignBitsForTargetNode - This method can be implemented by
@@ -1934,9 +1932,8 @@ static bool ValueHasExactlyOneBitSet(SDValue Val, const SelectionDAG &DAG) {
   // Fall back to ComputeMaskedBits to catch other known cases.
   EVT OpVT = Val.getValueType();
   unsigned BitWidth = OpVT.getScalarType().getSizeInBits();
-  APInt Mask = APInt::getAllOnesValue(BitWidth);
   APInt KnownZero, KnownOne;
-  DAG.ComputeMaskedBits(Val, Mask, KnownZero, KnownOne);
+  DAG.ComputeMaskedBits(Val, KnownZero, KnownOne);
   return (KnownZero.countPopulation() == BitWidth - 1) &&
          (KnownOne.countPopulation() == 1);
 }