2 files changed, 27 insertions, 7 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 7dd57d5420..631449ca79 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1930,6 +1930,8 @@ void SelectionDAG::ComputeMaskedBits(SDValue Op, APInt &KnownZero,
       KnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - MemBits);
     } else if (const MDNode *Ranges = LD->getRanges()) {
       computeMaskedBitsLoad(*Ranges, KnownZero);
+    } else if (ISD::isEXTLoad(Op.getNode())) {
+      TLI.computeMaskedBitsForAnyExtend(Op, KnownZero, KnownOne, *this, Depth);
     }
     return;
   }
@@ -1972,13 +1974,7 @@ void SelectionDAG::ComputeMaskedBits(SDValue Op, APInt &KnownZero,
     return;
   }
   case ISD::ANY_EXTEND: {
-    EVT InVT = Op.getOperand(0).getValueType();
-    unsigned InBits = InVT.getScalarType().getSizeInBits();
-    KnownZero = KnownZero.trunc(InBits);
-    KnownOne = KnownOne.trunc(InBits);
-    ComputeMaskedBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
-    KnownZero = KnownZero.zext(BitWidth);
-    KnownOne = KnownOne.zext(BitWidth);
+    TLI.computeMaskedBitsForAnyExtend(Op, KnownZero, KnownOne, *this, Depth);
     return;
   }
   case ISD::TRUNCATE: {
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 931c569d42..b410988dbd 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1856,6 +1856,30 @@ void TargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
   KnownZero = KnownOne = APInt(KnownOne.getBitWidth(), 0);
 }
 
+void TargetLowering::computeMaskedBitsForAnyExtend(const SDValue Op,
+                                                   APInt &KnownZero,
+                                                   APInt &KnownOne,
+                                                   const SelectionDAG &DAG,
+                                                   unsigned Depth) const {
+  unsigned BitWidth = Op.getValueType().getScalarType().getSizeInBits();
+  if (Op.getOpcode() == ISD::ANY_EXTEND) {
+    EVT InVT = Op.getOperand(0).getValueType();
+    unsigned InBits = InVT.getScalarType().getSizeInBits();
+    KnownZero = KnownZero.trunc(InBits);
+    KnownOne = KnownOne.trunc(InBits);
+    DAG.ComputeMaskedBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
+    KnownZero = KnownZero.zext(BitWidth);
+    KnownOne = KnownOne.zext(BitWidth);
+    return;
+  } else if (ISD::isEXTLoad(Op.getNode())) {
+    KnownZero = KnownOne = APInt(BitWidth, 0);
+    return;
+  }
+  
+  assert(0 && "Expecting an ANY_EXTEND or extload!");
+}
+
+
 /// ComputeNumSignBitsForTargetNode - This method can be implemented by
 /// targets that want to expose additional information about sign bits to the
 /// DAG Combiner.