diff --git a/include/llvm/Analysis/Dominators.h b/include/llvm/Analysis/Dominators.h
index 347e239..366d492 100644
--- a/include/llvm/Analysis/Dominators.h
+++ b/include/llvm/Analysis/Dominators.h
@@ -618,8 +618,9 @@
   }
   
   DomTreeNodeBase<NodeT> *getNodeForBlock(NodeT *BB) {
-    if (DomTreeNodeBase<NodeT> *BBNode = this->DomTreeNodes[BB])
-      return BBNode;
+    typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.find(BB);
+    if (I != this->DomTreeNodes.end() && I->second)
+      return I->second;
 
     // Haven't calculated this node yet?  Get or calculate the node for the
     // immediate dominator.
diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index ea29f73..bd994de 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -452,8 +452,9 @@
     if (Subtarget->GVRequiresExtraLoad(GV, TM, isCall)) {
       // Check to see if we've already materialized this
       // value in a register in this block.
-      if (unsigned Reg = LocalValueMap[V]) {
-        AM.Base.Reg = Reg;
+      DenseMap<const Value *, unsigned>::iterator I = LocalValueMap.find(V);
+      if (I != LocalValueMap.end() && I->second != 0) {
+        AM.Base.Reg = I->second;
         AM.GV = 0;
         return true;
       }
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index 5a70fc3..c3aee01 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -935,9 +935,11 @@
    
     // Remap operands to patch up intra-block references.
     for (unsigned i = 0, e = New->getNumOperands(); i != e; ++i)
-      if (Instruction *Inst = dyn_cast<Instruction>(New->getOperand(i)))
-        if (Value *Remapped = ValueMapping[Inst])
-          New->setOperand(i, Remapped);
+      if (Instruction *Inst = dyn_cast<Instruction>(New->getOperand(i))) {
+        DenseMap<Instruction*, Value*>::iterator I = ValueMapping.find(Inst);
+        if (I != ValueMapping.end())
+          New->setOperand(i, I->second);
+      }
   }
   
   // We didn't copy the terminator from BB over to NewBB, because there is now
@@ -953,9 +955,11 @@
     Value *IV = PN->getIncomingValueForBlock(BB);
     
     // Remap the value if necessary.
-    if (Instruction *Inst = dyn_cast<Instruction>(IV))
-      if (Value *MappedIV = ValueMapping[Inst])
-        IV = MappedIV;
+    if (Instruction *Inst = dyn_cast<Instruction>(IV)) {
+      DenseMap<Instruction*, Value*>::iterator I = ValueMapping.find(Inst);
+      if (I != ValueMapping.end())
+        IV = I->second;
+    }
     PN->addIncoming(IV, NewBB);
   }
   
diff --git a/lib/Transforms/Scalar/TailDuplication.cpp b/lib/Transforms/Scalar/TailDuplication.cpp
index 99a7dee..c037ee9 100644
--- a/lib/Transforms/Scalar/TailDuplication.cpp
+++ b/lib/Transforms/Scalar/TailDuplication.cpp
@@ -317,9 +317,12 @@
   //
   BI = Branch; ++BI;  // Get an iterator to the first new instruction
   for (; BI != SourceBlock->end(); ++BI)
-    for (unsigned i = 0, e = BI->getNumOperands(); i != e; ++i)
-      if (Value *Remapped = ValueMapping[BI->getOperand(i)])
-        BI->setOperand(i, Remapped);
+    for (unsigned i = 0, e = BI->getNumOperands(); i != e; ++i) {
+      std::map<Value*, Value*>::const_iterator I =
+        ValueMapping.find(BI->getOperand(i));
+      if (I != ValueMapping.end())
+        BI->setOperand(i, I->second);
+    }
 
   // Next we check to see if any of the successors of DestBlock had PHI nodes.
   // If so, we need to add entries to the PHI nodes for SourceBlock now.
@@ -333,8 +336,9 @@
       Value *IV = PN->getIncomingValueForBlock(DestBlock);
 
       // Remap the value if necessary...
-      if (Value *MappedIV = ValueMapping[IV])
-        IV = MappedIV;
+      std::map<Value*, Value*>::const_iterator I = ValueMapping.find(IV);
+      if (I != ValueMapping.end())
+        IV = I->second;
       PN->addIncoming(IV, SourceBlock);
     }
   }
diff --git a/tools/llvm-prof/llvm-prof.cpp b/tools/llvm-prof/llvm-prof.cpp
index cab87e7..2cff296 100644
--- a/tools/llvm-prof/llvm-prof.cpp
+++ b/tools/llvm-prof/llvm-prof.cpp
@@ -81,8 +81,10 @@
     virtual void emitBasicBlockStartAnnot(const BasicBlock *BB,
                                           raw_ostream &OS) {
       if (BlockFreqs.empty()) return;
-      if (unsigned Count = BlockFreqs[BB])
-        OS << "\t;;; Basic block executed " << Count << " times.\n";
+      std::map<const BasicBlock *, unsigned>::const_iterator I =
+        BlockFreqs.find(BB);
+      if (I != BlockFreqs.end())
+        OS << "\t;;; Basic block executed " << I->second << " times.\n";
       else
         OS << "\t;;; Never executed!\n";
     }