Index: include/clang/StaticAnalyzer/Core/PathSensitive/SMTSolver.h
===================================================================
--- include/clang/StaticAnalyzer/Core/PathSensitive/SMTSolver.h
+++ include/clang/StaticAnalyzer/Core/PathSensitive/SMTSolver.h
@@ -931,7 +931,8 @@
   virtual SMTExprRef getFloatRoundingMode() = 0;
 
   // If the a model is available, returns the value of a given bitvector symbol
-  virtual const llvm::APSInt getBitvector(const SMTExprRef &Exp) = 0;
+  virtual llvm::APSInt getBitvector(const SMTExprRef &Exp, unsigned BitWidth,
+                                    bool isUnsigned) = 0;
 
   // If the a model is available, returns the value of a given boolean symbol
   virtual bool getBoolean(const SMTExprRef &Exp) = 0;
Index: lib/StaticAnalyzer/Core/Z3ConstraintManager.cpp
===================================================================
--- lib/StaticAnalyzer/Core/Z3ConstraintManager.cpp
+++ lib/StaticAnalyzer/Core/Z3ConstraintManager.cpp
@@ -734,10 +734,11 @@
                                     toZ3Sort(*Sort).Sort)));
   }
 
-  const llvm::APSInt getBitvector(const SMTExprRef &Exp) override {
-    // FIXME: this returns a string and the bitWidth is overridden
-    return llvm::APSInt(
-        Z3_get_numeral_string(Context.Context, toZ3Expr(*Exp).AST));
+  llvm::APSInt getBitvector(const SMTExprRef &Exp, unsigned BitWidth,
+                            bool isUnsigned) override {
+    return llvm::APSInt(llvm::APInt(
+        BitWidth, Z3_get_numeral_string(Context.Context, toZ3Expr(*Exp).AST),
+        10));
   }
 
   bool getBoolean(const SMTExprRef &Exp) override {
@@ -814,26 +815,14 @@
         return false;
       }
 
-      uint64_t Value[2];
-      // Force cast because Z3 defines __uint64 to be a unsigned long long
-      // type, which isn't compatible with a unsigned long type, even if they
-      // are the same size.
-      Z3_get_numeral_uint64(Context.Context, toZ3Expr(*AST).AST,
-                            reinterpret_cast<__uint64 *>(&Value[0]));
-      if (Sort->getBitvectorSortSize() <= 64) {
-        Int = llvm::APSInt(llvm::APInt(Int.getBitWidth(), Value[0]),
-                           Int.isUnsigned());
-      } else if (Sort->getBitvectorSortSize() == 128) {
-        SMTExprRef ASTHigh = mkBVExtract(127, 64, AST);
-        Z3_get_numeral_uint64(Context.Context, toZ3Expr(*AST).AST,
-                              reinterpret_cast<__uint64 *>(&Value[1]));
-        Int = llvm::APSInt(llvm::APInt(Int.getBitWidth(), Value),
-                           Int.isUnsigned());
-      } else {
-        assert(false && "Bitwidth not supported!");
-        return false;
+      if (Sort->getBitvectorSortSize() <= 64 ||
+          Sort->getBitvectorSortSize() == 128) {
+        Int = getBitvector(AST, Int.getBitWidth(), Int.isUnsigned());
+        return true;
       }
-      return true;
+
+      assert(false && "Bitwidth not supported!");
+      return false;
     }
 
     if (Sort->isBooleanSort()) {