diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index 08a6065..b5fafd6 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -1399,7 +1399,7 @@
             ConstantInt::get(F->getContext(), Res),
             ConstantInt::get(Type::getInt1Ty(F->getContext()), Overflow)
           };
-          return ConstantStruct::get(F->getContext(), Ops, 2, false);
+          return ConstantStruct::get(cast<StructType>(F->getReturnType()), Ops);
         }
         }
       }
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 7b7e785..170ec44 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -1987,8 +1987,8 @@
         ParseToken(lltok::rbrace, "expected end of struct constant"))
       return true;
 
-    ID.ConstantVal = ConstantStruct::get(Context, Elts.data(),
-                                         Elts.size(), false);
+    // FIXME: Get this type from context instead of reconstructing it!
+    ID.ConstantVal = ConstantStruct::getAnon(Context, Elts);
     ID.Kind = ValID::t_Constant;
     return false;
   }
@@ -2007,8 +2007,8 @@
       return true;
 
     if (isPackedStruct) {
-      ID.ConstantVal =
-        ConstantStruct::get(Context, Elts.data(), Elts.size(), true);
+      // FIXME: Get this type from context instead of reconstructing it!
+      ID.ConstantVal = ConstantStruct::getAnon(Context, Elts, true);
       ID.Kind = ValID::t_Constant;
       return false;
     }
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 88c1575..ff67bc9 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -292,11 +292,9 @@
       // Make the new constant.
       Constant *NewC;
       if (ConstantArray *UserCA = dyn_cast<ConstantArray>(UserC)) {
-        NewC = ConstantArray::get(UserCA->getType(), &NewOps[0],
-                                        NewOps.size());
+        NewC = ConstantArray::get(UserCA->getType(), &NewOps[0], NewOps.size());
       } else if (ConstantStruct *UserCS = dyn_cast<ConstantStruct>(UserC)) {
-        NewC = ConstantStruct::get(Context, &NewOps[0], NewOps.size(),
-                                         UserCS->getType()->isPacked());
+        NewC = ConstantStruct::get(UserCS->getType(), NewOps);
       } else if (isa<ConstantVector>(UserC)) {
         NewC = ConstantVector::get(NewOps);
       } else {
diff --git a/lib/CodeGen/ShadowStackGC.cpp b/lib/CodeGen/ShadowStackGC.cpp
index 6ab0cb0..94dc3ed 100644
--- a/lib/CodeGen/ShadowStackGC.cpp
+++ b/lib/CodeGen/ShadowStackGC.cpp
@@ -194,7 +194,7 @@
 
   // Truncate the ShadowStackDescriptor if some metadata is null.
   unsigned NumMeta = 0;
-  SmallVector<Constant*,16> Metadata;
+  SmallVector<Constant*, 16> Metadata;
   for (unsigned I = 0; I != Roots.size(); ++I) {
     Constant *C = cast<Constant>(Roots[I].first->getArgOperand(1));
     if (!C->isNullValue())
@@ -202,19 +202,23 @@
     Metadata.push_back(ConstantExpr::getBitCast(C, VoidPtr));
   }
 
+  const Type *Int32Ty = Type::getInt32Ty(F.getContext());
+  
   Constant *BaseElts[] = {
-    ConstantInt::get(Type::getInt32Ty(F.getContext()), Roots.size(), false),
-    ConstantInt::get(Type::getInt32Ty(F.getContext()), NumMeta, false),
+    ConstantInt::get(Int32Ty, Roots.size(), false),
+    ConstantInt::get(Int32Ty, NumMeta, false),
   };
 
   Constant *DescriptorElts[] = {
-    ConstantStruct::get(F.getContext(), BaseElts, 2, false),
+    ConstantStruct::get(StructType::get(Int32Ty, Int32Ty, NULL), BaseElts),
     ConstantArray::get(ArrayType::get(VoidPtr, NumMeta),
                        Metadata.begin(), NumMeta)
   };
 
-  Constant *FrameMap = ConstantStruct::get(F.getContext(), DescriptorElts, 2,
-                                           false);
+  Constant *FrameMap =
+    ConstantStruct::get(StructType::get(DescriptorElts[0]->getType(),
+                                        DescriptorElts[1]->getType(), NULL),
+                        DescriptorElts);
 
   std::string TypeName("gc_map.");
   TypeName += utostr(NumMeta);
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index cdf7b76..4ac721d 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1999,9 +1999,13 @@
 static GlobalVariable *InstallGlobalCtors(GlobalVariable *GCL,
                                           const std::vector<Function*> &Ctors) {
   // If we made a change, reassemble the initializer list.
-  std::vector<Constant*> CSVals;
-  CSVals.push_back(ConstantInt::get(Type::getInt32Ty(GCL->getContext()),65535));
-  CSVals.push_back(0);
+  Constant *CSVals[2];
+  CSVals[0] = ConstantInt::get(Type::getInt32Ty(GCL->getContext()), 65535);
+  CSVals[1] = 0;
+
+  const StructType *StructTy =
+    cast <StructType>(
+    cast<ArrayType>(GCL->getType()->getElementType())->getElementType());
 
   // Create the new init list.
   std::vector<Constant*> CAList;
@@ -2016,12 +2020,10 @@
       CSVals[0] = ConstantInt::get(Type::getInt32Ty(GCL->getContext()),
                                    0x7fffffff);
     }
-    CAList.push_back(ConstantStruct::get(GCL->getContext(), CSVals, false));
+    CAList.push_back(ConstantStruct::get(StructTy, CSVals));
   }
 
   // Create the array initializer.
-  const Type *StructTy =
-      cast<ArrayType>(GCL->getType()->getElementType())->getElementType();
   Constant *CA = ConstantArray::get(ArrayType::get(StructTy,
                                                    CAList.size()), CAList);
 
@@ -2218,42 +2220,40 @@
     Elts[Idx] = EvaluateStoreInto(Elts[Idx], Val, Addr, OpNo+1);
 
     // Return the modified struct.
-    return ConstantStruct::get(Init->getContext(), &Elts[0], Elts.size(),
-                               STy->isPacked());
-  } else {
-    ConstantInt *CI = cast<ConstantInt>(Addr->getOperand(OpNo));
-    const SequentialType *InitTy = cast<SequentialType>(Init->getType());
-
-    uint64_t NumElts;
-    if (const ArrayType *ATy = dyn_cast<ArrayType>(InitTy))
-      NumElts = ATy->getNumElements();
-    else
-      NumElts = cast<VectorType>(InitTy)->getNumElements();
-
-
-    // Break up the array into elements.
-    if (ConstantArray *CA = dyn_cast<ConstantArray>(Init)) {
-      for (User::op_iterator i = CA->op_begin(), e = CA->op_end(); i != e; ++i)
-        Elts.push_back(cast<Constant>(*i));
-    } else if (ConstantVector *CV = dyn_cast<ConstantVector>(Init)) {
-      for (User::op_iterator i = CV->op_begin(), e = CV->op_end(); i != e; ++i)
-        Elts.push_back(cast<Constant>(*i));
-    } else if (isa<ConstantAggregateZero>(Init)) {
-      Elts.assign(NumElts, Constant::getNullValue(InitTy->getElementType()));
-    } else {
-      assert(isa<UndefValue>(Init) && "This code is out of sync with "
-             " ConstantFoldLoadThroughGEPConstantExpr");
-      Elts.assign(NumElts, UndefValue::get(InitTy->getElementType()));
-    }
-
-    assert(CI->getZExtValue() < NumElts);
-    Elts[CI->getZExtValue()] =
-      EvaluateStoreInto(Elts[CI->getZExtValue()], Val, Addr, OpNo+1);
-
-    if (Init->getType()->isArrayTy())
-      return ConstantArray::get(cast<ArrayType>(InitTy), Elts);
-    return ConstantVector::get(Elts);
+    return ConstantStruct::get(STy, Elts);
   }
+  
+  ConstantInt *CI = cast<ConstantInt>(Addr->getOperand(OpNo));
+  const SequentialType *InitTy = cast<SequentialType>(Init->getType());
+
+  uint64_t NumElts;
+  if (const ArrayType *ATy = dyn_cast<ArrayType>(InitTy))
+    NumElts = ATy->getNumElements();
+  else
+    NumElts = cast<VectorType>(InitTy)->getNumElements();
+
+  // Break up the array into elements.
+  if (ConstantArray *CA = dyn_cast<ConstantArray>(Init)) {
+    for (User::op_iterator i = CA->op_begin(), e = CA->op_end(); i != e; ++i)
+      Elts.push_back(cast<Constant>(*i));
+  } else if (ConstantVector *CV = dyn_cast<ConstantVector>(Init)) {
+    for (User::op_iterator i = CV->op_begin(), e = CV->op_end(); i != e; ++i)
+      Elts.push_back(cast<Constant>(*i));
+  } else if (isa<ConstantAggregateZero>(Init)) {
+    Elts.assign(NumElts, Constant::getNullValue(InitTy->getElementType()));
+  } else {
+    assert(isa<UndefValue>(Init) && "This code is out of sync with "
+           " ConstantFoldLoadThroughGEPConstantExpr");
+    Elts.assign(NumElts, UndefValue::get(InitTy->getElementType()));
+  }
+
+  assert(CI->getZExtValue() < NumElts);
+  Elts[CI->getZExtValue()] =
+    EvaluateStoreInto(Elts[CI->getZExtValue()], Val, Addr, OpNo+1);
+
+  if (Init->getType()->isArrayTy())
+    return ConstantArray::get(cast<ArrayType>(InitTy), Elts);
+  return ConstantVector::get(Elts);
 }
 
 /// CommitValueTo - We have decided that Addr (which satisfies the predicate
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index ef67701..455cd0a 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -412,7 +412,8 @@
           UndefValue::get(LHS->getType()),
           ConstantInt::getTrue(II->getContext())
         };
-        Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
+        const StructType *ST = cast<StructType>(II->getType());
+        Constant *Struct = ConstantStruct::get(ST, V);
         return InsertValueInst::Create(Struct, Add, 0);
       }
 
@@ -425,7 +426,8 @@
           UndefValue::get(LHS->getType()),
           ConstantInt::getFalse(II->getContext())
         };
-        Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
+        const StructType *ST = cast<StructType>(II->getType());
+        Constant *Struct = ConstantStruct::get(ST, V);
         return InsertValueInst::Create(Struct, Add, 0);
       }
     }
@@ -452,7 +454,8 @@
           UndefValue::get(II->getArgOperand(0)->getType()),
           ConstantInt::getFalse(II->getContext())
         };
-        Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
+        Constant *Struct =
+          ConstantStruct::get(cast<StructType>(II->getType()), V);
         return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
       }
     }
@@ -472,7 +475,8 @@
           UndefValue::get(II->getArgOperand(0)->getType()),
           ConstantInt::getFalse(II->getContext())
         };
-        Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
+        Constant *Struct = 
+          ConstantStruct::get(cast<StructType>(II->getType()), V);
         return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
       }
     }
@@ -503,7 +507,7 @@
         UndefValue::get(LHS->getType()),
         Builder->getFalse()
       };
-      Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
+      Constant *Struct = ConstantStruct::get(cast<StructType>(II->getType()),V);
       return InsertValueInst::Create(Struct, Mul, 0);
     }
   } // FALL THROUGH
@@ -532,7 +536,8 @@
           UndefValue::get(II->getArgOperand(0)->getType()),
           ConstantInt::getFalse(II->getContext())
         };
-        Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false);
+        Constant *Struct = 
+          ConstantStruct::get(cast<StructType>(II->getType()), V);
         return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
       }
     }
diff --git a/lib/Transforms/Instrumentation/ProfilingUtils.cpp b/lib/Transforms/Instrumentation/ProfilingUtils.cpp
index 7435bc3..4224ee3 100644
--- a/lib/Transforms/Instrumentation/ProfilingUtils.cpp
+++ b/lib/Transforms/Instrumentation/ProfilingUtils.cpp
@@ -164,7 +164,8 @@
   GlobalVariable *GlobalDtors = new GlobalVariable(
       *Mod, ArrayType::get(GlobalDtorElemTy, 1), false,
       GlobalValue::AppendingLinkage, NULL, "llvm.global_dtors");
-  dtors.push_back(ConstantStruct::get(Mod->getContext(), Elem, 2, false));
+                                    
+  dtors.push_back(ConstantStruct::get(GlobalDtorElemTy, Elem));
   GlobalDtors->setInitializer(ConstantArray::get(
       cast<ArrayType>(GlobalDtors->getType()->getElementType()), dtors));
 }
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 9985ada..e5ab15d 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -942,7 +942,7 @@
     }
     
     if (const StructType* ST = dyn_cast<StructType>(AggTy))
-      return ConstantStruct::get(ST->getContext(), Ops, ST->isPacked());
+      return ConstantStruct::get(ST, Ops);
     return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
   }
   
@@ -973,7 +973,7 @@
     }
     
     if (const StructType *ST = dyn_cast<StructType>(AggTy))
-      return ConstantStruct::get(ST->getContext(), Ops, ST->isPacked());
+      return ConstantStruct::get(ST, Ops);
     return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
   }
   
@@ -988,7 +988,7 @@
     }
     
     if (const StructType* ST = dyn_cast<StructType>(Agg->getType()))
-      return ConstantStruct::get(ST->getContext(), Ops, ST->isPacked());
+      return ConstantStruct::get(ST, Ops);
     return ConstantArray::get(cast<ArrayType>(Agg->getType()), Ops);
   }
 
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 0cf6c4e..22d43a7 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -621,6 +621,27 @@
   return get(ATy, ElementVals);
 }
 
+/// getTypeForElements - Return an anonymous struct type to use for a constant
+/// with the specified set of elements.  The list must not be empty.
+StructType *ConstantStruct::getTypeForElements(LLVMContext &Context,
+                                               ArrayRef<Constant*> V,
+                                               bool Packed) {
+  SmallVector<const Type*, 16> EltTypes;
+  for (unsigned i = 0, e = V.size(); i != e; ++i)
+    EltTypes.push_back(V[i]->getType());
+  
+  return StructType::get(Context, EltTypes, Packed);
+}
+
+
+StructType *ConstantStruct::getTypeForElements(ArrayRef<Constant*> V,
+                                               bool Packed) {
+  assert(!V.empty() &&
+         "ConstantStruct::getTypeForElements cannot be called on empty list");
+  return getTypeForElements(V[0]->getContext(), V, Packed);
+}
+
+
 ConstantStruct::ConstantStruct(const StructType *T,
                                const std::vector<Constant*> &V)
   : Constant(T, ConstantStructVal,
@@ -639,45 +660,28 @@
 }
 
 // ConstantStruct accessors.
-Constant *ConstantStruct::get(const StructType* T,
-                              const std::vector<Constant*>& V) {
-  LLVMContextImpl* pImpl = T->getContext().pImpl;
+Constant *ConstantStruct::get(const StructType *ST, ArrayRef<Constant*> V) {
+  assert(ST->getNumElements() == V.size() &&
+         "Incorrect # elements specified to ConstantStruct::get");
   
-  // Create a ConstantAggregateZero value if all elements are zeros...
+  // Create a ConstantAggregateZero value if all elements are zeros.
   for (unsigned i = 0, e = V.size(); i != e; ++i)
-    if (!V[i]->isNullValue())
-      return pImpl->StructConstants.getOrCreate(T, V);
+    if (!V[i]->isNullValue()) {
+      // FIXME: Eliminate temporary std::vector here!
+      return ST->getContext().pImpl->StructConstants.getOrCreate(ST, V.vec());
+    }
 
-  return ConstantAggregateZero::get(T);
+  return ConstantAggregateZero::get(ST);
 }
 
-Constant *ConstantStruct::get(LLVMContext &Context,
-                              const std::vector<Constant*>& V, bool packed) {
-  std::vector<const Type*> StructEls;
-  StructEls.reserve(V.size());
-  for (unsigned i = 0, e = V.size(); i != e; ++i)
-    StructEls.push_back(V[i]->getType());
-  return get(StructType::get(Context, StructEls, packed), V);
-}
-
-Constant *ConstantStruct::get(LLVMContext &Context,
-                              Constant *const *Vals, unsigned NumVals,
-                              bool Packed) {
-  // FIXME: make this the primary ctor method.
-  return get(Context, std::vector<Constant*>(Vals, Vals+NumVals), Packed);
-}
-
-Constant* ConstantStruct::get(LLVMContext &Context, bool Packed,
-                              Constant * Val, ...) {
+Constant* ConstantStruct::get(const StructType *T, ...) {
   va_list ap;
-  std::vector<Constant*> Values;
-  va_start(ap, Val);
-  while (Val) {
+  SmallVector<Constant*, 8> Values;
+  va_start(ap, T);
+  while (Constant *Val = va_arg(ap, llvm::Constant*))
     Values.push_back(Val);
-    Val = va_arg(ap, llvm::Constant*);
-  }
   va_end(ap);
-  return get(Context, Values, Packed);
+  return get(T, Values);
 }
 
 ConstantVector::ConstantVector(const VectorType *T,
diff --git a/lib/VMCore/Core.cpp b/lib/VMCore/Core.cpp
index 92f9440..16ccc7b 100644
--- a/lib/VMCore/Core.cpp
+++ b/lib/VMCore/Core.cpp
@@ -612,9 +612,10 @@
 LLVMValueRef LLVMConstStructInContext(LLVMContextRef C, 
                                       LLVMValueRef *ConstantVals,
                                       unsigned Count, LLVMBool Packed) {
-  return wrap(ConstantStruct::get(*unwrap(C),
-                                  unwrap<Constant>(ConstantVals, Count),
-                                  Count, Packed != 0));
+  Constant **Elements = unwrap<Constant>(ConstantVals, Count);
+  return wrap(ConstantStruct::getAnon(*unwrap(C),
+                                      ArrayRef<Constant*>(Elements, Count),
+                                      Packed != 0));
 }
 
 LLVMValueRef LLVMConstString(const char *Str, unsigned Length,