diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 3ec4efe..f7179be 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -548,11 +548,10 @@
       
   case Builtin::BI__builtin___memcpy_chk: {
     // fold __builtin_memcpy_chk(x, y, cst1, cst2) to memset iff cst1<=cst2.
-    if (!E->getArg(2)->isEvaluatable(CGM.getContext()) ||
-        !E->getArg(3)->isEvaluatable(CGM.getContext()))
+    llvm::APSInt Size, DstSize;
+    if (!E->getArg(2)->EvaluateAsInt(Size, CGM.getContext()) ||
+        !E->getArg(3)->EvaluateAsInt(DstSize, CGM.getContext()))
       break;
-    llvm::APSInt Size = E->getArg(2)->EvaluateAsInt(CGM.getContext());
-    llvm::APSInt DstSize = E->getArg(3)->EvaluateAsInt(CGM.getContext());
     if (Size.ugt(DstSize))
       break;
     Value *Dest = EmitScalarExpr(E->getArg(0));
@@ -573,11 +572,10 @@
 
   case Builtin::BI__builtin___memmove_chk: {
     // fold __builtin_memmove_chk(x, y, cst1, cst2) to memset iff cst1<=cst2.
-    if (!E->getArg(2)->isEvaluatable(CGM.getContext()) ||
-        !E->getArg(3)->isEvaluatable(CGM.getContext()))
+    llvm::APSInt Size, DstSize;
+    if (!E->getArg(2)->EvaluateAsInt(Size, CGM.getContext()) ||
+        !E->getArg(3)->EvaluateAsInt(DstSize, CGM.getContext()))
       break;
-    llvm::APSInt Size = E->getArg(2)->EvaluateAsInt(CGM.getContext());
-    llvm::APSInt DstSize = E->getArg(3)->EvaluateAsInt(CGM.getContext());
     if (Size.ugt(DstSize))
       break;
     Value *Dest = EmitScalarExpr(E->getArg(0));
@@ -606,11 +604,10 @@
   }
   case Builtin::BI__builtin___memset_chk: {
     // fold __builtin_memset_chk(x, y, cst1, cst2) to memset iff cst1<=cst2.
-    if (!E->getArg(2)->isEvaluatable(CGM.getContext()) ||
-        !E->getArg(3)->isEvaluatable(CGM.getContext()))
+    llvm::APSInt Size, DstSize;
+    if (!E->getArg(2)->EvaluateAsInt(Size, CGM.getContext()) ||
+        !E->getArg(3)->EvaluateAsInt(DstSize, CGM.getContext()))
       break;
-    llvm::APSInt Size = E->getArg(2)->EvaluateAsInt(CGM.getContext());
-    llvm::APSInt DstSize = E->getArg(3)->EvaluateAsInt(CGM.getContext());
     if (Size.ugt(DstSize))
       break;
     Value *Address = EmitScalarExpr(E->getArg(0));
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index eda7325..313c02d 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -603,7 +603,7 @@
 
 llvm::DIType CGDebugInfo::createFieldType(StringRef name,
                                           QualType type,
-                                          Expr *bitWidth,
+                                          uint64_t sizeInBitsOverride,
                                           SourceLocation loc,
                                           AccessSpecifier AS,
                                           uint64_t offsetInBits,
@@ -620,8 +620,8 @@
   if (!type->isIncompleteArrayType()) {
     llvm::tie(sizeInBits, alignInBits) = CGM.getContext().getTypeInfo(type);
 
-    if (bitWidth)
-      sizeInBits = bitWidth->EvaluateAsInt(CGM.getContext()).getZExtValue();
+    if (sizeInBitsOverride)
+      sizeInBits = sizeInBitsOverride;
   }
 
   unsigned flags = 0;
@@ -667,8 +667,14 @@
       continue;
     }
 
+    uint64_t SizeInBitsOverride = 0;
+    if (field->isBitField()) {
+      SizeInBitsOverride = field->getBitWidthValue(CGM.getContext());
+      assert(SizeInBitsOverride && "found named 0-width bitfield");
+    }
+
     llvm::DIType fieldType
-      = createFieldType(name, type, field->getBitWidth(),
+      = createFieldType(name, type, SizeInBitsOverride,
                         field->getLocation(), field->getAccess(),
                         layout.getFieldOffset(fieldNo), tunit, RecordTy);
 
@@ -1215,12 +1221,10 @@
     if (!FType->isIncompleteArrayType()) {
 
       // Bit size, align and offset of the type.
-      FieldSize = CGM.getContext().getTypeSize(FType);
-      Expr *BitWidth = Field->getBitWidth();
-      if (BitWidth)
-        FieldSize = BitWidth->EvaluateAsInt(CGM.getContext()).getZExtValue();
-
-      FieldAlign =  CGM.getContext().getTypeAlign(FType);
+      FieldSize = Field->isBitField()
+        ? Field->getBitWidthValue(CGM.getContext())
+        : CGM.getContext().getTypeSize(FType);
+      FieldAlign = CGM.getContext().getTypeAlign(FType);
     }
 
     // We can't know the offset of our ivar in the structure if we're using
diff --git a/lib/CodeGen/CGDebugInfo.h b/lib/CodeGen/CGDebugInfo.h
index 68b3985..e6c701a 100644
--- a/lib/CodeGen/CGDebugInfo.h
+++ b/lib/CodeGen/CGDebugInfo.h
@@ -139,7 +139,7 @@
                            llvm::DIFile F);
 
   llvm::DIType createFieldType(StringRef name, QualType type,
-                               Expr *bitWidth, SourceLocation loc,
+                               uint64_t sizeInBitsOverride, SourceLocation loc,
                                AccessSpecifier AS, uint64_t offsetInBits,
                                llvm::DIFile tunit,
                                llvm::DIDescriptor scope);
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index 1176eb1..30c978e 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -143,8 +143,7 @@
     AppendPadding(PadSize);
   }
 
-  uint64_t FieldSize =
-    Field->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
+  uint64_t FieldSize = Field->getBitWidthValue(Context);
 
   llvm::APInt FieldValue = CI->getValue();
 
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 1b317c4..308e0c7 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -3710,9 +3710,8 @@
   if (LastFieldBitfieldOrUnnamed) {
     if (LastFieldBitfieldOrUnnamed->isBitField()) {
       // Last field was a bitfield. Must update skip info.
-      Expr *BitWidth = LastFieldBitfieldOrUnnamed->getBitWidth();
-      uint64_t BitFieldSize =
-        BitWidth->EvaluateAsInt(CGM.getContext()).getZExtValue();
+      uint64_t BitFieldSize
+          = LastFieldBitfieldOrUnnamed->getBitWidthValue(CGM.getContext());
       GC_IVAR skivar;
       skivar.ivar_bytepos = BytePos + LastBitfieldOrUnnamedOffset;
       skivar.ivar_size = (BitFieldSize / ByteSizeInBits)
diff --git a/lib/CodeGen/CGObjCRuntime.cpp b/lib/CodeGen/CGObjCRuntime.cpp
index f1e49ac..ef426ce 100644
--- a/lib/CodeGen/CGObjCRuntime.cpp
+++ b/lib/CodeGen/CGObjCRuntime.cpp
@@ -119,8 +119,7 @@
   uint64_t BitOffset = FieldBitOffset % CGF.CGM.getContext().getCharWidth();
   uint64_t ContainingTypeAlign = CGF.CGM.getContext().getTargetInfo().getCharAlign();
   uint64_t ContainingTypeSize = TypeSizeInBits - (FieldBitOffset - BitOffset);
-  uint64_t BitFieldSize =
-    Ivar->getBitWidth()->EvaluateAsInt(CGF.getContext()).getZExtValue();
+  uint64_t BitFieldSize = Ivar->getBitWidthValue(CGF.getContext());
 
   // Allocate a new CGBitFieldInfo object to describe this access.
   //
diff --git a/lib/CodeGen/CGRecordLayoutBuilder.cpp b/lib/CodeGen/CGRecordLayoutBuilder.cpp
index d55ea51..6475cca 100644
--- a/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -363,8 +363,7 @@
 
 void CGRecordLayoutBuilder::LayoutBitField(const FieldDecl *D,
                                            uint64_t fieldOffset) {
-  uint64_t fieldSize =
-    D->getBitWidth()->EvaluateAsInt(Types.getContext()).getZExtValue();
+  uint64_t fieldSize = D->getBitWidthValue(Types.getContext());
 
   if (fieldSize == 0)
     return;
@@ -492,8 +491,7 @@
 CGRecordLayoutBuilder::LayoutUnionField(const FieldDecl *Field,
                                         const ASTRecordLayout &Layout) {
   if (Field->isBitField()) {
-    uint64_t FieldSize =
-      Field->getBitWidth()->EvaluateAsInt(Types.getContext()).getZExtValue();
+    uint64_t FieldSize = Field->getBitWidthValue(Types.getContext());
 
     // Ignore zero sized bit fields.
     if (FieldSize == 0)
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index ec876a4..06a045f 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -834,8 +834,8 @@
 void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S) {
   assert(S.getRHS() && "Expected RHS value in CaseStmt");
 
-  llvm::APSInt LHS = S.getLHS()->EvaluateAsInt(getContext());
-  llvm::APSInt RHS = S.getRHS()->EvaluateAsInt(getContext());
+  llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext());
+  llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext());
 
   // Emit the code for this case. We do this first to make sure it is
   // properly chained from our predecessor before generating the
@@ -894,7 +894,7 @@
   }
 
   llvm::ConstantInt *CaseVal =
-    Builder.getInt(S.getLHS()->EvaluateAsInt(getContext()));
+    Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext()));
 
   // If the body of the case is just a 'break', and if there was no fallthrough,
   // try to not emit an empty block.
@@ -935,7 +935,7 @@
   while (NextCase && NextCase->getRHS() == 0) {
     CurCase = NextCase;
     llvm::ConstantInt *CaseVal = 
-      Builder.getInt(CurCase->getLHS()->EvaluateAsInt(getContext()));
+      Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext()));
     SwitchInsn->addCase(CaseVal, CaseDest);
     NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());
   }
@@ -1125,7 +1125,7 @@
     if (CS->getRHS()) return false;
     
     // If we found our case, remember it as 'case'.
-    if (CS->getLHS()->EvaluateAsInt(C) == ConstantCondValue)
+    if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue)
       break;
   }
   
diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index ce729ce..97f9b71 100644
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -1337,8 +1337,7 @@
           continue;
 
         uint64_t Offset = OffsetBase + Layout.getFieldOffset(idx);
-        uint64_t Size =
-          i->getBitWidth()->EvaluateAsInt(getContext()).getZExtValue();
+        uint64_t Size = i->getBitWidthValue(getContext());
 
         uint64_t EB_Lo = Offset / 64;
         uint64_t EB_Hi = (Offset + Size - 1) / 64;