diff --git a/include/llvm/IR/Attributes.h b/include/llvm/IR/Attributes.h
index c49e19af78e..adcb7266073 100644
--- a/include/llvm/IR/Attributes.h
+++ b/include/llvm/IR/Attributes.h
@@ -285,7 +285,8 @@ class AttributeList {
 public:
   enum AttrIndex : unsigned {
     ReturnIndex = 0U,
-    FunctionIndex = ~0U
+    FunctionIndex = ~0U,
+    FirstArgIndex = 1,
   };
 
 private:
@@ -336,6 +337,13 @@ public:
   static AttributeList get(LLVMContext &C, unsigned Index,
                            const AttrBuilder &B);
 
+  /// Add an argument attribute to the list. Returns a new list because
+  /// attribute lists are immutable.
+  AttributeList addParamAttribute(LLVMContext &C, unsigned ArgNo,
+                                  Attribute::AttrKind Kind) const {
+    return addAttribute(C, ArgNo + FirstArgIndex, Kind);
+  }
+
   /// \brief Add an attribute to the attribute set at the given index. Because
   /// attribute sets are immutable, this returns a new set.
   AttributeList addAttribute(LLVMContext &C, unsigned Index,
@@ -433,7 +441,7 @@ public:
   /// may be faster.
   bool hasFnAttribute(StringRef Kind) const;
 
-  /// \brief Equivalent to hasAttribute(ArgNo + 1, Kind).
+  /// \brief Equivalent to hasAttribute(ArgNo + FirstArgIndex, Kind).
   bool hasParamAttribute(unsigned ArgNo, Attribute::AttrKind Kind) const;
 
   /// \brief Return true if the specified attribute is set for at least one
diff --git a/include/llvm/IR/CallSite.h b/include/llvm/IR/CallSite.h
index bad1d4e383d..d61431a51a9 100644
--- a/include/llvm/IR/CallSite.h
+++ b/include/llvm/IR/CallSite.h
@@ -339,6 +339,10 @@ public:
     CALLSITE_DELEGATE_SETTER(addAttribute(i, Attr));
   }
 
+  void addParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+    CALLSITE_DELEGATE_SETTER(addParamAttr(ArgNo, Kind));
+  }
+
   void removeAttribute(unsigned i, Attribute::AttrKind Kind) {
     CALLSITE_DELEGATE_SETTER(removeAttribute(i, Kind));
   }
@@ -347,6 +351,10 @@ public:
     CALLSITE_DELEGATE_SETTER(removeAttribute(i, Kind));
   }
 
+  void removeParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+    CALLSITE_DELEGATE_SETTER(removeParamAttr(ArgNo, Kind));
+  }
+
   /// Return true if this function has the given attribute.
   bool hasFnAttr(Attribute::AttrKind Kind) const {
     CALLSITE_DELEGATE_GETTER(hasFnAttr(Kind));
@@ -408,11 +416,9 @@ public:
     CALLSITE_DELEGATE_GETTER(getDereferenceableOrNullBytes(i));
   }
 
-  /// Determine if the parameter or return value is marked with NoAlias
-  /// attribute.
-  /// @param n The parameter to check. 1 is the first parameter, 0 is the return
-  bool doesNotAlias(unsigned n) const {
-    CALLSITE_DELEGATE_GETTER(doesNotAlias(n));
+  /// Determine if the return value is marked with NoAlias attribute.
+  bool returnDoesNotAlias() const {
+    CALLSITE_DELEGATE_GETTER(returnDoesNotAlias());
   }
 
   /// Return true if the call should not be treated as a call to a builtin.
diff --git a/include/llvm/IR/Function.h b/include/llvm/IR/Function.h
index 8cda785ef20..f9582f51ca8 100644
--- a/include/llvm/IR/Function.h
+++ b/include/llvm/IR/Function.h
@@ -204,6 +204,10 @@ public:
     addAttribute(AttributeList::FunctionIndex, Attr);
   }
 
+  void addParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+    addAttribute(ArgNo + AttributeList::FirstArgIndex, Kind);
+  }
+
   /// @brief Remove function attributes from this function.
   void removeFnAttr(Attribute::AttrKind Kind) {
     removeAttribute(AttributeList::FunctionIndex, Kind);
@@ -211,10 +215,14 @@ public:
 
   /// @brief Remove function attribute from this function.
   void removeFnAttr(StringRef Kind) {
-    setAttributes(AttributeSets.removeAttribute(
+    setAttributes(getAttributes().removeAttribute(
         getContext(), AttributeList::FunctionIndex, Kind));
   }
 
+  void removeParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+    removeAttribute(ArgNo + AttributeList::FirstArgIndex, Kind);
+  }
+
   /// \brief Set the entry count for this function.
   ///
   /// Entry count is the number of times this function was executed based on
@@ -459,35 +467,12 @@ public:
   /// @brief Determine if the parameter or return value is marked with NoAlias
   /// attribute.
   /// @param n The parameter to check. 1 is the first parameter, 0 is the return
-  bool doesNotAlias(unsigned n) const {
-    return AttributeSets.hasAttribute(n, Attribute::NoAlias);
+  bool returnDoesNotAlias() const {
+    return AttributeSets.hasAttribute(AttributeList::ReturnIndex,
+                                      Attribute::NoAlias);
   }
-  void setDoesNotAlias(unsigned n) {
-    addAttribute(n, Attribute::NoAlias);
-  }
-
-  /// @brief Determine if the parameter can be captured.
-  /// @param n The parameter to check. 1 is the first parameter, 0 is the return
-  bool doesNotCapture(unsigned n) const {
-    return AttributeSets.hasAttribute(n, Attribute::NoCapture);
-  }
-  void setDoesNotCapture(unsigned n) {
-    addAttribute(n, Attribute::NoCapture);
-  }
-
-  bool doesNotAccessMemory(unsigned n) const {
-    return AttributeSets.hasAttribute(n, Attribute::ReadNone);
-  }
-  void setDoesNotAccessMemory(unsigned n) {
-    addAttribute(n, Attribute::ReadNone);
-  }
-
-  bool onlyReadsMemory(unsigned n) const {
-    return doesNotAccessMemory(n) ||
-      AttributeSets.hasAttribute(n, Attribute::ReadOnly);
-  }
-  void setOnlyReadsMemory(unsigned n) {
-    addAttribute(n, Attribute::ReadOnly);
+  void setReturnDoesNotAlias() {
+    addAttribute(AttributeList::ReturnIndex, Attribute::NoAlias);
   }
 
   /// Optimize this function for minimum size (-Oz).
diff --git a/include/llvm/IR/Instructions.h b/include/llvm/IR/Instructions.h
index 4d3f1dc267f..844a7273eca 100644
--- a/include/llvm/IR/Instructions.h
+++ b/include/llvm/IR/Instructions.h
@@ -1658,12 +1658,18 @@ public:
   /// adds the attribute to the list of attributes.
   void addAttribute(unsigned i, Attribute Attr);
 
+  /// Adds the attribute to the indicated argument
+  void addParamAttr(unsigned ArgNo, Attribute::AttrKind Kind);
+
   /// removes the attribute from the list of attributes.
   void removeAttribute(unsigned i, Attribute::AttrKind Kind);
 
   /// removes the attribute from the list of attributes.
   void removeAttribute(unsigned i, StringRef Kind);
 
+  /// Removes the attribute from the given argument
+  void removeParamAttr(unsigned ArgNo, Attribute::AttrKind Kind);
+
   /// adds the dereferenceable attribute to the list of attributes.
   void addDereferenceableAttr(unsigned i, uint64_t Bytes);
 
@@ -1734,11 +1740,9 @@ public:
     return Attrs.getDereferenceableOrNullBytes(i);
   }
 
-  /// @brief Determine if the parameter or return value is marked with NoAlias
-  /// attribute.
-  /// @param n The parameter to check. 1 is the first parameter, 0 is the return
-  bool doesNotAlias(unsigned n) const {
-    return Attrs.hasAttribute(n, Attribute::NoAlias);
+  /// @brief Determine if the return value is marked with NoAlias attribute.
+  bool returnDoesNotAlias() const {
+    return Attrs.hasAttribute(AttributeList::ReturnIndex, Attribute::NoAlias);
   }
 
   /// Return true if the call should not be treated as a call to a
@@ -3750,12 +3754,18 @@ public:
   /// adds the attribute to the list of attributes.
   void addAttribute(unsigned i, Attribute Attr);
 
+  /// Adds the attribute to the indicated argument
+  void addParamAttr(unsigned ArgNo, Attribute::AttrKind Kind);
+
   /// removes the attribute from the list of attributes.
   void removeAttribute(unsigned i, Attribute::AttrKind Kind);
 
   /// removes the attribute from the list of attributes.
   void removeAttribute(unsigned i, StringRef Kind);
 
+  /// Removes the attribute from the given argument
+  void removeParamAttr(unsigned ArgNo, Attribute::AttrKind Kind);
+
   /// adds the dereferenceable attribute to the list of attributes.
   void addDereferenceableAttr(unsigned i, uint64_t Bytes);
 
@@ -3827,11 +3837,9 @@ public:
     return Attrs.getDereferenceableOrNullBytes(i);
   }
 
-  /// @brief Determine if the parameter or return value is marked with NoAlias
-  /// attribute.
-  /// @param n The parameter to check. 1 is the first parameter, 0 is the return
-  bool doesNotAlias(unsigned n) const {
-    return Attrs.hasAttribute(n, Attribute::NoAlias);
+  /// @brief Determine if the return value is marked with NoAlias attribute.
+  bool returnDoesNotAlias() const {
+    return Attrs.hasAttribute(AttributeList::ReturnIndex, Attribute::NoAlias);
   }
 
   /// Return true if the call should not be treated as a call to a
diff --git a/lib/Analysis/CFLGraph.h b/lib/Analysis/CFLGraph.h
index 06410bf01dd..a8fb12b7256 100644
--- a/lib/Analysis/CFLGraph.h
+++ b/lib/Analysis/CFLGraph.h
@@ -429,7 +429,7 @@ template <typename CFLAA> class CFLGraphBuilder {
 
       if (Inst->getType()->isPointerTy()) {
         auto *Fn = CS.getCalledFunction();
-        if (Fn == nullptr || !Fn->doesNotAlias(AttributeList::ReturnIndex))
+        if (Fn == nullptr || !Fn->returnDoesNotAlias())
           // No need to call addNode() since we've added Inst at the
           // beginning of this function and we know it is not a global.
           Graph.addAttr(InstantiatedValue{Inst, 0}, getAttrUnknown());
diff --git a/lib/CodeGen/GlobalISel/CallLowering.cpp b/lib/CodeGen/GlobalISel/CallLowering.cpp
index 47433eb126d..be0c5c2bb70 100644
--- a/lib/CodeGen/GlobalISel/CallLowering.cpp
+++ b/lib/CodeGen/GlobalISel/CallLowering.cpp
@@ -37,7 +37,7 @@ bool CallLowering::lowerCall(
   for (auto &Arg : CS.args()) {
     ArgInfo OrigArg{ArgRegs[i], Arg->getType(), ISD::ArgFlagsTy{},
                     i < NumFixedArgs};
-    setArgFlags(OrigArg, i + 1, DL, CS);
+    setArgFlags(OrigArg, i + AttributeList::FirstArgIndex, DL, CS);
     OrigArgs.push_back(OrigArg);
     ++i;
   }
diff --git a/lib/IR/Attributes.cpp b/lib/IR/Attributes.cpp
index 3d08ecdd484..3b1140ab542 100644
--- a/lib/IR/Attributes.cpp
+++ b/lib/IR/Attributes.cpp
@@ -1123,7 +1123,7 @@ AttributeList::addAllocSizeAttr(LLVMContext &C, unsigned Index,
 LLVMContext &AttributeList::getContext() const { return pImpl->getContext(); }
 
 AttributeSet AttributeList::getParamAttributes(unsigned ArgNo) const {
-  return getAttributes(ArgNo + 1);
+  return getAttributes(ArgNo + FirstArgIndex);
 }
 
 AttributeSet AttributeList::getRetAttributes() const {
@@ -1189,7 +1189,7 @@ unsigned AttributeList::getRetAlignment() const {
 }
 
 unsigned AttributeList::getParamAlignment(unsigned ArgNo) const {
-  return getAttributes(ArgNo + 1).getAlignment();
+  return getAttributes(ArgNo + FirstArgIndex).getAlignment();
 }
 
 unsigned AttributeList::getStackAlignment(unsigned Index) const {
diff --git a/lib/IR/Function.cpp b/lib/IR/Function.cpp
index 5d3df920be8..58c06055032 100644
--- a/lib/IR/Function.cpp
+++ b/lib/IR/Function.cpp
@@ -90,13 +90,15 @@ unsigned Argument::getParamAlignment() const {
 uint64_t Argument::getDereferenceableBytes() const {
   assert(getType()->isPointerTy() &&
          "Only pointers have dereferenceable bytes");
-  return getParent()->getDereferenceableBytes(getArgNo()+1);
+  return getParent()->getDereferenceableBytes(getArgNo() +
+                                              AttributeList::FirstArgIndex);
 }
 
 uint64_t Argument::getDereferenceableOrNullBytes() const {
   assert(getType()->isPointerTy() &&
          "Only pointers have dereferenceable bytes");
-  return getParent()->getDereferenceableOrNullBytes(getArgNo()+1);
+  return getParent()->getDereferenceableOrNullBytes(
+      getArgNo() + AttributeList::FirstArgIndex);
 }
 
 bool Argument::hasNestAttr() const {
@@ -139,20 +141,21 @@ bool Argument::onlyReadsMemory() const {
 
 void Argument::addAttrs(AttrBuilder &B) {
   AttributeList AL = getParent()->getAttributes();
-  AL = AL.addAttributes(Parent->getContext(), getArgNo() + 1, B);
+  AL = AL.addAttributes(Parent->getContext(),
+                        getArgNo() + AttributeList::FirstArgIndex, B);
   getParent()->setAttributes(AL);
 }
 
 void Argument::addAttr(Attribute::AttrKind Kind) {
-  getParent()->addAttribute(getArgNo() + 1, Kind);
+  getParent()->addAttribute(getArgNo() + AttributeList::FirstArgIndex, Kind);
 }
 
 void Argument::addAttr(Attribute Attr) {
-  getParent()->addAttribute(getArgNo() + 1, Attr);
+  getParent()->addAttribute(getArgNo() + AttributeList::FirstArgIndex, Attr);
 }
 
 void Argument::removeAttr(Attribute::AttrKind Kind) {
-  getParent()->removeAttribute(getArgNo() + 1, Kind);
+  getParent()->removeAttribute(getArgNo() + AttributeList::FirstArgIndex, Kind);
 }
 
 bool Argument::hasAttribute(Attribute::AttrKind Kind) const {
diff --git a/lib/IR/Instructions.cpp b/lib/IR/Instructions.cpp
index 59500992abb..a60cc375d56 100644
--- a/lib/IR/Instructions.cpp
+++ b/lib/IR/Instructions.cpp
@@ -335,12 +335,12 @@ Value *CallInst::getReturnedArgOperand() const {
   unsigned Index;
 
   if (Attrs.hasAttrSomewhere(Attribute::Returned, &Index) && Index)
-    return getArgOperand(Index-1);
+    return getArgOperand(Index - AttributeList::FirstArgIndex);
   if (const Function *F = getCalledFunction())
     if (F->getAttributes().hasAttrSomewhere(Attribute::Returned, &Index) &&
         Index)
-      return getArgOperand(Index-1);
-      
+      return getArgOperand(Index - AttributeList::FirstArgIndex);
+
   return nullptr;
 }
 
@@ -356,6 +356,10 @@ void CallInst::addAttribute(unsigned i, Attribute Attr) {
   setAttributes(PAL);
 }
 
+void CallInst::addParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+  addAttribute(ArgNo + AttributeList::FirstArgIndex, Kind);
+}
+
 void CallInst::removeAttribute(unsigned i, Attribute::AttrKind Kind) {
   AttributeList PAL = getAttributes();
   PAL = PAL.removeAttribute(getContext(), i, Kind);
@@ -368,6 +372,10 @@ void CallInst::removeAttribute(unsigned i, StringRef Kind) {
   setAttributes(PAL);
 }
 
+void CallInst::removeParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+  removeAttribute(ArgNo + AttributeList::FirstArgIndex, Kind);
+}
+
 void CallInst::addDereferenceableAttr(unsigned i, uint64_t Bytes) {
   AttributeList PAL = getAttributes();
   PAL = PAL.addDereferenceableAttr(getContext(), i, Bytes);
@@ -501,8 +509,8 @@ static Instruction *createMalloc(Instruction *InsertBefore,
   MCall->setTailCall();
   if (Function *F = dyn_cast<Function>(MallocFunc)) {
     MCall->setCallingConv(F->getCallingConv());
-    if (!F->doesNotAlias(AttributeList::ReturnIndex))
-      F->setDoesNotAlias(AttributeList::ReturnIndex);
+    if (!F->returnDoesNotAlias())
+      F->setReturnDoesNotAlias();
   }
   assert(!MCall->getType()->isVoidTy() && "Malloc has void return type");
 
@@ -695,12 +703,12 @@ Value *InvokeInst::getReturnedArgOperand() const {
   unsigned Index;
 
   if (Attrs.hasAttrSomewhere(Attribute::Returned, &Index) && Index)
-    return getArgOperand(Index-1);
+    return getArgOperand(Index - AttributeList::FirstArgIndex);
   if (const Function *F = getCalledFunction())
     if (F->getAttributes().hasAttrSomewhere(Attribute::Returned, &Index) &&
         Index)
-      return getArgOperand(Index-1);
-      
+      return getArgOperand(Index - AttributeList::FirstArgIndex);
+
   return nullptr;
 }
 
@@ -756,6 +764,10 @@ void InvokeInst::addAttribute(unsigned i, Attribute Attr) {
   setAttributes(PAL);
 }
 
+void InvokeInst::addParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+  addAttribute(ArgNo + AttributeList::FirstArgIndex, Kind);
+}
+
 void InvokeInst::removeAttribute(unsigned i, Attribute::AttrKind Kind) {
   AttributeList PAL = getAttributes();
   PAL = PAL.removeAttribute(getContext(), i, Kind);
@@ -768,6 +780,10 @@ void InvokeInst::removeAttribute(unsigned i, StringRef Kind) {
   setAttributes(PAL);
 }
 
+void InvokeInst::removeParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) {
+  removeAttribute(ArgNo + AttributeList::FirstArgIndex, Kind);
+}
+
 void InvokeInst::addDereferenceableAttr(unsigned i, uint64_t Bytes) {
   AttributeList PAL = getAttributes();
   PAL = PAL.addDereferenceableAttr(getContext(), i, Bytes);
diff --git a/lib/Target/AArch64/AArch64CallLowering.cpp b/lib/Target/AArch64/AArch64CallLowering.cpp
index b2f55a7e1e0..ff3e4c40e2c 100644
--- a/lib/Target/AArch64/AArch64CallLowering.cpp
+++ b/lib/Target/AArch64/AArch64CallLowering.cpp
@@ -247,7 +247,7 @@ bool AArch64CallLowering::lowerFormalArguments(MachineIRBuilder &MIRBuilder,
   unsigned i = 0;
   for (auto &Arg : F.args()) {
     ArgInfo OrigArg{VRegs[i], Arg.getType()};
-    setArgFlags(OrigArg, i + 1, DL, F);
+    setArgFlags(OrigArg, i + AttributeList::FirstArgIndex, DL, F);
     bool Split = false;
     LLT Ty = MRI.getType(VRegs[i]);
     unsigned Dst = VRegs[i];
diff --git a/lib/Target/ARM/ARMCallLowering.cpp b/lib/Target/ARM/ARMCallLowering.cpp
index a8188411bf5..9178c67afa6 100644
--- a/lib/Target/ARM/ARMCallLowering.cpp
+++ b/lib/Target/ARM/ARMCallLowering.cpp
@@ -354,7 +354,7 @@ bool ARMCallLowering::lowerFormalArguments(MachineIRBuilder &MIRBuilder,
   unsigned Idx = 0;
   for (auto &Arg : F.args()) {
     ArgInfo AInfo(VRegs[Idx], Arg.getType());
-    setArgFlags(AInfo, Idx + 1, DL, F);
+    setArgFlags(AInfo, Idx + AttributeList::FirstArgIndex, DL, F);
     splitToValueTypes(AInfo, ArgInfos, DL, MF.getRegInfo());
     Idx++;
   }
diff --git a/lib/Target/X86/X86WinEHState.cpp b/lib/Target/X86/X86WinEHState.cpp
index bc14630584e..500b26b3be1 100644
--- a/lib/Target/X86/X86WinEHState.cpp
+++ b/lib/Target/X86/X86WinEHState.cpp
@@ -412,7 +412,7 @@ Function *WinEHStatePass::generateLSDAInEAXThunk(Function *ParentFunc) {
   // Can't use musttail due to prototype mismatch, but we can use tail.
   Call->setTailCall(true);
   // Set inreg so we pass it in EAX.
-  Call->addAttribute(1, Attribute::InReg);
+  Call->addParamAttr(0, Attribute::InReg);
   Builder.CreateRet(Call);
   return Trampoline;
 }
diff --git a/lib/Transforms/Coroutines/CoroSplit.cpp b/lib/Transforms/Coroutines/CoroSplit.cpp
index f5bb5cc274d..12eb1678982 100644
--- a/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -216,8 +216,8 @@ static Function *createClone(Function &F, Twine Suffix, coro::Shape &Shape,
   Function *NewF =
       Function::Create(FnTy, GlobalValue::LinkageTypes::InternalLinkage,
                        F.getName() + Suffix, M);
-  NewF->addAttribute(1, Attribute::NonNull);
-  NewF->addAttribute(1, Attribute::NoAlias);
+  NewF->addParamAttr(0, Attribute::NonNull);
+  NewF->addParamAttr(0, Attribute::NoAlias);
 
   ValueToValueMapTy VMap;
   // Replace all args with undefs. The buildCoroutineFrame algorithm already
diff --git a/lib/Transforms/IPO/ArgumentPromotion.cpp b/lib/Transforms/IPO/ArgumentPromotion.cpp
index 25db0eff884..6408cad08d5 100644
--- a/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -839,12 +839,12 @@ promoteArguments(Function *F, function_ref<AAResults &(Function &F)> AARGetter,
     // avoiding a register copy.
     if (PtrArg->hasStructRetAttr()) {
       unsigned ArgNo = PtrArg->getArgNo();
-      F->removeAttribute(ArgNo + 1, Attribute::StructRet);
-      F->addAttribute(ArgNo + 1, Attribute::NoAlias);
+      F->removeParamAttr(ArgNo, Attribute::StructRet);
+      F->addParamAttr(ArgNo, Attribute::NoAlias);
       for (Use &U : F->uses()) {
         CallSite CS(U.getUser());
-        CS.removeAttribute(ArgNo + 1, Attribute::StructRet);
-        CS.addAttribute(ArgNo + 1, Attribute::NoAlias);
+        CS.removeParamAttr(ArgNo, Attribute::StructRet);
+        CS.addParamAttr(ArgNo, Attribute::NoAlias);
       }
     }
 
diff --git a/lib/Transforms/IPO/FunctionAttrs.cpp b/lib/Transforms/IPO/FunctionAttrs.cpp
index 031c3d8a9eb..28cc81c76d4 100644
--- a/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -835,7 +835,7 @@ static bool addNoAliasAttrs(const SCCNodeSet &SCCNodes) {
   // pointers.
   for (Function *F : SCCNodes) {
     // Already noalias.
-    if (F->doesNotAlias(0))
+    if (F->returnDoesNotAlias())
       continue;
 
     // We can infer and propagate function attributes only when we know that the
@@ -855,11 +855,11 @@ static bool addNoAliasAttrs(const SCCNodeSet &SCCNodes) {
 
   bool MadeChange = false;
   for (Function *F : SCCNodes) {
-    if (F->doesNotAlias(AttributeList::ReturnIndex) ||
+    if (F->returnDoesNotAlias() ||
         !F->getReturnType()->isPointerTy())
       continue;
 
-    F->setDoesNotAlias(AttributeList::ReturnIndex);
+    F->setReturnDoesNotAlias();
     ++NumNoAlias;
     MadeChange = true;
   }
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index e9286b1bf17..4fd90d78a63 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -3845,7 +3845,7 @@ Instruction *InstCombiner::visitCallSite(CallSite CS) {
     if (V->getType()->isPointerTy() &&
         !CS.paramHasAttr(ArgNo, Attribute::NonNull) &&
         isKnownNonNullAt(V, CS.getInstruction(), &DT))
-      Indices.push_back(ArgNo + 1);
+      Indices.push_back(ArgNo + AttributeList::FirstArgIndex);
     ArgNo++;
   }
 
diff --git a/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index 9fe6f87d4fb..8786781933e 100644
--- a/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -625,16 +625,16 @@ bool DataFlowSanitizer::runOnModule(Module &M) {
     F->addAttribute(AttributeList::FunctionIndex, Attribute::NoUnwind);
     F->addAttribute(AttributeList::FunctionIndex, Attribute::ReadNone);
     F->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
-    F->addAttribute(1, Attribute::ZExt);
-    F->addAttribute(2, Attribute::ZExt);
+    F->addParamAttr(0, Attribute::ZExt);
+    F->addParamAttr(1, Attribute::ZExt);
   }
   DFSanCheckedUnionFn = Mod->getOrInsertFunction("dfsan_union", DFSanUnionFnTy);
   if (Function *F = dyn_cast<Function>(DFSanCheckedUnionFn)) {
     F->addAttribute(AttributeList::FunctionIndex, Attribute::NoUnwind);
     F->addAttribute(AttributeList::FunctionIndex, Attribute::ReadNone);
     F->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
-    F->addAttribute(1, Attribute::ZExt);
-    F->addAttribute(2, Attribute::ZExt);
+    F->addParamAttr(0, Attribute::ZExt);
+    F->addParamAttr(1, Attribute::ZExt);
   }
   DFSanUnionLoadFn =
       Mod->getOrInsertFunction("__dfsan_union_load", DFSanUnionLoadFnTy);
@@ -648,7 +648,7 @@ bool DataFlowSanitizer::runOnModule(Module &M) {
   DFSanSetLabelFn =
       Mod->getOrInsertFunction("__dfsan_set_label", DFSanSetLabelFnTy);
   if (Function *F = dyn_cast<Function>(DFSanSetLabelFn)) {
-    F->addAttribute(1, Attribute::ZExt);
+    F->addParamAttr(0, Attribute::ZExt);
   }
   DFSanNonzeroLabelFn =
       Mod->getOrInsertFunction("__dfsan_nonzero_label", DFSanNonzeroLabelFnTy);
@@ -982,8 +982,8 @@ Value *DFSanFunction::combineShadows(Value *V1, Value *V2, Instruction *Pos) {
   if (AvoidNewBlocks) {
     CallInst *Call = IRB.CreateCall(DFS.DFSanCheckedUnionFn, {V1, V2});
     Call->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
-    Call->addAttribute(1, Attribute::ZExt);
-    Call->addAttribute(2, Attribute::ZExt);
+    Call->addParamAttr(0, Attribute::ZExt);
+    Call->addParamAttr(1, Attribute::ZExt);
 
     CCS.Block = Pos->getParent();
     CCS.Shadow = Call;
@@ -995,8 +995,8 @@ Value *DFSanFunction::combineShadows(Value *V1, Value *V2, Instruction *Pos) {
     IRBuilder<> ThenIRB(BI);
     CallInst *Call = ThenIRB.CreateCall(DFS.DFSanUnionFn, {V1, V2});
     Call->addAttribute(AttributeList::ReturnIndex, Attribute::ZExt);
-    Call->addAttribute(1, Attribute::ZExt);
-    Call->addAttribute(2, Attribute::ZExt);
+    Call->addParamAttr(0, Attribute::ZExt);
+    Call->addParamAttr(1, Attribute::ZExt);
 
     BasicBlock *Tail = BI->getSuccessor(0);
     PHINode *Phi = PHINode::Create(DFS.ShadowTy, 2, "", &Tail->front());
diff --git a/lib/Transforms/Instrumentation/InstrProfiling.cpp b/lib/Transforms/Instrumentation/InstrProfiling.cpp
index d91ac6ac788..9a82532d770 100644
--- a/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -241,7 +241,7 @@ static Constant *getOrInsertValueProfilingCall(Module &M,
 
   if (Function *FunRes = dyn_cast<Function>(Res)) {
     if (auto AK = TLI.getExtAttrForI32Param(false))
-      FunRes->addAttribute(3, AK);
+      FunRes->addParamAttr(2, AK);
   }
   return Res;
 }
@@ -292,7 +292,7 @@ void InstrProfiling::lowerValueProfileInst(InstrProfValueProfileInst *Ind) {
         Builder.CreateCall(getOrInsertValueProfilingCall(*M, *TLI, true), Args);
   }
   if (auto AK = TLI->getExtAttrForI32Param(false))
-    Call->addAttribute(3, AK);
+    Call->addParamAttr(2, AK);
   Ind->replaceAllUsesWith(Call);
   Ind->eraseFromParent();
 }
diff --git a/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h b/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h
index c541fa4c8be..cb3b5757f8d 100644
--- a/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h
+++ b/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h
@@ -163,7 +163,7 @@ private:
 
     AttributeList Attr = AttributeList().addAttribute(
         C, AttributeList::FunctionIndex, Attribute::NoUnwind);
-    Attr = Attr.addAttribute(C, 1, Attribute::NoCapture);
+    Attr = Attr.addParamAttribute(C, 0, Attribute::NoCapture);
 
     FunctionType *Fty = FunctionType::get(Type::getVoidTy(C), Params,
                                           /*isVarArg=*/false);
diff --git a/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
index dc864f48bf1..3f1a77b49a4 100644
--- a/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ b/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -318,7 +318,7 @@ static bool processCallSite(CallSite CS, LazyValueInfo *LVI) {
         LVI->getPredicateAt(ICmpInst::ICMP_EQ, V,
                             ConstantPointerNull::get(Type),
                             CS.getInstruction()) == LazyValueInfo::False)
-      Indices.push_back(ArgNo + 1);
+      Indices.push_back(ArgNo + AttributeList::FirstArgIndex);
     ArgNo++;
   }
 
diff --git a/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp b/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
index 9dc476785c7..77b2bd84f9b 100644
--- a/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ b/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -2286,7 +2286,7 @@ static void RemoveNonValidAttrAtIndex(LLVMContext &Ctx, AttrHolder &AH,
   if (AH.getDereferenceableOrNullBytes(Index))
     R.addAttribute(Attribute::get(Ctx, Attribute::DereferenceableOrNull,
                                   AH.getDereferenceableOrNullBytes(Index)));
-  if (AH.doesNotAlias(Index))
+  if (AH.getAttributes().hasAttribute(Index, Attribute::NoAlias))
     R.addAttribute(Attribute::NoAlias);
 
   if (!R.empty())
@@ -2299,7 +2299,8 @@ RewriteStatepointsForGC::stripNonValidAttributesFromPrototype(Function &F) {
 
   for (Argument &A : F.args())
     if (isa<PointerType>(A.getType()))
-      RemoveNonValidAttrAtIndex(Ctx, F, A.getArgNo() + 1);
+      RemoveNonValidAttrAtIndex(Ctx, F,
+                                A.getArgNo() + AttributeList::FirstArgIndex);
 
   if (isa<PointerType>(F.getReturnType()))
     RemoveNonValidAttrAtIndex(Ctx, F, AttributeList::ReturnIndex);
@@ -2335,7 +2336,7 @@ void RewriteStatepointsForGC::stripNonValidAttributesFromBody(Function &F) {
     if (CallSite CS = CallSite(&I)) {
       for (int i = 0, e = CS.arg_size(); i != e; i++)
         if (isa<PointerType>(CS.getArgument(i)->getType()))
-          RemoveNonValidAttrAtIndex(Ctx, CS, i + 1);
+          RemoveNonValidAttrAtIndex(Ctx, CS, i + AttributeList::FirstArgIndex);
       if (isa<PointerType>(CS.getType()))
         RemoveNonValidAttrAtIndex(Ctx, CS, AttributeList::ReturnIndex);
     }
diff --git a/lib/Transforms/Utils/BuildLibCalls.cpp b/lib/Transforms/Utils/BuildLibCalls.cpp
index c9884c750ae..1956697ccb8 100644
--- a/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -58,7 +58,7 @@ static bool setOnlyReadsMemory(Function &F) {
 static bool setOnlyAccessesArgMemory(Function &F) {
   if (F.onlyAccessesArgMemory())
     return false;
-  F.setOnlyAccessesArgMemory ();
+  F.setOnlyAccessesArgMemory();
   ++NumArgMemOnly;
   return true;
 }
@@ -71,37 +71,36 @@ static bool setDoesNotThrow(Function &F) {
   return true;
 }
 
-static bool setDoesNotCapture(Function &F, unsigned n) {
-  if (F.doesNotCapture(n))
+static bool setRetDoesNotAlias(Function &F) {
+  if (F.hasAttribute(AttributeList::ReturnIndex, Attribute::NoAlias))
     return false;
-  F.setDoesNotCapture(n);
-  ++NumNoCapture;
-  return true;
-}
-
-static bool setOnlyReadsMemory(Function &F, unsigned n) {
-  if (F.onlyReadsMemory(n))
-    return false;
-  F.setOnlyReadsMemory(n);
-  ++NumReadOnlyArg;
-  return true;
-}
-
-static bool setDoesNotAlias(Function &F, unsigned n) {
-  if (F.doesNotAlias(n))
-    return false;
-  F.setDoesNotAlias(n);
+  F.addAttribute(AttributeList::ReturnIndex, Attribute::NoAlias);
   ++NumNoAlias;
   return true;
 }
 
-static bool setNonNull(Function &F, unsigned n) {
-  assert(
-      (n != AttributeList::ReturnIndex || F.getReturnType()->isPointerTy()) &&
-      "nonnull applies only to pointers");
-  if (F.getAttributes().hasAttribute(n, Attribute::NonNull))
+static bool setDoesNotCapture(Function &F, unsigned ArgNo) {
+  if (F.hasParamAttribute(ArgNo, Attribute::NoCapture))
     return false;
-  F.addAttribute(n, Attribute::NonNull);
+  F.addParamAttr(ArgNo, Attribute::NoCapture);
+  ++NumNoCapture;
+  return true;
+}
+
+static bool setOnlyReadsMemory(Function &F, unsigned ArgNo) {
+  if (F.hasParamAttribute(ArgNo, Attribute::ReadOnly))
+    return false;
+  F.addParamAttr(ArgNo, Attribute::ReadOnly);
+  ++NumReadOnlyArg;
+  return true;
+}
+
+static bool setRetNonNull(Function &F) {
+  assert(F.getReturnType()->isPointerTy() &&
+         "nonnull applies only to pointers");
+  if (F.hasAttribute(AttributeList::ReturnIndex, Attribute::NonNull))
+    return false;
+  F.addAttribute(AttributeList::ReturnIndex, Attribute::NonNull);
   ++NumNonNull;
   return true;
 }
@@ -116,7 +115,7 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_strlen:
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_strchr:
   case LibFunc_strrchr:
@@ -131,8 +130,8 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_strtold:
   case LibFunc_strtoull:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_strcpy:
   case LibFunc_stpcpy:
@@ -141,14 +140,14 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_strncpy:
   case LibFunc_stpncpy:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_strxfrm:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_strcmp:      // 0,1
   case LibFunc_strspn:      // 0,1
@@ -159,84 +158,84 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_strncasecmp: //
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
     return Changed;
   case LibFunc_strstr:
   case LibFunc_strpbrk:
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_strtok:
   case LibFunc_strtok_r:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_scanf:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_setbuf:
   case LibFunc_setvbuf:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_strdup:
   case LibFunc_strndup:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setRetDoesNotAlias(F);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_stat:
   case LibFunc_statvfs:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_sscanf:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_sprintf:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc_snprintf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 3);
-    Changed |= setOnlyReadsMemory(F, 3);
-    return Changed;
-  case LibFunc_setitimer:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setDoesNotCapture(F, 3);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc_system:
-    // May throw; "system" is a valid pthread cancellation point.
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
+  case LibFunc_snprintf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc_setitimer:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc_system:
+    // May throw; "system" is a valid pthread cancellation point.
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
+    return Changed;
   case LibFunc_malloc:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setRetDoesNotAlias(F);
     return Changed;
   case LibFunc_memcmp:
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
     return Changed;
   case LibFunc_memchr:
   case LibFunc_memrchr:
@@ -247,100 +246,100 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_modff:
   case LibFunc_modfl:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_memcpy:
   case LibFunc_mempcpy:
   case LibFunc_memccpy:
   case LibFunc_memmove:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_memcpy_chk:
     Changed |= setDoesNotThrow(F);
     return Changed;
   case LibFunc_memalign:
-    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setRetDoesNotAlias(F);
     return Changed;
   case LibFunc_mkdir:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_mktime:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_realloc:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setRetDoesNotAlias(F);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_read:
     // May throw; "read" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_rewind:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_rmdir:
   case LibFunc_remove:
   case LibFunc_realpath:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_rename:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_readlink:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_write:
     // May throw; "write" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_bcopy:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_bcmp:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
     return Changed;
   case LibFunc_bzero:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_calloc:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setRetDoesNotAlias(F);
     return Changed;
   case LibFunc_chmod:
   case LibFunc_chown:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_ctermid:
   case LibFunc_clearerr:
   case LibFunc_closedir:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_atoi:
   case LibFunc_atol:
@@ -348,26 +347,26 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_atoll:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_access:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_fopen:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setRetDoesNotAlias(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_fdopen:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setRetDoesNotAlias(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_feof:
   case LibFunc_free:
@@ -384,11 +383,11 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_funlockfile:
   case LibFunc_ftrylockfile:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_ferror:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F);
     return Changed;
   case LibFunc_fputc:
@@ -398,51 +397,51 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_frexpl:
   case LibFunc_fstatvfs:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_fgets:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 3);
+    Changed |= setDoesNotCapture(F, 2);
     return Changed;
   case LibFunc_fread:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 4);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setDoesNotCapture(F, 3);
     return Changed;
   case LibFunc_fwrite:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 4);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setDoesNotCapture(F, 3);
     // FIXME: readonly #1?
     return Changed;
   case LibFunc_fputs:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_fscanf:
   case LibFunc_fprintf:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_fgetpos:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
     return Changed;
   case LibFunc_getc:
   case LibFunc_getlogin_r:
   case LibFunc_getc_unlocked:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_getenv:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_gets:
   case LibFunc_getchar:
@@ -450,132 +449,132 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
     return Changed;
   case LibFunc_getitimer:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_getpwnam:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_ungetc:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_uname:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_unlink:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_unsetenv:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_utime:
   case LibFunc_utimes:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_putc:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_puts:
   case LibFunc_printf:
   case LibFunc_perror:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_pread:
     // May throw; "pread" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_pwrite:
     // May throw; "pwrite" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_putchar:
     Changed |= setDoesNotThrow(F);
     return Changed;
   case LibFunc_popen:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setRetDoesNotAlias(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_pclose:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_vscanf:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_vsscanf:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_vfscanf:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_valloc:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setRetDoesNotAlias(F);
     return Changed;
   case LibFunc_vprintf:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_vfprintf:
   case LibFunc_vsprintf:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_vsnprintf:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 3);
-    Changed |= setOnlyReadsMemory(F, 3);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_open:
     // May throw; "open" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_opendir:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setRetDoesNotAlias(F);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_tmpfile:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setRetDoesNotAlias(F);
     return Changed;
   case LibFunc_times:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_htonl:
   case LibFunc_htons:
@@ -586,93 +585,93 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
     return Changed;
   case LibFunc_lstat:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_lchown:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_qsort:
     // May throw; places call through function pointer.
-    Changed |= setDoesNotCapture(F, 4);
+    Changed |= setDoesNotCapture(F, 3);
     return Changed;
   case LibFunc_dunder_strdup:
   case LibFunc_dunder_strndup:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setRetDoesNotAlias(F);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_dunder_strtok_r:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_under_IO_getc:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_under_IO_putc:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_dunder_isoc99_scanf:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_stat64:
   case LibFunc_lstat64:
   case LibFunc_statvfs64:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_dunder_isoc99_sscanf:
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_fopen64:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setRetDoesNotAlias(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_fseeko64:
   case LibFunc_ftello64:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_tmpfile64:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setRetDoesNotAlias(F);
     return Changed;
   case LibFunc_fstat64:
   case LibFunc_fstatvfs64:
     Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_open64:
     // May throw; "open" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_gettimeofday:
     // Currently some platforms have the restrict keyword on the arguments to
     // gettimeofday. To be conservative, do not add noalias to gettimeofday's
     // arguments.
     Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
     return Changed;
   case LibFunc_Znwj: // new(unsigned int)
   case LibFunc_Znwm: // new(unsigned long)
@@ -683,17 +682,17 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_msvc_new_array_int: // new[](unsigned int)
   case LibFunc_msvc_new_array_longlong: // new[](unsigned long long)
     // Operator new always returns a nonnull noalias pointer
-    Changed |= setNonNull(F, AttributeList::ReturnIndex);
-    Changed |= setDoesNotAlias(F, AttributeList::ReturnIndex);
+    Changed |= setRetNonNull(F);
+    Changed |= setRetDoesNotAlias(F);
     return Changed;
   //TODO: add LibFunc entries for:
   //case LibFunc_memset_pattern4:
   //case LibFunc_memset_pattern8:
   case LibFunc_memset_pattern16:
     Changed |= setOnlyAccessesArgMemory(F);
+    Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   // int __nvvm_reflect(const char *)
   case LibFunc_nvvm_reflect:
diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 2c1c30463a2..9e71d746de3 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -537,7 +537,7 @@ Value *LibCallSimplifier::optimizeStrTo(CallInst *CI, IRBuilder<> &B) {
   if (isa<ConstantPointerNull>(EndPtr)) {
     // With a null EndPtr, this function won't capture the main argument.
     // It would be readonly too, except that it still may write to errno.
-    CI->addAttribute(1, Attribute::NoCapture);
+    CI->addParamAttr(0, Attribute::NoCapture);
   }
 
   return nullptr;
diff --git a/unittests/ExecutionEngine/Orc/IndirectionUtilsTest.cpp b/unittests/ExecutionEngine/Orc/IndirectionUtilsTest.cpp
index 4af3aa707a9..ab43c4af13f 100644
--- a/unittests/ExecutionEngine/Orc/IndirectionUtilsTest.cpp
+++ b/unittests/ExecutionEngine/Orc/IndirectionUtilsTest.cpp
@@ -20,17 +20,15 @@ TEST(IndirectionUtilsTest, MakeStub) {
   LLVMContext Context;
   ModuleBuilder MB(Context, "x86_64-apple-macosx10.10", "");
   Function *F = MB.createFunctionDecl<void(DummyStruct, DummyStruct)>("");
-  SmallVector<AttributeList, 4> Attrs;
-  Attrs.push_back(
-      AttributeList::get(MB.getModule()->getContext(), 1U,
-                         AttrBuilder().addAttribute(Attribute::StructRet)));
-  Attrs.push_back(
-      AttributeList::get(MB.getModule()->getContext(), 2U,
-                         AttrBuilder().addAttribute(Attribute::ByVal)));
-  Attrs.push_back(
-      AttributeList::get(MB.getModule()->getContext(), ~0U,
-                         AttrBuilder().addAttribute(Attribute::NoUnwind)));
-  F->setAttributes(AttributeList::get(MB.getModule()->getContext(), Attrs));
+  AttributeSet FnAttrs = AttributeSet::get(
+      Context, AttrBuilder().addAttribute(Attribute::NoUnwind));
+  AttributeSet RetAttrs; // None
+  AttributeSet ArgAttrs[2] = {
+      AttributeSet::get(Context,
+                        AttrBuilder().addAttribute(Attribute::StructRet)),
+      AttributeSet::get(Context, AttrBuilder().addAttribute(Attribute::ByVal)),
+  };
+  F->setAttributes(AttributeList::get(Context, FnAttrs, RetAttrs, ArgAttrs));
 
   auto ImplPtr = orc::createImplPointer(*F->getType(), *MB.getModule(), "", nullptr);
   orc::makeStub(*F, *ImplPtr);
diff --git a/utils/TableGen/IntrinsicEmitter.cpp b/utils/TableGen/IntrinsicEmitter.cpp
index f9da9f1310d..caa52d28f77 100644
--- a/utils/TableGen/IntrinsicEmitter.cpp
+++ b/utils/TableGen/IntrinsicEmitter.cpp
@@ -563,8 +563,9 @@ void IntrinsicEmitter::EmitAttributes(const CodeGenIntrinsicTable &Ints,
     if (ae) {
       while (ai != ae) {
         unsigned argNo = intrinsic.ArgumentAttributes[ai].first;
+        unsigned attrIdx = argNo + 1; // Must match AttributeList::FirstArgIndex
 
-        OS <<  "      const Attribute::AttrKind AttrParam" << argNo + 1 <<"[]= {";
+        OS << "      const Attribute::AttrKind AttrParam" << attrIdx << "[]= {";
         bool addComma = false;
 
         do {
@@ -605,7 +606,7 @@ void IntrinsicEmitter::EmitAttributes(const CodeGenIntrinsicTable &Ints,
         } while (ai != ae && intrinsic.ArgumentAttributes[ai].first == argNo);
         OS << "};\n";
         OS << "      AS[" << numAttrs++ << "] = AttributeList::get(C, "
-           << argNo + 1 << ", AttrParam" << argNo + 1 << ");\n";
+           << attrIdx << ", AttrParam" << attrIdx << ");\n";
       }
     }