Index: llvm/include/llvm/IR/Intrinsics.td
===================================================================
--- llvm/include/llvm/IR/Intrinsics.td
+++ llvm/include/llvm/IR/Intrinsics.td
@@ -94,6 +94,11 @@
   int Align = align;
 }
 
+class Dereferenceable<AttrIndex idx, int bytes> : IntrinsicProperty {
+  int ArgNo = idx.Value;
+  int Bytes = bytes;
+}
+
 // Returned - The specified argument is always the return value of the
 // intrinsic.
 class Returned<AttrIndex idx> : IntrinsicProperty {
Index: llvm/test/TableGen/intrinsic-attrs.td
===================================================================
--- llvm/test/TableGen/intrinsic-attrs.td
+++ llvm/test/TableGen/intrinsic-attrs.td
@@ -9,7 +9,16 @@
   int isAny = 0;
 }
 
-def llvm_i32_ty        : LLVMType<i32>;
+def llvm_i32_ty     : LLVMType<i32>;
+def llvm_ptr_ty     : LLVMType<iPTR>;
+
+class AttrIndex<int idx> {
+  int Value = idx;
+}
+
+def FuncIndex : AttrIndex<-1>;
+def RetIndex : AttrIndex<0>;
+class ArgIndex<int argNo> : AttrIndex<!add(argNo, 1)>;
 
 class IntrinsicProperty<bit is_default = 0> {
   bit IsDefault = is_default;
@@ -17,6 +26,10 @@
 
 def IntrNoMem : IntrinsicProperty;
 def IntrHasSideEffects : IntrinsicProperty;
+class Dereferenceable<AttrIndex idx, int bytes> : IntrinsicProperty {
+  int ArgNo = idx.Value;
+  int Bytes = bytes;
+}
 
 class Intrinsic<list<LLVMType> ret_types,
                 list<LLVMType> param_types = [],
@@ -40,12 +53,33 @@
 // ... this intrinsic.
 def int_random_gen   : Intrinsic<[llvm_i32_ty], [], [IntrNoMem, IntrHasSideEffects]>;
 
+def int_deref_ptr_ret : Intrinsic<[llvm_ptr_ty], [], [Dereferenceable<RetIndex, 16>]>;
+
+// CHECK: static AttributeSet getIntrinsicArgAttributeSet(LLVMContext &C, unsigned ID) {
+// CHECK-NEXT:   switch (ID) {
+// CHECK-NEXT: default: llvm_unreachable("Invalid attribute set number");
+// CHECK-NEXT: case 0:
+// CHECK-NEXT:     return AttributeSet::get(C, {
+// CHECK-NEXT: Attribute::get(C, Attribute::Dereferenceable, 16),
+// CHECK-NEXT: });
+// CHECK-NEXT: }
+// CHECK-NEXT: }
+
 // CHECK: static AttributeSet getIntrinsicFnAttributeSet(
 // CHECK: case 0:
 // CHECK-NEXT: return AttributeSet::get(C, {
 // CHECK-NEXT: Attribute::get(C, Attribute::NoUnwind),
 // CHECK-NEXT: });
 
-// CHECK: 1, // llvm.random.gen
+
+// CHECK: 1, // llvm.deref.ptr.ret
+// CHECK: 2, // llvm.random.gen
+
 // CHECK: case 1:
-// CHECK-NEXT: AS[0] = {AttributeList::FunctionIndex, getIntrinsicFnAttributeSet(C, 0)};
+// CHECK-NEXT: AS[0] = {0, getIntrinsicArgAttributeSet(C, 0)};
+// CHECK-NEXT: AS[1] = {AttributeList::FunctionIndex, getIntrinsicFnAttributeSet(C, 0)};
+// CHECK-NEXT: NumAttrs = 2;
+
+// CHECK: case 2:
+// CHECK-NEXT: AS[0] = {AttributeList::FunctionIndex, getIntrinsicFnAttributeSet(C, 1)};
+// CHECK-NEXT: NumAttrs = 1;
Index: llvm/utils/TableGen/CodeGenIntrinsics.h
===================================================================
--- llvm/utils/TableGen/CodeGenIntrinsics.h
+++ llvm/utils/TableGen/CodeGenIntrinsics.h
@@ -113,7 +113,8 @@
     WriteOnly,
     ReadNone,
     ImmArg,
-    Alignment
+    Alignment,
+    Dereferenceable
   };
 
   struct ArgAttribute {
Index: llvm/utils/TableGen/CodeGenIntrinsics.cpp
===================================================================
--- llvm/utils/TableGen/CodeGenIntrinsics.cpp
+++ llvm/utils/TableGen/CodeGenIntrinsics.cpp
@@ -234,6 +234,10 @@
     unsigned ArgNo = R->getValueAsInt("ArgNo");
     uint64_t Align = R->getValueAsInt("Align");
     addArgAttribute(ArgNo, Alignment, Align);
+  } else if (R->isSubClassOf("Dereferenceable")) {
+    unsigned ArgNo = R->getValueAsInt("ArgNo");
+    uint64_t Bytes = R->getValueAsInt("Bytes");
+    addArgAttribute(ArgNo, Dereferenceable, Bytes);
   } else
     llvm_unreachable("Unknown property!");
 }
Index: llvm/utils/TableGen/IntrinsicEmitter.cpp
===================================================================
--- llvm/utils/TableGen/IntrinsicEmitter.cpp
+++ llvm/utils/TableGen/IntrinsicEmitter.cpp
@@ -474,6 +474,10 @@
           OS << "      Attribute::get(C, Attribute::Alignment, "
              << Attr.Value << "),\n";
           break;
+        case CodeGenIntrinsic::Dereferenceable:
+          OS << "      Attribute::get(C, Attribute::Dereferenceable, "
+             << Attr.Value << "),\n";
+          break;
         }
       }
       OS << "    });\n";