diff --git a/include/llvm/Support/Allocator.h b/include/llvm/Support/Allocator.h
index de317719714..94cf3e85f36 100644
--- a/include/llvm/Support/Allocator.h
+++ b/include/llvm/Support/Allocator.h
@@ -203,7 +203,8 @@ public:
   }
 
   /// \brief Allocate space at the specified alignment.
-  LLVM_ATTRIBUTE_RETURNS_NONNULL void *Allocate(size_t Size, size_t Alignment) {
+  LLVM_ATTRIBUTE_RETURNS_NONNULL LLVM_ATTRIBUTE_RETURNS_NOALIAS void *
+  Allocate(size_t Size, size_t Alignment) {
     assert(Alignment > 0 && "0-byte alignnment is not allowed. Use 1 instead.");
 
     // Keep track of how many bytes we've allocated.
diff --git a/include/llvm/Support/Compiler.h b/include/llvm/Support/Compiler.h
index 8534316600a..4684af5f34d 100644
--- a/include/llvm/Support/Compiler.h
+++ b/include/llvm/Support/Compiler.h
@@ -223,6 +223,16 @@
 #define LLVM_ATTRIBUTE_RETURNS_NONNULL
 #endif
 
+/// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
+/// pointer that does not alias any other valid pointer.
+#ifdef __GNUC__
+#define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
+#elif defined(_MSC_VER)
+#define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
+#else
+#define LLVM_ATTRIBUTE_RETURNS_NOALIAS
+#endif
+
 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
 /// pedantic diagnostics.
 #ifdef __GNUC__