diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake
index a243507791a..f9cb5d31021 100644
--- a/cmake/modules/HandleLLVMOptions.cmake
+++ b/cmake/modules/HandleLLVMOptions.cmake
@@ -530,14 +530,6 @@ if (MSVC)
           # is fixed.
       -wd4709 # Suppress comma operator within array index expression
 
-      # Ideally, we'd like this warning to be enabled, but MSVC 2013 doesn't
-      # support the 'aligned' attribute in the way that clang sources requires (for
-      # any code that uses the LLVM_ALIGNAS macro), so this is must be disabled to
-      # avoid unwanted alignment warnings.
-      # When we switch to requiring a version of MSVC that supports the 'alignas'
-      # specifier (MSVC 2015?) this warning can be re-enabled.
-      -wd4324 # Suppress 'structure was padded due to __declspec(align())'
-
       # Promoted warnings.
       -w14062 # Promote 'enumerator in switch of enum is not handled' to level 1 warning.
 
diff --git a/docs/doxygen.cfg.in b/docs/doxygen.cfg.in
index a8e84a31276..fe74edc0866 100644
--- a/docs/doxygen.cfg.in
+++ b/docs/doxygen.cfg.in
@@ -1926,7 +1926,7 @@ INCLUDE_FILE_PATTERNS  =
 # recursively expanded use the := operator instead of the = operator.
 # This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
 
-PREDEFINED             = LLVM_ALIGNAS(x)=
+PREDEFINED             =
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The
diff --git a/include/llvm/Support/Compiler.h b/include/llvm/Support/Compiler.h
index 3f4f465f396..356ff6f0486 100644
--- a/include/llvm/Support/Compiler.h
+++ b/include/llvm/Support/Compiler.h
@@ -338,14 +338,6 @@
 # define LLVM_ASSUME_ALIGNED(p, a) (p)
 #endif
 
-/// \macro LLVM_ALIGNAS
-/// Used to specify a minimum alignment for a structure or variable.
-#if __GNUC__ && !__has_feature(cxx_alignas) && !LLVM_GNUC_PREREQ(4, 8, 1)
-# define LLVM_ALIGNAS(x) __attribute__((aligned(x)))
-#else
-# define LLVM_ALIGNAS(x) alignas(x)
-#endif
-
 /// \macro LLVM_PACKED
 /// Used to specify a packed structure.
 /// LLVM_PACKED(
@@ -376,8 +368,8 @@
 
 /// \macro LLVM_PTR_SIZE
 /// A constant integer equivalent to the value of sizeof(void*).
-/// Generally used in combination with LLVM_ALIGNAS or when doing computation in
-/// the preprocessor.
+/// Generally used in combination with alignas or when doing computation in the
+/// preprocessor.
 #ifdef __SIZEOF_POINTER__
 # define LLVM_PTR_SIZE __SIZEOF_POINTER__
 #elif defined(_WIN64)
diff --git a/unittests/Support/AlignOfTest.cpp b/unittests/Support/AlignOfTest.cpp
index 780af95e2ab..d8cabde6c72 100644
--- a/unittests/Support/AlignOfTest.cpp
+++ b/unittests/Support/AlignOfTest.cpp
@@ -38,10 +38,10 @@ namespace {
 #endif
 
 // Define some fixed alignment types to use in these tests.
-struct LLVM_ALIGNAS(1) A1 {};
-struct LLVM_ALIGNAS(2) A2 {};
-struct LLVM_ALIGNAS(4) A4 {};
-struct LLVM_ALIGNAS(8) A8 {};
+struct alignas(1) A1 {};
+struct alignas(2) A2 {};
+struct alignas(4) A4 {};
+struct alignas(8) A8 {};
 
 struct S1 {};
 struct S2 { char a; };