diff --git a/compiler-rt/cmake/Modules/CompilerRTAIXUtils.cmake b/compiler-rt/cmake/Modules/CompilerRTAIXUtils.cmake
new file mode 100644
--- /dev/null
+++ b/compiler-rt/cmake/Modules/CompilerRTAIXUtils.cmake
@@ -0,0 +1,113 @@
+include(CMakeParseArguments)
+
+set(AIX_LIBATOMIC_EXPORTED_ROUTINES
+  __atomic_compare_exchange
+  __atomic_compare_exchange_1
+  __atomic_compare_exchange_2
+  __atomic_compare_exchange_4
+  __atomic_compare_exchange_8
+  __atomic_exchange
+  __atomic_exchange_1
+  __atomic_exchange_2
+  __atomic_exchange_4
+  __atomic_exchange_8
+  __atomic_fetch_add_1
+  __atomic_fetch_add_2
+  __atomic_fetch_add_4
+  __atomic_fetch_add_8
+  __atomic_fetch_and_1
+  __atomic_fetch_and_2
+  __atomic_fetch_and_4
+  __atomic_fetch_and_8
+  __atomic_fetch_or_1
+  __atomic_fetch_or_2
+  __atomic_fetch_or_4
+  __atomic_fetch_or_8
+  __atomic_fetch_sub_1
+  __atomic_fetch_sub_2
+  __atomic_fetch_sub_4
+  __atomic_fetch_sub_8
+  __atomic_fetch_xor_1
+  __atomic_fetch_xor_2
+  __atomic_fetch_xor_4
+  __atomic_fetch_xor_8
+  __atomic_is_lock_free
+  __atomic_load
+  __atomic_load_1
+  __atomic_load_2
+  __atomic_load_4
+  __atomic_load_8
+  __atomic_store
+  __atomic_store_1
+  __atomic_store_2
+  __atomic_store_4
+  __atomic_store_8
+)
+
+function(add_aix_atomic_dynlib bitmode out_dir export_list)
+  cmake_parse_arguments(LIB
+    ""
+    ""
+    "DEPENDS;SOURCES;LINK_FLAGS"
+    ${ARGN})
+  add_library(atomic_${bitmode} SHARED ${LIB_SOURCES})
+  if(LIB_DEPENDS)
+    add_dependencies(atomic_${bitmode} ${LIB_DEPENDS})
+  endif()
+  set_target_properties(atomic_${bitmode}
+                        PROPERTIES
+                        SOVERSION 1
+                        POSITION_INDEPENDENT_CODE OFF
+                        COMPILE_FLAGS -m${bitmode} -I -qmakedep=gcc
+                        LINK_FLAGS "-Wl,-b${bitmode} -Wl,-H512 -Wl,-D0 \
+                                    -Wl,-T512 -Wl,-bhalt:4 -Wl,-bernotok \
+                                    -Wl,-bnoentry -Wl,-bexport:${export_list} \
+                                    -Wl,-bmodtype:SRE -Wl,-lc")
+  # Copy it to ${out_dir}/libatomic.so.1 for compatibility.
+  add_custom_command(TARGET atomic_${bitmode}
+                     POST_BUILD
+                     COMMAND ${CMAKE_COMMAND} -E 
+                     copy "$<TARGET_FILE:atomic_${bitmode}>"
+                          "${out_dir}/libatomic.so.1")
+endfunction()
+
+function(add_aix_libatomic)
+  cmake_parse_arguments(LIB
+    ""
+    ""
+    "PARENT_TARGET;SOURCES"
+    ${ARGN})
+  # Write exported routines to export list file prior the build.
+  set(LIBATOMIC_EXPORT_LIST ${CMAKE_CURRENT_BINARY_DIR}/export_list.atomic)
+  STRING(REGEX REPLACE ";" "\n" LIBATOMIC_EXPORTED_ROUTINES_TEXT
+    "${AIX_LIBATOMIC_EXPORTED_ROUTINES}")
+  file(GENERATE
+       OUTPUT ${LIBATOMIC_EXPORT_LIST}
+       CONTENT ${LIBATOMIC_EXPORTED_ROUTINES_TEXT})
+  # Build 32/64 bit shared libraries.
+  set(AIX_LIBATOMIC_32_OUT_DIR "${CMAKE_CURRENT_BINARY_DIR}/libatomic_32.dir")
+  file(MAKE_DIRECTORY "${AIX_LIBATOMIC_32_OUT_DIR}")
+  set(AIX_LIBATOMIC_64_OUT_DIR "${CMAKE_CURRENT_BINARY_DIR}/libatomic_64.dir")
+  file(MAKE_DIRECTORY "${AIX_LIBATOMIC_64_OUT_DIR}")
+  add_aix_atomic_dynlib(32 ${AIX_LIBATOMIC_32_OUT_DIR} ${LIBATOMIC_EXPORT_LIST}
+    SOURCES ${LIB_SOURCES})
+  add_aix_atomic_dynlib(64 ${AIX_LIBATOMIC_64_OUT_DIR} ${LIBATOMIC_EXPORT_LIST}
+    SOURCES ${LIB_SOURCES})
+  # Archive built shared libraries to libatomic.a.
+  set(AIX_LIBATOMIC_ARCHIVE ${CMAKE_CURRENT_BINARY_DIR}/libatomic.a)
+  add_custom_command(OUTPUT ${AIX_LIBATOMIC_ARCHIVE}
+                     COMMAND ${CMAKE_AR} -r -X32_64
+                             -o ${AIX_LIBATOMIC_ARCHIVE}
+                             ${AIX_LIBATOMIC_32_OUT_DIR}/libatomic.so.1
+                             ${AIX_LIBATOMIC_64_OUT_DIR}/libatomic.so.1
+                     DEPENDS atomic_32 atomic_64)
+  add_custom_target(aix-libatomic DEPENDS ${AIX_LIBATOMIC_ARCHIVE})
+  # Set install step.
+  if (AIX_LIBATOMIC_INSTALL_DIR)
+    install(FILES ${AIX_LIBATOMIC_ARCHIVE}
+            DESTINATION ${AIX_LIBATOMIC_INSTALL_DIR})
+  endif()
+  if(LIB_PARENT_TARGET)
+    add_dependencies(${LIB_PARENT_TARGET} aix-libatomic)
+  endif()
+endfunction()
diff --git a/compiler-rt/lib/builtins/CMakeLists.txt b/compiler-rt/lib/builtins/CMakeLists.txt
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@@ -747,4 +747,12 @@
   endforeach ()
 endif ()
 
+# On AIX, we have to ship a libatomic.a for compatibility.
+if (${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+  include(CompilerRTAIXUtils)
+  add_aix_libatomic(
+    PARENT_TARGET builtins
+    SOURCES atomic.c)
+endif()
+
 add_dependencies(compiler-rt builtins)