diff --git a/llvm/lib/Object/ArchiveWriter.cpp b/llvm/lib/Object/ArchiveWriter.cpp
--- a/llvm/lib/Object/ArchiveWriter.cpp
+++ b/llvm/lib/Object/ArchiveWriter.cpp
@@ -76,9 +76,11 @@
     if (auto ObjOrErr = object::SymbolicFile::createSymbolicFile(
             MemBufferRef, file_magic::bitcode, &Context)) {
       auto &IRObject = cast<object::IRObjectFile>(**ObjOrErr);
-      return Triple(IRObject.getTargetTriple()).isOSDarwin()
+      auto TargetTriple = Triple(IRObject.getTargetTriple());
+      return TargetTriple.isOSDarwin()
                  ? object::Archive::K_DARWIN
-                 : object::Archive::K_GNU;
+                 : (TargetTriple.isOSAIX() ? object::Archive::K_AIXBIG
+                                           : object::Archive::K_GNU);
     } else {
       // Squelch the error in case this was not a SymbolicFile.
       consumeError(ObjOrErr.takeError());
diff --git a/llvm/test/tools/llvm-ar/Inputs/aix-foo.ll b/llvm/test/tools/llvm-ar/Inputs/aix-foo.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-ar/Inputs/aix-foo.ll
@@ -0,0 +1,8 @@
+target datalayout = "E-m:a-Fi64-i64:64-n32:64-S128-v256:256:256-v512:512:512"
+target triple = "powerpc64-ibm-aix7.2.0.0"
+
+define signext i32 @foo() {
+entry:
+  ret i32 42
+}
+
diff --git a/llvm/test/tools/llvm-ar/aix-bitcode.test b/llvm/test/tools/llvm-ar/aix-bitcode.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-ar/aix-bitcode.test
@@ -0,0 +1,7 @@
+# Check if llvm-ar correctly archives bitcode files on AIX.
+# RUN: rm -rf %t && mkdir -p %t
+# RUN: llvm-as %S/Inputs/aix-foo.ll -o %t/aix-foo.bc
+# RUN: llvm-ar qc %t/aix-foo.a %t/aix-foo.bc
+# RUN: FileCheck %s --input-file=%t/aix-foo.a
+
+# CHECK:  bigaf