diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td
--- a/clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -545,6 +545,8 @@
 def err_aix_default_altivec_abi : Error<
   "The default Altivec ABI on AIX is not yet supported, use '-mabi=vec-extabi' for the extended Altivec ABI">;
 
+def err_aix_unsupported_tls_model : Error<"TLS model '%0' is not yet supported on AIX">;
+
 def err_invalid_cxx_abi : Error<"Invalid C++ ABI name '%0'">;
 def err_unsupported_cxx_abi : Error<"C++ ABI '%0' is not supported on target triple '%1'">;
 
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3151,6 +3151,8 @@
 def err_attr_tlsmodel_arg : Error<"tls_model must be \"global-dynamic\", "
   "\"local-dynamic\", \"initial-exec\" or \"local-exec\"">;
 
+def err_aix_attr_unsupported_tls_model : Error<"TLS model '%0' is not yet supported on AIX">;
+
 def err_tls_var_aligned_over_maximum : Error<
   "alignment (%0) of thread-local variable %1 is greater than the maximum supported "
   "alignment (%2) for a thread-local variable on this target">;
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1808,6 +1808,14 @@
     Opts.ExplicitEmulatedTLS = true;
   }
 
+  if (Arg *A = Args.getLastArg(OPT_ftlsmodel_EQ)) {
+    if (T.isOSAIX()) {
+      StringRef Name = A->getValue();
+      if (Name != "global-dynamic")
+        Diags.Report(diag::err_aix_unsupported_tls_model) << Name;
+    }
+  }
+
   if (Arg *A = Args.getLastArg(OPT_fdenormal_fp_math_EQ)) {
     StringRef Val = A->getValue();
     Opts.FPDenormalMode = llvm::parseDenormalFPAttribute(Val);
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -1935,6 +1935,12 @@
     return;
   }
 
+  if (S.Context.getTargetInfo().getTriple().isOSAIX() &&
+      Model != "global-dynamic") {
+    S.Diag(LiteralLoc, diag::err_aix_attr_unsupported_tls_model) << Model;
+    return;
+  }
+
   D->addAttr(::new (S.Context) TLSModelAttr(S.Context, AL, Model));
 }
 
diff --git a/clang/test/CodeGen/aix-tls-model.cpp b/clang/test/CodeGen/aix-tls-model.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGen/aix-tls-model.cpp
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-GD
+// RUN: %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -ftls-model=global-dynamic -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-GD
+// RUN: not %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -ftls-model=local-dynamic -emit-llvm 2>&1 | FileCheck %s -check-prefix=CHECK-LD-ERROR
+// RUN: not %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -ftls-model=initial-exec -emit-llvm  2>&1 | FileCheck %s -check-prefix=CHECK-IE-ERROR
+// RUN: not %clang_cc1 %s -triple powerpc-unknown-aix -target-cpu pwr8 -ftls-model=local-exec -emit-llvm 2>&1 | FileCheck %s -check-prefix=CHECK-LE-ERROR
+// RUN: %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-GD
+// RUN: %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -ftls-model=global-dynamic -emit-llvm -o - | FileCheck %s -check-prefix=CHECK-GD
+// RUN: not %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -ftls-model=local-dynamic -emit-llvm 2>&1 | FileCheck %s -check-prefix=CHECK-LD-ERROR
+// RUN: not %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -ftls-model=initial-exec -emit-llvm  2>&1 | FileCheck %s -check-prefix=CHECK-IE-ERROR
+// RUN: not %clang_cc1 %s -triple powerpc64-unknown-aix -target-cpu pwr8 -ftls-model=local-exec -emit-llvm 2>&1 | FileCheck %s -check-prefix=CHECK-LE-ERROR
+
+int z1 = 0;
+int z2;
+int __thread x;
+int f() {
+  static int __thread y;
+  return y++;
+}
+
+// CHECK-GD: @z1 ={{.*}} global i32 0
+// CHECK-GD: @z2 ={{.*}} global i32 0
+// CHECK-GD: @x ={{.*}} thread_local global i32 0
+// CHECK-GD: @_ZZ1fvE1y = internal thread_local global i32 0
+// CHECK-LD-ERROR:  error: TLS model 'local-dynamic' is not yet supported on AIX
+// CHECK-IE-ERROR:  error: TLS model 'initial-exec' is not yet supported on AIX
+// CHECK-LE-ERROR:  error: TLS model 'local-exec' is not yet supported on AIX
diff --git a/clang/test/Sema/aix-attr-tls_model.c b/clang/test/Sema/aix-attr-tls_model.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Sema/aix-attr-tls_model.c
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -triple powerpc64-unknown-aix -target-cpu pwr8 -verify -fsyntax-only %s
+// RUN: %clang_cc1 -triple powerpc-unknown-aix -target-cpu pwr8 -verify -fsyntax-only %s
+
+#if !__has_attribute(tls_model)
+#error "Should support tls_model attribute"
+#endif
+
+static __thread int y __attribute((tls_model("global-dynamic"))); // no-warning
+static __thread int y __attribute((tls_model("local-dynamic"))); // expected-error {{TLS model 'local-dynamic' is not yet supported on AIX}}
+static __thread int y __attribute((tls_model("initial-exec"))); // expected-error {{TLS model 'initial-exec' is not yet supported on AIX}}
+static __thread int y __attribute((tls_model("local-exec"))); // expected-error {{TLS model 'local-exec' is not yet supported on AIX}}