diff --git a/clang/lib/Basic/Targets/PPC.h b/clang/lib/Basic/Targets/PPC.h
index fc23c30c68523..e4d6a02386da5 100644
--- a/clang/lib/Basic/Targets/PPC.h
+++ b/clang/lib/Basic/Targets/PPC.h
@@ -305,9 +305,11 @@ class LLVM_LIBRARY_VISIBILITY PPCTargetInfo : public TargetInfo {
               // asm statements)
       Info.setAllowsMemory();
       break;
-    case 'R': // AIX TOC entry
     case 'a': // Address operand that is an indexed or indirect from a
               // register (`p' is preferable for asm statements)
+              // TODO: Add full support for this constraint
+      return false;
+    case 'R': // AIX TOC entry
     case 'S': // Constant suitable as a 64-bit mask operand
     case 'T': // Constant suitable as a 32-bit mask operand
     case 'U': // System V Release 4 small data area reference
diff --git a/clang/test/CodeGen/PowerPC/inline-asm-constraints-error.c b/clang/test/CodeGen/PowerPC/inline-asm-constraints-error.c
new file mode 100644
index 0000000000000..eb443eee40e55
--- /dev/null
+++ b/clang/test/CodeGen/PowerPC/inline-asm-constraints-error.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -emit-llvm -triple powerpc64-ibm-aix-xcoff -verify %s
+// RUN: %clang_cc1 -emit-llvm -triple powerpc-ibm-aix-xcoff -verify %s
+// This test case exist to test marking the 'a' inline assembly constraint as
+// unsupported because powerpc previously marked it as supported.
+int foo(int arg){
+  asm goto ("bc 12,2,%l[TEST_LABEL]" : : "a"(&&TEST_LABEL) : : TEST_LABEL); //expected-error {{invalid input constraint 'a' in asm}}
+  return 0;
+TEST_LABEL: return arg + 1;
+}