diff --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp
--- a/clang/lib/Basic/TargetInfo.cpp
+++ b/clang/lib/Basic/TargetInfo.cpp
@@ -745,6 +745,7 @@
       Info.setAllowsMemory();
       break;
     case 'g': // general register, memory operand or immediate integer.
+    case 'p': // address operand.
     case 'X': // any operand.
       Info.setAllowsRegister();
       Info.setAllowsMemory();
diff --git a/clang/test/Sema/inline-asm-validate.c b/clang/test/Sema/inline-asm-validate.c
--- a/clang/test/Sema/inline-asm-validate.c
+++ b/clang/test/Sema/inline-asm-validate.c
@@ -7,8 +7,6 @@
   // Ensure we accept pointer and non-pointer arguments to "p" constrained
   // inputs.
   asm (""::"p"(t), "p"(p), "p"(&t));
-  // TODO: Ensure we accept p output constraints.
-  asm ("":"=p"(t)); // expected-error{{invalid output constraint '=p' in asm}}
-  asm ("":"=p"(p)); // expected-error{{invalid output constraint '=p' in asm}}
-  asm ("":"=p"(&t)); // expected-error{{invalid output constraint '=p' in asm}}
+  asm ("":"=p"(t), "=p"(p));
+  asm ("":"=p"(&t)); // expected-error{{invalid lvalue in asm output}}
 }