Index: lib/Basic/TargetInfo.cpp
===================================================================
--- lib/Basic/TargetInfo.cpp
+++ lib/Basic/TargetInfo.cpp
@@ -505,6 +505,11 @@
     case '?': // Disparage slightly code.
     case '!': // Disparage severely.
     case '*': // Ignore for choosing register preferences.
+    case 'i': // Ignore i,n,E,F as output constraints (match from the other
+              // chars)
+    case 'n':
+    case 'E':
+    case 'F':
       break;  // Pass them.
     }
 
Index: test/Sema/asm.c
===================================================================
--- test/Sema/asm.c
+++ test/Sema/asm.c
@@ -160,6 +160,41 @@
   return ret;
 }
 
+void iOutputConstraint(int x){
+  __asm ("nop" : "=ir" (x) : :); // no-error
+  __asm ("nop" : "=ri" (x) : :); // no-error
+  __asm ("nop" : "=ig" (x) : :); // no-error
+  __asm ("nop" : "=im" (x) : :); // no-error
+  __asm ("nop" : "=imr" (x) : :); // no-error
+  __asm ("nop" : "=i" (x) : :); // expected-error{{invalid output constraint '=i' in asm}}
+  __asm ("nop" : "+i" (x) : :); // expected-error{{invalid output constraint '+i' in asm}}
+  __asm ("nop" : "=ii" (x) : :); // expected-error{{invalid output constraint '=ii' in asm}}
+  __asm ("nop" : "=nr" (x) : :); // no-error
+  __asm ("nop" : "=rn" (x) : :); // no-error
+  __asm ("nop" : "=ng" (x) : :); // no-error
+  __asm ("nop" : "=nm" (x) : :); // no-error
+  __asm ("nop" : "=nmr" (x) : :); // no-error
+  __asm ("nop" : "=n" (x) : :); // expected-error{{invalid output constraint '=n' in asm}}
+  __asm ("nop" : "+n" (x) : :); // expected-error{{invalid output constraint '+n' in asm}}
+  __asm ("nop" : "=nn" (x) : :); // expected-error{{invalid output constraint '=nn' in asm}}
+  __asm ("nop" : "=Fr" (x) : :); // no-error
+  __asm ("nop" : "=rF" (x) : :); // no-error
+  __asm ("nop" : "=Fg" (x) : :); // no-error
+  __asm ("nop" : "=Fm" (x) : :); // no-error
+  __asm ("nop" : "=Fmr" (x) : :); // no-error
+  __asm ("nop" : "=F" (x) : :); // expected-error{{invalid output constraint '=F' in asm}}
+  __asm ("nop" : "+F" (x) : :); // expected-error{{invalid output constraint '+F' in asm}}
+  __asm ("nop" : "=FF" (x) : :); // expected-error{{invalid output constraint '=FF' in asm}}
+  __asm ("nop" : "=Er" (x) : :); // no-error
+  __asm ("nop" : "=rE" (x) : :); // no-error
+  __asm ("nop" : "=Eg" (x) : :); // no-error
+  __asm ("nop" : "=Em" (x) : :); // no-error
+  __asm ("nop" : "=Emr" (x) : :); // no-error
+  __asm ("nop" : "=E" (x) : :); // expected-error{{invalid output constraint '=E' in asm}}
+  __asm ("nop" : "+E" (x) : :); // expected-error{{invalid output constraint '+E' in asm}}
+  __asm ("nop" : "=EE" (x) : :); // expected-error{{invalid output constraint '=EE' in asm}}
+}
+
 // PR19837
 struct foo {
   int a;