Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -4165,6 +4165,8 @@
   "cannot jump from this goto statement to label %0 inside an inline assembly block">;
 def note_goto_ms_asm_label : Note<
   "inline assembly label %0 declared here">;
+def err_cross_block_asm_label_use : Error<
+  "cannot use inline assembly label %0 defined outside of an inline assembly block">;
 def warn_unused_label : Warning<"unused label %0">,
   InGroup<UnusedLabel>, DefaultIgnore;
 
Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h
+++ include/clang/Sema/Sema.h
@@ -3166,6 +3166,7 @@
   LabelDecl *GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
                                    SourceLocation Location,
                                    bool AlwaysCreate);
+  void DiagnoseCrossBlockLabelUse(const LabelDecl *Label);
 
   VarDecl *BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType ExceptionType,
                                   SourceLocation StartLoc,
Index: lib/Parse/ParseStmtAsm.cpp
===================================================================
--- lib/Parse/ParseStmtAsm.cpp
+++ lib/Parse/ParseStmtAsm.cpp
@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include <set>
 #include "clang/Parse/Parser.h"
 #include "RAIIObjectsForParser.h"
 #include "clang/AST/ASTContext.h"
@@ -45,6 +46,9 @@
   /// The offset of each token in AsmToks within AsmString.
   ArrayRef<unsigned> AsmTokOffsets;
 
+  /// The LabelDecls encountered when parsing the asm block.
+  std::set<LabelDecl*> LabelDecls;
+
 public:
   ClangAsmParserCallback(Parser &P, SourceLocation Loc, StringRef AsmString,
                          ArrayRef<Token> Toks, ArrayRef<unsigned> Offsets)
@@ -99,6 +103,7 @@
     SourceLocation Loc = translateLocation(LSM, Location);
     LabelDecl *Label =
       TheParser.getActions().GetOrCreateMSAsmLabel(Identifier, Loc, Create);
+    LabelDecls.insert(Label);
     return Label->getMSAsmLabel();
   }
 
@@ -108,6 +113,14 @@
                                                        AsmLoc);
   }
 
+  void CheckExternalLabels() {
+    for (const auto *Label : LabelDecls) {
+      if (!Label->isResolvedMSAsmLabel()) {
+        TheParser.getActions().DiagnoseCrossBlockLabelUse(Label);
+      }
+    }
+  }
+
   static void DiagHandlerCallback(const llvm::SMDiagnostic &D, void *Context) {
     ((ClangAsmParserCallback *)Context)->handleDiagnostic(D);
   }
@@ -581,6 +594,8 @@
     Exprs[i] = OpExpr;
   }
 
+  Callback.CheckExternalLabels();
+
   // FIXME: We should be passing source locations for better diagnostics.
   return Actions.ActOnMSAsmStmt(AsmLoc, LBraceLocs[0], AsmToks, AsmStringIR,
                                 NumOutputs, NumInputs, ConstraintRefs,
Index: lib/Sema/SemaStmtAsm.cpp
===================================================================
--- lib/Sema/SemaStmtAsm.cpp
+++ lib/Sema/SemaStmtAsm.cpp
@@ -585,3 +585,8 @@
 
   return Label;
 }
+
+void Sema::DiagnoseCrossBlockLabelUse(const LabelDecl *Label) {
+  Diag(Label->getLocStart(), diag::err_cross_block_asm_label_use)
+    << Label->getIdentifier();
+}
Index: test/Parser/ms-inline-asm.c
===================================================================
--- test/Parser/ms-inline-asm.c
+++ test/Parser/ms-inline-asm.c
@@ -49,7 +49,38 @@
   do { __asm mov eax, 0 __asm { __asm mov edx, 1 } } while(0);
 }
 void t12() {
-  __asm jmp label // expected-error {{use of undeclared label 'label'}}
+  __asm jmp label // expected-error {{use of undeclared label 'label'}} expected-error {{cannot use inline assembly label 'label' defined outside of an inline assembly block}}
+}
+void t13() {
+  __asm {
+    jmp lbl1 // expected-error {{cannot use inline assembly label 'lbl1' defined outside of an inline assembly block}}
+  }
+  __asm {
+    lbl1:
+    nop
+  }
+}
+void t14() {
+  __asm {
+    jmp lbl2 // expected-error {{cannot use inline assembly label 'lbl2' defined outside of an inline assembly block}}
+  }
+  for (;;) {
+    __asm {
+      lbl2:
+      nop
+    }
+  }
+}
+void t15() {
+  for (;;) {
+    __asm {
+      jmp lbl2 // expected-error {{cannot use inline assembly label 'lbl2' defined outside of an inline assembly block}}
+    }
+  }
+  __asm {
+    lbl2:
+    nop
+  }
 }
 int t_fail() { // expected-note {{to match this}}
   __asm 
Index: test/Sema/ms-inline-asm.c
===================================================================
--- test/Sema/ms-inline-asm.c
+++ test/Sema/ms-inline-asm.c
@@ -106,7 +106,7 @@
 }
 
 __declspec(naked) int t5(int x) { // expected-note {{attribute is here}}
-  asm { movl eax, x } // expected-error {{parameter references not allowed in naked functions}} expected-error {{use of undeclared label 'x'}}
+  asm { movl eax, x } // expected-error {{parameter references not allowed in naked functions}} expected-error {{use of undeclared label 'x'}} expected-error {{cannot use inline assembly label 'x' defined outside of an inline assembly block}}
   asm { retl }
 }
 
@@ -146,7 +146,7 @@
 
 void t11() {
 foo:
-  __asm mov eax, foo // expected-error {{use of undeclared label 'foo'}} expected-warning {{unused label 'foo'}}
+  __asm mov eax, foo // expected-error {{use of undeclared label 'foo'}} expected-error {{cannot use inline assembly label 'foo' defined outside of an inline assembly block}}
 }
 
 void t12() {