Index: cfe/trunk/lib/CodeGen/CGStmt.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGStmt.cpp
+++ cfe/trunk/lib/CodeGen/CGStmt.cpp
@@ -1999,6 +1999,15 @@
   Result->addAttribute(llvm::AttributeSet::FunctionIndex,
                        llvm::Attribute::NoUnwind);
 
+  if (isa<MSAsmStmt>(&S)) {
+    // If the assembly contains any labels, mark the call noduplicate to prevent
+    // defining the same ASM label twice (PR23715). This is pretty hacky, but it
+    // works.
+    if (AsmString.find("__MSASMLABEL_") != std::string::npos)
+      Result->addAttribute(llvm::AttributeSet::FunctionIndex,
+                           llvm::Attribute::NoDuplicate);
+  }
+
   // Attach readnone and readonly attributes.
   if (!HasSideEffect) {
     if (ReadNone)
Index: cfe/trunk/test/CodeGen/ms-inline-asm.c
===================================================================
--- cfe/trunk/test/CodeGen/ms-inline-asm.c
+++ cfe/trunk/test/CodeGen/ms-inline-asm.c
@@ -533,8 +533,8 @@
     label:
     jmp label
   }
-  // CHECK-LABEL: define void @label1
-  // CHECK: call void asm sideeffect inteldialect "{{.*}}__MSASMLABEL_.1__label:\0A\09jmp {{.*}}__MSASMLABEL_.1__label", "~{dirflag},~{fpsr},~{flags}"()
+  // CHECK-LABEL: define void @label1()
+  // CHECK: call void asm sideeffect inteldialect "{{.*}}__MSASMLABEL_.1__label:\0A\09jmp {{.*}}__MSASMLABEL_.1__label", "~{dirflag},~{fpsr},~{flags}"() [[ATTR1:#[0-9]+]]
 }
 
 void label2() {
@@ -581,3 +581,6 @@
 }
 // CHECK-LABEL: define i32 @test_indirect_field(
 // CHECK: call i32 asm sideeffect inteldialect "mov eax, dword ptr $1",
+
+// MS ASM containing labels must not be duplicated (PR23715).
+// CHECK: attributes [[ATTR1]] = { {{.*}}noduplicate{{.*}} }