Index: clang/include/clang/Basic/BuiltinsX86.def
===================================================================
--- clang/include/clang/Basic/BuiltinsX86.def
+++ clang/include/clang/Basic/BuiltinsX86.def
@@ -33,6 +33,8 @@
 BUILTIN(__builtin_cpu_supports, "bcC*", "nc")
 BUILTIN(__builtin_cpu_is, "bcC*", "nc")
 
+TARGET_BUILTIN(__SSC_MARK, "vIi", "n", "")
+
 // Undefined Values
 //
 TARGET_BUILTIN(__builtin_ia32_undef128, "V2d", "ncV:128:", "")
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -12545,6 +12545,24 @@
   case X86::BI__rdtsc: {
     return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::x86_rdtsc));
   }
+  case X86::BI__SSC_MARK: {
+    llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, {Int32Ty}, false);
+    std::string Constraints = "i,~{ebx}";
+    std::string MachineClobbers = this->getTarget().getClobbers();
+    if (!MachineClobbers.empty()) {
+      Constraints += ',';
+      Constraints += MachineClobbers;
+    }
+    llvm::InlineAsm *IA =
+        llvm::InlineAsm::get(FTy, "movl $0, %ebx; .byte 0x64, 0x67, 0x90",
+                             Constraints, /*hasSideEffects=*/true);
+    llvm::AttributeList NoReturnAttr = llvm::AttributeList::get(
+        getLLVMContext(), llvm::AttributeList::FunctionIndex,
+        llvm::Attribute::NoReturn);
+    llvm::CallInst *CI = Builder.CreateCall(IA, Ops[0]);
+    CI->setAttributes(NoReturnAttr);
+    return CI;
+  }
   case X86::BI__builtin_ia32_rdtscp: {
     Value *Call = Builder.CreateCall(CGM.getIntrinsic(Intrinsic::x86_rdtscp));
     Builder.CreateDefaultAlignedStore(Builder.CreateExtractValue(Call, 1),
Index: clang/test/CodeGen/X86/ssc-mark.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/X86/ssc-mark.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -ffreestanding %s -triple=i386-unknown-unknown -emit-llvm -o - -Wall -Werror | FileCheck %s
+// RUN: %clang_cc1 -ffreestanding %s -triple x86_64-unknown-unknown -emit-llvm -o - -Wall -Werror | FileCheck %s
+
+void test_ssc_mark() {
+  // CHECK-LABEL: test_ssc_mark()
+  // CHECK: call void asm sideeffect "movl $0, %ebx; .byte 0x64, 0x67, 0x90", "i,~{ebx},~{dirflag},~{fpsr},~{flags}"(i32 7)
+  // CHECK: ret void
+  return __SSC_MARK(7);
+}