diff --git a/clang/include/clang/Basic/Builtins.def b/clang/include/clang/Basic/Builtins.def
--- a/clang/include/clang/Basic/Builtins.def
+++ b/clang/include/clang/Basic/Builtins.def
@@ -655,6 +655,7 @@
 BUILTIN(__builtin_alloca_with_align, "v*zIz", "Fn")
 BUILTIN(__builtin_alloca_with_align_uninitialized, "v*zIz", "Fn")
 BUILTIN(__builtin_call_with_static_chain, "v.", "nt")
+BUILTIN(__builtin_nondet, "v.", "nt")
 
 BUILTIN(__builtin_elementwise_abs, "v.", "nct")
 BUILTIN(__builtin_elementwise_max, "v.", "nct")
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -13529,6 +13529,8 @@
   bool PrepareBuiltinElementwiseMathOneArgCall(CallExpr *TheCall);
   bool PrepareBuiltinReduceMathOneArgCall(CallExpr *TheCall);
 
+  bool SemaBuiltinNonDet(CallExpr *TheCall);
+
   // Matrix builtin handling.
   ExprResult SemaBuiltinMatrixTranspose(CallExpr *TheCall,
                                         ExprResult CallResult);
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3060,6 +3060,12 @@
     return RValue::get(V);
   }
 
+  case Builtin::BI__builtin_nondet: {
+    Value *Result = PoisonValue::get(ConvertType(E->getArg(0)->getType()));
+    Result = Builder.CreateFreeze(Result);
+    return RValue::get(Result);
+  }
+
   case Builtin::BI__builtin_elementwise_abs: {
     Value *Result;
     QualType QT = E->getArg(0)->getType();
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2580,6 +2580,12 @@
     break;
   }
 
+  case Builtin::BI__builtin_nondet: {
+    if (SemaBuiltinNonDet(TheCall))
+      return ExprError();
+    break;
+  }
+
   // __builtin_elementwise_abs restricts the element type to signed integers or
   // floating point types only.
   case Builtin::BI__builtin_elementwise_abs: {
@@ -17799,6 +17805,16 @@
   return false;
 }
 
+bool Sema::SemaBuiltinNonDet(CallExpr *TheCall) {
+  if (checkArgCount(*this, TheCall, 1))
+    return true;
+
+  ExprResult Arg = TheCall->getArg(0);
+  QualType TyArg = Arg.get()->getType();
+  TheCall->setType(TyArg);
+  return false;
+}
+
 ExprResult Sema::SemaBuiltinMatrixTranspose(CallExpr *TheCall,
                                             ExprResult CallResult) {
   if (checkArgCount(*this, TheCall, 1))
diff --git a/clang/test/CodeGen/builtins-nondet.c b/clang/test/CodeGen/builtins-nondet.c
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGen/builtins-nondet.c
@@ -0,0 +1,40 @@
+// RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s
+
+typedef float float4 __attribute__((ext_vector_type(4)));
+
+int clang_nondet_i( int x ) {
+// CHECK-LABEL: entry
+// CHECK: [[A:%.*]] = alloca i32, align 4
+// CHECK: store i32 [[X:%.*]], ptr [[A]], align 4
+// CHECK: [[R:%.*]] = freeze i32 poison
+// CHECK: ret i32 [[R]]
+  return __builtin_nondet(x);
+} 
+
+float clang_nondet_f( float x ) {
+// CHECK-LABEL: entry
+// CHECK: [[A:%.*]] = alloca float, align 4
+// CHECK: store float [[X:%.*]], ptr [[A]], align 4
+// CHECK: [[R:%.*]] = freeze float poison
+// CHECK: ret float [[R]]
+  return __builtin_nondet(x);
+}
+
+double clang_nondet_d( double x ) {
+// CHECK-LABEL: entry
+// CHECK: [[A:%.*]] = alloca double, align 8
+// CHECK: store double [[X:%.*]], ptr [[A]], align 8
+// CHECK: [[R:%.*]] = freeze double poison
+// CHECK: ret double [[R]]
+  return __builtin_nondet(x);
+} 
+
+float4 clang_nondet_v( float4 x ) {
+// CHECK-LABEL: entry
+// CHECK: [[A:%.*]] = alloca <4 x float>, align 16
+// CHECK: store <4 x float> [[X:%.*]], ptr [[A]], align 16
+// CHECK: [[R:%.*]] = freeze <4 x float> poison
+// CHECK: ret <4 x float> [[R]]
+  return __builtin_nondet(x);
+} 
+