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
@@ -720,7 +720,7 @@
 ATOMIC_BUILTIN(__c11_atomic_fetch_xor, "v.", "t")
 BUILTIN(__c11_atomic_thread_fence, "vi", "n")
 BUILTIN(__c11_atomic_signal_fence, "vi", "n")
-BUILTIN(__c11_atomic_is_lock_free, "iz", "n")
+BUILTIN(__c11_atomic_is_lock_free, "bz", "n")
 
 // GNU atomic builtins.
 ATOMIC_BUILTIN(__atomic_load, "v.", "t")
@@ -748,7 +748,7 @@
 BUILTIN(__atomic_thread_fence, "vi", "n")
 BUILTIN(__atomic_signal_fence, "vi", "n")
 BUILTIN(__atomic_always_lock_free, "izvCD*", "n")
-BUILTIN(__atomic_is_lock_free, "izvCD*", "n")
+BUILTIN(__atomic_is_lock_free, "bzvCD*", "n")
 
 // OpenCL 2.0 atomic builtins.
 ATOMIC_BUILTIN(__opencl_atomic_init, "v.", "t")
diff --git a/clang/test/CodeGen/atomic-ops.c b/clang/test/CodeGen/atomic-ops.c
--- a/clang/test/CodeGen/atomic-ops.c
+++ b/clang/test/CodeGen/atomic-ops.c
@@ -343,20 +343,20 @@
 int lock_free(struct Incomplete *incomplete) {
   // CHECK-LABEL: @lock_free
 
-  // CHECK: call i32 @__atomic_is_lock_free(i32 3, i8* null)
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i32 3, i8* null)
   __c11_atomic_is_lock_free(3);
 
-  // CHECK: call i32 @__atomic_is_lock_free(i32 16, i8* {{.*}}@sixteen{{.*}})
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i32 16, i8* {{.*}}@sixteen{{.*}})
   __atomic_is_lock_free(16, &sixteen);
 
-  // CHECK: call i32 @__atomic_is_lock_free(i32 17, i8* {{.*}}@seventeen{{.*}})
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i32 17, i8* {{.*}}@seventeen{{.*}})
   __atomic_is_lock_free(17, &seventeen);
 
-  // CHECK: call i32 @__atomic_is_lock_free(i32 4, {{.*}})
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i32 4, {{.*}})
   __atomic_is_lock_free(4, incomplete);
 
   char cs[20];
-  // CHECK: call i32 @__atomic_is_lock_free(i32 4, {{.*}})
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i32 4, {{.*}})
   __atomic_is_lock_free(4, cs+1);
 
   // CHECK-NOT: call
diff --git a/clang/test/CodeGen/big-atomic-ops.c b/clang/test/CodeGen/big-atomic-ops.c
--- a/clang/test/CodeGen/big-atomic-ops.c
+++ b/clang/test/CodeGen/big-atomic-ops.c
@@ -198,20 +198,20 @@
 int lock_free(struct Incomplete *incomplete) {
   // CHECK: @lock_free
 
-  // CHECK: call i32 @__atomic_is_lock_free(i64 3, i8* null)
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i64 3, i8* null)
   __c11_atomic_is_lock_free(3);
 
-  // CHECK: call i32 @__atomic_is_lock_free(i64 16, i8* {{.*}}@sixteen{{.*}})
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i64 16, i8* {{.*}}@sixteen{{.*}})
   __atomic_is_lock_free(16, &sixteen);
 
-  // CHECK: call i32 @__atomic_is_lock_free(i64 17, i8* {{.*}}@seventeen{{.*}})
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i64 17, i8* {{.*}}@seventeen{{.*}})
   __atomic_is_lock_free(17, &seventeen);
 
-  // CHECK: call i32 @__atomic_is_lock_free(i64 4, {{.*}})
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i64 4, {{.*}})
   __atomic_is_lock_free(4, incomplete);
 
   char cs[20];
-  // CHECK: call i32 @__atomic_is_lock_free(i64 4, {{.*}})
+  // CHECK: call zeroext i1 @__atomic_is_lock_free(i64 4, {{.*}})
   __atomic_is_lock_free(4, cs+1);
 
   // CHECK-NOT: call