[Clang][Builtin] add __builtin_exit

Author: W-50243

clang/include/clang/Basic/Builtins.def

@@ -948,6 +948,7 @@ BUILTIN(__sync_fetch_and_umin, "UiUiD*Ui", "n")
 BUILTIN(__sync_fetch_and_umax, "UiUiD*Ui", "n")
 
 // Random libc builtins.
+BUILTIN(__builtin_exit, "vi", "Fnr")
 BUILTIN(__builtin_abort, "v", "Fnr")
 BUILTIN(__builtin_index, "c*cC*i", "Fn")
 BUILTIN(__builtin_rindex, "c*cC*i", "Fn")

clang/test/CodeGen/builtin-exit-test.c

@@ -0,0 +1,9 @@
+//RUN: %clang_cc1 -no-opaque-pointers -emit-llvm -Wno-strict-prototypes -triple aarch64-target-linux-gnu %s -o - | FileCheck %s
+
+//CHECK: define dso_local void @test() #0 {
+//CHECK: call void @exit(i32 noundef 1)
+//CHECK: unreachable
+
+void test(void){
+	__builtin_exit(1);
+}