diff --git a/compiler-rt/cmake/config-ix.cmake b/compiler-rt/cmake/config-ix.cmake
--- a/compiler-rt/cmake/config-ix.cmake
+++ b/compiler-rt/cmake/config-ix.cmake
@@ -133,6 +133,18 @@
 check_library_exists(pthread pthread_create "" COMPILER_RT_HAS_LIBPTHREAD)
 check_library_exists(execinfo backtrace "" COMPILER_RT_HAS_LIBEXECINFO)
 
+# system calls
+check_c_source_compiles(
+"
+#include <stdlib.h>
+void exit_handler() {}
+int main() {
+ at_quick_exit(exit_handler);
+ return 0;
+}
+" COMPILER_RT_TARGET_HAS_AT_QUICK_EXIT)
+
+
 # Look for terminfo library, used in unittests that depend on LLVMSupport.
 if(LLVM_ENABLE_TERMINFO STREQUAL FORCE_ON)
   set(MAYBE_REQUIRED REQUIRED)
diff --git a/compiler-rt/lib/profile/CMakeLists.txt b/compiler-rt/lib/profile/CMakeLists.txt
--- a/compiler-rt/lib/profile/CMakeLists.txt
+++ b/compiler-rt/lib/profile/CMakeLists.txt
@@ -111,6 +111,12 @@
      -DCOMPILER_RT_HAS_UNAME=1)
 endif()
 
+if(COMPILER_RT_TARGET_HAS_AT_QUICK_EXIT)
+ set(EXTRA_FLAGS
+     ${EXTRA_FLAGS}
+     -DCOMPILER_RT_TARGET_HAS_AT_QUICK_EXIT=1)
+endif()
+
 # We don't use the C++ Standard Library here, so avoid including it by mistake.
 append_list_if(COMPILER_RT_HAS_NOSTDINCXX_FLAG -nostdinc++ EXTRA_FLAGS)
 # XRay uses C++ standard library headers.
diff --git a/compiler-rt/lib/profile/InstrProfilingFile.c b/compiler-rt/lib/profile/InstrProfilingFile.c
--- a/compiler-rt/lib/profile/InstrProfilingFile.c
+++ b/compiler-rt/lib/profile/InstrProfilingFile.c
@@ -1166,7 +1166,11 @@
   lprofSetupValueProfiler();
 
   HasBeenRegistered = 1;
-  return atexit(writeFileWithoutReturn);
+  int rc = atexit(writeFileWithoutReturn);
+#if defined(COMPILER_RT_TARGET_HAS_AT_QUICK_EXIT)
+  rc = rc || at_quick_exit(writeFileWithoutReturn);
+#endif
+  return rc;
 }
 
 #endif
diff --git a/compiler-rt/test/lit.common.configured.in b/compiler-rt/test/lit.common.configured.in
--- a/compiler-rt/test/lit.common.configured.in
+++ b/compiler-rt/test/lit.common.configured.in
@@ -51,8 +51,12 @@
 # and using `config.compiler_rt_libdir` instead. This only matters when the runtime
 # library paths differ.
 set_default("test_suite_supports_overriding_runtime_lib_path", False)
+set_default("quick_exit_available", @COMPILER_RT_TARGET_HAS_AT_QUICK_EXIT@)
 config.available_features.add('target-is-%s' % config.target_arch)
 
+if not config.quick_exit_available:
+  config.available_features.add("quick_exit_unavailable")
+
 if config.enable_per_target_runtime_dir:
   set_default("target_suffix", "")
 elif config.android:
diff --git a/compiler-rt/test/profile/instrprof-write-file-at-quick-exit-explicitly.c b/compiler-rt/test/profile/instrprof-write-file-at-quick-exit-explicitly.c
new file mode 100644
--- /dev/null
+++ b/compiler-rt/test/profile/instrprof-write-file-at-quick-exit-explicitly.c
@@ -0,0 +1,20 @@
+// RUN: %clang_profgen -o %t -O3 %s
+// RUN: %run %t %t.profraw
+// RUN: llvm-profdata merge -o %t.profdata %t.profraw
+// RUN: %clang_profuse=%t.profdata -o - -S -emit-llvm %s | FileCheck %s
+// UNSUPPORTED: quick_exit_unavailable
+
+#include <stdlib.h>
+
+int __llvm_profile_runtime = 0;
+int __llvm_profile_register_write_file_atexit(void);
+void __llvm_profile_set_filename(const char *);
+int main(int argc, const char *argv[]) {
+  __llvm_profile_register_write_file_atexit();
+  // CHECK: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}, !prof ![[PD1:[0-9]+]]
+  if (argc < 2)
+    return 1;
+  __llvm_profile_set_filename(argv[1]);
+  quick_exit(0);
+}
+// CHECK: ![[PD1]] = !{!"branch_weights", i32 1, i32 2}