Index: compiler-rt/test/dfsan/libatomic.c
===================================================================
--- compiler-rt/test/dfsan/libatomic.c
+++ compiler-rt/test/dfsan/libatomic.c
@@ -1,7 +1,7 @@
-// RUN: %clang_dfsan -g3 -DDATA_BYTES=3 %s -fno-exceptions -latomic -o %t && %run %t
-// RUN: %clang_dfsan -g3 -DDATA_BYTES=3 -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 %s -fno-exceptions -latomic -o %t && %run %t
-// RUN: %clang_dfsan -g3 -DDATA_BYTES=32 %s -fno-exceptions -latomic -o %t && %run %t
-// RUN: %clang_dfsan -g3 -DDATA_BYTES=32 -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 %s -fno-exceptions -latomic -o %t && %run %t
+// RUN: %clang_dfsan -g3 -DDATA_BYTES=3 %s -fno-exceptions %libatomic -o %t && %run %t
+// RUN: %clang_dfsan -g3 -DDATA_BYTES=3 -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 %s -fno-exceptions %libatomic -o %t && %run %t
+// RUN: %clang_dfsan -g3 -DDATA_BYTES=32 %s -fno-exceptions %libatomic -o %t && %run %t
+// RUN: %clang_dfsan -g3 -DDATA_BYTES=32 -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 %s -fno-exceptions %libatomic -o %t && %run %t
 
 #include <assert.h>
 #include <sanitizer/dfsan_interface.h>
Index: compiler-rt/test/lit.common.cfg.py
===================================================================
--- compiler-rt/test/lit.common.cfg.py
+++ compiler-rt/test/lit.common.cfg.py
@@ -877,3 +877,13 @@
 # related is likely to cause issues with sanitizer tests, because it may
 # preempt something we're looking to trap (e.g. _FORTIFY_SOURCE vs our ASAN).
 config.environment["CLANG_NO_DEFAULT_CONFIG"] = "1"
+
+if config.has_compiler_rt_libatomic:
+  base_lib = os.path.join(config.compiler_rt_libdir, "libclang_rt.atomic%s.so"
+                          % config.target_suffix)
+  if sys.platform in ['win32'] and execute_external:
+    # Don't pass dosish path separator to msys bash.exe.
+    base_lib = base_lib.replace('\\', '/')
+  config.substitutions.append(("%libatomic", base_lib + f" -Wl,-rpath,{config.compiler_rt_libdir}"))
+else:
+  config.substitutions.append(("%libatomic", "-latomic"))
Index: compiler-rt/test/msan/libatomic.c
===================================================================
--- compiler-rt/test/msan/libatomic.c
+++ compiler-rt/test/msan/libatomic.c
@@ -1,6 +1,6 @@
-// RUN: %clang_msan -fsanitize-memory-track-origins=2 -latomic -DTEST_STORE -O0 %s -o %t && %run %t 2>&1
-// RUN: %clang_msan -fsanitize-memory-track-origins=0 -latomic -DTEST_LOAD -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK
-// RUN: %clang_msan -fsanitize-memory-track-origins=2 -latomic -DTEST_LOAD -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-SHADOW
+// RUN: %clang_msan -fsanitize-memory-track-origins=2 %libatomic -DTEST_STORE -O0 %s -o %t && %run %t 2>&1
+// RUN: %clang_msan -fsanitize-memory-track-origins=0 %libatomic -DTEST_LOAD -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK
+// RUN: %clang_msan -fsanitize-memory-track-origins=2 %libatomic -DTEST_LOAD -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-SHADOW
 
 // PPC has no libatomic
 // UNSUPPORTED: powerpc64-target-arch
Index: compiler-rt/test/msan/libatomic_load_exceptions.cpp
===================================================================
--- compiler-rt/test/msan/libatomic_load_exceptions.cpp
+++ compiler-rt/test/msan/libatomic_load_exceptions.cpp
@@ -1,4 +1,4 @@
-// RUN: %clangxx_msan -fexceptions -fsanitize-memory-track-origins=2 -latomic -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-SHADOW
+// RUN: %clangxx_msan -fexceptions -fsanitize-memory-track-origins=2 %libatomic -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-SHADOW
 
 // PPC has no libatomic
 // UNSUPPORTED: powerpc64-target-arch