diff --git a/openmp/libomptarget/deviceRTLs/nvptx/test/lit.cfg b/openmp/libomptarget/deviceRTLs/nvptx/test/lit.cfg
--- a/openmp/libomptarget/deviceRTLs/nvptx/test/lit.cfg
+++ b/openmp/libomptarget/deviceRTLs/nvptx/test/lit.cfg
@@ -67,4 +67,4 @@
 config.substitutions.append(("%flags", config.test_flags))
 
 config.substitutions.append(("%run", "%t"))
-config.substitutions.append((r"\bnot\b", config.libomptarget_not))
+config.substitutions.append(("%not", config.libomptarget_not))
diff --git a/openmp/libomptarget/test/lit.cfg b/openmp/libomptarget/test/lit.cfg
--- a/openmp/libomptarget/test/lit.cfg
+++ b/openmp/libomptarget/test/lit.cfg
@@ -103,7 +103,7 @@
             "%t-" + libomptarget_target))
         config.substitutions.append(("%libomptarget-run-fail-" + \
             libomptarget_target, \
-            "not %t-" + libomptarget_target))
+            "%not %t-" + libomptarget_target))
         config.substitutions.append(("%clangxx-" + libomptarget_target, \
             "%clangxx %openmp_flags %flags -fopenmp-targets=" + libomptarget_target))
         config.substitutions.append(("%clang-" + libomptarget_target, \
@@ -146,4 +146,4 @@
 config.substitutions.append(("%clang", config.test_c_compiler))
 config.substitutions.append(("%openmp_flags", config.test_openmp_flags))
 config.substitutions.append(("%flags", config.test_flags))
-config.substitutions.append((r"\bnot\b", config.libomptarget_not))
+config.substitutions.append(("%not", config.libomptarget_not))
diff --git a/openmp/runtime/test/lit.cfg b/openmp/runtime/test/lit.cfg
--- a/openmp/runtime/test/lit.cfg
+++ b/openmp/runtime/test/lit.cfg
@@ -127,7 +127,7 @@
 config.substitutions.append(("%openmp_flags", config.test_openmp_flags))
 config.substitutions.append(("%flags", config.test_flags))
 config.substitutions.append(("%python", '"%s"' % (sys.executable)))
-config.substitutions.append((r"\bnot\b", config.test_not))
+config.substitutions.append(("%not", config.test_not))
 
 if config.has_ompt:
     config.substitutions.append(("FileCheck", "tee %%t.out | %s" % config.test_filecheck))
diff --git a/openmp/tools/archer/tests/lit.cfg b/openmp/tools/archer/tests/lit.cfg
--- a/openmp/tools/archer/tests/lit.cfg
+++ b/openmp/tools/archer/tests/lit.cfg
@@ -111,7 +111,7 @@
 config.substitutions.append(("%deflake", os.path.join(os.path.dirname(__file__), "deflake.bash")))
 
 config.substitutions.append(("FileCheck", config.test_filecheck))
-config.substitutions.append((r"\bnot\b", config.test_not))
+config.substitutions.append(("%not", config.test_not))
 config.substitutions.append(("%sort-threads", "sort --numeric-sort --stable"))
 if config.operating_system == 'Windows':
     # No such environment variable on Windows.