diff --git a/tools/clang/test/lit.cfg b/tools/clang/test/lit.cfg
index 53c51a4720..eb73ae113e 100644
--- a/tools/clang/test/lit.cfg
+++ b/tools/clang/test/lit.cfg
@@ -530,9 +530,13 @@ def get_dxil_version():
         result = subprocess.run([lit.util.which('dxc', llvm_tools_dir), "--version"], stdout=subprocess.PIPE, env=config.environment)
     else:
         result = subprocess.run([lit.util.which('dxc', llvm_tools_dir), "--version"], stdout=subprocess.PIPE)
+    if result.returncode != 0:
+        raise RuntimeError("dxc --version failed with return code %d" % result.returncode)
     output = result.stdout.decode("utf-8")
     dxcPat = re.compile(r"(dxcompiler\.dll|libdxcompiler\.so|libdxcompiler\.dylib): (?P<dxcMajor>[0-9]+)\.(?P<dxcMinor>[0-9]+)")
     m = dxcPat.search(output)
+    if not m:
+        raise RuntimeError("Could not find dxc version in output:\n" + output)
     dxcMajor = int(m.group("dxcMajor"))
     dxcMinor = int(m.group("dxcMinor"))