Index: clang/lib/Driver/ToolChains/Cuda.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Cuda.cpp
+++ clang/lib/Driver/ToolChains/Cuda.cpp
@@ -80,9 +80,19 @@
   // In decreasing order so we prefer newer versions to older versions.
   std::initializer_list<const char *> Versions = {"8.0", "7.5", "7.0"};
 
+  // Special case for Debian to have nvidia-cuda-toolkit work
+  // out of the box. More info on http://bugs.debian.org/882505
+  const char *NvidiaCudaToolkit =
+      (Distro(D.getVFS()).IsDebian() || Distro(D.getVFS()).IsUbuntu())
+          ? "/usr/lib/cuda"
+          : nullptr;
+
   if (Args.hasArg(clang::driver::options::OPT_cuda_path_EQ)) {
-    Candidates.emplace_back(
-        Args.getLastArgValue(clang::driver::options::OPT_cuda_path_EQ).str());
+    std::string CudaPath =
+        Args.getLastArgValue(clang::driver::options::OPT_cuda_path_EQ).str();
+    Candidates.emplace_back(CudaPath);
+    if (NvidiaCudaToolkit && CudaPath == "/usr")
+      Candidates.emplace_back(D.SysRoot + NvidiaCudaToolkit);
   } else if (HostTriple.isOSWindows()) {
     for (const char *Ver : Versions)
       Candidates.emplace_back(
@@ -114,10 +124,8 @@
     for (const char *Ver : Versions)
       Candidates.emplace_back(D.SysRoot + "/usr/local/cuda-" + Ver);
 
-    if (Distro(D.getVFS()).IsDebian())
-      // Special case for Debian to have nvidia-cuda-toolkit work
-      // out of the box. More info on http://bugs.debian.org/882505
-      Candidates.emplace_back(D.SysRoot + "/usr/lib/cuda");
+    if (NvidiaCudaToolkit)
+      Candidates.emplace_back(D.SysRoot + NvidiaCudaToolkit);
   }
 
   bool NoCudaLib = Args.hasArg(options::OPT_nocudalib);