Index: cfe/trunk/lib/Driver/ToolChains/Cuda.cpp
===================================================================
--- cfe/trunk/lib/Driver/ToolChains/Cuda.cpp
+++ cfe/trunk/lib/Driver/ToolChains/Cuda.cpp
@@ -87,8 +87,7 @@
     LibDevicePath = InstallPath + "/nvvm/libdevice";
 
     auto &FS = D.getVFS();
-    if (!(FS.exists(IncludePath) && FS.exists(BinPath) &&
-          FS.exists(LibDevicePath)))
+    if (!(FS.exists(IncludePath) && FS.exists(BinPath)))
       continue;
 
     // On Linux, we have both lib and lib64 directories, and we need to choose
@@ -167,17 +166,9 @@
       }
     }
 
-    // This code prevents IsValid from being set when
-    // no libdevice has been found.
-    bool allEmpty = true;
-    std::string LibDeviceFile;
-    for (auto key : LibDeviceMap.keys()) {
-      LibDeviceFile = LibDeviceMap.lookup(key);
-      if (!LibDeviceFile.empty())
-        allEmpty = false;
-    }
-
-    if (allEmpty)
+    // Check that we have found at least one libdevice that we can link in if
+    // -nocudalib hasn't been specified.
+    if (LibDeviceMap.empty() && !Args.hasArg(options::OPT_nocudalib))
       continue;
 
     IsValid = true;
Index: cfe/trunk/test/Driver/cuda-detect.cu
===================================================================
--- cfe/trunk/test/Driver/cuda-detect.cu
+++ cfe/trunk/test/Driver/cuda-detect.cu
@@ -2,7 +2,7 @@
 // REQUIRES: x86-registered-target
 // REQUIRES: nvptx-registered-target
 //
-// # Check that we properly detect CUDA installation.
+// Check that we properly detect CUDA installation.
 // RUN: %clang -v --target=i386-unknown-linux \
 // RUN:   --sysroot=%S/no-cuda-there 2>&1 | FileCheck %s -check-prefix NOCUDA
 // RUN: %clang -v --target=i386-apple-macosx \
@@ -18,6 +18,19 @@
 // RUN: %clang -v --target=i386-apple-macosx \
 // RUN:   --cuda-path=%S/Inputs/CUDA/usr/local/cuda 2>&1 | FileCheck %s
 
+// Check that we don't find a CUDA installation without libdevice ...
+// RUN: %clang -v --target=i386-unknown-linux \
+// RUN:   --sysroot=%S/Inputs/CUDA-nolibdevice 2>&1 | FileCheck %s -check-prefix NOCUDA
+// RUN: %clang -v --target=i386-apple-macosx \
+// RUN:   --sysroot=%S/Inputs/CUDA-nolibdevice 2>&1 | FileCheck %s -check-prefix NOCUDA
+
+// ... unless the user doesn't need libdevice
+// RUN: %clang -v --target=i386-unknown-linux -nocudalib \
+// RUN:   --sysroot=%S/Inputs/CUDA-nolibdevice 2>&1 | FileCheck %s -check-prefix NO-LIBDEVICE
+// RUN: %clang -v --target=i386-apple-macosx -nocudalib \
+// RUN:   --sysroot=%S/Inputs/CUDA-nolibdevice 2>&1 | FileCheck %s -check-prefix NO-LIBDEVICE
+
+
 // Make sure we map libdevice bitcode files to proper GPUs. These
 // tests use Inputs/CUDA_80 which has full set of libdevice files.
 // However, libdevice mapping only matches CUDA-7.x at the moment.
@@ -112,6 +125,7 @@
 // RUN: | FileCheck %s --check-prefix CHECK-CXXINCLUDE
 
 // CHECK: Found CUDA installation: {{.*}}/Inputs/CUDA/usr/local/cuda
+// NO-LIBDEVICE: Found CUDA installation: {{.*}}/Inputs/CUDA-nolibdevice/usr/local/cuda
 // NOCUDA-NOT: Found CUDA installation:
 
 // MISSINGLIBDEVICE: error: cannot find libdevice for sm_20.