[CUDA] Use Triple::isNVPTX() instead of enumerating nvptx && nvptx64.

[jlebar]

Summary

No functional changes.

[echristo]

Probably qualifies as obvious. Also can you add some text to the assert
while you're there?

[jlebar]

In D16495#334383, @echristo wrote:

Probably qualifies as obvious. Also can you add some text to the assert
while you're there?

Done in my local tree, will submit with that change.

cfe/trunk/lib/Driver/Tools.cpp

 
 void NVPTX::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
                                     const InputInfo &Output,
                                     const InputInfoList &Inputs,
                                     const ArgList &Args,
                                     const char *LinkingOutput) const {
   const auto &TC =
       static_cast<const toolchains::CudaToolChain &>(getToolChain());
-  assert(TC.getArch() == llvm::Triple::nvptx ||
-         TC.getArch() == llvm::Triple::nvptx64);
+  assert(TC.getTriple().isNVPTX() && "Wrong platform");
 
   std::vector<std::string> gpu_archs =
       Args.getAllArgValues(options::OPT_march_EQ);
   assert(gpu_archs.size() == 1 && "Exactly one GPU Arch required for ptxas.");
   const std::string& gpu_arch = gpu_archs[0];
 
 
   ArgStringList CmdArgs;

 // correspond to.
 void NVPTX::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                  const InputInfo &Output,
                                  const InputInfoList &Inputs,
                                  const ArgList &Args,
                                  const char *LinkingOutput) const {
   const auto &TC =
       static_cast<const toolchains::CudaToolChain &>(getToolChain());
-  assert(TC.getArch() == llvm::Triple::nvptx ||
-         TC.getArch() == llvm::Triple::nvptx64);
+  assert(TC.getTriple().isNVPTX() && "Wrong platform");
 
   ArgStringList CmdArgs;
   CmdArgs.push_back("--cuda");
   CmdArgs.push_back(TC.getTriple().isArch64Bit() ? "-64" : "-32");
   CmdArgs.push_back(Args.MakeArgString("--create"));
   CmdArgs.push_back(Args.MakeArgString(Output.getFilename()));
 
   for (const auto& II : Inputs) {