Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -2033,6 +2033,12 @@
   if (getLangOpts().Modules || getLangOpts().C11)
     return;
   
+  // Added isImplicit() check, because implicit TypeDecl::getLocation()
+  // returns 0. The're many implicit typedefs in OpenCL, e.g. atomic_flag.
+  if (Old->isImplicit() || New->isImplicit()) {
+    return;
+  }
+
   // If we have a redefinition of a typedef in C, emit a warning.  This warning
   // is normally mapped to an error, but can be controlled with
   // -Wtypedef-redefinition.  If either the original or the redefinition is
Index: test/SemaOpenCL/implicit-typedef.cl
===================================================================
--- test/SemaOpenCL/implicit-typedef.cl
+++ test/SemaOpenCL/implicit-typedef.cl
@@ -0,0 +1,2 @@
+// RUN: %clang_cc1 "-cc1" "-emit-llvm" "-D" "cl_khr_fp64" "-D" "cl_khr_int64_base_atomics" "-fno-dwarf-directory-asm" "-fmessage-length" "205" "-fdiagnostics-show-option" "-cl-std=CL2.0" "-x" "cl" "%s" "-fcolor-diagnostics" -o -
+typedef atomic_int atomic_flag;
Index: tools/driver/driver.cpp
===================================================================
--- tools/driver/driver.cpp
+++ tools/driver/driver.cpp
@@ -314,14 +314,34 @@
   if (llvm::sys::Process::FixupStandardFileDescriptors())
     return 1;
 
-  SmallVector<const char *, 256> argv;
+  SmallVector<const char *, 256> _argv_;
   llvm::SpecificBumpPtrAllocator<char> ArgAllocator;
   std::error_code EC = llvm::sys::Process::GetArgumentVector(
-      argv, llvm::makeArrayRef(argv_, argc_), ArgAllocator);
+    _argv_, llvm::makeArrayRef(argv_, argc_), ArgAllocator);
   if (EC) {
     llvm::errs() << "error: couldn't get arguments: " << EC.message() << '\n';
     return 1;
   }
+    
+#if defined(_WINDOWS) && defined(_DEBUG)
+  // Sometimes when debugging in MSVC2015 some parameter(s) may end with "\n".
+  // The code below code removes wrong symbol.
+  std::vector<std::string> argvStorage;
+  SmallVector<const char *, 256> argv;
+  for (int I = 0, Count = _argv_.size(); I < Count; ++I) {
+      const char* P = _argv_[I];
+      size_t PLen = strlen(P);
+      if (PLen > 0 && P[PLen - 1] == '\n') {
+          std::string Reduced(P, 0, PLen - 1);
+          argvStorage.push_back(Reduced);
+          argv.push_back(argvStorage.back().c_str());
+      } else {
+          argv.push_back(P);
+      }
+  }
+#else
+  SmallVector<const char *, 256>& argv = _argv_;
+#endif
 
   llvm::InitializeAllTargets();
   std::string ProgName = argv[0];