diff --git a/include/clang/Basic/TargetInfo.h b/include/clang/Basic/TargetInfo.h
index c5dc390..ee3a28d 100644
--- a/include/clang/Basic/TargetInfo.h
+++ b/include/clang/Basic/TargetInfo.h
@@ -354,11 +354,11 @@
   unsigned getUnwindWordWidth() const { return getPointerWidth(0); }
 
   /// \brief Return the "preferred" register width on this target.
-  uint64_t getRegisterWidth() const {
+  unsigned getRegisterWidth() const {
     // Currently we assume the register width on the target matches the pointer
     // width, we can introduce a new variable for this if/when some target wants
     // it.
-    return LongWidth; 
+    return PointerWidth;
   }
 
   /// \brief Returns the default value of the __USER_LABEL_PREFIX__ macro,
diff --git a/lib/Basic/TargetInfo.cpp b/lib/Basic/TargetInfo.cpp
index 20ec599..38cb411 100644
--- a/lib/Basic/TargetInfo.cpp
+++ b/lib/Basic/TargetInfo.cpp
@@ -233,6 +233,35 @@
     UseBitFieldTypeAlignment = false;
   if (Opts.ShortWChar)
     WCharType = UnsignedShort;
+
+  if (Opts.OpenCL) {
+    // OpenCL C requires specific widths for types, irrespective of
+    // what these normally are for the target.
+    // We also define long long and long double here, although the
+    // OpenCL standard only mentions these as "reserved".
+    IntWidth = IntAlign = 32;
+    LongWidth = LongAlign = 64;
+    LongLongWidth = LongLongAlign = 128;
+    HalfWidth = HalfAlign = 16;
+    FloatWidth = FloatAlign = 32;
+    DoubleWidth = DoubleAlign = 64;
+    LongDoubleWidth = LongDoubleAlign = 128;
+
+    assert(PointerWidth == 32 || PointerWidth == 64);
+    bool is32BitArch = PointerWidth == 32;
+    SizeType = is32BitArch ? UnsignedInt : UnsignedLong;
+    PtrDiffType = is32BitArch ? SignedInt : SignedLong;
+    IntPtrType = is32BitArch ? SignedInt : SignedLong;
+
+    IntMaxType = SignedLongLong;
+    UIntMaxType = UnsignedLongLong;
+    Int64Type = SignedLong;
+
+    HalfFormat = &llvm::APFloat::IEEEhalf;
+    FloatFormat = &llvm::APFloat::IEEEsingle;
+    DoubleFormat = &llvm::APFloat::IEEEdouble;
+    LongDoubleFormat = &llvm::APFloat::IEEEquad;
+  }
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 7e21f55..ce4fdc3 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1274,7 +1274,7 @@
   Opts.Blocks = Args.hasArg(OPT_fblocks);
   Opts.BlocksRuntimeOptional = Args.hasArg(OPT_fblocks_runtime_optional);
   Opts.Modules = Args.hasArg(OPT_fmodules);
-  Opts.CharIsSigned = !Args.hasArg(OPT_fno_signed_char);
+  Opts.CharIsSigned = Opts.OpenCL || !Args.hasArg(OPT_fno_signed_char);
   Opts.WChar = Opts.CPlusPlus && !Args.hasArg(OPT_fno_wchar);
   Opts.ShortWChar = Args.hasArg(OPT_fshort_wchar);
   Opts.ShortEnums = Args.hasArg(OPT_fshort_enums);
@@ -1285,7 +1285,7 @@
   Opts.HeinousExtensions = Args.hasArg(OPT_fheinous_gnu_extensions);
   Opts.AccessControl = !Args.hasArg(OPT_fno_access_control);
   Opts.ElideConstructors = !Args.hasArg(OPT_fno_elide_constructors);
-  Opts.MathErrno = Args.hasArg(OPT_fmath_errno);
+  Opts.MathErrno = !Opts.OpenCL && Args.hasArg(OPT_fmath_errno);
   Opts.InstantiationDepth =
       getLastArgIntValue(Args, OPT_ftemplate_depth, 256, Diags);
   Opts.ConstexprCallDepth =