Fix half regression due to LangOpts change for half printing

- Override printing policy based on HLSL instead of enabling
  LangOptions::Half, which enables keyword and changes behavior.

tools/clang/include/clang/AST/PrettyPrinter.h

@@ -41,7 +41,8 @@ struct PrintingPolicy {
       ConstantArraySizeAsWritten(false), AnonymousTagLocations(true),
       SuppressStrongLifetime(false), SuppressLifetimeQualifiers(false),
       Bool(LO.Bool), TerseOutput(false), PolishForDeclaration(false),
-      Half(LO.Half), MSWChar(LO.MicrosoftExt && !LO.WChar),
+      Half(LO.HLSL || LO.Half), // HLSL Change - always print 'half' for HLSL
+      MSWChar(LO.MicrosoftExt && !LO.WChar),
       IncludeNewlines(true) { }
 
   /// \brief What language we're printing.

tools/clang/include/clang/Basic/LangOptions.fixed.def

@@ -88,7 +88,7 @@ LANGOPT(AppExt , 1, 0, "Objective-C App Extension")
 LANGOPT(Trigraphs         , 1, 0,"trigraphs")
 LANGOPT(LineComment       , 1, 1, "'//' comments")
 LANGOPT(Bool              , 1, 1, "bool, true, and false keywords")
-LANGOPT(Half              , 1, 1, "half keyword")
+LANGOPT(Half              , 1, 0, "half keyword")
 LANGOPT(WChar             , 1, CPlusPlus, "wchar_t keyword")
 BENIGN_LANGOPT(DollarIdents   , 1, 1, "'$' in identifiers")
 BENIGN_LANGOPT(AsmPreprocessor, 1, 0, "preprocessor in asm mode")

tools/clang/test/HLSL/intrinsic-examples.hlsl

@@ -45,13 +45,13 @@ float4 RWByteAddressBufferMain(uint2 a : A, uint2 b : B) : SV_Target
   r += uav1.Load2<float>(16);                               /* expected-error {{Explicit template arguments on intrinsic Load2 are not supported.}} */
   r += uav1.Load3<int>(20);                                 /* expected-error {{Explicit template arguments on intrinsic Load3 are not supported.}} */
   r += uav1.Load4<int16_t>(24);                             /* expected-error {{Explicit template arguments on intrinsic Load4 are not supported.}} */
-  r += uav1.Load<half3x4>(24);                              /* expected-error {{Explicit template arguments on intrinsic Load requires HLSL version 2018 or above.}} expected-error {{cannot convert from 'matrix<__fp16, 3, 4>' to 'float4'}} */
+  r += uav1.Load<half3x4>(24);                              /* expected-error {{Explicit template arguments on intrinsic Load requires HLSL version 2018 or above.}} expected-error {{cannot convert from 'matrix<half, 3, 4>' to 'float4'}} */
   r += uav1.Load<float, float3>(16, status);                /* expected-error {{Explicit template arguments on intrinsic Load requires HLSL version 2018 or above.}} */
   r += uav1.Load<double3>(16, status);                      /* expected-error {{Explicit template arguments on intrinsic Load requires HLSL version 2018 or above.}} expected-error {{cannot convert from 'vector<double, 3>' to 'float4'}} */
   r += uav1.Load2<float>(16, status);                       /* expected-error {{Explicit template arguments on intrinsic Load2 are not supported.}} */
   r += uav1.Load3<int>(20, status);                         /* expected-error {{Explicit template arguments on intrinsic Load3 are not supported.}} */
   r += uav1.Load4<int16_t>(24, status);                     /* expected-error {{Explicit template arguments on intrinsic Load4 are not supported.}} */
-  r += uav1.Load<half3x4>(24, status);                      /* expected-error {{Explicit template arguments on intrinsic Load requires HLSL version 2018 or above.}} expected-error {{cannot convert from 'matrix<__fp16, 3, 4>' to 'float4'}} */
+  r += uav1.Load<half3x4>(24, status);                      /* expected-error {{Explicit template arguments on intrinsic Load requires HLSL version 2018 or above.}} expected-error {{cannot convert from 'matrix<half, 3, 4>' to 'float4'}} */
   // valid template argument
   uav1.Store(0, r);
   uav1.Store(0, r.x);