[clang] [HLSL] Correctly set `__HLSL_ENABLE_16_BIT` (PR #89788)

[Chris B via cfe-commits]

https://github.com/llvm-beanz created https://github.com/llvm/llvm-project/pull/89788

The preprocessor define `__HLSL_ENABLE_16_BIT` should be set to 1 if native 16-bit types are enabled and not set if they are not.

Previously we were setting the value to match the HLSL active language version, and we had no test coverage verifing the value was set and not set as expected.

Fixes #89787

>From a44bb91986dcde7265666391c6aa46bc0876070d Mon Sep 17 00:00:00 2001
From: Chris Bieneman <chris.bieneman at me.com>
Date: Tue, 23 Apr 2024 11:13:09 -0500
Subject: [PATCH] [HLSL] Correctly set `__HLSL_ENABLE_16_BIT`

The preprocessor define `__HLSL_ENABLE_16_BIT` should be set to 1 if
native 16-bit types are enabled and not set if they are not.

Previously we were setting the value to match the HLSL active language
version, and we had no test coverage verifing the value was set and not
set as expected.

Fixes #89787
---
 clang/lib/Frontend/InitPreprocessor.cpp       |  3 +--
 .../Preprocessor/predefined-macros-hlsl.hlsl  | 25 ++++++++++++-------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 4f44c3b7b89d4d..6bdd734e8a2752 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -389,8 +389,7 @@ static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
                         Twine((unsigned)LangOpts.getHLSLVersion()));
 
     if (LangOpts.NativeHalfType)
-      Builder.defineMacro("__HLSL_ENABLE_16_BIT",
-                          Twine((unsigned)LangOpts.getHLSLVersion()));
+      Builder.defineMacro("__HLSL_ENABLE_16_BIT", "1");
 
     // Shader target information
     // "enums" for shader stages
diff --git a/clang/test/Preprocessor/predefined-macros-hlsl.hlsl b/clang/test/Preprocessor/predefined-macros-hlsl.hlsl
index 251362cd03c0f8..9827e654f114e0 100644
--- a/clang/test/Preprocessor/predefined-macros-hlsl.hlsl
+++ b/clang/test/Preprocessor/predefined-macros-hlsl.hlsl
@@ -1,14 +1,19 @@
-// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-amplification | FileCheck -match-full-lines %s --check-prefixes=CHECK,AMPLIFICATION
-// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-compute | FileCheck -match-full-lines %s --check-prefixes=CHECK,COMPUTE
-// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-domain | FileCheck -match-full-lines %s --check-prefixes=CHECK,DOMAIN
-// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-geometry | FileCheck -match-full-lines %s --check-prefixes=CHECK,GEOMETRY
-// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-hull | FileCheck -match-full-lines %s --check-prefixes=CHECK,HULL
-// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-library | FileCheck -match-full-lines %s --check-prefixes=CHECK,LIBRARY
-// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-mesh | FileCheck -match-full-lines %s --check-prefixes=CHECK,MESH
-// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-pixel | FileCheck -match-full-lines %s --check-prefixes=CHECK,PIXEL
-// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-vertex | FileCheck -match-full-lines %s --check-prefixes=CHECK,VERTEX
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-amplification | FileCheck -match-full-lines %s --check-prefixes=CHECK,AMPLIFICATION,NOHALF
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-compute | FileCheck -match-full-lines %s --check-prefixes=CHECK,COMPUTE,NOHALF
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-domain | FileCheck -match-full-lines %s --check-prefixes=CHECK,DOMAIN,NOHALF
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-geometry | FileCheck -match-full-lines %s --check-prefixes=CHECK,GEOMETRY,NOHALF
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-hull | FileCheck -match-full-lines %s --check-prefixes=CHECK,HULL,NOHALF
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-library | FileCheck -match-full-lines %s --check-prefixes=CHECK,LIBRARY,NOHALF
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-mesh | FileCheck -match-full-lines %s --check-prefixes=CHECK,MESH,NOHALF
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-pixel | FileCheck -match-full-lines %s --check-prefixes=CHECK,PIXEL,NOHALF
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.0-vertex | FileCheck -match-full-lines %s --check-prefixes=CHECK,VERTEX,NOHALF
+// RUN: %clang_cc1 %s -E -dM -o - -triple dxil-pc-shadermodel6.3-vertex -fnative-half-type | FileCheck -match-full-lines %s --check-prefixes=CHECK,VERTEX,HALF
+
+// HALF: #define __HLSL_ENABLE_16_BIT 1
+// NOHALF-NOT: __HLSL_ENABLE_16_BIT
 
 // CHECK: #define __HLSL_VERSION 2021
+
 // CHECK: #define __SHADER_STAGE_AMPLIFICATION 14
 // CHECK: #define __SHADER_STAGE_COMPUTE 5
 // CHECK: #define __SHADER_STAGE_DOMAIN 4
@@ -46,3 +51,5 @@
 
 // RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-library %s -E -dM -o - -x hlsl -std=hlsl202x | FileCheck -match-full-lines %s --check-prefixes=STD202x
 // STD202x: #define __HLSL_VERSION 2029
+
+